Spring Boot Reference Guide

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Spring Boot Reference Guide
2.0.4.RELEASE
Phillip Webb , Dave Syer , Josh Long , Stéphane Nicoll , Rob Winch , Andy Wilkinson , Marcel Overdijk ,
Christian Dupuis , Sébastien Deleuze , Michael Simons , Vedran Pavi# , Jay Bryant , Madhura Bhave
Copyright © 2012-2018
Copies of this document may be made for your own use and for distribution to others, provided that you do not charge any fee
for such copies and further provided that each copy contains this Copyright Notice, whether distributed in print or electronically.
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Table of Contents
I. Spring Boot Documentation ...................................................................................................... 1
1. About the Documentation ................................................................................................ 2
2. Getting Help ................................................................................................................... 3
3. First Steps ...................................................................................................................... 4
4. Working with Spring Boot ................................................................................................ 5
5. Learning about Spring Boot Features .............................................................................. 6
6. Moving to Production ...................................................................................................... 7
7. Advanced Topics ............................................................................................................ 8
II. Getting Started ....................................................................................................................... 9
8. Introducing Spring Boot ................................................................................................. 10
9. System Requirements ................................................................................................... 11
9.1. Servlet Containers .............................................................................................. 11
10. Installing Spring Boot .................................................................................................. 12
10.1. Installation Instructions for the Java Developer .................................................. 12
Maven Installation ............................................................................................. 12
Gradle Installation ............................................................................................. 13
10.2. Installing the Spring Boot CLI ........................................................................... 14
Manual Installation ............................................................................................ 14
Installation with SDKMAN! ................................................................................. 14
OSX Homebrew Installation ............................................................................... 15
MacPorts Installation ......................................................................................... 15
Command-line Completion ................................................................................ 15
Windows Scoop Installation ............................................................................... 15
Quick-start Spring CLI Example ......................................................................... 16
10.3. Upgrading from an Earlier Version of Spring Boot .............................................. 16
11. Developing Your First Spring Boot Application .............................................................. 18
11.1. Creating the POM ............................................................................................ 18
11.2. Adding Classpath Dependencies ....................................................................... 19
11.3. Writing the Code .............................................................................................. 19
The @RestController and @RequestMapping Annotations .................................. 20
The @EnableAutoConfiguration Annotation ........................................................ 20
The “main” Method ........................................................................................... 20
11.4. Running the Example ....................................................................................... 20
11.5. Creating an Executable Jar ............................................................................... 21
12. What to Read Next ..................................................................................................... 23
III. Using Spring Boot ................................................................................................................ 24
13. Build Systems ............................................................................................................. 25
13.1. Dependency Management ................................................................................ 25
13.2. Maven ............................................................................................................. 25
Inheriting the Starter Parent .............................................................................. 26
Using Spring Boot without the Parent POM ........................................................ 26
Using the Spring Boot Maven Plugin ................................................................. 27
13.3. Gradle ............................................................................................................. 27
13.4. Ant .................................................................................................................. 27
13.5. Starters ............................................................................................................ 28
14. Structuring Your Code ................................................................................................. 34
14.1. Using the “default” Package .............................................................................. 34
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14.2. Locating the Main Application Class .................................................................. 34
15. Configuration Classes ................................................................................................. 36
15.1. Importing Additional Configuration Classes ........................................................ 36
15.2. Importing XML Configuration ............................................................................. 36
16. Auto-configuration ....................................................................................................... 37
16.1. Gradually Replacing Auto-configuration ............................................................. 37
16.2. Disabling Specific Auto-configuration Classes .................................................... 37
17. Spring Beans and Dependency Injection ...................................................................... 38
18. Using the @SpringBootApplication Annotation .............................................................. 39
19. Running Your Application ............................................................................................ 41
19.1. Running from an IDE ....................................................................................... 41
19.2. Running as a Packaged Application .................................................................. 41
19.3. Using the Maven Plugin ................................................................................... 41
19.4. Using the Gradle Plugin ................................................................................... 42
19.5. Hot Swapping .................................................................................................. 42
20. Developer Tools .......................................................................................................... 43
20.1. Property Defaults ............................................................................................. 43
20.2. Automatic Restart ............................................................................................. 44
Logging changes in condition evaluation ............................................................ 45
Excluding Resources ......................................................................................... 45
Watching Additional Paths ................................................................................. 45
Disabling Restart .............................................................................................. 45
Using a Trigger File .......................................................................................... 46
Customizing the Restart Classloader ................................................................. 46
Known Limitations ............................................................................................. 47
20.3. LiveReload ....................................................................................................... 47
20.4. Global Settings ................................................................................................. 47
20.5. Remote Applications ......................................................................................... 47
Running the Remote Client Application .............................................................. 48
Remote Update ................................................................................................ 49
21. Packaging Your Application for Production ................................................................... 50
22. What to Read Next ..................................................................................................... 51
IV. Spring Boot features ............................................................................................................ 52
23. SpringApplication ........................................................................................................ 53
23.1. Startup Failure ................................................................................................. 53
23.2. Customizing the Banner ................................................................................... 54
23.3. Customizing SpringApplication .......................................................................... 55
23.4. Fluent Builder API ............................................................................................ 55
23.5. Application Events and Listeners ...................................................................... 56
23.6. Web Environment ............................................................................................. 57
23.7. Accessing Application Arguments ...................................................................... 57
23.8. Using the ApplicationRunner or CommandLineRunner ....................................... 58
23.9. Application Exit ................................................................................................ 58
23.10. Admin Features .............................................................................................. 59
24. Externalized Configuration ........................................................................................... 60
24.1. Configuring Random Values ............................................................................. 61
24.2. Accessing Command Line Properties ................................................................ 61
24.3. Application Property Files ................................................................................. 62
24.4. Profile-specific Properties ................................................................................. 63
24.5. Placeholders in Properties ................................................................................ 64
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24.6. Using YAML Instead of Properties .................................................................... 64
Loading YAML .................................................................................................. 64
Exposing YAML as Properties in the Spring Environment .................................... 65
Multi-profile YAML Documents ........................................................................... 65
YAML Shortcomings ......................................................................................... 66
24.7. Type-safe Configuration Properties ................................................................... 66
Third-party Configuration ................................................................................... 69
Relaxed Binding ................................................................................................ 69
Merging Complex Types ................................................................................... 71
Properties Conversion ....................................................................................... 72
Converting durations ................................................................................. 73
@ConfigurationProperties Validation .................................................................. 74
@ConfigurationProperties vs. @Value ............................................................... 75
25. Profiles ....................................................................................................................... 76
25.1. Adding Active Profiles ...................................................................................... 76
25.2. Programmatically Setting Profiles ...................................................................... 77
25.3. Profile-specific Configuration Files ..................................................................... 77
26. Logging ...................................................................................................................... 78
26.1. Log Format ...................................................................................................... 78
26.2. Console Output ................................................................................................ 78
Color-coded Output ........................................................................................... 79
26.3. File Output ....................................................................................................... 80
26.4. Log Levels ....................................................................................................... 80
26.5. Custom Log Configuration ................................................................................ 81
26.6. Logback Extensions ......................................................................................... 83
Profile-specific Configuration ............................................................................. 83
Environment Properties ..................................................................................... 83
27. Developing Web Applications ...................................................................................... 85
27.1. The “Spring Web MVC Framework” .................................................................. 85
Spring MVC Auto-configuration .......................................................................... 85
HttpMessageConverters .................................................................................... 86
Custom JSON Serializers and Deserializers ....................................................... 86
MessageCodesResolver .................................................................................... 87
Static Content ................................................................................................... 87
Welcome Page ................................................................................................. 89
Custom Favicon ................................................................................................ 89
Path Matching and Content Negotiation ............................................................. 89
ConfigurableWebBindingInitializer ...................................................................... 89
Template Engines ............................................................................................. 90
Error Handling .................................................................................................. 90
Custom Error Pages ................................................................................. 91
Mapping Error Pages outside of Spring MVC ............................................. 92
Spring HATEOAS ............................................................................................. 92
CORS Support .................................................................................................. 93
27.2. The “Spring WebFlux Framework” ..................................................................... 93
Spring WebFlux Auto-configuration .................................................................... 94
HTTP Codecs with HttpMessageReaders and HttpMessageWriters ..................... 95
Static Content ................................................................................................... 95
Template Engines ............................................................................................. 96
Error Handling .................................................................................................. 96
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Custom Error Pages ................................................................................. 97
Web Filters ....................................................................................................... 97
27.3. JAX-RS and Jersey .......................................................................................... 97
27.4. Embedded Servlet Container Support ................................................................ 99
Servlets, Filters, and listeners ............................................................................ 99
Registering Servlets, Filters, and Listeners as Spring Beans ........................ 99
Servlet Context Initialization ............................................................................. 100
Scanning for Servlets, Filters, and listeners .............................................. 100
The ServletWebServerApplicationContext ......................................................... 100
Customizing Embedded Servlet Containers ...................................................... 100
Programmatic Customization ................................................................... 101
Customizing ConfigurableServletWebServerFactory Directly ...................... 101
JSP Limitations ............................................................................................... 102
28. Security .................................................................................................................... 103
28.1. MVC Security ................................................................................................. 103
28.2. WebFlux Security ........................................................................................... 104
28.3. OAuth2 .......................................................................................................... 104
Client .............................................................................................................. 104
Server ............................................................................................................. 105
28.4. Actuator Security ............................................................................................ 106
Cross Site Request Forgery Protection ............................................................ 106
29. Working with SQL Databases .................................................................................... 107
29.1. Configure a DataSource ................................................................................. 107
Embedded Database Support .......................................................................... 107
Connection to a Production Database .............................................................. 108
Connection to a JNDI DataSource ................................................................... 109
29.2. Using JdbcTemplate ....................................................................................... 109
29.3. JPA and “Spring Data” ................................................................................... 110
Entity Classes ................................................................................................. 110
Spring Data JPA Repositories ......................................................................... 111
Creating and Dropping JPA Databases ............................................................ 112
Open EntityManager in View ........................................................................... 112
29.4. Using H2’s Web Console ................................................................................ 112
Changing the H2 Console’s Path ..................................................................... 113
29.5. Using jOOQ ................................................................................................... 113
Code Generation ............................................................................................. 113
Using DSLContext ........................................................................................... 113
jOOQ SQL Dialect .......................................................................................... 114
Customizing jOOQ .......................................................................................... 114
30. Working with NoSQL Technologies ............................................................................ 115
30.1. Redis ............................................................................................................. 115
Connecting to Redis ........................................................................................ 115
30.2. MongoDB ....................................................................................................... 116
Connecting to a MongoDB Database ............................................................... 116
MongoTemplate .............................................................................................. 117
Spring Data MongoDB Repositories ................................................................. 117
Embedded Mongo ........................................................................................... 118
30.3. Neo4j ............................................................................................................. 118
Connecting to a Neo4j Database ..................................................................... 118
Using the Embedded Mode ............................................................................. 119
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Neo4jSession .................................................................................................. 119
Spring Data Neo4j Repositories ....................................................................... 119
Repository Example ........................................................................................ 119
30.4. Gemfire .......................................................................................................... 120
30.5. Solr ................................................................................................................ 120
Connecting to Solr .......................................................................................... 120
Spring Data Solr Repositories .......................................................................... 120
30.6. Elasticsearch .................................................................................................. 121
Connecting to Elasticsearch by Using Jest ....................................................... 121
Connecting to Elasticsearch by Using Spring Data ............................................ 121
Spring Data Elasticsearch Repositories ............................................................ 122
30.7. Cassandra ...................................................................................................... 122
Connecting to Cassandra ................................................................................ 122
Spring Data Cassandra Repositories ................................................................ 122
30.8. Couchbase ..................................................................................................... 123
Connecting to Couchbase ............................................................................... 123
Spring Data Couchbase Repositories ............................................................... 123
30.9. LDAP ............................................................................................................. 124
Connecting to an LDAP Server ........................................................................ 124
Spring Data LDAP Repositories ....................................................................... 125
Embedded In-memory LDAP Server ................................................................ 125
30.10. InfluxDB ....................................................................................................... 126
Connecting to InfluxDB .................................................................................... 126
31. Caching .................................................................................................................... 127
31.1. Supported Cache Providers ............................................................................ 128
Generic ........................................................................................................... 129
JCache (JSR-107) ........................................................................................... 129
EhCache 2.x ................................................................................................... 130
Hazelcast ........................................................................................................ 130
Infinispan ........................................................................................................ 130
Couchbase ...................................................................................................... 130
Redis .............................................................................................................. 131
Caffeine .......................................................................................................... 131
Simple ............................................................................................................ 132
None .............................................................................................................. 132
32. Messaging ................................................................................................................ 133
32.1. JMS ............................................................................................................... 133
ActiveMQ Support ........................................................................................... 133
Artemis Support .............................................................................................. 134
Using a JNDI ConnectionFactory ..................................................................... 134
Sending a Message ........................................................................................ 134
Receiving a Message ...................................................................................... 135
32.2. AMQP ............................................................................................................ 136
RabbitMQ support ........................................................................................... 136
Sending a Message ........................................................................................ 136
Receiving a Message ...................................................................................... 137
32.3. Apache Kafka Support .................................................................................... 138
Sending a Message ........................................................................................ 139
Receiving a Message ...................................................................................... 139
Additional Kafka Properties .............................................................................. 139
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33. Calling REST Services with RestTemplate .............................................................. 141
33.1. RestTemplate Customization ........................................................................... 141
34. Calling REST Services with WebClient .................................................................... 143
34.1. WebClient Customization ................................................................................ 143
35. Validation .................................................................................................................. 144
36. Sending Email ........................................................................................................... 145
37. Distributed Transactions with JTA .............................................................................. 146
37.1. Using an Atomikos Transaction Manager ......................................................... 146
37.2. Using a Bitronix Transaction Manager ............................................................. 146
37.3. Using a Narayana Transaction Manager .......................................................... 147
37.4. Using a Java EE Managed Transaction Manager ............................................. 147
37.5. Mixing XA and Non-XA JMS Connections ........................................................ 147
37.6. Supporting an Alternative Embedded Transaction Manager .............................. 148
38. Hazelcast .................................................................................................................. 149
39. Quartz Scheduler ...................................................................................................... 150
40. Spring Integration ...................................................................................................... 152
41. Spring Session .......................................................................................................... 153
42. Monitoring and Management over JMX ...................................................................... 154
43. Testing ..................................................................................................................... 155
43.1. Test Scope Dependencies .............................................................................. 155
43.2. Testing Spring Applications ............................................................................. 155
43.3. Testing Spring Boot Applications ..................................................................... 155
Detecting Web Application Type ...................................................................... 156
Detecting Test Configuration ............................................................................ 157
Excluding Test Configuration ........................................................................... 157
Testing with a mock environment ..................................................................... 158
Testing with a running server .......................................................................... 159
Using JMX ...................................................................................................... 160
Mocking and Spying Beans ............................................................................. 160
Auto-configured Tests ..................................................................................... 161
Auto-configured JSON Tests ........................................................................... 162
Auto-configured Spring MVC Tests .................................................................. 163
Auto-configured Spring WebFlux Tests ............................................................ 164
Auto-configured Data JPA Tests ...................................................................... 166
Auto-configured JDBC Tests ............................................................................ 167
Auto-configured jOOQ Tests ............................................................................ 167
Auto-configured Data MongoDB Tests ............................................................. 168
Auto-configured Data Neo4j Tests ................................................................... 169
Auto-configured Data Redis Tests .................................................................... 169
Auto-configured Data LDAP Tests ................................................................... 170
Auto-configured REST Clients ......................................................................... 170
Auto-configured Spring REST Docs Tests ........................................................ 171
Auto-configured Spring REST Docs Tests with Mock MVC ........................ 171
Auto-configured Spring REST Docs Tests with REST Assured ................... 172
User Configuration and Slicing ........................................................................ 173
Using Spock to Test Spring Boot Applications .................................................. 174
43.4. Test Utilities ................................................................................................... 174
ConfigFileApplicationContextInitializer .............................................................. 174
TestPropertyValues ......................................................................................... 174
OutputCapture ................................................................................................. 175
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TestRestTemplate ........................................................................................... 175
44. WebSockets .............................................................................................................. 177
45. Web Services ........................................................................................................... 178
46. Creating Your Own Auto-configuration ....................................................................... 179
46.1. Understanding Auto-configured Beans ............................................................. 179
46.2. Locating Auto-configuration Candidates ........................................................... 179
46.3. Condition Annotations ..................................................................................... 179
Class Conditions ............................................................................................. 180
Bean Conditions .............................................................................................. 180
Property Conditions ......................................................................................... 181
Resource Conditions ....................................................................................... 181
Web Application Conditions ............................................................................. 181
SpEL Expression Conditions ............................................................................ 181
46.4. Testing your Auto-configuration ....................................................................... 181
Simulating a Web Context ............................................................................... 182
Overriding the Classpath ................................................................................. 182
46.5. Creating Your Own Starter .............................................................................. 182
Naming ........................................................................................................... 183
autoconfigure Module ................................................................................ 183
Starter Module ................................................................................................ 184
47. Kotlin support ............................................................................................................ 185
47.1. Requirements ................................................................................................. 185
47.2. Null-safety ...................................................................................................... 185
47.3. Kotlin API ....................................................................................................... 186
runApplication ................................................................................................. 186
Extensions ...................................................................................................... 186
47.4. Dependency management .............................................................................. 186
47.5. @ConfigurationProperties ...................................................................... 187
47.6. Testing ........................................................................................................... 187
47.7. Resources ...................................................................................................... 187
Further reading ............................................................................................... 187
Examples ........................................................................................................ 188
48. What to Read Next ................................................................................................... 189
V. Spring Boot Actuator: Production-ready features .................................................................. 190
49. Enabling Production-ready Features ........................................................................... 191
50. Endpoints .................................................................................................................. 192
50.1. Enabling Endpoints ......................................................................................... 193
50.2. Exposing Endpoints ........................................................................................ 194
50.3. Securing HTTP Endpoints ............................................................................... 195
50.4. Configuring Endpoints ..................................................................................... 196
50.5. Hypermedia for Actuator Web Endpoints ......................................................... 196
50.6. Actuator Web Endpoint Paths ......................................................................... 197
50.7. CORS Support ............................................................................................... 197
50.8. Implementing Custom Endpoints ..................................................................... 197
Receiving Input ............................................................................................... 198
Input type conversion .............................................................................. 198
Custom Web Endpoints ................................................................................... 198
Web Endpoint Request Predicates ........................................................... 198
Path ........................................................................................................ 198
HTTP method ......................................................................................... 198
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Consumes .............................................................................................. 199
Produces ................................................................................................ 199
Web Endpoint Response Status .............................................................. 199
Web Endpoint Range Requests ............................................................... 199
Web Endpoint Security ............................................................................ 199
Servlet endpoints ............................................................................................ 199
Controller endpoints ........................................................................................ 200
50.9. Health Information .......................................................................................... 200
Auto-configured HealthIndicators ...................................................................... 200
Writing Custom HealthIndicators ...................................................................... 201
Reactive Health Indicators ............................................................................... 202
Auto-configured ReactiveHealthIndicators ......................................................... 203
50.10. Application Information .................................................................................. 203
Auto-configured InfoContributors ...................................................................... 203
Custom Application Information ....................................................................... 203
Git Commit Information ................................................................................... 204
Build Information ............................................................................................. 204
Writing Custom InfoContributors ...................................................................... 204
51. Monitoring and Management over HTTP .................................................................... 206
51.1. Customizing the Management Endpoint Paths ................................................. 206
51.2. Customizing the Management Server Port ....................................................... 206
51.3. Configuring Management-specific SSL ............................................................ 206
51.4. Customizing the Management Server Address ................................................. 207
51.5. Disabling HTTP Endpoints .............................................................................. 207
52. Monitoring and Management over JMX ...................................................................... 208
52.1. Customizing MBean Names ............................................................................ 208
52.2. Disabling JMX Endpoints ................................................................................ 208
52.3. Using Jolokia for JMX over HTTP ................................................................... 208
Customizing Jolokia ........................................................................................ 208
Disabling Jolokia ............................................................................................. 209
53. Loggers .................................................................................................................... 210
53.1. Configure a Logger ......................................................................................... 210
54. Metrics ...................................................................................................................... 211
54.1. Getting started ............................................................................................... 211
54.2. Supported monitoring systems ........................................................................ 212
Atlas ............................................................................................................... 212
Datadog .......................................................................................................... 212
Ganglia ........................................................................................................... 212
Graphite .......................................................................................................... 213
Influx .............................................................................................................. 213
JMX ................................................................................................................ 213
New Relic ....................................................................................................... 213
Prometheus .................................................................................................... 214
SignalFx ......................................................................................................... 214
Simple ............................................................................................................ 214
StatsD ............................................................................................................ 214
Wavefront ....................................................................................................... 215
54.3. Supported Metrics .......................................................................................... 215
Spring MVC Metrics ........................................................................................ 215
Spring WebFlux Metrics .................................................................................. 216
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RestTemplate Metrics ...................................................................................... 217
Cache Metrics ................................................................................................. 217
DataSource Metrics ......................................................................................... 217
RabbitMQ Metrics ........................................................................................... 218
54.4. Registering custom metrics ............................................................................. 218
54.5. Customizing individual metrics ........................................................................ 218
Per-meter properties ....................................................................................... 218
54.6. Metrics endpoint ............................................................................................. 219
55. Auditing .................................................................................................................... 221
56. HTTP Tracing ........................................................................................................... 222
56.1. Custom HTTP tracing ..................................................................................... 222
57. Process Monitoring .................................................................................................... 223
57.1. Extending Configuration .................................................................................. 223
57.2. Programmatically ............................................................................................ 223
58. Cloud Foundry Support ............................................................................................. 224
58.1. Disabling Extended Cloud Foundry Actuator Support ........................................ 224
58.2. Cloud Foundry Self-signed Certificates ............................................................ 224
58.3. Custom context path ...................................................................................... 224
59. What to Read Next ................................................................................................... 226
VI. Deploying Spring Boot Applications .................................................................................... 227
60. Deploying to the Cloud .............................................................................................. 228
60.1. Cloud Foundry ............................................................................................... 228
Binding to Services ......................................................................................... 229
60.2. Heroku ........................................................................................................... 230
60.3. OpenShift ....................................................................................................... 231
60.4. Amazon Web Services (AWS) ........................................................................ 231
AWS Elastic Beanstalk .................................................................................... 231
Using the Tomcat Platform ...................................................................... 231
Using the Java SE Platform .................................................................... 231
Summary ........................................................................................................ 232
60.5. Boxfuse and Amazon Web Services ................................................................ 232
60.6. Google Cloud ................................................................................................. 233
61. Installing Spring Boot Applications ............................................................................. 235
61.1. Supported Operating Systems ......................................................................... 235
61.2. Unix/Linux Services ........................................................................................ 235
Installation as an init.d Service (System V) .................................................. 235
Securing an init.d Service ................................................................... 236
Installation as a systemd Service ................................................................... 237
Customizing the Startup Script ........................................................................ 238
Customizing the Start Script when It Is Written ......................................... 238
Customizing a Script When It Runs ......................................................... 239
61.3. Microsoft Windows Services ............................................................................ 240
62. What to Read Next ................................................................................................... 241
VII. Spring Boot CLI ................................................................................................................ 242
63. Installing the CLI ....................................................................................................... 243
64. Using the CLI ........................................................................................................... 244
64.1. Running Applications with the CLI ................................................................... 244
Deduced “grab” Dependencies ........................................................................ 245
Deduced “grab” Coordinates ............................................................................ 246
Default Import Statements ............................................................................... 246
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Automatic Main Method ................................................................................... 246
Custom Dependency Management .................................................................. 246
64.2. Applications with Multiple Source Files ............................................................ 247
64.3. Packaging Your Application ............................................................................ 247
64.4. Initialize a New Project ................................................................................... 247
64.5. Using the Embedded Shell ............................................................................. 248
64.6. Adding Extensions to the CLI .......................................................................... 248
65. Developing Applications with the Groovy Beans DSL .................................................. 250
66. Configuring the CLI with settings.xml ................................................................... 251
67. What to Read Next ................................................................................................... 252
VIII. Build tool plugins ............................................................................................................. 253
68. Spring Boot Maven Plugin ......................................................................................... 254
68.1. Including the Plugin ........................................................................................ 254
68.2. Packaging Executable Jar and War Files ......................................................... 255
69. Spring Boot Gradle Plugin ......................................................................................... 256
70. Spring Boot AntLib Module ........................................................................................ 257
70.1. Spring Boot Ant Tasks .................................................................................... 257
spring-boot:exejar .................................................................................. 257
Examples ........................................................................................................ 258
70.2. spring-boot:findmainclass .................................................................... 258
Examples ........................................................................................................ 258
71. Supporting Other Build Systems ................................................................................ 259
71.1. Repackaging Archives .................................................................................... 259
71.2. Nested Libraries ............................................................................................. 259
71.3. Finding a Main Class ...................................................................................... 259
71.4. Example Repackage Implementation ............................................................... 259
72. What to Read Next ................................................................................................... 260
IX. ‘How-to’ guides .................................................................................................................. 261
73. Spring Boot Application ............................................................................................. 262
73.1. Create Your Own FailureAnalyzer ................................................................... 262
73.2. Troubleshoot Auto-configuration ...................................................................... 262
73.3. Customize the Environment or ApplicationContext Before It Starts ..................... 263
73.4. Build an ApplicationContext Hierarchy (Adding a Parent or Root Context) .......... 264
73.5. Create a Non-web Application ......................................................................... 264
74. Properties and Configuration ..................................................................................... 265
74.1. Automatically Expand Properties at Build Time ................................................ 265
Automatic Property Expansion Using Maven .................................................... 265
Automatic Property Expansion Using Gradle .................................................... 266
74.2. Externalize the Configuration of SpringApplication .................................... 266
74.3. Change the Location of External Properties of an Application ............................ 267
74.4. Use ‘Short’ Command Line Arguments ............................................................ 267
74.5. Use YAML for External Properties ................................................................... 268
74.6. Set the Active Spring Profiles ......................................................................... 268
74.7. Change Configuration Depending on the Environment ...................................... 269
74.8. Discover Built-in Options for External Properties .............................................. 269
75. Embedded Web Servers ............................................................................................ 270
75.1. Use Another Web Server ................................................................................ 270
75.2. Disabling the Web Server ............................................................................... 271
75.3. Change the HTTP Port ................................................................................... 271
75.4. Use a Random Unassigned HTTP Port ........................................................... 271
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75.5. Discover the HTTP Port at Runtime ................................................................ 271
75.6. Enable HTTP Response Compression ............................................................. 272
75.7. Configure SSL ................................................................................................ 272
75.8. Configure HTTP/2 .......................................................................................... 272
HTTP/2 with Undertow .................................................................................... 273
HTTP/2 with Jetty ........................................................................................... 273
HTTP/2 with Tomcat ....................................................................................... 273
75.9. Configure the Web Server .............................................................................. 273
75.10. Add a Servlet, Filter, or Listener to an Application .......................................... 274
Add a Servlet, Filter, or Listener by Using a Spring Bean .................................. 274
Disable Registration of a Servlet or Filter ................................................. 274
Add Servlets, Filters, and Listeners by Using Classpath Scanning ...................... 275
75.11. Configure Access Logging ............................................................................ 275
75.12. Running Behind a Front-end Proxy Server ..................................................... 275
Customize Tomcat’s Proxy Configuration ......................................................... 276
75.13. Enable Multiple Connectors with Tomcat ....................................................... 276
75.14. Use Tomcat’s LegacyCookieProcessor .......................................................... 277
75.15. Enable Multiple Listeners with Undertow ........................................................ 277
75.16. Create WebSocket Endpoints Using @ServerEndpoint ................................... 277
76. Spring MVC .............................................................................................................. 279
76.1. Write a JSON REST Service .......................................................................... 279
76.2. Write an XML REST Service ........................................................................... 279
76.3. Customize the Jackson ObjectMapper ............................................................. 280
76.4. Customize the @ResponseBody Rendering ..................................................... 281
76.5. Handling Multipart File Uploads ....................................................................... 281
76.6. Switch Off the Spring MVC DispatcherServlet .................................................. 281
76.7. Switch off the Default MVC Configuration ........................................................ 282
76.8. Customize ViewResolvers ............................................................................... 282
77. Jersey ....................................................................................................................... 284
77.1. Secure Jersey endpoints with Spring Security .................................................. 284
78. HTTP Clients ............................................................................................................ 285
78.1. Configure RestTemplate to Use a Proxy .......................................................... 285
79. Logging ..................................................................................................................... 286
79.1. Configure Logback for Logging ....................................................................... 286
Configure Logback for File-only Output ............................................................ 287
79.2. Configure Log4j for Logging ............................................................................ 287
Use YAML or JSON to Configure Log4j 2 ........................................................ 288
80. Data Access ............................................................................................................. 289
80.1. Configure a Custom DataSource ..................................................................... 289
80.2. Configure Two DataSources ........................................................................... 291
80.3. Use Spring Data Repositories ......................................................................... 292
80.4. Separate @Entity Definitions from Spring Configuration .................................... 292
80.5. Configure JPA Properties ................................................................................ 292
80.6. Configure Hibernate Naming Strategy .............................................................. 293
80.7. Use a Custom EntityManagerFactory .............................................................. 294
80.8. Use Two EntityManagers ................................................................................ 294
80.9. Use a Traditional persistence.xml File ....................................................... 295
80.10. Use Spring Data JPA and Mongo Repositories .............................................. 295
80.11. Expose Spring Data Repositories as REST Endpoint ...................................... 295
80.12. Configure a Component that is Used by JPA ................................................. 295
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80.13. Configure jOOQ with Two DataSources ......................................................... 296
81. Database Initialization ................................................................................................ 297
81.1. Initialize a Database Using JPA ...................................................................... 297
81.2. Initialize a Database Using Hibernate .............................................................. 297
81.3. Initialize a Database ....................................................................................... 297
81.4. Initialize a Spring Batch Database ................................................................... 298
81.5. Use a Higher-level Database Migration Tool .................................................... 298
Execute Flyway Database Migrations on Startup .............................................. 298
Execute Liquibase Database Migrations on Startup .......................................... 299
82. Messaging ................................................................................................................ 300
82.1. Disable Transacted JMS Session .................................................................... 300
83. Batch Applications ..................................................................................................... 301
83.1. Execute Spring Batch Jobs on Startup ............................................................ 301
84. Actuator .................................................................................................................... 302
84.1. Change the HTTP Port or Address of the Actuator Endpoints ............................ 302
84.2. Customize the ‘whitelabel’ Error Page ............................................................. 302
84.3. Sanitize sensible values .................................................................................. 302
85. Security .................................................................................................................... 303
85.1. Switch off the Spring Boot Security Configuration ............................................. 303
85.2. Change the UserDetailsService and Add User Accounts ................................... 303
85.3. Enable HTTPS When Running behind a Proxy Server ...................................... 303
86. Hot Swapping ........................................................................................................... 304
86.1. Reload Static Content ..................................................................................... 304
86.2. Reload Templates without Restarting the Container .......................................... 304
Thymeleaf Templates ...................................................................................... 304
FreeMarker Templates .................................................................................... 304
Groovy Templates ........................................................................................... 304
86.3. Fast Application Restarts ................................................................................ 304
86.4. Reload Java Classes without Restarting the Container ..................................... 305
87. Build ......................................................................................................................... 306
87.1. Generate Build Information ............................................................................. 306
87.2. Generate Git Information ................................................................................ 306
87.3. Customize Dependency Versions .................................................................... 307
87.4. Create an Executable JAR with Maven ............................................................ 307
87.5. Use a Spring Boot Application as a Dependency .............................................. 308
87.6. Extract Specific Libraries When an Executable Jar Runs .................................. 309
87.7. Create a Non-executable JAR with Exclusions ................................................. 309
87.8. Remote Debug a Spring Boot Application Started with Maven ........................... 310
87.9. Build an Executable Archive from Ant without Using spring-boot-antlib ..... 310
88. Traditional Deployment .............................................................................................. 312
88.1. Create a Deployable War File ......................................................................... 312
88.2. Convert an Existing Application to Spring Boot ................................................. 313
88.3. Deploying a WAR to WebLogic ....................................................................... 315
88.4. Use Jedis Instead of Lettuce ........................................................................... 315
X. Appendices ........................................................................................................................ 317
A. Common application properties ................................................................................... 318
B. Configuration Metadata ............................................................................................... 346
B.1. Metadata Format ............................................................................................. 346
Group Attributes .............................................................................................. 347
Property Attributes .......................................................................................... 348
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Hint Attributes ................................................................................................. 350
Repeated Metadata Items ............................................................................... 351
B.2. Providing Manual Hints .................................................................................... 351
Value Hint ....................................................................................................... 351
Value Providers .............................................................................................. 352
Any ......................................................................................................... 352
Class Reference ..................................................................................... 353
Handle As ............................................................................................... 353
Logger Name .......................................................................................... 354
Spring Bean Reference ........................................................................... 355
Spring Profile Name ................................................................................ 356
B.3. Generating Your Own Metadata by Using the Annotation Processor .................... 356
Nested Properties ........................................................................................... 357
Adding Additional Metadata ............................................................................. 358
C. Auto-configuration classes .......................................................................................... 359
C.1. From the “spring-boot-autoconfigure” module .................................................... 359
C.2. From the “spring-boot-actuator-autoconfigure” module ....................................... 362
D. Test auto-configuration annotations ............................................................................. 366
E. The Executable Jar Format ......................................................................................... 369
E.1. Nested JARs ................................................................................................... 369
The Executable Jar File Structure .................................................................... 369
The Executable War File Structure .................................................................. 369
E.2. Spring Boot’s “JarFile” Class ............................................................................ 370
Compatibility with the Standard Java “JarFile” .................................................. 370
E.3. Launching Executable Jars ............................................................................... 370
Launcher Manifest ........................................................................................... 371
Exploded Archives .......................................................................................... 371
E.4. PropertiesLauncher Features ..................................................................... 371
E.5. Executable Jar Restrictions .............................................................................. 373
E.6. Alternative Single Jar Solutions ........................................................................ 373
F. Dependency versions .................................................................................................. 374
Part I. Spring Boot Documentation
This section provides a brief overview of Spring Boot reference documentation. It serves as a map for
the rest of the document.
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1. About the Documentation
The Spring Boot reference guide is available as
•HTML
•PDF
•EPUB
The latest copy is available at docs.spring.io/spring-boot/docs/current/reference.
Copies of this document may be made for your own use and for distribution to others, provided that
you do not charge any fee for such copies and further provided that each copy contains this Copyright
Notice, whether distributed in print or electronically.
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2. Getting Help
If you have trouble with Spring Boot, we would like to help.
• Try the How-to documents. They provide solutions to the most common questions.
• Learn the Spring basics. Spring Boot builds on many other Spring projects. Check the spring.io web-
site for a wealth of reference documentation. If you are starting out with Spring, try one of the guides.
• Ask a question. We monitor stackoverflow.com for questions tagged with spring-boot.
• Report bugs with Spring Boot at github.com/spring-projects/spring-boot/issues.
Note
All of Spring Boot is open source, including the documentation. If you find problems with the docs
or if you want to improve them, please get involved.
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3. First Steps
If you are getting started with Spring Boot or 'Spring' in general, start with the following topics:
•From scratch: Overview | Requirements | Installation
•Tutorial: Part 1 | Part 2
•Running your example: Part 1 | Part 2
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4. Working with Spring Boot
Ready to actually start using Spring Boot? We have you covered:
•Build systems: Maven | Gradle | Ant | Starters
•Best practices: Code Structure | @Configuration | @EnableAutoConfiguration | Beans and
Dependency Injection
•Running your code IDE | Packaged | Maven | Gradle
•Packaging your app: Production jars
•Spring Boot CLI: Using the CLI
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5. Learning about Spring Boot Features
Need more details about Spring Boot’s core features? The following content is for you:
•Core Features: SpringApplication | External Configuration | Profiles | Logging
•Web Applications: MVC | Embedded Containers
•Working with data: SQL | NO-SQL
•Messaging: Overview | JMS
•Testing: Overview | Boot Applications | Utils
•Extending: Auto-configuration | @Conditions
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6. Moving to Production
When you are ready to push your Spring Boot application to production, we have some tricks that you
might like:
•Management endpoints: Overview | Customization
•Connection options: HTTP | JMX
•Monitoring: Metrics | Auditing | Tracing | Process
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7. Advanced Topics
Finally, we have a few topics for more advanced users:
•Spring Boot Applications Deployment: Cloud Deployment | OS Service
•Build tool plugins: Maven | Gradle
•Appendix: Application Properties | Auto-configuration classes | Executable Jars
Part II. Getting Started
If you are getting started with Spring Boot, or “Spring” in general, start by reading this section. It answers
the basic “what?”, “how?” and “why?” questions. It includes an introduction to Spring Boot, along with
installation instructions. We then walk you through building your first Spring Boot application, discussing
some core principles as we go.
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8. Introducing Spring Boot
Spring Boot makes it easy to create stand-alone, production-grade Spring-based Applications that you
can run. We take an opinionated view of the Spring platform and third-party libraries, so that you can
get started with minimum fuss. Most Spring Boot applications need very little Spring configuration.
You can use Spring Boot to create Java applications that can be started by using java -jar or more
traditional war deployments. We also provide a command line tool that runs “spring scripts”.
Our primary goals are:
• Provide a radically faster and widely accessible getting-started experience for all Spring development.
• Be opinionated out of the box but get out of the way quickly as requirements start to diverge from
the defaults.
• Provide a range of non-functional features that are common to large classes of projects (such as
embedded servers, security, metrics, health checks, and externalized configuration).
• Absolutely no code generation and no requirement for XML configuration.
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9. System Requirements
Spring Boot 2.0.4.RELEASE requires Java 8 or 9 and Spring Framework 5.0.8.RELEASE or above.
Explicit build support is provided for Maven 3.2+ and Gradle 4.
9.1 Servlet Containers
Spring Boot supports the following embedded servlet containers:
Name Servlet Version
Tomcat 8.5 3.1
Jetty 9.4 3.1
Undertow 1.4 3.1
You can also deploy Spring Boot applications to any Servlet 3.1+ compatible container.
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10. Installing Spring Boot
Spring Boot can be used with “classic” Java development tools or installed as a command line tool.
Either way, you need Java SDK v1.8 or higher. Before you begin, you should check your current Java
installation by using the following command:
$ java -version
If you are new to Java development or if you want to experiment with Spring Boot, you might want
to try the Spring Boot CLI (Command Line Interface) first. Otherwise, read on for “classic” installation
instructions.
10.1 Installation Instructions for the Java Developer
You can use Spring Boot in the same way as any standard Java library. To do so, include the
appropriate spring-boot-*.jar files on your classpath. Spring Boot does not require any special
tools integration, so you can use any IDE or text editor. Also, there is nothing special about a Spring Boot
application, so you can run and debug a Spring Boot application as you would any other Java program.
Although you could copy Spring Boot jars, we generally recommend that you use a build tool that
supports dependency management (such as Maven or Gradle).
Maven Installation
Spring Boot is compatible with Apache Maven 3.2 or above. If you do not already have Maven installed,
you can follow the instructions at maven.apache.org.
Tip
On many operating systems, Maven can be installed with a package manager. If you use OSX
Homebrew, try brew install maven. Ubuntu users can run sudo apt-get install
maven. Windows users with Chocolatey can run choco install maven from an elevated
(administrator) prompt.
Spring Boot dependencies use the org.springframework.boot groupId. Typically, your Maven
POM file inherits from the spring-boot-starter-parent project and declares dependencies to
one or more “Starters”. Spring Boot also provides an optional Maven plugin to create executable jars.
The following listing shows a typical pom.xml file:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example</groupId>
<artifactId>myproject</artifactId>
<version>0.0.1-SNAPSHOT</version>
<!-- Inherit defaults from Spring Boot -->
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.4.RELEASE</version>
</parent>
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<!-- Add typical dependencies for a web application -->
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
<!-- Package as an executable jar -->
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
Tip
The spring-boot-starter-parent is a great way to use Spring Boot, but it might not be
suitable all of the time. Sometimes you may need to inherit from a different parent POM, or you
might not like our default settings. In those cases, see the section called “Using Spring Boot
without the Parent POM” for an alternative solution that uses an import scope.
Gradle Installation
Spring Boot is compatible with Gradle 4. If you do not already have Gradle installed, you can follow the
instructions at gradle.org.
Spring Boot dependencies can be declared by using the org.springframework.boot group.
Typically, your project declares dependencies to one or more “Starters”. Spring Boot provides a useful
Gradle plugin that can be used to simplify dependency declarations and to create executable jars.
Gradle Wrapper
The Gradle Wrapper provides a nice way of “obtaining” Gradle when you need to build a project.
It is a small script and library that you commit alongside your code to bootstrap the build process.
See docs.gradle.org/4.2.1/userguide/gradle_wrapper.html for details.
The following example shows a typical build.gradle file:
plugins {
id 'org.springframework.boot' version '2.0.4.RELEASE'
id 'java'
}
jar {
baseName = 'myproject'
version = '0.0.1-SNAPSHOT'
}
repositories {
jcenter()
}
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dependencies {
compile("org.springframework.boot:spring-boot-starter-web")
testCompile("org.springframework.boot:spring-boot-starter-test")
}
10.2 Installing the Spring Boot CLI
The Spring Boot CLI (Command Line Interface) is a command line tool that you can use to quickly
prototype with Spring. It lets you run Groovy scripts, which means that you have a familiar Java-like
syntax without so much boilerplate code.
You do not need to use the CLI to work with Spring Boot, but it is definitely the quickest way to get a
Spring application off the ground.
Manual Installation
You can download the Spring CLI distribution from the Spring software repository:
•spring-boot-cli-2.0.4.RELEASE-bin.zip
•spring-boot-cli-2.0.4.RELEASE-bin.tar.gz
Cutting edge snapshot distributions are also available.
Once downloaded, follow the INSTALL.txt instructions from the unpacked archive. In summary, there is
a spring script (spring.bat for Windows) in a bin/ directory in the .zip file. Alternatively, you can
use java -jar with the .jar file (the script helps you to be sure that the classpath is set correctly).
Installation with SDKMAN!
SDKMAN! (The Software Development Kit Manager) can be used for managing multiple versions of
various binary SDKs, including Groovy and the Spring Boot CLI. Get SDKMAN! from sdkman.io and
install Spring Boot by using the following commands:
$ sdk install springboot
$ spring --version
Spring Boot v2.0.4.RELEASE
If you develop features for the CLI and want easy access to the version you built, use the following
commands:
$ sdk install springboot dev /path/to/spring-boot/spring-boot-cli/target/spring-boot-cli-2.0.4.RELEASE-
bin/spring-2.0.4.RELEASE/
$ sdk default springboot dev
$ spring --version
Spring CLI v2.0.4.RELEASE
The preceding instructions install a local instance of spring called the dev instance. It points at your
target build location, so every time you rebuild Spring Boot, spring is up-to-date.
You can see it by running the following command:
$ sdk ls springboot
================================================================================
Available Springboot Versions
================================================================================
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> + dev
* 2.0.4.RELEASE
================================================================================
+ - local version
* - installed
> - currently in use
================================================================================
OSX Homebrew Installation
If you are on a Mac and use Homebrew, you can install the Spring Boot CLI by using the following
commands:
$ brew tap pivotal/tap
$ brew install springboot
Homebrew installs spring to /usr/local/bin.
Note
If you do not see the formula, your installation of brew might be out-of-date. In that case, run brew
update and try again.
MacPorts Installation
If you are on a Mac and use MacPorts, you can install the Spring Boot CLI by using the following
command:
$ sudo port install spring-boot-cli
Command-line Completion
The Spring Boot CLI includes scripts that provide command completion for the BASH and zsh shells. You
can source the script (also named spring) in any shell or put it in your personal or system-wide bash
completion initialization. On a Debian system, the system-wide scripts are in /shell-completion/
bash and all scripts in that directory are executed when a new shell starts. For example, to run the script
manually if you have installed by using SDKMAN!, use the following commands:
$ . ~/.sdkman/candidates/springboot/current/shell-completion/bash/spring
$ spring <HIT TAB HERE>
grab help jar run test version
Note
If you install the Spring Boot CLI by using Homebrew or MacPorts, the command-line completion
scripts are automatically registered with your shell.
Windows Scoop Installation
If you are on a Windows and use Scoop, you can install the Spring Boot CLI by using the following
commands:
> scoop bucket add extras
> scoop install springboot
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Scoop installs spring to ~/scoop/apps/springboot/current/bin.
Note
If you do not see the app manifest, your installation of scoop might be out-of-date. In that case,
run scoop update and try again.
Quick-start Spring CLI Example
You can use the following web application to test your installation. To start, create a file called
app.groovy, as follows:
@RestController
class ThisWillActuallyRun {
@RequestMapping("/")
String home() {
"Hello World!"
}
}
Then run it from a shell, as follows:
$ spring run app.groovy
Note
The first run of your application is slow, as dependencies are downloaded. Subsequent runs are
much quicker.
Open localhost:8080 in your favorite web browser. You should see the following output:
Hello World!
10.3 Upgrading from an Earlier Version of Spring Boot
If you are upgrading from an earlier release of Spring Boot, check the “migration guide” on the project
wiki that provides detailed upgrade instructions. Check also the “release notes” for a list of “new and
noteworthy” features for each release.
When upgrading to a new feature release, some properties may have been renamed or removed. Spring
Boot provides a way to analyze your application’s environment and print diagnostics at startup, but also
temporarily migrate properties at runtime for you. To enable that feature, add the following dependency
to your project:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-properties-migrator</artifactId>
<scope>runtime</scope>
</dependency>
Warning
properties that are added late to the environment, such as when using @PropertySource, will
not be taken into account.
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Note
Once you’re done with the migration, please make sure to remove this module from your project’s
dependencies.
To upgrade an existing CLI installation, use the appropriate package manager command (for example,
brew upgrade) or, if you manually installed the CLI, follow the standard instructions, remembering to
update your PATH environment variable to remove any older references.
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11. Developing Your First Spring Boot Application
This section describes how to develop a simple “Hello World!” web application that highlights some of
Spring Boot’s key features. We use Maven to build this project, since most IDEs support it.
Tip
The spring.io web site contains many “Getting Started” guides that use Spring Boot. If you need
to solve a specific problem, check there first.
You can shortcut the steps below by going to start.spring.io and choosing the "Web" starter from
the dependencies searcher. Doing so generates a new project structure so that you can start
coding right away. Check the Spring Initializr documentation for more details.
Before we begin, open a terminal and run the following commands to ensure that you have valid versions
of Java and Maven installed:
$ java -version
java version "1.8.0_102"
Java(TM) SE Runtime Environment (build 1.8.0_102-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.102-b14, mixed mode)
$ mvn -v
Apache Maven 3.3.9 (bb52d8502b132ec0a5a3f4c09453c07478323dc5; 2015-11-10T16:41:47+00:00)
Maven home: /usr/local/Cellar/maven/3.3.9/libexec
Java version: 1.8.0_102, vendor: Oracle Corporation
Note
This sample needs to be created in its own folder. Subsequent instructions assume that you have
created a suitable folder and that it is your current directory.
11.1 Creating the POM
We need to start by creating a Maven pom.xml file. The pom.xml is the recipe that is used to build
your project. Open your favorite text editor and add the following:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example</groupId>
<artifactId>myproject</artifactId>
<version>0.0.1-SNAPSHOT</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.4.RELEASE</version>
</parent>
<!-- Additional lines to be added here... -->
</project>
The preceding listing should give you a working build. You can test it by running mvn package (for
now, you can ignore the “jar will be empty - no content was marked for inclusion!” warning).
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Note
At this point, you could import the project into an IDE (most modern Java IDEs include built-in
support for Maven). For simplicity, we continue to use a plain text editor for this example.
11.2 Adding Classpath Dependencies
Spring Boot provides a number of “Starters” that let you add jars to your classpath. Our sample
application has already used spring-boot-starter-parent in the parent section of the POM.
The spring-boot-starter-parent is a special starter that provides useful Maven defaults. It
also provides a dependency-management section so that you can omit version tags for “blessed”
dependencies.
Other “Starters” provide dependencies that you are likely to need when developing a specific type
of application. Since we are developing a web application, we add a spring-boot-starter-web
dependency. Before that, we can look at what we currently have by running the following command:
$ mvn dependency:tree
[INFO] com.example:myproject:jar:0.0.1-SNAPSHOT
The mvn dependency:tree command prints a tree representation of your project dependencies.
You can see that spring-boot-starter-parent provides no dependencies by itself. To add the
necessary dependencies, edit your pom.xml and add the spring-boot-starter-web dependency
immediately below the parent section:
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
If you run mvn dependency:tree again, you see that there are now a number of additional
dependencies, including the Tomcat web server and Spring Boot itself.
11.3 Writing the Code
To finish our application, we need to create a single Java file. By default, Maven compiles sources from
src/main/java, so you need to create that folder structure and then add a file named src/main/
java/Example.java to contain the following code:
import org.springframework.boot.*;
import org.springframework.boot.autoconfigure.*;
import org.springframework.web.bind.annotation.*;
@RestController
@EnableAutoConfiguration
public class Example {
@RequestMapping("/")
String home() {
return "Hello World!";
}
public static void main(String[] args) throws Exception {
SpringApplication.run(Example.class, args);
}
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}
Although there is not much code here, quite a lot is going on. We step through the important parts in
the next few sections.
The @RestController and @RequestMapping Annotations
The first annotation on our Example class is @RestController. This is known as a stereotype
annotation. It provides hints for people reading the code and for Spring that the class plays a specific
role. In this case, our class is a web @Controller, so Spring considers it when handling incoming
web requests.
The @RequestMapping annotation provides “routing” information. It tells Spring that any HTTP request
with the / path should be mapped to the home method. The @RestController annotation tells Spring
to render the resulting string directly back to the caller.
Tip
The @RestController and @RequestMapping annotations are Spring MVC annotations.
(They are not specific to Spring Boot.) See the MVC section in the Spring Reference
Documentation for more details.
The @EnableAutoConfiguration Annotation
The second class-level annotation is @EnableAutoConfiguration. This annotation tells Spring Boot
to “guess” how you want to configure Spring, based on the jar dependencies that you have added. Since
spring-boot-starter-web added Tomcat and Spring MVC, the auto-configuration assumes that
you are developing a web application and sets up Spring accordingly.
Starters and Auto-configuration
Auto-configuration is designed to work well with “Starters”, but the two concepts are not directly
tied. You are free to pick and choose jar dependencies outside of the starters. Spring Boot still
does its best to auto-configure your application.
The “main” Method
The final part of our application is the main method. This is just a standard method that follows
the Java convention for an application entry point. Our main method delegates to Spring Boot’s
SpringApplication class by calling run. SpringApplication bootstraps our application, starting
Spring, which, in turn, starts the auto-configured Tomcat web server. We need to pass Example.class
as an argument to the run method to tell SpringApplication which is the primary Spring component.
The args array is also passed through to expose any command-line arguments.
11.4 Running the Example
At this point, your application should work. Since you used the spring-boot-starter-parent POM,
you have a useful run goal that you can use to start the application. Type mvn spring-boot:run
from the root project directory to start the application. You should see output similar to the following:
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$ mvn spring-boot:run
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.0.4.RELEASE)
....... . . .
....... . . . (log output here)
....... . . .
........ Started Example in 2.222 seconds (JVM running for 6.514)
If you open a web browser to localhost:8080, you should see the following output:
Hello World!
To gracefully exit the application, press ctrl-c.
11.5 Creating an Executable Jar
We finish our example by creating a completely self-contained executable jar file that we could run in
production. Executable jars (sometimes called “fat jars”) are archives containing your compiled classes
along with all of the jar dependencies that your code needs to run.
Executable jars and Java
Java does not provide a standard way to load nested jar files (jar files that are themselves contained
within a jar). This can be problematic if you are looking to distribute a self-contained application.
To solve this problem, many developers use “uber” jars. An uber jar packages all the classes from
all the application’s dependencies into a single archive. The problem with this approach is that it
becomes hard to see which libraries are in your application. It can also be problematic if the same
filename is used (but with different content) in multiple jars.
Spring Boot takes a different approach and lets you actually nest jars directly.
To create an executable jar, we need to add the spring-boot-maven-plugin to our pom.xml. To
do so, insert the following lines just below the dependencies section:
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
Note
The spring-boot-starter-parent POM includes <executions> configuration to bind the
repackage goal. If you do not use the parent POM, you need to declare this configuration
yourself. See the plugin documentation for details.
Save your pom.xml and run mvn package from the command line, as follows:
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$ mvn package
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building myproject 0.0.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] .... ..
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ myproject ---
[INFO] Building jar: /Users/developer/example/spring-boot-example/target/myproject-0.0.1-SNAPSHOT.jar
[INFO]
[INFO] --- spring-boot-maven-plugin:2.0.4.RELEASE:repackage (default) @ myproject ---
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
If you look in the target directory, you should see myproject-0.0.1-SNAPSHOT.jar. The file
should be around 10 MB in size. If you want to peek inside, you can use jar tvf, as follows:
$ jar tvf target/myproject-0.0.1-SNAPSHOT.jar
You should also see a much smaller file named myproject-0.0.1-SNAPSHOT.jar.original in
the target directory. This is the original jar file that Maven created before it was repackaged by Spring
Boot.
To run that application, use the java -jar command, as follows:
$ java -jar target/myproject-0.0.1-SNAPSHOT.jar
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.0.4.RELEASE)
....... . . .
....... . . . (log output here)
....... . . .
........ Started Example in 2.536 seconds (JVM running for 2.864)
As before, to exit the application, press ctrl-c.
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12. What to Read Next
Hopefully, this section provided some of the Spring Boot basics and got you on your way to writing your
own applications. If you are a task-oriented type of developer, you might want to jump over to spring.io
and check out some of the getting started guides that solve specific “How do I do that with Spring?”
problems. We also have Spring Boot-specific “How-to” reference documentation.
The Spring Boot repository also has a bunch of samples you can run. The samples are independent of
the rest of the code (that is, you do not need to build the rest to run or use the samples).
Otherwise, the next logical step is to read Part III, “Using Spring Boot”. If you are really impatient, you
could also jump ahead and read about Spring Boot features.
Part III. Using Spring Boot
This section goes into more detail about how you should use Spring Boot. It covers topics such as build
systems, auto-configuration, and how to run your applications. We also cover some Spring Boot best
practices. Although there is nothing particularly special about Spring Boot (it is just another library that
you can consume), there are a few recommendations that, when followed, make your development
process a little easier.
If you are starting out with Spring Boot, you should probably read the Getting Started guide before diving
into this section.
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13. Build Systems
It is strongly recommended that you choose a build system that supports dependency management and
that can consume artifacts published to the “Maven Central” repository. We would recommend that you
choose Maven or Gradle. It is possible to get Spring Boot to work with other build systems (Ant, for
example), but they are not particularly well supported.
13.1 Dependency Management
Each release of Spring Boot provides a curated list of dependencies that it supports. In practice, you
do not need to provide a version for any of these dependencies in your build configuration, as Spring
Boot manages that for you. When you upgrade Spring Boot itself, these dependencies are upgraded
as well in a consistent way.
Note
You can still specify a version and override Spring Boot’s recommendations if you need to do so.
The curated list contains all the spring modules that you can use with Spring Boot as well as a
refined list of third party libraries. The list is available as a standard Bills of Materials (spring-boot-
dependencies) that can be used with both Maven and Gradle.
Warning
Each release of Spring Boot is associated with a base version of the Spring Framework. We
highly recommend that you not specify its version.
13.2 Maven
Maven users can inherit from the spring-boot-starter-parent project to obtain sensible defaults.
The parent project provides the following features:
• Java 1.8 as the default compiler level.
• UTF-8 source encoding.
• A Dependency Management section, inherited from the spring-boot-dependencies pom, that
manages the versions of common dependencies. This dependency management lets you omit
<version> tags for those dependencies when used in your own pom.
• Sensible resource filtering.
• Sensible plugin configuration (exec plugin, Git commit ID, and shade).
• Sensible resource filtering for application.properties and application.yml including
profile-specific files (for example, application-dev.properties and application-dev.yml)
Note that, since the application.properties and application.yml files accept Spring style
placeholders (${…}), the Maven filtering is changed to use @..@ placeholders. (You can override that
by setting a Maven property called resource.delimiter.)
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Inheriting the Starter Parent
To configure your project to inherit from the spring-boot-starter-parent, set the parent as
follows:
<!-- Inherit defaults from Spring Boot -->
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.4.RELEASE</version>
</parent>
Note
You should need to specify only the Spring Boot version number on this dependency. If you import
additional starters, you can safely omit the version number.
With that setup, you can also override individual dependencies by overriding a property in your own
project. For instance, to upgrade to another Spring Data release train, you would add the following to
your pom.xml:
<properties>
<spring-data-releasetrain.version>Fowler-SR2</spring-data-releasetrain.version>
</properties>
Tip
Check the spring-boot-dependencies pom for a list of supported properties.
Using Spring Boot without the Parent POM
Not everyone likes inheriting from the spring-boot-starter-parent POM. You may have your
own corporate standard parent that you need to use or you may prefer to explicitly declare all your
Maven configuration.
If you do not want to use the spring-boot-starter-parent, you can still keep the benefit of the
dependency management (but not the plugin management) by using a scope=import dependency,
as follows:
<dependencyManagement>
<dependencies>
<dependency>
<!-- Import dependency management from Spring Boot -->
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<version>2.0.4.RELEASE</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
The preceding sample setup does not let you override individual dependencies by using a property, as
explained above. To achieve the same result, you need to add an entry in the dependencyManagement
of your project before the spring-boot-dependencies entry. For instance, to upgrade to another
Spring Data release train, you could add the following element to your pom.xml:
<dependencyManagement>
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<dependencies>
<!-- Override Spring Data release train provided by Spring Boot -->
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-releasetrain</artifactId>
<version>Fowler-SR2</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<version>2.0.4.RELEASE</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
Note
In the preceding example, we specify a BOM, but any dependency type can be overridden in the
same way.
Using the Spring Boot Maven Plugin
Spring Boot includes a Maven plugin that can package the project as an executable jar. Add the plugin
to your <plugins> section if you want to use it, as shown in the following example:
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
Note
If you use the Spring Boot starter parent pom, you need to add only the plugin. There is no need
to configure it unless you want to change the settings defined in the parent.
13.3 Gradle
To learn about using Spring Boot with Gradle, please refer to the documentation for Spring Boot’s Gradle
plugin:
• Reference (HTML and PDF)
•API
13.4 Ant
It is possible to build a Spring Boot project using Apache Ant+Ivy. The spring-boot-antlib “AntLib”
module is also available to help Ant create executable jars.
To declare dependencies, a typical ivy.xml file looks something like the following example:
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<ivy-module version="2.0">
<info organisation="org.springframework.boot" module="spring-boot-sample-ant" />
<configurations>
<conf name="compile" description="everything needed to compile this module" />
<conf name="runtime" extends="compile" description="everything needed to run this module" />
</configurations>
<dependencies>
<dependency org="org.springframework.boot" name="spring-boot-starter"
rev="${spring-boot.version}" conf="compile" />
</dependencies>
</ivy-module>
A typical build.xml looks like the following example:
<project
xmlns:ivy="antlib:org.apache.ivy.ant"
xmlns:spring-boot="antlib:org.springframework.boot.ant"
name="myapp" default="build">
<property name="spring-boot.version" value="2.0.4.RELEASE" />
<target name="resolve" description="--> retrieve dependencies with ivy">
<ivy:retrieve pattern="lib/[conf]/[artifact]-[type]-[revision].[ext]" />
</target>
<target name="classpaths" depends="resolve">
<path id="compile.classpath">
<fileset dir="lib/compile" includes="*.jar" />
</path>
</target>
<target name="init" depends="classpaths">
<mkdir dir="build/classes" />
</target>
<target name="compile" depends="init" description="compile">
<javac srcdir="src/main/java" destdir="build/classes" classpathref="compile.classpath" />
</target>
<target name="build" depends="compile">
<spring-boot:exejar destfile="build/myapp.jar" classes="build/classes">
<spring-boot:lib>
<fileset dir="lib/runtime" />
</spring-boot:lib>
</spring-boot:exejar>
</target>
</project>
Tip
If you do not want to use the spring-boot-antlib module, see the Section 87.9, “Build an
Executable Archive from Ant without Using spring-boot-antlib” “How-to” .
13.5 Starters
Starters are a set of convenient dependency descriptors that you can include in your application. You
get a one-stop shop for all the Spring and related technologies that you need without having to hunt
through sample code and copy-paste loads of dependency descriptors. For example, if you want to get
started using Spring and JPA for database access, include the spring-boot-starter-data-jpa
dependency in your project.
The starters contain a lot of the dependencies that you need to get a project up and running quickly and
with a consistent, supported set of managed transitive dependencies.
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What’s in a name
All official starters follow a similar naming pattern; spring-boot-starter-*, where * is a
particular type of application. This naming structure is intended to help when you need to find a
starter. The Maven integration in many IDEs lets you search dependencies by name. For example,
with the appropriate Eclipse or STS plugin installed, you can press ctrl-space in the POM editor
and type “spring-boot-starter” for a complete list.
As explained in the “Creating Your Own Starter” section, third party starters should not start
with spring-boot, as it is reserved for official Spring Boot artifacts. Rather, a third-party
starter typically starts with the name of the project. For example, a third-party starter project
called thirdpartyproject would typically be named thirdpartyproject-spring-boot-
starter.
The following application starters are provided by Spring Boot under the
org.springframework.boot group:
Table 13.1. Spring Boot application starters
Name Description Pom
spring-boot-starter Core starter, including auto-
configuration support, logging
and YAML
Pom
spring-boot-starter-
activemq
Starter for JMS messaging
using Apache ActiveMQ
Pom
spring-boot-starter-
amqp
Starter for using Spring AMQP
and Rabbit MQ
Pom
spring-boot-starter-aop Starter for aspect-oriented
programming with Spring AOP
and AspectJ
Pom
spring-boot-starter-
artemis
Starter for JMS messaging
using Apache Artemis
Pom
spring-boot-starter-
batch
Starter for using Spring Batch Pom
spring-boot-starter-
cache
Starter for using Spring
Framework’s caching support
Pom
spring-boot-starter-
cloud-connectors
Starter for using Spring Cloud
Connectors which simplifies
connecting to services in cloud
platforms like Cloud Foundry
and Heroku
Pom
spring-boot-starter-
data-cassandra
Starter for using Cassandra
distributed database and Spring
Data Cassandra
Pom
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Name Description Pom
spring-boot-starter-
data-cassandra-reactive
Starter for using Cassandra
distributed database and Spring
Data Cassandra Reactive
Pom
spring-boot-starter-
data-couchbase
Starter for using Couchbase
document-oriented database
and Spring Data Couchbase
Pom
spring-boot-starter-
data-couchbase-reactive
Starter for using Couchbase
document-oriented database
and Spring Data Couchbase
Reactive
Pom
spring-boot-starter-
data-elasticsearch
Starter for using Elasticsearch
search and analytics engine
and Spring Data Elasticsearch
Pom
spring-boot-starter-
data-jpa
Starter for using Spring Data
JPA with Hibernate
Pom
spring-boot-starter-
data-ldap
Starter for using Spring Data
LDAP
Pom
spring-boot-starter-
data-mongodb
Starter for using MongoDB
document-oriented database
and Spring Data MongoDB
Pom
spring-boot-starter-
data-mongodb-reactive
Starter for using MongoDB
document-oriented database
and Spring Data MongoDB
Reactive
Pom
spring-boot-starter-
data-neo4j
Starter for using Neo4j graph
database and Spring Data
Neo4j
Pom
spring-boot-starter-
data-redis
Starter for using Redis key-
value data store with Spring
Data Redis and the Lettuce
client
Pom
spring-boot-starter-
data-redis-reactive
Starter for using Redis key-
value data store with Spring
Data Redis reactive and the
Lettuce client
Pom
spring-boot-starter-
data-rest
Starter for exposing Spring
Data repositories over REST
using Spring Data REST
Pom
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Name Description Pom
spring-boot-starter-
data-solr
Starter for using the Apache
Solr search platform with Spring
Data Solr
Pom
spring-boot-starter-
freemarker
Starter for building MVC web
applications using FreeMarker
views
Pom
spring-boot-starter-
groovy-templates
Starter for building MVC web
applications using Groovy
Templates views
Pom
spring-boot-starter-
hateoas
Starter for building hypermedia-
based RESTful web application
with Spring MVC and Spring
HATEOAS
Pom
spring-boot-starter-
integration
Starter for using Spring
Integration
Pom
spring-boot-starter-
jdbc
Starter for using JDBC with the
HikariCP connection pool
Pom
spring-boot-starter-
jersey
Starter for building RESTful
web applications using JAX-RS
and Jersey. An alternative to
spring-boot-starter-web
Pom
spring-boot-starter-
jooq
Starter for using jOOQ to
access SQL databases. An
alternative to spring-boot-
starter-data-jpa or
spring-boot-starter-
jdbc
Pom
spring-boot-starter-
json
Starter for reading and writing
json
Pom
spring-boot-starter-
jta-atomikos
Starter for JTA transactions
using Atomikos
Pom
spring-boot-starter-
jta-bitronix
Starter for JTA transactions
using Bitronix
Pom
spring-boot-starter-
jta-narayana
Starter for JTA transactions
using Narayana
Pom
spring-boot-starter-
mail
Starter for using Java Mail
and Spring Framework’s email
sending support
Pom
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Name Description Pom
spring-boot-starter-
mustache
Starter for building web
applications using Mustache
views
Pom
spring-boot-starter-
quartz
Starter for using the Quartz
scheduler
Pom
spring-boot-starter-
security
Starter for using Spring Security Pom
spring-boot-starter-
test
Starter for testing Spring Boot
applications with libraries
including JUnit, Hamcrest and
Mockito
Pom
spring-boot-starter-
thymeleaf
Starter for building MVC web
applications using Thymeleaf
views
Pom
spring-boot-starter-
validation
Starter for using Java Bean
Validation with Hibernate
Validator
Pom
spring-boot-starter-web Starter for building web,
including RESTful, applications
using Spring MVC. Uses
Tomcat as the default
embedded container
Pom
spring-boot-starter-
web-services
Starter for using Spring Web
Services
Pom
spring-boot-starter-
webflux
Starter for building WebFlux
applications using Spring
Framework’s Reactive Web
support
Pom
spring-boot-starter-
websocket
Starter for building WebSocket
applications using Spring
Framework’s WebSocket
support
Pom
In addition to the application starters, the following starters can be used to add production ready features:
Table 13.2. Spring Boot production starters
Name Description Pom
spring-boot-starter-
actuator
Starter for using Spring Boot’s
Actuator which provides
production ready features to
help you monitor and manage
your application
Pom
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Finally, Spring Boot also includes the following starters that can be used if you want to exclude or swap
specific technical facets:
Table 13.3. Spring Boot technical starters
Name Description Pom
spring-boot-starter-
jetty
Starter for using Jetty as the
embedded servlet container. An
alternative to spring-boot-
starter-tomcat
Pom
spring-boot-starter-
log4j2
Starter for using Log4j2 for
logging. An alternative to
spring-boot-starter-
logging
Pom
spring-boot-starter-
logging
Starter for logging using
Logback. Default logging starter
Pom
spring-boot-starter-
reactor-netty
Starter for using Reactor Netty
as the embedded reactive
HTTP server.
Pom
spring-boot-starter-
tomcat
Starter for using Tomcat as the
embedded servlet container.
Default servlet container starter
used by spring-boot-
starter-web
Pom
spring-boot-starter-
undertow
Starter for using Undertow
as the embedded servlet
container. An alternative to
spring-boot-starter-
tomcat
Pom
Tip
For a list of additional community contributed starters, see the README file in the spring-boot-
starters module on GitHub.
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14. Structuring Your Code
Spring Boot does not require any specific code layout to work. However, there are some best practices
that help.
14.1 Using the “default” Package
When a class does not include a package declaration, it is considered to be in the “default package”.
The use of the “default package” is generally discouraged and should be avoided. It can cause
particular problems for Spring Boot applications that use the @ComponentScan, @EntityScan, or
@SpringBootApplication annotations, since every class from every jar is read.
Tip
We recommend that you follow Java’s recommended package naming conventions and use a
reversed domain name (for example, com.example.project).
14.2 Locating the Main Application Class
We generally recommend that you locate your main application class in a root package above other
classes. The @SpringBootApplication annotation is often placed on your main class, and it
implicitly defines a base “search package” for certain items. For example, if you are writing a JPA
application, the package of the @SpringBootApplication annotated class is used to search for
@Entity items. Using a root package also allows component scan to apply only on your project.
Tip
If you don’t want to use @SpringBootApplication, the @EnableAutoConfiguration and
@ComponentScan annotations that it imports defines that behaviour so you can also use that
instead.
The following listing shows a typical layout:
com
+- example
+- myapplication
+- Application.java
|
+- customer
| +- Customer.java
| +- CustomerController.java
| +- CustomerService.java
| +- CustomerRepository.java
|
+- order
+- Order.java
+- OrderController.java
+- OrderService.java
+- OrderRepository.java
The Application.java file would declare the main method, along with the basic
@SpringBootApplication, as follows:
package com.example.myapplication;
import org.springframework.boot.SpringApplication;
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import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
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15. Configuration Classes
Spring Boot favors Java-based configuration. Although it is possible to use SpringApplication with
XML sources, we generally recommend that your primary source be a single @Configuration class.
Usually the class that defines the main method is a good candidate as the primary @Configuration.
Tip
Many Spring configuration examples have been published on the Internet that use XML
configuration. If possible, always try to use the equivalent Java-based configuration. Searching
for Enable* annotations can be a good starting point.
15.1 Importing Additional Configuration Classes
You need not put all your @Configuration into a single class. The @Import annotation can be used
to import additional configuration classes. Alternatively, you can use @ComponentScan to automatically
pick up all Spring components, including @Configuration classes.
15.2 Importing XML Configuration
If you absolutely must use XML based configuration, we recommend that you still start with
a @Configuration class. You can then use an @ImportResource annotation to load XML
configuration files.
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16. Auto-configuration
Spring Boot auto-configuration attempts to automatically configure your Spring application based on the
jar dependencies that you have added. For example, if HSQLDB is on your classpath, and you have not
manually configured any database connection beans, then Spring Boot auto-configures an in-memory
database.
You need to opt-in to auto-configuration by adding the @EnableAutoConfiguration or
@SpringBootApplication annotations to one of your @Configuration classes.
Tip
You should only ever add one @SpringBootApplication or @EnableAutoConfiguration
annotation. We generally recommend that you add one or the other to your primary
@Configuration class only.
16.1 Gradually Replacing Auto-configuration
Auto-configuration is non-invasive. At any point, you can start to define your own configuration to replace
specific parts of the auto-configuration. For example, if you add your own DataSource bean, the default
embedded database support backs away.
If you need to find out what auto-configuration is currently being applied, and why, start your application
with the --debug switch. Doing so enables debug logs for a selection of core loggers and logs a
conditions report to the console.
16.2 Disabling Specific Auto-configuration Classes
If you find that specific auto-configuration classes that you do not want are being applied, you can
use the exclude attribute of @EnableAutoConfiguration to disable them, as shown in the following
example:
import org.springframework.boot.autoconfigure.*;
import org.springframework.boot.autoconfigure.jdbc.*;
import org.springframework.context.annotation.*;
@Configuration
@EnableAutoConfiguration(exclude={DataSourceAutoConfiguration.class})
public class MyConfiguration {
}
If the class is not on the classpath, you can use the excludeName attribute of the annotation and specify
the fully qualified name instead. Finally, you can also control the list of auto-configuration classes to
exclude by using the spring.autoconfigure.exclude property.
Tip
You can define exclusions both at the annotation level and by using the property.
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17. Spring Beans and Dependency Injection
You are free to use any of the standard Spring Framework techniques to define your beans and their
injected dependencies. For simplicity, we often find that using @ComponentScan (to find your beans)
and using @Autowired (to do constructor injection) works well.
If you structure your code as suggested above (locating your application class in a root package), you
can add @ComponentScan without any arguments. All of your application components (@Component,
@Service, @Repository, @Controller etc.) are automatically registered as Spring Beans.
The following example shows a @Service Bean that uses constructor injection to obtain a required
RiskAssessor bean:
package com.example.service;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service
public class DatabaseAccountService implements AccountService {
private final RiskAssessor riskAssessor;
@Autowired
public DatabaseAccountService(RiskAssessor riskAssessor) {
this.riskAssessor = riskAssessor;
}
// ...
}
If a bean has one constructor, you can omit the @Autowired, as shown in the following example:
@Service
public class DatabaseAccountService implements AccountService {
private final RiskAssessor riskAssessor;
public DatabaseAccountService(RiskAssessor riskAssessor) {
this.riskAssessor = riskAssessor;
}
// ...
}
Tip
Notice how using constructor injection lets the riskAssessor field be marked as final,
indicating that it cannot be subsequently changed.
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18. Using the @SpringBootApplication Annotation
Many Spring Boot developers like their apps to use auto-configuration, component scan and be able to
define extra configuration on their "application class". A single @SpringBootApplication annotation
can be used to enable those three features, that is:
•@EnableAutoConfiguration: enable Spring Boot’s auto-configuration mechanism
•@ComponentScan: enable @Component scan on the package where the application is located (see
the best practices)
•@Configuration: allow to register extra beans in the context or import additional configuration
classes
The @SpringBootApplication annotation is equivalent to using @Configuration,
@EnableAutoConfiguration, and @ComponentScan with their default attributes, as shown in the
following example:
package com.example.myapplication;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication // same as @Configuration @EnableAutoConfiguration @ComponentScan
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
Note
@SpringBootApplication also provides aliases to customize the attributes of
@EnableAutoConfiguration and @ComponentScan.
Note
None of these features are mandatory and you may chose to replace this single annotation by
any of the features that it enables. For instance, you may not want to use component scan in
your application:
package com.example.myapplication;
import org.springframework.boot.SpringApplication;
import org.springframework.context.annotation.ComponentScan
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
@Configuration
@EnableAutoConfiguration
@Import({ MyConfig.class, MyAnotherConfig.class })
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
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In this example, Application is just like any other Spring Boot application except that
@Component-annotated classes are not detected automatically and the user-defined beans are
imported explicitly (see @Import).
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19. Running Your Application
One of the biggest advantages of packaging your application as a jar and using an embedded HTTP
server is that you can run your application as you would any other. Debugging Spring Boot applications
is also easy. You do not need any special IDE plugins or extensions.
Note
This section only covers jar based packaging. If you choose to package your application as a war
file, you should refer to your server and IDE documentation.
19.1 Running from an IDE
You can run a Spring Boot application from your IDE as a simple Java application. However, you first
need to import your project. Import steps vary depending on your IDE and build system. Most IDEs can
import Maven projects directly. For example, Eclipse users can select Import… → Existing Maven
Projects from the File menu.
If you cannot directly import your project into your IDE, you may be able to generate IDE metadata by
using a build plugin. Maven includes plugins for Eclipse and IDEA. Gradle offers plugins for various IDEs.
Tip
If you accidentally run a web application twice, you see a “Port already in use” error. STS users
can use the Relaunch button rather than the Run button to ensure that any existing instance
is closed.
19.2 Running as a Packaged Application
If you use the Spring Boot Maven or Gradle plugins to create an executable jar, you can run your
application using java -jar, as shown in the following example:
$ java -jar target/myapplication-0.0.1-SNAPSHOT.jar
It is also possible to run a packaged application with remote debugging support enabled. Doing so lets
you attach a debugger to your packaged application, as shown in the following example:
$ java -Xdebug -Xrunjdwp:server=y,transport=dt_socket,address=8000,suspend=n \
-jar target/myapplication-0.0.1-SNAPSHOT.jar
19.3 Using the Maven Plugin
The Spring Boot Maven plugin includes a run goal that can be used to quickly compile and run your
application. Applications run in an exploded form, as they do in your IDE. The following example shows
a typical Maven command to run a Spring Boot application:
$ mvn spring-boot:run
You might also want to use the MAVEN_OPTS operating system environment variable, as shown in the
following example:
$ export MAVEN_OPTS=-Xmx1024m
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19.4 Using the Gradle Plugin
The Spring Boot Gradle plugin also includes a bootRun task that can be used to run your application in
an exploded form. The bootRun task is added whenever you apply the org.springframework.boot
and java plugins and is shown in the following example:
$ gradle bootRun
You might also want to use the JAVA_OPTS operating system environment variable, as shown in the
following example:
$ export JAVA_OPTS=-Xmx1024m
19.5 Hot Swapping
Since Spring Boot applications are just plain Java applications, JVM hot-swapping should work out of the
box. JVM hot swapping is somewhat limited with the bytecode that it can replace. For a more complete
solution, JRebel can be used.
The spring-boot-devtools module also includes support for quick application restarts. See the
Chapter 20, Developer Tools section later in this chapter and the Hot swapping “How-to” for details.
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20. Developer Tools
Spring Boot includes an additional set of tools that can make the application development experience a
little more pleasant. The spring-boot-devtools module can be included in any project to provide
additional development-time features. To include devtools support, add the module dependency to your
build, as shown in the following listings for Maven and Gradle:
Maven.
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<optional>true</optional>
</dependency>
</dependencies>
Gradle.
dependencies {
compile("org.springframework.boot:spring-boot-devtools")
}
Note
Developer tools are automatically disabled when running a fully packaged application. If your
application is launched from java -jar or if it is started from a special classloader, then it is
considered a “production application”. Flagging the dependency as optional in Maven or using
compileOnly in Gradle is a best practice that prevents devtools from being transitively applied
to other modules that use your project.
Tip
Repackaged archives do not contain devtools by default. If you want to use a certain remote
devtools feature, you need to disable the excludeDevtools build property to include it. The
property is supported with both the Maven and Gradle plugins.
20.1 Property Defaults
Several of the libraries supported by Spring Boot use caches to improve performance. For example,
template engines cache compiled templates to avoid repeatedly parsing template files. Also, Spring
MVC can add HTTP caching headers to responses when serving static resources.
While caching is very beneficial in production, it can be counter-productive during development,
preventing you from seeing the changes you just made in your application. For this reason, spring-boot-
devtools disables the caching options by default.
Cache options are usually configured by settings in your application.properties file. For
example, Thymeleaf offers the spring.thymeleaf.cache property. Rather than needing to set
these properties manually, the spring-boot-devtools module automatically applies sensible
development-time configuration.
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Tip
For a complete list of the properties that are applied by the devtools, see
DevToolsPropertyDefaultsPostProcessor.
20.2 Automatic Restart
Applications that use spring-boot-devtools automatically restart whenever files on the classpath
change. This can be a useful feature when working in an IDE, as it gives a very fast feedback loop for
code changes. By default, any entry on the classpath that points to a folder is monitored for changes.
Note that certain resources, such as static assets and view templates, do not need to restart the
application.
Triggering a restart
As DevTools monitors classpath resources, the only way to trigger a restart is to update the
classpath. The way in which you cause the classpath to be updated depends on the IDE that you
are using. In Eclipse, saving a modified file causes the classpath to be updated and triggers a
restart. In IntelliJ IDEA, building the project (Build -> Build Project) has the same effect.
Note
As long as forking is enabled, you can also start your application by using the supported build
plugins (Maven and Gradle), since DevTools needs an isolated application classloader to operate
properly. By default, Gradle and Maven do that when they detect DevTools on the classpath.
Tip
Automatic restart works very well when used with LiveReload. See the LiveReload section for
details. If you use JRebel, automatic restarts are disabled in favor of dynamic class reloading.
Other devtools features (such as LiveReload and property overrides) can still be used.
Note
DevTools relies on the application context’s shutdown hook to close it during
a restart. It does not work correctly if you have disabled the shutdown hook
(SpringApplication.setRegisterShutdownHook(false)).
Note
When deciding if an entry on the classpath should trigger a restart when it changes, DevTools
automatically ignores projects named spring-boot, spring-boot-devtools, spring-
boot-autoconfigure, spring-boot-actuator, and spring-boot-starter.
Note
DevTools needs to customize the ResourceLoader used by the ApplicationContext. If your
application provides one already, it is going to be wrapped. Direct override of the getResource
method on the ApplicationContext is not supported.
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Restart vs Reload
The restart technology provided by Spring Boot works by using two classloaders. Classes that do
not change (for example, those from third-party jars) are loaded into a base classloader. Classes
that you are actively developing are loaded into a restart classloader. When the application is
restarted, the restart classloader is thrown away and a new one is created. This approach means
that application restarts are typically much faster than “cold starts”, since the base classloader is
already available and populated.
If you find that restarts are not quick enough for your applications or you encounter classloading
issues, you could consider reloading technologies such as JRebel from ZeroTurnaround. These
work by rewriting classes as they are loaded to make them more amenable to reloading.
Logging changes in condition evaluation
By default, each time your application restarts, a report showing the condition evaluation delta is logged.
The report shows the changes to your application’s auto-configuration as you make changes such as
adding or removing beans and setting configuration properties.
To disable the logging of the report, set the following property:
spring.devtools.restart.log-condition-evaluation-delta=false
Excluding Resources
Certain resources do not necessarily need to trigger a restart when they are changed. For example,
Thymeleaf templates can be edited in-place. By default, changing resources in /META-INF/maven,
/META-INF/resources, /resources, /static, /public, or /templates does not trigger a
restart but does trigger a live reload. If you want to customize these exclusions, you can use the
spring.devtools.restart.exclude property. For example, to exclude only /static and /
public you would set the following property:
spring.devtools.restart.exclude=static/**,public/**
Tip
If you want to keep those defaults and add additional exclusions, use the
spring.devtools.restart.additional-exclude property instead.
Watching Additional Paths
You may want your application to be restarted or reloaded when you make changes to files
that are not on the classpath. To do so, use the spring.devtools.restart.additional-
paths property to configure additional paths to watch for changes. You can use the
spring.devtools.restart.exclude property described earlier to control whether changes
beneath the additional paths trigger a full restart or a live reload.
Disabling Restart
If you do not want to use the restart feature, you can disable it by using the
spring.devtools.restart.enabled property. In most cases, you can set this property in your
application.properties (doing so still initializes the restart classloader, but it does not watch for
file changes).
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If you need to completely disable restart support (for example, because it does not work with a specific
library), you need to set the spring.devtools.restart.enabled System property to false
before calling SpringApplication.run(…), as shown in the following example:
public static void main(String[] args) {
System.setProperty("spring.devtools.restart.enabled", "false");
SpringApplication.run(MyApp.class, args);
}
Using a Trigger File
If you work with an IDE that continuously compiles changed files, you might prefer to trigger restarts only
at specific times. To do so, you can use a “trigger file”, which is a special file that must be modified when
you want to actually trigger a restart check. Changing the file only triggers the check and the restart
only occurs if Devtools has detected it has to do something. The trigger file can be updated manually
or with an IDE plugin.
To use a trigger file, set the spring.devtools.restart.trigger-file property to the path of
your trigger file.
Tip
You might want to set spring.devtools.restart.trigger-file as a global setting, so
that all your projects behave in the same way.
Customizing the Restart Classloader
As described earlier in the Restart vs Reload section, restart functionality is implemented by using
two classloaders. For most applications, this approach works well. However, it can sometimes cause
classloading issues.
By default, any open project in your IDE is loaded with the “restart” classloader, and any regular .jar
file is loaded with the “base” classloader. If you work on a multi-module project, and not every module
is imported into your IDE, you may need to customize things. To do so, you can create a META-INF/
spring-devtools.properties file.
The spring-devtools.properties file can contain properties prefixed with restart.exclude
and restart.include. The include elements are items that should be pulled up into the “restart”
classloader, and the exclude elements are items that should be pushed down into the “base”
classloader. The value of the property is a regex pattern that is applied to the classpath, as shown in
the following example:
restart.exclude.companycommonlibs=/mycorp-common-[\\w-]+\.jar
restart.include.projectcommon=/mycorp-myproj-[\\w-]+\.jar
Note
All property keys must be unique. As long as a property starts with restart.include. or
restart.exclude. it is considered.
Tip
All META-INF/spring-devtools.properties from the classpath are loaded. You can
package files inside your project, or in the libraries that the project consumes.
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Known Limitations
Restart functionality does not work well with objects that are deserialized by
using a standard ObjectInputStream. If you need to deserialize data, you
may need to use Spring’s ConfigurableObjectInputStream in combination with
Thread.currentThread().getContextClassLoader().
Unfortunately, several third-party libraries deserialize without considering the context classloader. If you
find such a problem, you need to request a fix with the original authors.
20.3 LiveReload
The spring-boot-devtools module includes an embedded LiveReload server that can be used
to trigger a browser refresh when a resource is changed. LiveReload browser extensions are freely
available for Chrome, Firefox and Safari from livereload.com.
If you do not want to start the LiveReload server when your application runs, you can set the
spring.devtools.livereload.enabled property to false.
Note
You can only run one LiveReload server at a time. Before starting your application, ensure that
no other LiveReload servers are running. If you start multiple applications from your IDE, only the
first has LiveReload support.
20.4 Global Settings
You can configure global devtools settings by adding a file named .spring-boot-
devtools.properties to your $HOME folder (note that the filename starts with “.”). Any properties
added to this file apply to all Spring Boot applications on your machine that use devtools. For example,
to configure restart to always use a trigger file, you would add the following property:
~/.spring-boot-devtools.properties.
spring.devtools.reload.trigger-file=.reloadtrigger
20.5 Remote Applications
The Spring Boot developer tools are not limited to local development. You can also use several features
when running applications remotely. Remote support is opt-in. To enable it, you need to make sure that
devtools is included in the repackaged archive, as shown in the following listing:
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<excludeDevtools>false</excludeDevtools>
</configuration>
</plugin>
</plugins>
</build>
Then you need to set a spring.devtools.remote.secret property, as shown in the following
example:
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spring.devtools.remote.secret=mysecret
Warning
Enabling spring-boot-devtools on a remote application is a security risk. You should never
enable support on a production deployment.
Remote devtools support is provided in two parts: a server-side endpoint that accepts connections and
a client application that you run in your IDE. The server component is automatically enabled when
the spring.devtools.remote.secret property is set. The client component must be launched
manually.
Running the Remote Client Application
The remote client application is designed to be run from within your IDE. You need to run
org.springframework.boot.devtools.RemoteSpringApplication with the same classpath
as the remote project that you connect to. The application’s single required argument is the remote URL
to which it connects.
For example, if you are using Eclipse or STS and you have a project named my-app that you have
deployed to Cloud Foundry, you would do the following:
• Select Run Configurations… from the Run menu.
• Create a new Java Application “launch configuration”.
• Browse for the my-app project.
• Use org.springframework.boot.devtools.RemoteSpringApplication as the main class.
• Add https://myapp.cfapps.io to the Program arguments (or whatever your remote URL is).
A running remote client might resemble the following listing:
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ ___ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | | _ \___ _ __ ___| |_ ___ \ \ \ \
\\/ ___)| |_)| | | | | || (_| []::::::[] / -_) ' \/ _ \ _/ -_) ) ) ) )
' |____| .__|_| |_|_| |_\__, | |_|_\___|_|_|_\___/\__\___|/ / / /
=========|_|==============|___/===================================/_/_/_/
:: Spring Boot Remote :: 2.0.4.RELEASE
2015-06-10 18:25:06.632 INFO 14938 --- [ main] o.s.b.devtools.RemoteSpringApplication :
Starting RemoteSpringApplication on pwmbp with PID 14938 (/Users/pwebb/projects/spring-boot/code/
spring-boot-devtools/target/classes started by pwebb in /Users/pwebb/projects/spring-boot/code/spring-
boot-samples/spring-boot-sample-devtools)
2015-06-10 18:25:06.671 INFO 14938 --- [ main] s.c.a.AnnotationConfigApplicationContext :
Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@2a17b7b6: startup
date [Wed Jun 10 18:25:06 PDT 2015]; root of context hierarchy
2015-06-10 18:25:07.043 WARN 14938 --- [ main] o.s.b.d.r.c.RemoteClientConfiguration : The
connection to http://localhost:8080 is insecure. You should use a URL starting with 'https://'.
2015-06-10 18:25:07.074 INFO 14938 --- [ main] o.s.b.d.a.OptionalLiveReloadServer :
LiveReload server is running on port 35729
2015-06-10 18:25:07.130 INFO 14938 --- [ main] o.s.b.devtools.RemoteSpringApplication :
Started RemoteSpringApplication in 0.74 seconds (JVM running for 1.105)
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Note
Because the remote client is using the same classpath as the real application it can directly read
application properties. This is how the spring.devtools.remote.secret property is read
and passed to the server for authentication.
Tip
It is always advisable to use https:// as the connection protocol, so that traffic is encrypted
and passwords cannot be intercepted.
Tip
If you need to use a proxy to access the remote application, configure the
spring.devtools.remote.proxy.host and spring.devtools.remote.proxy.port
properties.
Remote Update
The remote client monitors your application classpath for changes in the same way as the local restart.
Any updated resource is pushed to the remote application and (if required) triggers a restart. This can
be helpful if you iterate on a feature that uses a cloud service that you do not have locally. Generally,
remote updates and restarts are much quicker than a full rebuild and deploy cycle.
Note
Files are only monitored when the remote client is running. If you change a file before starting the
remote client, it is not pushed to the remote server.
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21. Packaging Your Application for Production
Executable jars can be used for production deployment. As they are self-contained, they are also ideally
suited for cloud-based deployment.
For additional “production ready” features, such as health, auditing, and metric REST or JMX end-
points, consider adding spring-boot-actuator. See Part V, “Spring Boot Actuator: Production-
ready features” for details.
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22. What to Read Next
You should now understand how you can use Spring Boot and some best practices that you should
follow. You can now go on to learn about specific Spring Boot features in depth, or you could skip ahead
and read about the “production ready” aspects of Spring Boot.
Part IV. Spring Boot features
This section dives into the details of Spring Boot. Here you can learn about the key features that you may
want to use and customize. If you have not already done so, you might want to read the "Part II, “Getting
Started”" and "Part III, “Using Spring Boot”" sections, so that you have a good grounding of the basics.
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23. SpringApplication
The SpringApplication class provides a convenient way to bootstrap a Spring application
that is started from a main() method. In many situations, you can delegate to the static
SpringApplication.run method, as shown in the following example:
public static void main(String[] args) {
SpringApplication.run(MySpringConfiguration.class, args);
}
When your application starts, you should see something similar to the following output:
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: v2.0.4.RELEASE
2013-07-31 00:08:16.117 INFO 56603 --- [ main] o.s.b.s.app.SampleApplication :
Starting SampleApplication v0.1.0 on mycomputer with PID 56603 (/apps/myapp.jar started by pwebb)
2013-07-31 00:08:16.166 INFO 56603 --- [ main]
ationConfigServletWebServerApplicationContext : Refreshing
org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@6e5a8246:
startup date [Wed Jul 31 00:08:16 PDT 2013]; root of context hierarchy
2014-03-04 13:09:54.912 INFO 41370 --- [ main] .t.TomcatServletWebServerFactory : Server
initialized with port: 8080
2014-03-04 13:09:56.501 INFO 41370 --- [ main] o.s.b.s.app.SampleApplication :
Started SampleApplication in 2.992 seconds (JVM running for 3.658)
By default, INFO logging messages are shown, including some relevant startup details, such as the
user that launched the application. If you need a log level other than INFO, you can set it, as described
in Section 26.4, “Log Levels”,
23.1 Startup Failure
If your application fails to start, registered FailureAnalyzers get a chance to provide a dedicated
error message and a concrete action to fix the problem. For instance, if you start a web application on
port 8080 and that port is already in use, you should see something similar to the following message:
***************************
APPLICATION FAILED TO START
***************************
Description:
Embedded servlet container failed to start. Port 8080 was already in use.
Action:
Identify and stop the process that's listening on port 8080 or configure this application to listen on
another port.
Note
Spring Boot provides numerous FailureAnalyzer implementations, and you can add your own.
If no failure analyzers are able to handle the exception, you can still
display the full conditions report to better understand what went wrong. To do
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so, you need to enable the debug property or enable DEBUG logging for
org.springframework.boot.autoconfigure.logging.ConditionEvaluationReportLoggingListener.
For instance, if you are running your application by using java -jar, you can enable the debug
property as follows:
$ java -jar myproject-0.0.1-SNAPSHOT.jar --debug
23.2 Customizing the Banner
The banner that is printed on start up can be changed by adding a banner.txt file to your classpath
or by setting the spring.banner.location property to the location of such a file. If the file has
an encoding other than UTF-8, you can set spring.banner.charset. In addition to a text file, you
can also add a banner.gif, banner.jpg, or banner.png image file to your classpath or set the
spring.banner.image.location property. Images are converted into an ASCII art representation
and printed above any text banner.
Inside your banner.txt file, you can use any of the following placeholders:
Table 23.1. Banner variables
Variable Description
${application.version} The version number of your application, as
declared in MANIFEST.MF. For example,
Implementation-Version: 1.0 is printed
as 1.0.
${application.formatted-version} The version number of your application, as
declared in MANIFEST.MF and formatted for
display (surrounded with brackets and prefixed
with v). For example (v1.0).
${spring-boot.version} The Spring Boot version that you are using. For
example 2.0.4.RELEASE.
${spring-boot.formatted-version} The Spring Boot version that you are using,
formatted for display (surrounded with
brackets and prefixed with v). For example
(v2.0.4.RELEASE).
${Ansi.NAME} (or ${AnsiColor.NAME},
${AnsiBackground.NAME},
${AnsiStyle.NAME})
Where NAME is the name of an ANSI escape
code. See AnsiPropertySource for details.
${application.title} The title of your application, as declared
in MANIFEST.MF. For example
Implementation-Title: MyApp is printed
as MyApp.
Tip
The SpringApplication.setBanner(…) method can be used if you want to generate
a banner programmatically. Use the org.springframework.boot.Banner interface and
implement your own printBanner() method.
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You can also use the spring.main.banner-mode property to determine if the banner has to be
printed on System.out (console), sent to the configured logger (log), or not produced at all (off).
The printed banner is registered as a singleton bean under the following name: springBootBanner.
Note
YAML maps off to false, so be sure to add quotes if you want to disable the banner in your
application, as shown in the following example:
spring:
main:
banner-mode: "off"
23.3 Customizing SpringApplication
If the SpringApplication defaults are not to your taste, you can instead create a local instance and
customize it. For example, to turn off the banner, you could write:
public static void main(String[] args) {
SpringApplication app = new SpringApplication(MySpringConfiguration.class);
app.setBannerMode(Banner.Mode.OFF);
app.run(args);
}
Note
The constructor arguments passed to SpringApplication are configuration sources for Spring
beans. In most cases, these are references to @Configuration classes, but they could also be
references to XML configuration or to packages that should be scanned.
It is also possible to configure the SpringApplication by using an application.properties
file. See Chapter 24, Externalized Configuration for details.
For a complete list of the configuration options, see the SpringApplication Javadoc.
23.4 Fluent Builder API
If you need to build an ApplicationContext hierarchy (multiple contexts with a parent/
child relationship) or if you prefer using a “fluent” builder API, you can use the
SpringApplicationBuilder.
The SpringApplicationBuilder lets you chain together multiple method calls and includes parent
and child methods that let you create a hierarchy, as shown in the following example:
new SpringApplicationBuilder()
.sources(Parent.class)
.child(Application.class)
.bannerMode(Banner.Mode.OFF)
.run(args);
Note
There are some restrictions when creating an ApplicationContext hierarchy. For example,
Web components must be contained within the child context, and the same Environment is
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used for both parent and child contexts. See the SpringApplicationBuilder Javadoc for
full details.
23.5 Application Events and Listeners
In addition to the usual Spring Framework events, such as ContextRefreshedEvent, a
SpringApplication sends some additional application events.
Note
Some events are actually triggered before the ApplicationContext is created,
so you cannot register a listener on those as a @Bean. You can
register them with the SpringApplication.addListeners(…) method or the
SpringApplicationBuilder.listeners(…) method.
If you want those listeners to be registered automatically, regardless of the way the application is
created, you can add a META-INF/spring.factories file to your project and reference your
listener(s) by using the org.springframework.context.ApplicationListener key, as
shown in the following example:
org.springframework.context.ApplicationListener=com.example.project.MyListener
Application events are sent in the following order, as your application runs:
1. An ApplicationStartingEvent is sent at the start of a run but before any processing, except
for the registration of listeners and initializers.
2. An ApplicationEnvironmentPreparedEvent is sent when the Environment to be used in the
context is known but before the context is created.
3. An ApplicationPreparedEvent is sent just before the refresh is started but after bean definitions
have been loaded.
4. An ApplicationStartedEvent is sent after the context has been refreshed but before any
application and command-line runners have been called.
5. An ApplicationReadyEvent is sent after any application and command-line runners have been
called. It indicates that the application is ready to service requests.
6. An ApplicationFailedEvent is sent if there is an exception on startup.
Tip
You often need not use application events, but it can be handy to know that they exist. Internally,
Spring Boot uses events to handle a variety of tasks.
Application events are sent by using Spring Framework’s event publishing mechanism. Part of this
mechanism ensures that an event published to the listeners in a child context is also published
to the listeners in any ancestor contexts. As a result of this, if your application uses a hierarchy
of SpringApplication instances, a listener may receive multiple instances of the same type of
application event.
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To allow your listener to distinguish between an event for its context and an event for a
descendant context, it should request that its application context is injected and then compare
the injected context with the context of the event. The context can be injected by implementing
ApplicationContextAware or, if the listener is a bean, by using @Autowired.
23.6 Web Environment
A SpringApplication attempts to create the right type of ApplicationContext on your behalf.
The algorithm used to determine a WebApplicationType is fairly simple:
• If Spring MVC is present, an AnnotationConfigServletWebServerApplicationContext is
used
• If Spring MVC is not present and Spring WebFlux is present, an
AnnotationConfigReactiveWebServerApplicationContext is used
• Otherwise, AnnotationConfigApplicationContext is used
This means that if you are using Spring MVC and the new WebClient from Spring WebFlux in
the same application, Spring MVC will be used by default. You can override that easily by calling
setWebApplicationType(WebApplicationType).
It is also possible to take complete control of the ApplicationContext type that is used by calling
setApplicationContextClass(…).
Tip
It is often desirable to call setWebApplicationType(WebApplicationType.NONE) when
using SpringApplication within a JUnit test.
23.7 Accessing Application Arguments
If you need to access the application arguments that were passed to SpringApplication.run(…
), you can inject a org.springframework.boot.ApplicationArguments bean. The
ApplicationArguments interface provides access to both the raw String[] arguments as well as
parsed option and non-option arguments, as shown in the following example:
import org.springframework.boot.*;
import org.springframework.beans.factory.annotation.*;
import org.springframework.stereotype.*;
@Component
public class MyBean {
@Autowired
public MyBean(ApplicationArguments args) {
boolean debug = args.containsOption("debug");
List<String> files = args.getNonOptionArgs();
// if run with "--debug logfile.txt" debug=true, files=["logfile.txt"]
}
}
Tip
Spring Boot also registers a CommandLinePropertySource with the Spring Environment.
This lets you also inject single application arguments by using the @Value annotation.
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23.8 Using the ApplicationRunner or CommandLineRunner
If you need to run some specific code once the SpringApplication has started, you can implement
the ApplicationRunner or CommandLineRunner interfaces. Both interfaces work in the same way
and offer a single run method, which is called just before SpringApplication.run(…) completes.
The CommandLineRunner interfaces provides access to application arguments as a simple string
array, whereas the ApplicationRunner uses the ApplicationArguments interface discussed
earlier. The following example shows a CommandLineRunner with a run method:
import org.springframework.boot.*;
import org.springframework.stereotype.*;
@Component
public class MyBean implements CommandLineRunner {
public void run(String... args) {
// Do something...
}
}
If several CommandLineRunner or ApplicationRunner beans are defined that must be called in a
specific order, you can additionally implement the org.springframework.core.Ordered interface
or use the org.springframework.core.annotation.Order annotation.
23.9 Application Exit
Each SpringApplication registers a shutdown hook with the JVM to ensure that the
ApplicationContext closes gracefully on exit. All the standard Spring lifecycle callbacks (such as
the DisposableBean interface or the @PreDestroy annotation) can be used.
In addition, beans may implement the org.springframework.boot.ExitCodeGenerator
interface if they wish to return a specific exit code when SpringApplication.exit() is called. This
exit code can then be passed to System.exit() to return it as a status code, as shown in the following
example:
@SpringBootApplication
public class ExitCodeApplication {
@Bean
public ExitCodeGenerator exitCodeGenerator() {
return () -> 42;
}
public static void main(String[] args) {
System.exit(SpringApplication
.exit(SpringApplication.run(ExitCodeApplication.class, args)));
}
}
Also, the ExitCodeGenerator interface may be implemented by exceptions. When such an exception
is encountered, Spring Boot returns the exit code provided by the implemented getExitCode()
method.
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23.10 Admin Features
It is possible to enable admin-related features for the application by
specifying the spring.application.admin.enabled property. This exposes the
SpringApplicationAdminMXBean on the platform MBeanServer. You could use this feature to
administer your Spring Boot application remotely. This feature could also be useful for any service
wrapper implementation.
Tip
If you want to know on which HTTP port the application is running, get the property with a key
of local.server.port.
Caution
Take care when enabling this feature, as the MBean exposes a method to shutdown the
application.
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24. Externalized Configuration
Spring Boot lets you externalize your configuration so that you can work with the same application
code in different environments. You can use properties files, YAML files, environment variables, and
command-line arguments to externalize configuration. Property values can be injected directly into your
beans by using the @Value annotation, accessed through Spring’s Environment abstraction, or be
bound to structured objects through @ConfigurationProperties.
Spring Boot uses a very particular PropertySource order that is designed to allow sensible overriding
of values. Properties are considered in the following order:
1. Devtools global settings properties on your home directory (~/.spring-boot-
devtools.properties when devtools is active).
2. @TestPropertySource annotations on your tests.
3. @SpringBootTest#properties annotation attribute on your tests.
4. Command line arguments.
5. Properties from SPRING_APPLICATION_JSON (inline JSON embedded in an environment variable
or system property).
6. ServletConfig init parameters.
7. ServletContext init parameters.
8. JNDI attributes from java:comp/env.
9. Java System properties (System.getProperties()).
10.OS environment variables.
11.A RandomValuePropertySource that has properties only in random.*.
12.Profile-specific application properties outside of your packaged jar (application-
{profile}.properties and YAML variants).
13.Profile-specific application properties packaged inside your jar (application-
{profile}.properties and YAML variants).
14.Application properties outside of your packaged jar (application.properties and YAML
variants).
15.Application properties packaged inside your jar (application.properties and YAML variants).
16.@PropertySource annotations on your @Configuration classes.
17.Default properties (specified by setting SpringApplication.setDefaultProperties).
To provide a concrete example, suppose you develop a @Component that uses a name property, as
shown in the following example:
import org.springframework.stereotype.*;
import org.springframework.beans.factory.annotation.*;
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@Component
public class MyBean {
@Value("${name}")
private String name;
// ...
}
On your application classpath (for example, inside your jar) you can have an
application.properties file that provides a sensible default property value for name. When
running in a new environment, an application.properties file can be provided outside of your jar
that overrides the name. For one-off testing, you can launch with a specific command line switch (for
example, java -jar app.jar --name="Spring").
Tip
The SPRING_APPLICATION_JSON properties can be supplied on the command line with an
environment variable. For example, you could use the following line in a UN*X shell:
$ SPRING_APPLICATION_JSON='{"acme":{"name":"test"}}' java -jar myapp.jar
In the preceding example, you end up with acme.name=test in the Spring Environment. You
can also supply the JSON as spring.application.json in a System property, as shown in
the following example:
$ java -Dspring.application.json='{"name":"test"}' -jar myapp.jar
You can also supply the JSON by using a command line argument, as shown in the following
example:
$ java -jar myapp.jar --spring.application.json='{"name":"test"}'
You can also supply the JSON as a JNDI variable, as follows: java:comp/env/
spring.application.json.
24.1 Configuring Random Values
The RandomValuePropertySource is useful for injecting random values (for example, into secrets
or test cases). It can produce integers, longs, uuids, or strings, as shown in the following example:
my.secret=${random.value}
my.number=${random.int}
my.bignumber=${random.long}
my.uuid=${random.uuid}
my.number.less.than.ten=${random.int(10)}
my.number.in.range=${random.int[1024,65536]}
The random.int* syntax is OPEN value (,max) CLOSE where the OPEN,CLOSE are any character
and value,max are integers. If max is provided, then value is the minimum value and max is the
maximum value (exclusive).
24.2 Accessing Command Line Properties
By default, SpringApplication converts any command line option arguments (that is, arguments
starting with --, such as --server.port=9000) to a property and adds them to the Spring
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Environment. As mentioned previously, command line properties always take precedence over other
property sources.
If you do not want command line properties to be added to the Environment, you can disable them
by using SpringApplication.setAddCommandLineProperties(false).
24.3 Application Property Files
SpringApplication loads properties from application.properties files in the following
locations and adds them to the Spring Environment:
1. A /config subdirectory of the current directory
2. The current directory
3. A classpath /config package
4. The classpath root
The list is ordered by precedence (properties defined in locations higher in the list override those defined
in lower locations).
Note
You can also use YAML ('.yml') files as an alternative to '.properties'.
If you do not like application.properties as the configuration file name, you can switch to another
file name by specifying a spring.config.name environment property. You can also refer to an explicit
location by using the spring.config.location environment property (which is a comma-separated
list of directory locations or file paths). The following example shows how to specify a different file name:
$ java -jar myproject.jar --spring.config.name=myproject
The following example shows how to specify two locations:
$ java -jar myproject.jar --spring.config.location=classpath:/default.properties,classpath:/
override.properties
Warning
spring.config.name and spring.config.location are used very early to determine
which files have to be loaded, so they must be defined as an environment property (typically an
OS environment variable, a system property, or a command-line argument).
If spring.config.location contains directories (as opposed to files), they should end in / (and,
at runtime, be appended with the names generated from spring.config.name before being loaded,
including profile-specific file names). Files specified in spring.config.location are used as-is,
with no support for profile-specific variants, and are overridden by any profile-specific properties.
Config locations are searched in reverse order. By default, the configured locations are
classpath:/,classpath:/config/,file:./,file:./config/. The resulting search order is
the following:
1. file:./config/
2. file:./
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3. classpath:/config/
4. classpath:/
When custom config locations are configured by using spring.config.location, they
replace the default locations. For example, if spring.config.location is configured with the
value classpath:/custom-config/,file:./custom-config/, the search order becomes the
following:
1. file:./custom-config/
2. classpath:custom-config/
Alternatively, when custom config locations are configured by using spring.config.additional-
location, they are used in addition to the default locations. Additional locations are searched
before the default locations. For example, if additional locations of classpath:/custom-
config/,file:./custom-config/ are configured, the search order becomes the following:
1. file:./custom-config/
2. classpath:custom-config/
3. file:./config/
4. file:./
5. classpath:/config/
6. classpath:/
This search ordering lets you specify default values in one configuration file and then selectively
override those values in another. You can provide default values for your application in
application.properties (or whatever other basename you choose with spring.config.name)
in one of the default locations. These default values can then be overridden at runtime with a different
file located in one of the custom locations.
Note
If you use environment variables rather than system properties, most operating systems
disallow period-separated key names, but you can use underscores instead (for example,
SPRING_CONFIG_NAME instead of spring.config.name).
Note
If your application runs in a container, then JNDI properties (in java:comp/env) or servlet
context initialization parameters can be used instead of, or as well as, environment variables or
system properties.
24.4 Profile-specific Properties
In addition to application.properties files, profile-specific properties can also be defined by using
the following naming convention: application-{profile}.properties. The Environment has
a set of default profiles (by default, [default]) that are used if no active profiles are set. In other words,
if no profiles are explicitly activated, then properties from application-default.properties are
loaded.
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Profile-specific properties are loaded from the same locations as standard
application.properties, with profile-specific files always overriding the non-specific ones,
whether or not the profile-specific files are inside or outside your packaged jar.
If several profiles are specified, a last-wins strategy applies. For example, profiles specified
by the spring.profiles.active property are added after those configured through the
SpringApplication API and therefore take precedence.
Note
If you have specified any files in spring.config.location, profile-specific variants of those
files are not considered. Use directories in spring.config.location if you want to also use
profile-specific properties.
24.5 Placeholders in Properties
The values in application.properties are filtered through the existing Environment when they
are used, so you can refer back to previously defined values (for example, from System properties).
app.name=MyApp
app.description=${app.name} is a Spring Boot application
Tip
You can also use this technique to create “short” variants of existing Spring Boot properties. See
the Section 74.4, “Use ‘Short’ Command Line Arguments” how-to for details.
24.6 Using YAML Instead of Properties
YAML is a superset of JSON and, as such, is a convenient format for specifying hierarchical configuration
data. The SpringApplication class automatically supports YAML as an alternative to properties
whenever you have the SnakeYAML library on your classpath.
Note
If you use “Starters”, SnakeYAML is automatically provided by spring-boot-starter.
Loading YAML
Spring Framework provides two convenient classes that can be used to load YAML documents. The
YamlPropertiesFactoryBean loads YAML as Properties and the YamlMapFactoryBean loads
YAML as a Map.
For example, consider the following YAML document:
environments:
dev:
url: http://dev.example.com
name: Developer Setup
prod:
url: http://another.example.com
name: My Cool App
The preceding example would be transformed into the following properties:
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environments.dev.url=http://dev.example.com
environments.dev.name=Developer Setup
environments.prod.url=http://another.example.com
environments.prod.name=My Cool App
YAML lists are represented as property keys with [index] dereferencers. For example, consider the
following YAML:
my:
servers:
- dev.example.com
- another.example.com
The preceding example would be transformed into these properties:
my.servers[0]=dev.example.com
my.servers[1]=another.example.com
To bind to properties like that by using Spring Boot’s Binder utilities (which is what
@ConfigurationProperties does), you need to have a property in the target bean of type
java.util.List (or Set) and you either need to provide a setter or initialize it with a mutable value.
For example, the following example binds to the properties shown previously:
@ConfigurationProperties(prefix="my")
public class Config {
private List<String> servers = new ArrayList<String>();
public List<String> getServers() {
return this.servers;
}
}
Exposing YAML as Properties in the Spring Environment
The YamlPropertySourceLoader class can be used to expose YAML as a PropertySource in
the Spring Environment. Doing so lets you use the @Value annotation with placeholders syntax to
access YAML properties.
Multi-profile YAML Documents
You can specify multiple profile-specific YAML documents in a single file by using a spring.profiles
key to indicate when the document applies, as shown in the following example:
server:
address: 192.168.1.100
---
spring:
profiles: development
server:
address: 127.0.0.1
---
spring:
profiles: production
server:
address: 192.168.1.120
In the preceding example, if the development profile is active, the server.address property
is 127.0.0.1. Similarly, if the production profile is active, the server.address property is
192.168.1.120. If the development and production profiles are not enabled, then the value for
the property is 192.168.1.100.
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If none are explicitly active when the application context starts, the default profiles are activated. So,
in the following YAML, we set a value for spring.security.user.password that is available only
in the "default" profile:
server:
port: 8000
---
spring:
profiles: default
security:
user:
password: weak
Whereas, in the following example, the password is always set because it is not attached to any profile,
and it would have to be explicitly reset in all other profiles as necessary:
server:
port: 8000
spring:
security:
user:
password: weak
Spring profiles designated by using the spring.profiles element may optionally be negated by
using the ! character. If both negated and non-negated profiles are specified for a single document, at
least one non-negated profile must match, and no negated profiles may match.
YAML Shortcomings
YAML files cannot be loaded by using the @PropertySource annotation. So, in the case that you need
to load values that way, you need to use a properties file.
24.7 Type-safe Configuration Properties
Using the @Value("${property}") annotation to inject configuration properties can sometimes be
cumbersome, especially if you are working with multiple properties or your data is hierarchical in nature.
Spring Boot provides an alternative method of working with properties that lets strongly typed beans
govern and validate the configuration of your application, as shown in the following example:
package com.example;
import java.net.InetAddress;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import org.springframework.boot.context.properties.ConfigurationProperties;
@ConfigurationProperties("acme")
public class AcmeProperties {
private boolean enabled;
private InetAddress remoteAddress;
private final Security security = new Security();
public boolean isEnabled() { ... }
public void setEnabled(boolean enabled) { ... }
public InetAddress getRemoteAddress() { ... }
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public void setRemoteAddress(InetAddress remoteAddress) { ... }
public Security getSecurity() { ... }
public static class Security {
private String username;
private String password;
private List<String> roles = new ArrayList<>(Collections.singleton("USER"));
public String getUsername() { ... }
public void setUsername(String username) { ... }
public String getPassword() { ... }
public void setPassword(String password) { ... }
public List<String> getRoles() { ... }
public void setRoles(List<String> roles) { ... }
}
}
The preceding POJO defines the following properties:
•acme.enabled, with a value of false by default.
•acme.remote-address, with a type that can be coerced from String.
•acme.security.username, with a nested "security" object whose name is determined by the
name of the property. In particular, the return type is not used at all there and could have been
SecurityProperties.
•acme.security.password.
•acme.security.roles, with a collection of String.
Note
Getters and setters are usually mandatory, since binding is through standard Java Beans property
descriptors, just like in Spring MVC. A setter may be omitted in the following cases:
• Maps, as long as they are initialized, need a getter but not necessarily a setter, since they can
be mutated by the binder.
• Collections and arrays can be accessed either through an index (typically with YAML) or by
using a single comma-separated value (properties). In the latter case, a setter is mandatory.
We recommend to always add a setter for such types. If you initialize a collection, make sure
it is not immutable (as in the preceding example).
• If nested POJO properties are initialized (like the Security field in the preceding example), a
setter is not required. If you want the binder to create the instance on the fly by using its default
constructor, you need a setter.
Some people use Project Lombok to add getters and setters automatically. Make sure that Lombok
does not generate any particular constructor for such a type, as it is used automatically by the
container to instantiate the object.
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Finally, only standard Java Bean properties are considered and binding on static properties is
not supported.
Tip
See also the differences between @Value and @ConfigurationProperties.
You also need to list the properties classes to register in the @EnableConfigurationProperties
annotation, as shown in the following example:
@Configuration
@EnableConfigurationProperties(AcmeProperties.class)
public class MyConfiguration {
}
Note
When the @ConfigurationProperties bean is registered that way, the bean has a
conventional name: <prefix>-<fqn>, where <prefix> is the environment key prefix specified
in the @ConfigurationProperties annotation and <fqn> is the fully qualified name of the
bean. If the annotation does not provide any prefix, only the fully qualified name of the bean is
used.
The bean name in the example above is acme-com.example.AcmeProperties.
Even if the preceding configuration creates a regular bean for AcmeProperties, we recommend
that @ConfigurationProperties only deal with the environment and, in particular, does not
inject other beans from the context. Having said that, the @EnableConfigurationProperties
annotation is also automatically applied to your project so that any existing bean annotated
with @ConfigurationProperties is configured from the Environment. You could shortcut
MyConfiguration by making sure AcmeProperties is already a bean, as shown in the following
example:
@Component
@ConfigurationProperties(prefix="acme")
public class AcmeProperties {
// ... see the preceding example
}
This style of configuration works particularly well with the SpringApplication external YAML
configuration, as shown in the following example:
# application.yml
acme:
remote-address: 192.168.1.1
security:
username: admin
roles:
- USER
- ADMIN
# additional configuration as required
To work with @ConfigurationProperties beans, you can inject them in the same way as any other
bean, as shown in the following example:
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@Service
public class MyService {
private final AcmeProperties properties;
@Autowired
public MyService(AcmeProperties properties) {
this.properties = properties;
}
//...
@PostConstruct
public void openConnection() {
Server server = new Server(this.properties.getRemoteAddress());
// ...
}
}
Tip
Using @ConfigurationProperties also lets you generate metadata files that can be used by
IDEs to offer auto-completion for your own keys. See the Appendix B, Configuration Metadata
appendix for details.
Third-party Configuration
As well as using @ConfigurationProperties to annotate a class, you can also use it on public
@Bean methods. Doing so can be particularly useful when you want to bind properties to third-party
components that are outside of your control.
To configure a bean from the Environment properties, add @ConfigurationProperties to its
bean registration, as shown in the following example:
@ConfigurationProperties(prefix = "another")
@Bean
public AnotherComponent anotherComponent() {
...
}
Any property defined with the another prefix is mapped onto that AnotherComponent bean in manner
similar to the preceding AcmeProperties example.
Relaxed Binding
Spring Boot uses some relaxed rules for binding Environment properties to
@ConfigurationProperties beans, so there does not need to be an exact match between the
Environment property name and the bean property name. Common examples where this is useful
include dash-separated environment properties (for example, context-path binds to contextPath),
and capitalized environment properties (for example, PORT binds to port).
For example, consider the following @ConfigurationProperties class:
@ConfigurationProperties(prefix="acme.my-project.person")
public class OwnerProperties {
private String firstName;
public String getFirstName() {
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return this.firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
}
In the preceding example, the following properties names can all be used:
Table 24.1. relaxed binding
Property Note
acme.my-
project.person.first-
name
Kebab case, which is recommended for use in .properties and .yml files.
acme.myProject.person.firstNameStandard camel case syntax.
acme.my_project.person.first_nameUnderscore notation, which is an alternative format for use in .properties
and .yml files.
ACME_MYPROJECT_PERSON_FIRSTNAMEUpper case format, which is recommended when using system environment
variables.
Note
The prefix value for the annotation must be in kebab case (lowercase and separated by -, such
as acme.my-project.person).
Table 24.2. relaxed binding rules per property source
Property Source Simple List
Properties Files Camel case, kebab case, or
underscore notation
Standard list syntax using [ ] or
comma-separated values
YAML Files Camel case, kebab case, or
underscore notation
Standard YAML list syntax or comma-
separated values
Environment
Variables
Upper case format with underscore
as the delimiter. _ should not be used
within a property name
Numeric values surrounded
by underscores, such as
MY_ACME_1_OTHER =
my.acme[1].other
System properties Camel case, kebab case, or
underscore notation
Standard list syntax using [ ] or
comma-separated values
Tip
We recommend that, when possible, properties are stored in lower-case kebab format, such as
my.property-name=acme.
When binding to Map properties, if the key contains anything other than lowercase alpha-numeric
characters or -, you need to use the bracket notation so that the original value is preserved. If the key
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is not surrounded by [], any characters that are not alpha-numeric or - are removed. For example,
consider binding the following properties to a Map:
acme:
map:
"[/key1]": value1
"[/key2]": value2
/key3: value3
The properties above will bind to a Map with /key1, /key2 and key3 as the keys in the map.
Merging Complex Types
When lists are configured in more than one place, overriding works by replacing the entire list.
For example, assume a MyPojo object with name and description attributes that are null by default.
The following example exposes a list of MyPojo objects from AcmeProperties:
@ConfigurationProperties("acme")
public class AcmeProperties {
private final List<MyPojo> list = new ArrayList<>();
public List<MyPojo> getList() {
return this.list;
}
}
Consider the following configuration:
acme:
list:
- name: my name
description: my description
---
spring:
profiles: dev
acme:
list:
- name: my another name
If the dev profile is not active, AcmeProperties.list contains one MyPojo entry, as previously
defined. If the dev profile is enabled, however, the list still contains only one entry (with a name of
my another name and a description of null). This configuration does not add a second MyPojo
instance to the list, and it does not merge the items.
When a List is specified in multiple profiles, the one with the highest priority (and only that one) is
used. Consider the following example:
acme:
list:
- name: my name
description: my description
- name: another name
description: another description
---
spring:
profiles: dev
acme:
list:
- name: my another name
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In the preceding example, if the dev profile is active, AcmeProperties.list contains one MyPojo
entry (with a name of my another name and a description of null). For YAML, both comma-separated
lists and YAML lists can be used for completely overriding the contents of the list.
For Map properties, you can bind with property values drawn from multiple sources. However, for the
same property in multiple sources, the one with the highest priority is used. The following example
exposes a Map<String, MyPojo> from AcmeProperties:
@ConfigurationProperties("acme")
public class AcmeProperties {
private final Map<String, MyPojo> map = new HashMap<>();
public Map<String, MyPojo> getMap() {
return this.map;
}
}
Consider the following configuration:
acme:
map:
key1:
name: my name 1
description: my description 1
---
spring:
profiles: dev
acme:
map:
key1:
name: dev name 1
key2:
name: dev name 2
description: dev description 2
If the dev profile is not active, AcmeProperties.map contains one entry with key key1 (with a name
of my name 1 and a description of my description 1). If the dev profile is enabled, however, map
contains two entries with keys key1 (with a name of dev name 1 and a description of my description
1) and key2 (with a name of dev name 2 and a description of dev description 2).
Note
The preceding merging rules apply to properties from all property sources and not just YAML files.
Properties Conversion
Spring Boot attempts to coerce the external application properties to the right type when it binds
to the @ConfigurationProperties beans. If you need custom type conversion, you can provide
a ConversionService bean (with a bean named conversionService) or custom property
editors (through a CustomEditorConfigurer bean) or custom Converters (with bean definitions
annotated as @ConfigurationPropertiesBinding).
Note
As this bean is requested very early during the application lifecycle, make sure to limit the
dependencies that your ConversionService is using. Typically, any dependency that you
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require may not be fully initialized at creation time. You may want to rename your custom
ConversionService if it is not required for configuration keys coercion and only rely on custom
converters qualified with @ConfigurationPropertiesBinding.
Converting durations
Spring Boot has dedicated support for expressing durations. If you expose a java.time.Duration
property, the following formats in application properties are available:
• A regular long representation (using milliseconds as the default unit unless a @DurationUnit has
been specified)
• The standard ISO-8601 format used by java.util.Duration
• A more readable format where the value and the unit are coupled (e.g. 10s means 10 seconds)
Consider the following example:
@ConfigurationProperties("app.system")
public class AppSystemProperties {
@DurationUnit(ChronoUnit.SECONDS)
private Duration sessionTimeout = Duration.ofSeconds(30);
private Duration readTimeout = Duration.ofMillis(1000);
public Duration getSessionTimeout() {
return this.sessionTimeout;
}
public void setSessionTimeout(Duration sessionTimeout) {
this.sessionTimeout = sessionTimeout;
}
public Duration getReadTimeout() {
return this.readTimeout;
}
public void setReadTimeout(Duration readTimeout) {
this.readTimeout = readTimeout;
}
}
To specify a session timeout of 30 seconds, 30, PT30S and 30s are all equivalent. A read timeout of
500ms can be specified in any of the following form: 500, PT0.5S and 500ms.
You can also use any of the supported unit. These are:
•ns for nanoseconds
•us for microseconds
•ms for milliseconds
•s for seconds
•m for minutes
•h for hours
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•d for days
The default unit is milliseconds and can be overridden using @DurationUnit as illustrated in the
sample above.
Tip
If you are upgrading from a previous version that is simply using Long to express the duration,
make sure to define the unit (using @DurationUnit) if it isn’t milliseconds alongside the switch
to Duration. Doing so gives a transparent upgrade path while supporting a much richer format.
@ConfigurationProperties Validation
Spring Boot attempts to validate @ConfigurationProperties classes whenever they are annotated
with Spring’s @Validated annotation. You can use JSR-303 javax.validation constraint
annotations directly on your configuration class. To do so, ensure that a compliant JSR-303
implementation is on your classpath and then add constraint annotations to your fields, as shown in
the following example:
@ConfigurationProperties(prefix="acme")
@Validated
public class AcmeProperties {
@NotNull
private InetAddress remoteAddress;
// ... getters and setters
}
Tip
You can also trigger validation by annotating the @Bean method that creates the configuration
properties with @Validated.
Although nested properties will also be validated when bound, it’s good practice to also annotate the
associated field as @Valid. This ensure that validation is triggered even if no nested properties are
found. The following example builds on the preceding AcmeProperties example:
@ConfigurationProperties(prefix="acme")
@Validated
public class AcmeProperties {
@NotNull
private InetAddress remoteAddress;
@Valid
private final Security security = new Security();
// ... getters and setters
public static class Security {
@NotEmpty
public String username;
// ... getters and setters
}
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}
You can also add a custom Spring Validator by creating a bean definition called
configurationPropertiesValidator. The @Bean method should be declared static. The
configuration properties validator is created very early in the application’s lifecycle, and declaring the
@Bean method as static lets the bean be created without having to instantiate the @Configuration
class. Doing so avoids any problems that may be caused by early instantiation. There is a property
validation sample that shows how to set things up.
Tip
The spring-boot-actuator module includes an endpoint that exposes all
@ConfigurationProperties beans. Point your web browser to /actuator/configprops
or use the equivalent JMX endpoint. See the "Production ready features" section for details.
@ConfigurationProperties vs. @Value
The @Value annotation is a core container feature, and it does not provide the same features as
type-safe configuration properties. The following table summarizes the features that are supported by
@ConfigurationProperties and @Value:
Feature @ConfigurationProperties@Value
Relaxed binding Yes No
Meta-data support Yes No
SpEL evaluation No Yes
If you define a set of configuration keys for your own components, we recommend you group them in a
POJO annotated with @ConfigurationProperties. You should also be aware that, since @Value
does not support relaxed binding, it is not a good candidate if you need to provide the value by using
environment variables.
Finally, while you can write a SpEL expression in @Value, such expressions are not processed from
application property files.
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25. Profiles
Spring Profiles provide a way to segregate parts of your application configuration and make it be
available only in certain environments. Any @Component or @Configuration can be marked with
@Profile to limit when it is loaded, as shown in the following example:
@Configuration
@Profile("production")
public class ProductionConfiguration {
// ...
}
You can use a spring.profiles.active Environment property to specify which profiles are
active. You can specify the property in any of the ways described earlier in this chapter. For example,
you could include it in your application.properties, as shown in the following example:
spring.profiles.active=dev,hsqldb
You could also specify it on the command line by using the following switch: --
spring.profiles.active=dev,hsqldb.
25.1 Adding Active Profiles
The spring.profiles.active property follows the same ordering rules as other properties:
The highest PropertySource wins. This means that you can specify active profiles in
application.properties and then replace them by using the command line switch.
Sometimes, it is useful to have profile-specific properties that add to the active profiles rather
than replace them. The spring.profiles.include property can be used to unconditionally add
active profiles. The SpringApplication entry point also has a Java API for setting additional
profiles (that is, on top of those activated by the spring.profiles.active property). See the
setAdditionalProfiles() method in SpringApplication.
For example, when an application with the following properties is run by using the switch, --
spring.profiles.active=prod, the proddb and prodmq profiles are also activated:
---
my.property: fromyamlfile
---
spring.profiles: prod
spring.profiles.include:
- proddb
- prodmq
Note
Remember that the spring.profiles property can be defined in a YAML document to
determine when this particular document is included in the configuration. See Section 74.7,
“Change Configuration Depending on the Environment” for more details.
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25.2 Programmatically Setting Profiles
You can programmatically set active profiles by calling
SpringApplication.setAdditionalProfiles(…) before your application runs. It is also
possible to activate profiles by using Spring’s ConfigurableEnvironment interface.
25.3 Profile-specific Configuration Files
Profile-specific variants of both application.properties (or application.yml) and files
referenced through @ConfigurationProperties are considered as files and loaded. See
"Section 24.4, “Profile-specific Properties”" for details.
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26. Logging
Spring Boot uses Commons Logging for all internal logging but leaves the underlying log implementation
open. Default configurations are provided for Java Util Logging, Log4J2, and Logback. In each case,
loggers are pre-configured to use console output with optional file output also available.
By default, if you use the “Starters”, Logback is used for logging. Appropriate Logback routing is also
included to ensure that dependent libraries that use Java Util Logging, Commons Logging, Log4J, or
SLF4J all work correctly.
Tip
There are a lot of logging frameworks available for Java. Do not worry if the above list seems
confusing. Generally, you do not need to change your logging dependencies and the Spring Boot
defaults work just fine.
26.1 Log Format
The default log output from Spring Boot resembles the following example:
2014-03-05 10:57:51.112 INFO 45469 --- [ main] org.apache.catalina.core.StandardEngine :
Starting Servlet Engine: Apache Tomcat/7.0.52
2014-03-05 10:57:51.253 INFO 45469 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] :
Initializing Spring embedded WebApplicationContext
2014-03-05 10:57:51.253 INFO 45469 --- [ost-startStop-1] o.s.web.context.ContextLoader :
Root WebApplicationContext: initialization completed in 1358 ms
2014-03-05 10:57:51.698 INFO 45469 --- [ost-startStop-1] o.s.b.c.e.ServletRegistrationBean :
Mapping servlet: 'dispatcherServlet' to [/]
2014-03-05 10:57:51.702 INFO 45469 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean :
Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
The following items are output:
• Date and Time: Millisecond precision and easily sortable.
• Log Level: ERROR, WARN, INFO, DEBUG, or TRACE.
• Process ID.
• A --- separator to distinguish the start of actual log messages.
• Thread name: Enclosed in square brackets (may be truncated for console output).
• Logger name: This is usually the source class name (often abbreviated).
• The log message.
Note
Logback does not have a FATAL level. It is mapped to ERROR.
26.2 Console Output
The default log configuration echoes messages to the console as they are written. By default, ERROR-
level, WARN-level, and INFO-level messages are logged. You can also enable a “debug” mode by starting
your application with a --debug flag.
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$ java -jar myapp.jar --debug
Note
You can also specify debug=true in your application.properties.
When the debug mode is enabled, a selection of core loggers (embedded container, Hibernate, and
Spring Boot) are configured to output more information. Enabling the debug mode does not configure
your application to log all messages with DEBUG level.
Alternatively, you can enable a “trace” mode by starting your application with a --trace flag (or
trace=true in your application.properties). Doing so enables trace logging for a selection of
core loggers (embedded container, Hibernate schema generation, and the whole Spring portfolio).
Color-coded Output
If your terminal supports ANSI, color output is used to aid readability. You can set
spring.output.ansi.enabled to a supported value to override the auto detection.
Color coding is configured by using the %clr conversion word. In its simplest form, the converter colors
the output according to the log level, as shown in the following example:
%clr(%5p)
The following table describes the mapping of log levels to colors:
Level Color
FATAL Red
ERROR Red
WARN Yellow
INFO Green
DEBUG Green
TRACE Green
Alternatively, you can specify the color or style that should be used by providing it as an option to the
conversion. For example, to make the text yellow, use the following setting:
%clr(%d{yyyy-MM-dd HH:mm:ss.SSS}){yellow}
The following colors and styles are supported:
•blue
•cyan
•faint
•green
•magenta
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•red
•yellow
26.3 File Output
By default, Spring Boot logs only to the console and does not write log files. If you want to write log files
in addition to the console output, you need to set a logging.file or logging.path property (for
example, in your application.properties).
The following table shows how the logging.* properties can be used together:
Table 26.1. Logging properties
logging.filelogging.pathExample Description
(none) (none) Console only logging.
Specific file (none) my.log Writes to the specified log file. Names can be an exact
location or relative to the current directory.
(none) Specific
directory
/var/log Writes spring.log to the specified directory. Names
can be an exact location or relative to the current
directory.
Log files rotate when they reach 10 MB and, as with console output, ERROR-level, WARN-level, and INFO-
level messages are logged by default. Size limits can be changed using the logging.file.max-size
property. Previously rotated files are archived indefinitely unless the logging.file.max-history
property has been set.
Note
The logging system is initialized early in the application lifecycle. Consequently, logging properties
are not found in property files loaded through @PropertySource annotations.
Tip
Logging properties are independent of the actual logging infrastructure. As a result, specific
configuration keys (such as logback.configurationFile for Logback) are not managed by
spring Boot.
26.4 Log Levels
All the supported logging systems can have the logger levels set in the Spring Environment (for
example, in application.properties) by using logging.level.<logger-name>=<level>
where level is one of TRACE, DEBUG, INFO, WARN, ERROR, FATAL, or OFF. The root logger can
be configured by using logging.level.root.
The following example shows potential logging settings in application.properties:
logging.level.root=WARN
logging.level.org.springframework.web=DEBUG
logging.level.org.hibernate=ERROR
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26.5 Custom Log Configuration
The various logging systems can be activated by including the appropriate libraries on the classpath
and can be further customized by providing a suitable configuration file in the root of the classpath or in
a location specified by the following Spring Environment property: logging.config.
You can force Spring Boot to use a particular logging system by using the
org.springframework.boot.logging.LoggingSystem system property. The value should be
the fully qualified class name of a LoggingSystem implementation. You can also disable Spring Boot’s
logging configuration entirely by using a value of none.
Note
Since logging is initialized before the ApplicationContext is created, it is not possible to
control logging from @PropertySources in Spring @Configuration files. The only way to
change the logging system or disable it entirely is via System properties.
Depending on your logging system, the following files are loaded:
Logging System Customization
Logback logback-spring.xml, logback-
spring.groovy, logback.xml, or
logback.groovy
Log4j2 log4j2-spring.xml or log4j2.xml
JDK (Java Util Logging) logging.properties
Note
When possible, we recommend that you use the -spring variants for your logging configuration
(for example, logback-spring.xml rather than logback.xml). If you use standard
configuration locations, Spring cannot completely control log initialization.
Warning
There are known classloading issues with Java Util Logging that cause problems when running
from an 'executable jar'. We recommend that you avoid it when running from an 'executable jar'
if at all possible.
To help with the customization, some other properties are transferred from the Spring Environment
to System properties, as described in the following table:
Spring Environment System Property Comments
logging.exception-
conversion-word
LOG_EXCEPTION_CONVERSION_WORDThe conversion word used
when logging exceptions.
logging.file LOG_FILE If defined, it is used in the
default log configuration.
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Spring Environment System Property Comments
logging.file.max-size LOG_FILE_MAX_SIZE Maximum log file size (if
LOG_FILE enabled). (Only
supported with the default
Logback setup.)
logging.file.max-
history
LOG_FILE_MAX_HISTORY Maximum number of archive
log files to keep (if LOG_FILE
enabled). (Only supported with
the default Logback setup.)
logging.path LOG_PATH If defined, it is used in the
default log configuration.
logging.pattern.console CONSOLE_LOG_PATTERN The log pattern to use on
the console (stdout). (Only
supported with the default
Logback setup.)
logging.pattern.dateformatLOG_DATEFORMAT_PATTERN Appender pattern for log date
format. (Only supported with the
default Logback setup.)
logging.pattern.file FILE_LOG_PATTERN The log pattern to use in a
file (if LOG_FILE is enabled).
(Only supported with the default
Logback setup.)
logging.pattern.level LOG_LEVEL_PATTERN The format to use when
rendering the log level (default
%5p). (Only supported with the
default Logback setup.)
PID PID The current process ID
(discovered if possible and
when not already defined as an
OS environment variable).
All the supported logging systems can consult System properties when parsing their configuration files.
See the default configurations in spring-boot.jar for examples:
•Logback
•Log4j 2
•Java Util logging
Tip
If you want to use a placeholder in a logging property, you should use Spring Boot’s syntax and
not the syntax of the underlying framework. Notably, if you use Logback, you should use : as the
delimiter between a property name and its default value and not use :-.
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Tip
You can add MDC and other ad-hoc content to log lines by overriding only the
LOG_LEVEL_PATTERN (or logging.pattern.level with Logback). For example, if you use
logging.pattern.level=user:%X{user} %5p, then the default log format contains an
MDC entry for "user", if it exists, as shown in the following example.
2015-09-30 12:30:04.031 user:someone INFO 22174 --- [ nio-8080-exec-0] demo.Controller
Handling authenticated request
26.6 Logback Extensions
Spring Boot includes a number of extensions to Logback that can help with advanced configuration.
You can use these extensions in your logback-spring.xml configuration file.
Note
Because the standard logback.xml configuration file is loaded too early, you cannot use
extensions in it. You need to either use logback-spring.xml or define a logging.config
property.
Warning
The extensions cannot be used with Logback’s configuration scanning. If you attempt to do so,
making changes to the configuration file results in an error similar to one of the following being
logged:
ERROR in ch.qos.logback.core.joran.spi.Interpreter@4:71 - no applicable action for [springProperty],
current ElementPath is [[configuration][springProperty]]
ERROR in ch.qos.logback.core.joran.spi.Interpreter@4:71 - no applicable action for [springProfile],
current ElementPath is [[configuration][springProfile]]
Profile-specific Configuration
The <springProfile> tag lets you optionally include or exclude sections of configuration based
on the active Spring profiles. Profile sections are supported anywhere within the <configuration>
element. Use the name attribute to specify which profile accepts the configuration. Multiple profiles can
be specified with a comma-separated list. The following listing shows three sample profiles:
<springProfile name="staging">
<!-- configuration to be enabled when the "staging" profile is active -->
</springProfile>
<springProfile name="dev, staging">
<!-- configuration to be enabled when the "dev" or "staging" profiles are active -->
</springProfile>
<springProfile name="!production">
<!-- configuration to be enabled when the "production" profile is not active -->
</springProfile>
Environment Properties
The <springProperty> tag lets you expose properties from the Spring Environment for use within
Logback. Doing so can be useful if you want to access values from your application.properties
file in your Logback configuration. The tag works in a similar way to Logback’s standard <property>
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tag. However, rather than specifying a direct value, you specify the source of the property (from the
Environment). If you need to store the property somewhere other than in local scope, you can use
the scope attribute. If you need a fallback value (in case the property is not set in the Environment),
you can use the defaultValue attribute. The following example shows how to expose properties for
use within Logback:
<springProperty scope="context" name="fluentHost" source="myapp.fluentd.host"
defaultValue="localhost"/>
<appender name="FLUENT" class="ch.qos.logback.more.appenders.DataFluentAppender">
<remoteHost>${fluentHost}</remoteHost>
...
</appender>
Note
The source must be specified in kebab case (such as my.property-name). However,
properties can be added to the Environment by using the relaxed rules.
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27. Developing Web Applications
Spring Boot is well suited for web application development. You can create a self-contained HTTP
server by using embedded Tomcat, Jetty, Undertow, or Netty. Most web applications use the spring-
boot-starter-web module to get up and running quickly. You can also choose to build reactive web
applications by using the spring-boot-starter-webflux module.
If you have not yet developed a Spring Boot web application, you can follow the "Hello World!" example
in the Getting started section.
27.1 The “Spring Web MVC Framework”
The Spring Web MVC framework (often referred to as simply “Spring MVC”) is a rich “model view
controller” web framework. Spring MVC lets you create special @Controller or @RestController
beans to handle incoming HTTP requests. Methods in your controller are mapped to HTTP by using
@RequestMapping annotations.
The following code shows a typical @RestController that serves JSON data:
@RestController
@RequestMapping(value="/users")
public class MyRestController {
@RequestMapping(value="/{user}", method=RequestMethod.GET)
public User getUser(@PathVariable Long user) {
// ...
}
@RequestMapping(value="/{user}/customers", method=RequestMethod.GET)
List<Customer> getUserCustomers(@PathVariable Long user) {
// ...
}
@RequestMapping(value="/{user}", method=RequestMethod.DELETE)
public User deleteUser(@PathVariable Long user) {
// ...
}
}
Spring MVC is part of the core Spring Framework, and detailed information is available in the reference
documentation. There are also several guides that cover Spring MVC available at spring.io/guides.
Spring MVC Auto-configuration
Spring Boot provides auto-configuration for Spring MVC that works well with most applications.
The auto-configuration adds the following features on top of Spring’s defaults:
• Inclusion of ContentNegotiatingViewResolver and BeanNameViewResolver beans.
• Support for serving static resources, including support for WebJars (covered later in this document)).
• Automatic registration of Converter, GenericConverter, and Formatter beans.
• Support for HttpMessageConverters (covered later in this document).
• Automatic registration of MessageCodesResolver (covered later in this document).
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• Static index.html support.
• Custom Favicon support (covered later in this document).
• Automatic use of a ConfigurableWebBindingInitializer bean (covered later in this
document).
If you want to keep Spring Boot MVC features and you want to add additional MVC configuration
(interceptors, formatters, view controllers, and other features), you can add your own @Configuration
class of type WebMvcConfigurer but without @EnableWebMvc. If you wish to provide
custom instances of RequestMappingHandlerMapping, RequestMappingHandlerAdapter, or
ExceptionHandlerExceptionResolver, you can declare a WebMvcRegistrationsAdapter
instance to provide such components.
If you want to take complete control of Spring MVC, you can add your own @Configuration annotated
with @EnableWebMvc.
HttpMessageConverters
Spring MVC uses the HttpMessageConverter interface to convert HTTP requests and responses.
Sensible defaults are included out of the box. For example, objects can be automatically converted to
JSON (by using the Jackson library) or XML (by using the Jackson XML extension, if available, or by
using JAXB if the Jackson XML extension is not available). By default, strings are encoded in UTF-8.
If you need to add or customize converters, you can use Spring Boot’s HttpMessageConverters
class, as shown in the following listing:
import org.springframework.boot.autoconfigure.web.HttpMessageConverters;
import org.springframework.context.annotation.*;
import org.springframework.http.converter.*;
@Configuration
public class MyConfiguration {
@Bean
public HttpMessageConverters customConverters() {
HttpMessageConverter<?> additional = ...
HttpMessageConverter<?> another = ...
return new HttpMessageConverters(additional, another);
}
}
Any HttpMessageConverter bean that is present in the context is added to the list of converters.
You can also override default converters in the same way.
Custom JSON Serializers and Deserializers
If you use Jackson to serialize and deserialize JSON data, you might want to write your own
JsonSerializer and JsonDeserializer classes. Custom serializers are usually registered with
Jackson through a module, but Spring Boot provides an alternative @JsonComponent annotation that
makes it easier to directly register Spring Beans.
You can use the @JsonComponent annotation directly on JsonSerializer or JsonDeserializer
implementations. You can also use it on classes that contain serializers/deserializers as inner classes,
as shown in the following example:
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import java.io.*;
import com.fasterxml.jackson.core.*;
import com.fasterxml.jackson.databind.*;
import org.springframework.boot.jackson.*;
@JsonComponent
public class Example {
public static class Serializer extends JsonSerializer<SomeObject> {
// ...
}
public static class Deserializer extends JsonDeserializer<SomeObject> {
// ...
}
}
All @JsonComponent beans in the ApplicationContext are automatically registered with Jackson.
Because @JsonComponent is meta-annotated with @Component, the usual component-scanning rules
apply.
Spring Boot also provides JsonObjectSerializer and JsonObjectDeserializer base classes
that provide useful alternatives to the standard Jackson versions when serializing objects. See
JsonObjectSerializer and JsonObjectDeserializer in the Javadoc for details.
MessageCodesResolver
Spring MVC has a strategy for generating error codes for rendering error messages from binding errors:
MessageCodesResolver. If you set the spring.mvc.message-codes-resolver.format
property PREFIX_ERROR_CODE or POSTFIX_ERROR_CODE, Spring Boot creates one for you (see the
enumeration in DefaultMessageCodesResolver.Format).
Static Content
By default, Spring Boot serves static content from a directory called /static (or /public or /
resources or /META-INF/resources) in the classpath or from the root of the ServletContext.
It uses the ResourceHttpRequestHandler from Spring MVC so that you can modify that behavior
by adding your own WebMvcConfigurer and overriding the addResourceHandlers method.
In a stand-alone web application, the default servlet from the container is also enabled and acts as a
fallback, serving content from the root of the ServletContext if Spring decides not to handle it. Most
of the time, this does not happen (unless you modify the default MVC configuration), because Spring
can always handle requests through the DispatcherServlet.
By default, resources are mapped on /**, but you can tune that with the spring.mvc.static-
path-pattern property. For instance, relocating all resources to /resources/** can be achieved
as follows:
spring.mvc.static-path-pattern=/resources/**
You can also customize the static resource locations by using the spring.resources.static-
locations property (replacing the default values with a list of directory locations). The root Servlet
context path, "/", is automatically added as a location as well.
In addition to the “standard” static resource locations mentioned earlier, a special case is made for
Webjars content. Any resources with a path in /webjars/** are served from jar files if they are
packaged in the Webjars format.
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Tip
Do not use the src/main/webapp directory if your application is packaged as a jar. Although
this directory is a common standard, it works only with war packaging, and it is silently ignored
by most build tools if you generate a jar.
Spring Boot also supports the advanced resource handling features provided by Spring MVC, allowing
use cases such as cache-busting static resources or using version agnostic URLs for Webjars.
To use version agnostic URLs for Webjars, add the webjars-locator-core dependency. Then
declare your Webjar. Using jQuery as an example, adding "/webjars/jquery/jquery.min.js"
results in "/webjars/jquery/x.y.z/jquery.min.js". where x.y.z is the Webjar version.
Note
If you use JBoss, you need to declare the webjars-locator-jboss-vfs dependency instead
of the webjars-locator-core. Otherwise, all Webjars resolve as a 404.
To use cache busting, the following configuration configures a cache busting solution for
all static resources, effectively adding a content hash, such as <link href="/css/
spring-2a2d595e6ed9a0b24f027f2b63b134d6.css"/>, in URLs:
spring.resources.chain.strategy.content.enabled=true
spring.resources.chain.strategy.content.paths=/**
Note
Links to resources are rewritten in templates at runtime, thanks to a
ResourceUrlEncodingFilter that is auto-configured for Thymeleaf and FreeMarker. You
should manually declare this filter when using JSPs. Other template engines are currently not
automatically supported but can be with custom template macros/helpers and the use of the
ResourceUrlProvider.
When loading resources dynamically with, for example, a JavaScript module loader, renaming files is not
an option. That is why other strategies are also supported and can be combined. A "fixed" strategy adds
a static version string in the URL without changing the file name, as shown in the following example:
spring.resources.chain.strategy.content.enabled=true
spring.resources.chain.strategy.content.paths=/**
spring.resources.chain.strategy.fixed.enabled=true
spring.resources.chain.strategy.fixed.paths=/js/lib/
spring.resources.chain.strategy.fixed.version=v12
With this configuration, JavaScript modules located under "/js/lib/" use a fixed versioning strategy
("/v12/js/lib/mymodule.js"), while other resources still use the content one (<link href="/
css/spring-2a2d595e6ed9a0b24f027f2b63b134d6.css"/>).
See ResourceProperties for more supported options.
Tip
This feature has been thoroughly described in a dedicated blog post and in Spring Framework’s
reference documentation.
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Welcome Page
Spring Boot supports both static and templated welcome pages. It first looks for an index.html file in
the configured static content locations. If one is not found, it then looks for an index template. If either
is found, it is automatically used as the welcome page of the application.
Custom Favicon
Spring Boot looks for a favicon.ico in the configured static content locations and the root of the
classpath (in that order). If such a file is present, it is automatically used as the favicon of the application.
Path Matching and Content Negotiation
Spring MVC can map incoming HTTP requests to handlers by looking at the request path and matching
it to the mappings defined in your application (for example, @GetMapping annotations on Controller
methods).
Spring Boot chooses to disable suffix pattern matching by default, which means that requests
like "GET /projects/spring-boot.json" won’t be matched to @GetMapping("/projects/
spring-boot") mappings. This is considered as a best practice for Spring MVC applications. This
feature was mainly useful in the past for HTTP clients which did not send proper "Accept" request
headers; we needed to make sure to send the correct Content Type to the client. Nowadays, Content
Negotiation is much more reliable.
There are other ways to deal with HTTP clients that don’t consistently send proper "Accept" request
headers. Instead of using suffix matching, we can use a query parameter to ensure that requests like
"GET /projects/spring-boot?format=json" will be mapped to @GetMapping("/projects/
spring-boot"):
spring.mvc.contentnegotiation.favor-parameter=true
# We can change the parameter name, which is "format" by default:
# spring.mvc.contentnegotiation.parameter-name=myparam
# We can also register additional file extensions/media types with:
spring.mvc.contentnegotiation.media-types.markdown=text/markdown
If you understand the caveats and would still like your application to use suffix pattern matching, the
following configuration is required:
spring.mvc.contentnegotiation.favor-path-extension=true
# You can also restrict that feature to known extensions only
# spring.mvc.pathmatch.use-registered-suffix-pattern=true
# We can also register additional file extensions/media types with:
# spring.mvc.contentnegotiation.media-types.adoc=text/asciidoc
ConfigurableWebBindingInitializer
Spring MVC uses a WebBindingInitializer to initialize a WebDataBinder for a particular request.
If you create your own ConfigurableWebBindingInitializer @Bean, Spring Boot automatically
configures Spring MVC to use it.
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Template Engines
As well as REST web services, you can also use Spring MVC to serve dynamic HTML content. Spring
MVC supports a variety of templating technologies, including Thymeleaf, FreeMarker, and JSPs. Also,
many other templating engines include their own Spring MVC integrations.
Spring Boot includes auto-configuration support for the following templating engines:
•FreeMarker
•Groovy
•Thymeleaf
•Mustache
Tip
If possible, JSPs should be avoided. There are several known limitations when using them with
embedded servlet containers.
When you use one of these templating engines with the default configuration, your templates are picked
up automatically from src/main/resources/templates.
Tip
Depending on how you run your application, IntelliJ IDEA orders the classpath differently. Running
your application in the IDE from its main method results in a different ordering than when you
run your application by using Maven or Gradle or from its packaged jar. This can cause Spring
Boot to fail to find the templates on the classpath. If you have this problem, you can reorder the
classpath in the IDE to place the module’s classes and resources first. Alternatively, you can
configure the template prefix to search every templates directory on the classpath, as follows:
classpath*:/templates/.
Error Handling
By default, Spring Boot provides an /error mapping that handles all errors in a sensible way, and
it is registered as a “global” error page in the servlet container. For machine clients, it produces a
JSON response with details of the error, the HTTP status, and the exception message. For browser
clients, there is a “whitelabel” error view that renders the same data in HTML format (to customize it,
add a View that resolves to error). To replace the default behavior completely, you can implement
ErrorController and register a bean definition of that type or add a bean of type ErrorAttributes
to use the existing mechanism but replace the contents.
Tip
The BasicErrorController can be used as a base class for a custom ErrorController.
This is particularly useful if you want to add a handler for a new content type (the default
is to handle text/html specifically and provide a fallback for everything else). To do so,
extend BasicErrorController, add a public method with a @RequestMapping that has a
produces attribute, and create a bean of your new type.
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You can also define a class annotated with @ControllerAdvice to customize the JSON document
to return for a particular controller and/or exception type, as shown in the following example:
@ControllerAdvice(basePackageClasses = AcmeController.class)
public class AcmeControllerAdvice extends ResponseEntityExceptionHandler {
@ExceptionHandler(YourException.class)
@ResponseBody
ResponseEntity<?> handleControllerException(HttpServletRequest request, Throwable ex) {
HttpStatus status = getStatus(request);
return new ResponseEntity<>(new CustomErrorType(status.value(), ex.getMessage()), status);
}
private HttpStatus getStatus(HttpServletRequest request) {
Integer statusCode = (Integer) request.getAttribute("javax.servlet.error.status_code");
if (statusCode == null) {
return HttpStatus.INTERNAL_SERVER_ERROR;
}
return HttpStatus.valueOf(statusCode);
}
}
In the preceding example, if YourException is thrown by a controller defined in the same package
as AcmeController, a JSON representation of the CustomErrorType POJO is used instead of the
ErrorAttributes representation.
Custom Error Pages
If you want to display a custom HTML error page for a given status code, you can add a file to an /error
folder. Error pages can either be static HTML (that is, added under any of the static resource folders)
or be built by using templates. The name of the file should be the exact status code or a series mask.
For example, to map 404 to a static HTML file, your folder structure would be as follows:
src/
+- main/
+- java/
| + <source code>
+- resources/
+- public/
+- error/
| +- 404.html
+- <other public assets>
To map all 5xx errors by using a FreeMarker template, your folder structure would be as follows:
src/
+- main/
+- java/
| + <source code>
+- resources/
+- templates/
+- error/
| +- 5xx.ftl
+- <other templates>
For more complex mappings, you can also add beans that implement the ErrorViewResolver
interface, as shown in the following example:
public class MyErrorViewResolver implements ErrorViewResolver {
@Override
public ModelAndView resolveErrorView(HttpServletRequest request,
HttpStatus status, Map<String, Object> model) {
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// Use the request or status to optionally return a ModelAndView
return ...
}
}
You can also use regular Spring MVC features such as @ExceptionHandler methods and
@ControllerAdvice. The ErrorController then picks up any unhandled exceptions.
Mapping Error Pages outside of Spring MVC
For applications that do not use Spring MVC, you can use the ErrorPageRegistrar interface to
directly register ErrorPages. This abstraction works directly with the underlying embedded servlet
container and works even if you do not have a Spring MVC DispatcherServlet.
@Bean
public ErrorPageRegistrar errorPageRegistrar(){
return new MyErrorPageRegistrar();
}
// ...
private static class MyErrorPageRegistrar implements ErrorPageRegistrar {
@Override
public void registerErrorPages(ErrorPageRegistry registry) {
registry.addErrorPages(new ErrorPage(HttpStatus.BAD_REQUEST, "/400"));
}
}
Note
If you register an ErrorPage with a path that ends up being handled by a Filter (as is common
with some non-Spring web frameworks, like Jersey and Wicket), then the Filter has to be
explicitly registered as an ERROR dispatcher, as shown in the following example:
@Bean
public FilterRegistrationBean myFilter() {
FilterRegistrationBean registration = new FilterRegistrationBean();
registration.setFilter(new MyFilter());
...
registration.setDispatcherTypes(EnumSet.allOf(DispatcherType.class));
return registration;
}
Note that the default FilterRegistrationBean does not include the ERROR dispatcher type.
CAUTION:When deployed to a servlet container, Spring Boot uses its error page filter to
forward a request with an error status to the appropriate error page. The request can only
be forwarded to the correct error page if the response has not already been committed. By
default, WebSphere Application Server 8.0 and later commits the response upon successful
completion of a servlet’s service method. You should disable this behavior by setting
com.ibm.ws.webcontainer.invokeFlushAfterService to false.
Spring HATEOAS
If you develop a RESTful API that makes use of hypermedia, Spring Boot provides auto-configuration
for Spring HATEOAS that works well with most applications. The auto-configuration replaces the
need to use @EnableHypermediaSupport and registers a number of beans to ease building
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hypermedia-based applications, including a LinkDiscoverers (for client side support) and an
ObjectMapper configured to correctly marshal responses into the desired representation. The
ObjectMapper is customized by setting the various spring.jackson.* properties or, if one exists,
by a Jackson2ObjectMapperBuilder bean.
You can take control of Spring HATEOAS’s configuration by using @EnableHypermediaSupport.
Note that doing so disables the ObjectMapper customization described earlier.
CORS Support
Cross-origin resource sharing (CORS) is a W3C specification implemented by most browsers that lets
you specify in a flexible way what kind of cross-domain requests are authorized, instead of using some
less secure and less powerful approaches such as IFRAME or JSONP.
As of version 4.2, Spring MVC supports CORS. Using controller method CORS configuration with
@CrossOrigin annotations in your Spring Boot application does not require any specific configuration.
Global CORS configuration can be defined by registering a WebMvcConfigurer bean with a
customized addCorsMappings(CorsRegistry) method, as shown in the following example:
@Configuration
public class MyConfiguration {
@Bean
public WebMvcConfigurer corsConfigurer() {
return new WebMvcConfigurer() {
@Override
public void addCorsMappings(CorsRegistry registry) {
registry.addMapping("/api/**");
}
};
}
}
27.2 The “Spring WebFlux Framework”
Spring WebFlux is the new reactive web framework introduced in Spring Framework 5.0. Unlike Spring
MVC, it does not require the Servlet API, is fully asynchronous and non-blocking, and implements the
Reactive Streams specification through the Reactor project.
Spring WebFlux comes in two flavors: functional and annotation-based. The annotation-based one is
quite close to the Spring MVC model, as shown in the following example:
@RestController
@RequestMapping("/users")
public class MyRestController {
@GetMapping("/{user}")
public Mono<User> getUser(@PathVariable Long user) {
// ...
}
@GetMapping("/{user}/customers")
public Flux<Customer> getUserCustomers(@PathVariable Long user) {
// ...
}
@DeleteMapping("/{user}")
public Mono<User> deleteUser(@PathVariable Long user) {
// ...
}
}
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“WebFlux.fn”, the functional variant, separates the routing configuration from the actual handling of the
requests, as shown in the following example:
@Configuration
public class RoutingConfiguration {
@Bean
public RouterFunction<ServerResponse> monoRouterFunction(UserHandler userHandler) {
return route(GET("/{user}").and(accept(APPLICATION_JSON)), userHandler::getUser)
.andRoute(GET("/{user}/customers").and(accept(APPLICATION_JSON)), userHandler::getUserCustomers)
.andRoute(DELETE("/{user}").and(accept(APPLICATION_JSON)), userHandler::deleteUser);
}
}
@Component
public class UserHandler {
public Mono<ServerResponse> getUser(ServerRequest request) {
// ...
}
public Mono<ServerResponse> getUserCustomers(ServerRequest request) {
// ...
}
public Mono<ServerResponse> deleteUser(ServerRequest request) {
// ...
}
}
WebFlux is part of the Spring Framework and detailed information is available in its reference
documentation.
Tip
You can define as many RouterFunction beans as you like to modularize the definition of the
router. Beans can be ordered if you need to apply a precedence.
To get started, add the spring-boot-starter-webflux module to your application.
Note
Adding both spring-boot-starter-web and spring-boot-starter-webflux modules
in your application results in Spring Boot auto-configuring Spring MVC, not WebFlux.
This behavior has been chosen because many Spring developers add spring-boot-
starter-webflux to their Spring MVC application to use the reactive WebClient.
You can still enforce your choice by setting the chosen application type to
SpringApplication.setWebApplicationType(WebApplicationType.REACTIVE).
Spring WebFlux Auto-configuration
Spring Boot provides auto-configuration for Spring WebFlux that works well with most applications.
The auto-configuration adds the following features on top of Spring’s defaults:
• Configuring codecs for HttpMessageReader and HttpMessageWriter instances (described later
in this document).
• Support for serving static resources, including support for WebJars (described later in this document).
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If you want to keep Spring Boot WebFlux features and you want to add additional WebFlux
configuration, you can add your own @Configuration class of type WebFluxConfigurer but
without @EnableWebFlux.
If you want to take complete control of Spring WebFlux, you can add your own @Configuration
annotated with @EnableWebFlux.
HTTP Codecs with HttpMessageReaders and HttpMessageWriters
Spring WebFlux uses the HttpMessageReader and HttpMessageWriter interfaces to convert
HTTP requests and responses. They are configured with CodecConfigurer to have sensible defaults
by looking at the libraries available in your classpath.
Spring Boot applies further customization by using CodecCustomizer instances. For example,
spring.jackson.* configuration keys are applied to the Jackson codec.
If you need to add or customize codecs, you can create a custom CodecCustomizer component, as
shown in the following example:
import org.springframework.boot.web.codec.CodecCustomizer;
@Configuration
public class MyConfiguration {
@Bean
public CodecCustomizer myCodecCustomizer() {
return codecConfigurer -> {
// ...
}
}
}
You can also leverage Boot’s custom JSON serializers and deserializers.
Static Content
By default, Spring Boot serves static content from a directory called /static (or /public or /
resources or /META-INF/resources) in the classpath. It uses the ResourceWebHandler from
Spring WebFlux so that you can modify that behavior by adding your own WebFluxConfigurer and
overriding the addResourceHandlers method.
By default, resources are mapped on /**, but you can tune that by setting the
spring.webflux.static-path-pattern property. For instance, relocating all resources to /
resources/** can be achieved as follows:
spring.webflux.static-path-pattern=/resources/**
You can also customize the static resource locations by using spring.resources.static-
locations. Doing so replaces the default values with a list of directory locations. If you do so, the
default welcome page detection switches to your custom locations. So, if there is an index.html in
any of your locations on startup, it is the home page of the application.
In addition to the “standard” static resource locations listed earlier, a special case is made for Webjars
content. Any resources with a path in /webjars/** are served from jar files if they are packaged in
the Webjars format.
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Tip
Spring WebFlux applications do not strictly depend on the Servlet API, so they cannot be deployed
as war files and do not use the src/main/webapp directory.
Template Engines
As well as REST web services, you can also use Spring WebFlux to serve dynamic HTML content.
Spring WebFlux supports a variety of templating technologies, including Thymeleaf, FreeMarker, and
Mustache.
Spring Boot includes auto-configuration support for the following templating engines:
•FreeMarker
•Thymeleaf
•Mustache
When you use one of these templating engines with the default configuration, your templates are picked
up automatically from src/main/resources/templates.
Error Handling
Spring Boot provides a WebExceptionHandler that handles all errors in a sensible way. Its position
in the processing order is immediately before the handlers provided by WebFlux, which are considered
last. For machine clients, it produces a JSON response with details of the error, the HTTP status, and the
exception message. For browser clients, there is a “whitelabel” error handler that renders the same data
in HTML format. You can also provide your own HTML templates to display errors (see the next section).
The first step to customizing this feature often involves using the existing mechanism but replacing or
augmenting the error contents. For that, you can add a bean of type ErrorAttributes.
To change the error handling behavior, you can implement ErrorWebExceptionHandler and register
a bean definition of that type. Because a WebExceptionHandler is quite low-level, Spring Boot also
provides a convenient AbstractErrorWebExceptionHandler to let you handle errors in a WebFlux
functional way, as shown in the following example:
public class CustomErrorWebExceptionHandler extends AbstractErrorWebExceptionHandler {
// Define constructor here
@Override
protected RouterFunction<ServerResponse> getRoutingFunction(ErrorAttributes errorAttributes) {
return RouterFunctions
.route(aPredicate, aHandler)
.andRoute(anotherPredicate, anotherHandler);
}
}
For a more complete picture, you can also subclass DefaultErrorWebExceptionHandler directly
and override specific methods.
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Custom Error Pages
If you want to display a custom HTML error page for a given status code, you can add a file to an /
error folder. Error pages can either be static HTML (that is, added under any of the static resource
folders) or built with templates. The name of the file should be the exact status code or a series mask.
For example, to map 404 to a static HTML file, your folder structure would be as follows:
src/
+- main/
+- java/
| + <source code>
+- resources/
+- public/
+- error/
| +- 404.html
+- <other public assets>
To map all 5xx errors by using a Mustache template, your folder structure would be as follows:
src/
+- main/
+- java/
| + <source code>
+- resources/
+- templates/
+- error/
| +- 5xx.mustache
+- <other templates>
Web Filters
Spring WebFlux provides a WebFilter interface that can be implemented to filter HTTP request-
response exchanges. WebFilter beans found in the application context will be automatically used to
filter each exchange.
Where the order of the filters is important they can implement Ordered or be annotated with @Order.
Spring Boot auto-configuration may configure web filters for you. When it does so, the orders shown
in the following table will be used:
Web Filter Order
MetricsWebFilter Ordered.HIGHEST_PRECEDENCE + 1
WebFilterChainProxy (Spring Security) -100
HttpTraceWebFilter Ordered.LOWEST_PRECEDENCE - 10
27.3 JAX-RS and Jersey
If you prefer the JAX-RS programming model for REST endpoints, you can use one of the available
implementations instead of Spring MVC. Jersey 1.x and Apache CXF work quite well out of the box if
you register their Servlet or Filter as a @Bean in your application context. Jersey 2.x has some
native Spring support, so we also provide auto-configuration support for it in Spring Boot, together with
a starter.
To get started with Jersey 2.x, include the spring-boot-starter-jersey as a dependency and
then you need one @Bean of type ResourceConfig in which you register all the endpoints, as shown
in the following example:
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@Component
public class JerseyConfig extends ResourceConfig {
public JerseyConfig() {
register(Endpoint.class);
}
}
Warning
Jersey’s support for scanning executable archives is rather limited. For example, it cannot scan
for endpoints in a package found in WEB-INF/classes when running an executable war file.
To avoid this limitation, the packages method should not be used, and endpoints should be
registered individually by using the register method, as shown in the preceding example.
For more advanced customizations, you can also register an arbitrary number of beans that implement
ResourceConfigCustomizer.
All the registered endpoints should be @Components with HTTP resource annotations (@GET and
others), as shown in the following example:
@Component
@Path("/hello")
public class Endpoint {
@GET
public String message() {
return "Hello";
}
}
Since the Endpoint is a Spring @Component, its lifecycle is managed by Spring and you can use
the @Autowired annotation to inject dependencies and use the @Value annotation to inject external
configuration. By default, the Jersey servlet is registered and mapped to /*. You can change the
mapping by adding @ApplicationPath to your ResourceConfig.
By default, Jersey is set up as a Servlet in a @Bean of type ServletRegistrationBean named
jerseyServletRegistration. By default, the servlet is initialized lazily, but you can customize
that behavior by setting spring.jersey.servlet.load-on-startup. You can disable or override
that bean by creating one of your own with the same name. You can also use a filter instead
of a servlet by setting spring.jersey.type=filter (in which case, the @Bean to replace or
override is jerseyFilterRegistration). The filter has an @Order, which you can set with
spring.jersey.filter.order. Both the servlet and the filter registrations can be given init
parameters by using spring.jersey.init.* to specify a map of properties.
There is a Jersey sample so that you can see how to set things up. There is also a Jersey 1.x sample.
Note that, in the Jersey 1.x sample, the spring-boot maven plugin has been configured to unpack some
Jersey jars so that they can be scanned by the JAX-RS implementation (because the sample asks for
them to be scanned in its Filter registration). If any of your JAX-RS resources are packaged as nested
jars, you may need to do the same.
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27.4 Embedded Servlet Container Support
Spring Boot includes support for embedded Tomcat, Jetty, and Undertow servers. Most developers use
the appropriate “Starter” to obtain a fully configured instance. By default, the embedded server listens
for HTTP requests on port 8080.
Warning
If you choose to use Tomcat on CentOS, be aware that, by default, a temporary directory is used
to store compiled JSPs, file uploads, and so on. This directory may be deleted by tmpwatch
while your application is running, leading to failures. To avoid this behavior, you may want
to customize your tmpwatch configuration such that tomcat.* directories are not deleted or
configure server.tomcat.basedir such that embedded Tomcat uses a different location.
Servlets, Filters, and listeners
When using an embedded servlet container, you can register servlets, filters, and all the listeners (such
as HttpSessionListener) from the Servlet spec, either by using Spring beans or by scanning for
Servlet components.
Registering Servlets, Filters, and Listeners as Spring Beans
Any Servlet, Filter, or servlet *Listener instance that is a Spring bean is registered with the
embedded container. This can be particularly convenient if you want to refer to a value from your
application.properties during configuration.
By default, if the context contains only a single Servlet, it is mapped to /. In the case of multiple servlet
beans, the bean name is used as a path prefix. Filters map to /*.
If convention-based mapping is not flexible enough, you can use the ServletRegistrationBean,
FilterRegistrationBean, and ServletListenerRegistrationBean classes for complete
control.
Spring Boot ships with many auto-configurations that may define Filter beans. Here are a few examples
of Filters and their respective order (lower order value means higher precedence):
Servlet Filter Order
OrderedCharacterEncodingFilter Ordered.HIGHEST_PRECEDENCE
WebMvcMetricsFilter Ordered.HIGHEST_PRECEDENCE + 1
ErrorPageFilter Ordered.HIGHEST_PRECEDENCE + 1
HttpTraceFilter Ordered.LOWEST_PRECEDENCE - 10
It is usually safe to leave Filter beans unordered.
If a specific order is required, you should avoid configuring a Filter that reads the request body at
Ordered.HIGHEST_PRECEDENCE, since it might go against the character encoding configuration of
your application. If a Servlet filter wraps the request, it should be configured with an order that is less
than or equal to FilterRegistrationBean.REQUEST_WRAPPER_FILTER_MAX_ORDER.
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Servlet Context Initialization
Embedded servlet containers do not directly execute the Servlet
3.0+ javax.servlet.ServletContainerInitializer interface or Spring’s
org.springframework.web.WebApplicationInitializer interface. This is an intentional
design decision intended to reduce the risk that third party libraries designed to run inside a war may
break Spring Boot applications.
If you need to perform servlet context initialization in a Spring
Boot application, you should register a bean that implements the
org.springframework.boot.web.servlet.ServletContextInitializer interface. The
single onStartup method provides access to the ServletContext and, if necessary, can easily be
used as an adapter to an existing WebApplicationInitializer.
Scanning for Servlets, Filters, and listeners
When using an embedded container, automatic registration of classes annotated with @WebServlet,
@WebFilter, and @WebListener can be enabled by using @ServletComponentScan.
Tip
@ServletComponentScan has no effect in a standalone container, where the container’s built-
in discovery mechanisms are used instead.
The ServletWebServerApplicationContext
Under the hood, Spring Boot uses a different type of ApplicationContext for
embedded servlet container support. The ServletWebServerApplicationContext is a
special type of WebApplicationContext that bootstraps itself by searching for a
single ServletWebServerFactory bean. Usually a TomcatServletWebServerFactory,
JettyServletWebServerFactory, or UndertowServletWebServerFactory has been auto-
configured.
Note
You usually do not need to be aware of these implementation classes. Most applications are auto-
configured, and the appropriate ApplicationContext and ServletWebServerFactory are
created on your behalf.
Customizing Embedded Servlet Containers
Common servlet container settings can be configured by using Spring Environment properties.
Usually, you would define the properties in your application.properties file.
Common server settings include:
• Network settings: Listen port for incoming HTTP requests (server.port), interface address to bind
to server.address, and so on.
• Session settings: Whether the session is persistent (server.servlet.session.persistence),
session timeout (server.servlet.session.timeout), location of session
data (server.servlet.session.store-dir), and session-cookie configuration
(server.servlet.session.cookie.*).
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• Error management: Location of the error page (server.error.path) and so on.
•SSL
•HTTP compression
Spring Boot tries as much as possible to expose common settings, but this is not always possible.
For those cases, dedicated namespaces offer server-specific customizations (see server.tomcat
and server.undertow). For instance, access logs can be configured with specific features of the
embedded servlet container.
Tip
See the ServerProperties class for a complete list.
Programmatic Customization
If you need to programmatically configure your embedded servlet
container, you can register a Spring bean that implements the
WebServerFactoryCustomizer interface. WebServerFactoryCustomizer provides access to
the ConfigurableServletWebServerFactory, which includes numerous customization setter
methods. The following example shows programmatically setting the port:
import org.springframework.boot.web.server.WebServerFactoryCustomizer;
import org.springframework.boot.web.servlet.server.ConfigurableServletWebServerFactory;
import org.springframework.stereotype.Component;
@Component
public class CustomizationBean implements
WebServerFactoryCustomizer<ConfigurableServletWebServerFactory> {
@Override
public void customize(ConfigurableServletWebServerFactory server) {
server.setPort(9000);
}
}
Note
TomcatServletWebServerFactory, JettyServletWebServerFactory and
UndertowServletWebServerFactory are dedicated variants of
ConfigurableServletWebServerFactory that have additional customization setter
methods for Tomcat, Jetty and Undertow respectively.
Customizing ConfigurableServletWebServerFactory Directly
If the preceding customization techniques are too limited, you can
register the TomcatServletWebServerFactory, JettyServletWebServerFactory, or
UndertowServletWebServerFactory bean yourself.
@Bean
public ConfigurableServletWebServerFactory webServerFactory() {
TomcatServletWebServerFactory factory = new TomcatServletWebServerFactory();
factory.setPort(9000);
factory.setSessionTimeout(10, TimeUnit.MINUTES);
factory.addErrorPages(new ErrorPage(HttpStatus.NOT_FOUND, "/notfound.html"));
return factory;
}
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Setters are provided for many configuration options. Several protected method “hooks” are also provided
should you need to do something more exotic. See the source code documentation for details.
JSP Limitations
When running a Spring Boot application that uses an embedded servlet container (and is packaged as
an executable archive), there are some limitations in the JSP support.
• With Jetty and Tomcat, it should work if you use war packaging. An executable war will work when
launched with java -jar, and will also be deployable to any standard container. JSPs are not
supported when using an executable jar.
• Undertow does not support JSPs.
• Creating a custom error.jsp page does not override the default view for error handling. Custom
error pages should be used instead.
There is a JSP sample so that you can see how to set things up.
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28. Security
If Spring Security is on the classpath, then web applications are secured by default. Spring
Boot relies on Spring Security’s content-negotiation strategy to determine whether to use
httpBasic or formLogin. To add method-level security to a web application, you can also add
@EnableGlobalMethodSecurity with your desired settings. Additional information can be found in
the Spring Security Reference Guide.
The default UserDetailsService has a single user. The user name is user, and the password is
random and is printed at INFO level when the application starts, as shown in the following example:
Using generated security password: 78fa095d-3f4c-48b1-ad50-e24c31d5cf35
Note
If you fine-tune your logging configuration, ensure that the
org.springframework.boot.autoconfigure.security category is set to log INFO-level
messages. Otherwise, the default password is not printed.
You can change the username and password by providing a spring.security.user.name and
spring.security.user.password.
The basic features you get by default in a web application are:
• A UserDetailsService (or ReactiveUserDetailsService in case of a WebFlux
application) bean with in-memory store and a single user with a generated password (see
SecurityProperties.User for the properties of the user).
• Form-based login or HTTP Basic security (depending on Content-Type) for the entire application
(including actuator endpoints if actuator is on the classpath).
• A DefaultAuthenticationEventPublisher for publishing authentication events.
You can provide a different AuthenticationEventPublisher by adding a bean for it.
28.1 MVC Security
The default security configuration is implemented in SecurityAutoConfiguration
and UserDetailsServiceAutoConfiguration. SecurityAutoConfiguration imports
SpringBootWebSecurityConfiguration for web security and
UserDetailsServiceAutoConfiguration configures authentication, which is also relevant in
non-web applications. To switch off the default web application security configuration completely,
you can add a bean of type WebSecurityConfigurerAdapter (doing so does not disable the
UserDetailsService configuration or Actuator’s security).
To also switch off the UserDetailsService configuration, you can add a bean of type
UserDetailsService, AuthenticationProvider, or AuthenticationManager. There are
several secure applications in the Spring Boot samples to get you started with common use cases.
Access rules can be overridden by adding a custom WebSecurityConfigurerAdapter. Spring Boot
provides convenience methods that can be used to override access rules for actuator endpoints and
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static resources. EndpointRequest can be used to create a RequestMatcher that is based on
the management.endpoints.web.base-path property. PathRequest can be used to create a
RequestMatcher for resources in commonly used locations.
28.2 WebFlux Security
Similar to Spring MVC applications, you can secure your WebFlux applications by adding the
spring-boot-starter-security dependency. The default security configuration is implemented
in ReactiveSecurityAutoConfiguration and UserDetailsServiceAutoConfiguration.
ReactiveSecurityAutoConfiguration imports WebFluxSecurityConfiguration for web
security and UserDetailsServiceAutoConfiguration configures authentication, which is also
relevant in non-web applications. To switch off the default web application security configuration
completely, you can add a bean of type WebFilterChainProxy (doing so does not disable the
UserDetailsService configuration or Actuator’s security).
To also switch off the UserDetailsService configuration, you can add a bean of type
ReactiveUserDetailsService or ReactiveAuthenticationManager.
Access rules can be configured by adding a custom SecurityWebFilterChain. Spring Boot provides
convenience methods that can be used to override access rules for actuator endpoints and static
resources. EndpointRequest can be used to create a ServerWebExchangeMatcher that is based
on the management.endpoints.web.base-path property.
PathRequest can be used to create a ServerWebExchangeMatcher for resources in commonly
used locations.
For example, you can customize your security configuration by adding something like:
@Bean
public SecurityWebFilterChain springSecurityFilterChain(ServerHttpSecurity http) {
return http
.authorizeExchange()
.matchers(PathRequest.toStaticResources().atCommonLocations()).permitAll()
.pathMatchers("/foo", "/bar")
.authenticated().and()
.formLogin().and()
.build();
}
28.3 OAuth2
OAuth2 is a widely used authorization framework that is supported by Spring.
Client
If you have spring-security-oauth2-client on your classpath, you can take advantage of some
auto-configuration to make it easy to set up an OAuth2 Client. This configuration makes use of the
properties under OAuth2ClientProperties.
You can register multiple OAuth2 clients and providers under the
spring.security.oauth2.client prefix, as shown in the following example:
spring.security.oauth2.client.registration.my-client-1.client-id=abcd
spring.security.oauth2.client.registration.my-client-1.client-secret=password
spring.security.oauth2.client.registration.my-client-1.client-name=Client for user scope
spring.security.oauth2.client.registration.my-client-1.provider=my-oauth-provider
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spring.security.oauth2.client.registration.my-client-1.scope=user
spring.security.oauth2.client.registration.my-client-1.redirect-uri-template=http://my-redirect-uri.com
spring.security.oauth2.client.registration.my-client-1.client-authentication-method=basic
spring.security.oauth2.client.registration.my-client-1.authorization-grant-type=authorization_code
spring.security.oauth2.client.registration.my-client-2.client-id=abcd
spring.security.oauth2.client.registration.my-client-2.client-secret=password
spring.security.oauth2.client.registration.my-client-2.client-name=Client for email scope
spring.security.oauth2.client.registration.my-client-2.provider=my-oauth-provider
spring.security.oauth2.client.registration.my-client-2.scope=email
spring.security.oauth2.client.registration.my-client-2.redirect-uri-template=http://my-redirect-uri.com
spring.security.oauth2.client.registration.my-client-2.client-authentication-method=basic
spring.security.oauth2.client.registration.my-client-2.authorization-grant-type=authorization_code
spring.security.oauth2.client.provider.my-oauth-provider.authorization-uri=http://my-auth-server/oauth/
authorize
spring.security.oauth2.client.provider.my-oauth-provider.token-uri=http://my-auth-server/oauth/token
spring.security.oauth2.client.provider.my-oauth-provider.user-info-uri=http://my-auth-server/userinfo
spring.security.oauth2.client.provider.my-oauth-provider.jwk-set-uri=http://my-auth-server/token_keys
spring.security.oauth2.client.provider.my-oauth-provider.user-name-attribute=name
By default, Spring Security’s OAuth2LoginAuthenticationFilter only processes URLs matching
/login/oauth2/code/*. If you want to customize the redirect-uri-template to use a different
pattern, you need to provide configuration to process that custom pattern. For example, you can add
your own WebSecurityConfigurerAdapter that resembles the following:
public class OAuth2LoginSecurityConfig extends WebSecurityConfigurerAdapter {
@Override
protected void configure(HttpSecurity http) throws Exception {
http
.authorizeRequests()
.anyRequest().authenticated()
.and()
.oauth2Login()
.redirectionEndpoint()
.baseUri("/custom-callback");
}
}
For common OAuth2 and OpenID providers, including Google, Github, Facebook, and Okta, we provide
a set of provider defaults (google, github, facebook, and okta, respectively).
If you do not need to customize these providers, you can set the provider attribute to the one for
which you need to infer defaults. Also, if the ID of your client matches the default supported provider,
Spring Boot infers that as well.
In other words, the two configurations in the following example use the Google provider:
spring.security.oauth2.client.registration.my-client.client-id=abcd
spring.security.oauth2.client.registration.my-client.client-secret=password
spring.security.oauth2.client.registration.my-client.provider=google
spring.security.oauth2.client.registration.google.client-id=abcd
spring.security.oauth2.client.registration.google.client-secret=password
Server
Currently, Spring Security does not provide support for implementing an OAuth 2.0 Authorization
Server or Resource Server. However, this functionality is available from the Spring Security OAuth
project, which will eventually be superseded by Spring Security completely. Until then, you can use the
spring-security-oauth2-autoconfigure module to easily set up an OAuth 2.0 server; see its
documentation for instructions.
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28.4 Actuator Security
For security purposes, all actuators other than /health and /info are disabled by default. The
management.endpoints.web.exposure.include property can be used to enable the actuators.
If Spring Security is on the classpath and no other WebSecurityConfigurerAdapter is
present, the actuators are secured by Spring Boot auto-config. If you define a custom
WebSecurityConfigurerAdapter, Spring Boot auto-config will back off and you will be in full control
of actuator access rules.
Note
Before setting the management.endpoints.web.exposure.include, ensure that the
exposed actuators do not contain sensitive information and/or are secured by placing them behind
a firewall or by something like Spring Security.
Cross Site Request Forgery Protection
Since Spring Boot relies on Spring Security’s defaults, CSRF protection is turned on by default. This
means that the actuator endpoints that require a POST (shutdown and loggers endpoints), PUT or
DELETE will get a 403 forbidden error when the default security configuration is in use.
Note
We recommend disabling CSRF protection completely only if you are creating a service that is
used by non-browser clients.
Additional information about CSRF protection can be found in the Spring Security Reference Guide.
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29. Working with SQL Databases
The Spring Framework provides extensive support for working with SQL databases, from direct JDBC
access using JdbcTemplate to complete “object relational mapping” technologies such as Hibernate.
Spring Data provides an additional level of functionality: creating Repository implementations directly
from interfaces and using conventions to generate queries from your method names.
29.1 Configure a DataSource
Java’s javax.sql.DataSource interface provides a standard method of working with database
connections. Traditionally, a 'DataSource' uses a URL along with some credentials to establish a
database connection.
Tip
See the “How-to” section for more advanced examples, typically to take full control over the
configuration of the DataSource.
Embedded Database Support
It is often convenient to develop applications by using an in-memory embedded database. Obviously,
in-memory databases do not provide persistent storage. You need to populate your database when your
application starts and be prepared to throw away data when your application ends.
Tip
The “How-to” section includes a section on how to initialize a database.
Spring Boot can auto-configure embedded H2, HSQL, and Derby databases. You need not provide any
connection URLs. You need only include a build dependency to the embedded database that you want
to use.
Note
If you are using this feature in your tests, you may notice that the same database is reused
by your whole test suite regardless of the number of application contexts that you use. If you
want to make sure that each context has a separate embedded database, you should set
spring.datasource.generate-unique-name to true.
For example, the typical POM dependencies would be as follows:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.hsqldb</groupId>
<artifactId>hsqldb</artifactId>
<scope>runtime</scope>
</dependency>
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Note
You need a dependency on spring-jdbc for an embedded database to be auto-configured. In
this example, it is pulled in transitively through spring-boot-starter-data-jpa.
Tip
If, for whatever reason, you do configure the connection URL for an embedded database,
take care to ensure that the database’s automatic shutdown is disabled. If you use H2, you
should use DB_CLOSE_ON_EXIT=FALSE to do so. If you use HSQLDB, you should ensure that
shutdown=true is not used. Disabling the database’s automatic shutdown lets Spring Boot
control when the database is closed, thereby ensuring that it happens once access to the database
is no longer needed.
Connection to a Production Database
Production database connections can also be auto-configured by using a pooling DataSource. Spring
Boot uses the following algorithm for choosing a specific implementation:
1. We prefer HikariCP for its performance and concurrency. If HikariCP is available, we always choose it.
2. Otherwise, if the Tomcat pooling DataSource is available, we use it.
3. If neither HikariCP nor the Tomcat pooling datasource are available and if Commons DBCP2 is
available, we use it.
If you use the spring-boot-starter-jdbc or spring-boot-starter-data-jpa “starters”, you
automatically get a dependency to HikariCP.
Note
You can bypass that algorithm completely and specify the connection pool to use by setting the
spring.datasource.type property. This is especially important if you run your application in
a Tomcat container, as tomcat-jdbc is provided by default.
Tip
Additional connection pools can always be configured manually. If you define your own
DataSource bean, auto-configuration does not occur.
DataSource configuration is controlled by external configuration properties in spring.datasource.*.
For example, you might declare the following section in application.properties:
spring.datasource.url=jdbc:mysql://localhost/test
spring.datasource.username=dbuser
spring.datasource.password=dbpass
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
Note
You should at least specify the URL by setting the spring.datasource.url property.
Otherwise, Spring Boot tries to auto-configure an embedded database.
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Tip
You often do not need to specify the driver-class-name, since Spring Boot can deduce it for
most databases from the url.
Note
For a pooling DataSource to be created, we need to be able to verify that a valid Driver
class is available, so we check for that before doing anything. In other words, if you
set spring.datasource.driver-class-name=com.mysql.jdbc.Driver, then that class
has to be loadable.
See DataSourceProperties for more of the supported options. These are the standard
options that work regardless of the actual implementation. It is also possible to fine-tune
implementation-specific settings by using their respective prefix (spring.datasource.hikari.*,
spring.datasource.tomcat.*, and spring.datasource.dbcp2.*). Refer to the
documentation of the connection pool implementation you are using for more details.
For instance, if you use the Tomcat connection pool, you could customize many additional settings, as
shown in the following example:
# Number of ms to wait before throwing an exception if no connection is available.
spring.datasource.tomcat.max-wait=10000
# Maximum number of active connections that can be allocated from this pool at the same time.
spring.datasource.tomcat.max-active=50
# Validate the connection before borrowing it from the pool.
spring.datasource.tomcat.test-on-borrow=true
Connection to a JNDI DataSource
If you deploy your Spring Boot application to an Application Server, you might want to configure and
manage your DataSource by using your Application Server’s built-in features and access it by using
JNDI.
The spring.datasource.jndi-name property can be used as an
alternative to the spring.datasource.url, spring.datasource.username, and
spring.datasource.password properties to access the DataSource from a specific JNDI location.
For example, the following section in application.properties shows how you can access a JBoss
AS defined DataSource:
spring.datasource.jndi-name=java:jboss/datasources/customers
29.2 Using JdbcTemplate
Spring’s JdbcTemplate and NamedParameterJdbcTemplate classes are auto-configured, and you
can @Autowire them directly into your own beans, as shown in the following example:
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Component;
@Component
public class MyBean {
private final JdbcTemplate jdbcTemplate;
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@Autowired
public MyBean(JdbcTemplate jdbcTemplate) {
this.jdbcTemplate = jdbcTemplate;
}
// ...
}
You can customize some properties of the template by using the spring.jdbc.template.*
properties, as shown in the following example:
spring.jdbc.template.max-rows=500
Note
The NamedParameterJdbcTemplate reuses the same JdbcTemplate instance behind the
scenes. If more than one JdbcTemplate is defined and no primary candidate exists, the
NamedParameterJdbcTemplate is not auto-configured.
29.3 JPA and “Spring Data”
The Java Persistence API is a standard technology that lets you “map” objects to relational databases.
The spring-boot-starter-data-jpa POM provides a quick way to get started. It provides the
following key dependencies:
• Hibernate: One of the most popular JPA implementations.
• Spring Data JPA: Makes it easy to implement JPA-based repositories.
• Spring ORMs: Core ORM support from the Spring Framework.
Tip
We do not go into too many details of JPA or Spring Data here. You can follow the “Accessing
Data with JPA” guide from spring.io and read the Spring Data JPA and Hibernate reference
documentation.
Entity Classes
Traditionally, JPA “Entity” classes are specified in a persistence.xml file. With Spring Boot,
this file is not necessary and “Entity Scanning” is used instead. By default, all packages
below your main configuration class (the one annotated with @EnableAutoConfiguration or
@SpringBootApplication) are searched.
Any classes annotated with @Entity, @Embeddable, or @MappedSuperclass are considered. A
typical entity class resembles the following example:
package com.example.myapp.domain;
import java.io.Serializable;
import javax.persistence.*;
@Entity
public class City implements Serializable {
@Id
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@GeneratedValue
private Long id;
@Column(nullable = false)
private String name;
@Column(nullable = false)
private String state;
// ... additional members, often include @OneToMany mappings
protected City() {
// no-args constructor required by JPA spec
// this one is protected since it shouldn't be used directly
}
public City(String name, String state) {
this.name = name;
this.country = country;
}
public String getName() {
return this.name;
}
public String getState() {
return this.state;
}
// ... etc
}
Tip
You can customize entity scanning locations by using the @EntityScan annotation. See the
“Section 80.4, “Separate @Entity Definitions from Spring Configuration”” how-to.
Spring Data JPA Repositories
Spring Data JPA repositories are interfaces that you can define to access data. JPA queries are created
automatically from your method names. For example, a CityRepository interface might declare a
findAllByState(String state) method to find all the cities in a given state.
For more complex queries, you can annotate your method with Spring Data’s Query annotation.
Spring Data repositories usually extend from the Repository or CrudRepository interfaces. If you
use auto-configuration, repositories are searched from the package containing your main configuration
class (the one annotated with @EnableAutoConfiguration or @SpringBootApplication) down.
The following example shows a typical Spring Data repository interface definition:
package com.example.myapp.domain;
import org.springframework.data.domain.*;
import org.springframework.data.repository.*;
public interface CityRepository extends Repository<City, Long> {
Page<City> findAll(Pageable pageable);
City findByNameAndCountryAllIgnoringCase(String name, String country);
}
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Tip
We have barely scratched the surface of Spring Data JPA. For complete details, see the Spring
Data JPA reference documentation.
Creating and Dropping JPA Databases
By default, JPA databases are automatically created only if you use an embedded database (H2, HSQL,
or Derby). You can explicitly configure JPA settings by using spring.jpa.* properties. For example,
to create and drop tables you can add the following line to your application.properties:
spring.jpa.hibernate.ddl-auto=create-drop
Note
Hibernate’s own internal property name for this (if you happen to remember it better) is
hibernate.hbm2ddl.auto. You can set it, along with other Hibernate native properties, by
using spring.jpa.properties.* (the prefix is stripped before adding them to the entity
manager). The following line shows an example of setting JPA properties for Hibernate:
spring.jpa.properties.hibernate.globally_quoted_identifiers=true
The line in the preceding example passes a value of true for the
hibernate.globally_quoted_identifiers property to the Hibernate entity manager.
By default, the DDL execution (or validation) is deferred until the ApplicationContext has started.
There is also a spring.jpa.generate-ddl flag, but it is not used if Hibernate auto-configuration is
active, because the ddl-auto settings are more fine-grained.
Open EntityManager in View
If you are running a web application, Spring Boot by default registers
OpenEntityManagerInViewInterceptor to apply the “Open EntityManager in View” pattern, to
allow for lazy loading in web views. If you do not want this behavior, you should set spring.jpa.open-
in-view to false in your application.properties.
29.4 Using H2’s Web Console
The H2 database provides a browser-based console that Spring Boot can auto-configure for you. The
console is auto-configured when the following conditions are met:
• You are developing a servlet-based web application.
•com.h2database:h2 is on the classpath.
• You are using Spring Boot’s developer tools.
Tip
If you are not using Spring Boot’s developer tools but would still like to make use of H2’s console,
you can configure the spring.h2.console.enabled property with a value of true.
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Note
The H2 console is only intended for use during development, so you should take care to ensure
that spring.h2.console.enabled is not set to true in production.
Changing the H2 Console’s Path
By default, the console is available at /h2-console. You can customize the console’s path by using
the spring.h2.console.path property.
29.5 Using jOOQ
Java Object Oriented Querying (jOOQ) is a popular product from Data Geekery which generates Java
code from your database and lets you build type-safe SQL queries through its fluent API. Both the
commercial and open source editions can be used with Spring Boot.
Code Generation
In order to use jOOQ type-safe queries, you need to generate Java classes from your database schema.
You can follow the instructions in the jOOQ user manual. If you use the jooq-codegen-maven plugin
and you also use the spring-boot-starter-parent “parent POM”, you can safely omit the plugin’s
<version> tag. You can also use Spring Boot-defined version variables (such as h2.version) to
declare the plugin’s database dependency. The following listing shows an example:
<plugin>
<groupId>org.jooq</groupId>
<artifactId>jooq-codegen-maven</artifactId>
<executions>
...
</executions>
<dependencies>
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<version>${h2.version}</version>
</dependency>
</dependencies>
<configuration>
<jdbc>
<driver>org.h2.Driver</driver>
<url>jdbc:h2:~/yourdatabase</url>
</jdbc>
<generator>
...
</generator>
</configuration>
</plugin>
Using DSLContext
The fluent API offered by jOOQ is initiated through the org.jooq.DSLContext interface. Spring Boot
auto-configures a DSLContext as a Spring Bean and connects it to your application DataSource. To
use the DSLContext, you can @Autowire it, as shown in the following example:
@Component
public class JooqExample implements CommandLineRunner {
private final DSLContext create;
@Autowired
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public JooqExample(DSLContext dslContext) {
this.create = dslContext;
}
}
Tip
The jOOQ manual tends to use a variable named create to hold the DSLContext.
You can then use the DSLContext to construct your queries, as shown in the following example:
public List<GregorianCalendar> authorsBornAfter1980() {
return this.create.selectFrom(AUTHOR)
.where(AUTHOR.DATE_OF_BIRTH.greaterThan(new GregorianCalendar(1980, 0, 1)))
.fetch(AUTHOR.DATE_OF_BIRTH);
}
jOOQ SQL Dialect
Unless the spring.jooq.sql-dialect property has been configured, Spring Boot determines the
SQL dialect to use for your datasource. If Spring Boot could not detect the dialect, it uses DEFAULT.
Note
Spring Boot can only auto-configure dialects supported by the open source version of jOOQ.
Customizing jOOQ
More advanced customizations can be achieved by defining your own @Bean definitions, which is used
when the jOOQ Configuration is created. You can define beans for the following jOOQ Types:
•ConnectionProvider
•TransactionProvider
•RecordMapperProvider
•RecordUnmapperProvider
•RecordListenerProvider
•ExecuteListenerProvider
•VisitListenerProvider
•TransactionListenerProvider
You can also create your own org.jooq.Configuration @Bean if you want to take complete control
of the jOOQ configuration.
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30. Working with NoSQL Technologies
Spring Data provides additional projects that help you access a variety of NoSQL technologies,
including: MongoDB, Neo4J, Elasticsearch, Solr, Redis, Gemfire, Cassandra, Couchbase and LDAP.
Spring Boot provides auto-configuration for Redis, MongoDB, Neo4j, Elasticsearch, Solr Cassandra,
Couchbase, and LDAP. You can make use of the other projects, but you must configure them yourself.
Refer to the appropriate reference documentation at projects.spring.io/spring-data.
30.1 Redis
Redis is a cache, message broker, and richly-featured key-value store. Spring Boot offers basic auto-
configuration for the Lettuce and Jedis client libraries and the abstractions on top of them provided by
Spring Data Redis.
There is a spring-boot-starter-data-redis “Starter” for collecting the dependencies in a
convenient way. By default, it uses Lettuce. That starter handles both traditional and reactive
applications.
Tip
we also provide a spring-boot-starter-data-redis-reactive “Starter” for consistency
with the other stores with reactive support.
Connecting to Redis
You can inject an auto-configured RedisConnectionFactory, StringRedisTemplate, or vanilla
RedisTemplate instance as you would any other Spring Bean. By default, the instance tries to connect
to a Redis server at localhost:6379. The following listing shows an example of such a bean:
@Component
public class MyBean {
private StringRedisTemplate template;
@Autowired
public MyBean(StringRedisTemplate template) {
this.template = template;
}
// ...
}
Tip
You can also register an arbitrary number of beans that implement
LettuceClientConfigurationBuilderCustomizer for more advanced customizations. If
you use Jedis, JedisClientConfigurationBuilderCustomizer is also available.
If you add your own @Bean of any of the auto-configured types, it replaces the default (except in the
case of RedisTemplate, when the exclusion is based on the bean name, redisTemplate, not its
type). By default, if commons-pool2 is on the classpath, you get a pooled connection factory.
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30.2 MongoDB
MongoDB is an open-source NoSQL document database that uses a JSON-like schema instead
of traditional table-based relational data. Spring Boot offers several conveniences for working with
MongoDB, including the spring-boot-starter-data-mongodb and spring-boot-starter-
data-mongodb-reactive “Starters”.
Connecting to a MongoDB Database
To access Mongo databases, you can inject an auto-configured
org.springframework.data.mongodb.MongoDbFactory. By default, the instance tries to
connect to a MongoDB server at mongodb://localhost/test The following example shows how
to connect to a MongoDB database:
import org.springframework.data.mongodb.MongoDbFactory;
import com.mongodb.DB;
@Component
public class MyBean {
private final MongoDbFactory mongo;
@Autowired
public MyBean(MongoDbFactory mongo) {
this.mongo = mongo;
}
// ...
public void example() {
DB db = mongo.getDb();
// ...
}
}
You can set the spring.data.mongodb.uri property to change the URL and configure additional
settings such as the replica set, as shown in the following example:
spring.data.mongodb.uri=mongodb://user:secret@mongo1.example.com:12345,mongo2.example.com:23456/test
Alternatively, as long as you use Mongo 2.x, you can specify a host/port. For example, you might
declare the following settings in your application.properties:
spring.data.mongodb.host=mongoserver
spring.data.mongodb.port=27017
Note
If you use the Mongo 3.0 Java driver, spring.data.mongodb.host
and spring.data.mongodb.port are not supported. In such cases,
spring.data.mongodb.uri should be used to provide all of the configuration.
Tip
If spring.data.mongodb.port is not specified, the default of 27017 is used. You could delete
this line from the example shown earlier.
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Tip
If you do not use Spring Data Mongo, you can inject com.mongodb.MongoClient beans instead
of using MongoDbFactory. If you want to take complete control of establishing the MongoDB
connection, you can also declare your own MongoDbFactory or MongoClient bean.
Note
If you are using the reactive driver, Netty is required for SSL. The auto-configuration configures this
factory automatically if Netty is available and the factory to use hasn’t been customized already.
MongoTemplate
Spring Data MongoDB provides a MongoTemplate class that is very similar in its design to Spring’s
JdbcTemplate. As with JdbcTemplate, Spring Boot auto-configures a bean for you to inject the
template, as follows:
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.stereotype.Component;
@Component
public class MyBean {
private final MongoTemplate mongoTemplate;
@Autowired
public MyBean(MongoTemplate mongoTemplate) {
this.mongoTemplate = mongoTemplate;
}
// ...
}
See the MongoOperations Javadoc for complete details.
Spring Data MongoDB Repositories
Spring Data includes repository support for MongoDB. As with the JPA repositories discussed earlier,
the basic principle is that queries are constructed automatically, based on method names.
In fact, both Spring Data JPA and Spring Data MongoDB share the same common infrastructure. You
could take the JPA example from earlier and, assuming that City is now a Mongo data class rather
than a JPA @Entity, it works in the same way, as shown in the following example:
package com.example.myapp.domain;
import org.springframework.data.domain.*;
import org.springframework.data.repository.*;
public interface CityRepository extends Repository<City, Long> {
Page<City> findAll(Pageable pageable);
City findByNameAndCountryAllIgnoringCase(String name, String country);
}
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Tip
You can customize document scanning locations by using the @EntityScan annotation.
Tip
For complete details of Spring Data MongoDB, including its rich object mapping technologies,
refer to its reference documentation.
Embedded Mongo
Spring Boot offers auto-configuration for Embedded Mongo. To use it in your Spring Boot application,
add a dependency on de.flapdoodle.embed:de.flapdoodle.embed.mongo.
The port that Mongo listens on can be configured by setting the spring.data.mongodb.port
property. To use a randomly allocated free port, use a value of 0. The MongoClient created by
MongoAutoConfiguration is automatically configured to use the randomly allocated port.
Note
If you do not configure a custom port, the embedded support uses a random port (rather than
27017) by default.
If you have SLF4J on the classpath, the output produced by Mongo is automatically routed to a logger
named org.springframework.boot.autoconfigure.mongo.embedded.EmbeddedMongo.
You can declare your own IMongodConfig and IRuntimeConfig beans to take control of the Mongo
instance’s configuration and logging routing.
30.3 Neo4j
Neo4j is an open-source NoSQL graph database that uses a rich data model of nodes related
by first class relationships, which is better suited for connected big data than traditional rdbms
approaches. Spring Boot offers several conveniences for working with Neo4j, including the spring-
boot-starter-data-neo4j “Starter”.
Connecting to a Neo4j Database
You can inject an auto-configured Neo4jSession, Session, or Neo4jOperations instance as
you would any other Spring Bean. By default, the instance tries to connect to a Neo4j server at
localhost:7474. The following example shows how to inject a Neo4j bean:
@Component
public class MyBean {
private final Neo4jTemplate neo4jTemplate;
@Autowired
public MyBean(Neo4jTemplate neo4jTemplate) {
this.neo4jTemplate = neo4jTemplate;
}
// ...
}
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You can take full control of the configuration by adding a org.neo4j.ogm.config.Configuration
@Bean of your own. Also, adding a @Bean of type Neo4jOperations disables the auto-configuration.
You can configure the user and credentials to use by setting the spring.data.neo4j.* properties,
as shown in the following example:
spring.data.neo4j.uri=http://my-server:7474
spring.data.neo4j.username=neo4j
spring.data.neo4j.password=secret
Using the Embedded Mode
If you add org.neo4j:neo4j-ogm-embedded-driver to the dependencies of your application,
Spring Boot automatically configures an in-process embedded instance of Neo4j that does not
persist any data when your application shuts down. You can explicitly disable that mode by
setting spring.data.neo4j.embedded.enabled=false. You can also enable persistence for the
embedded mode by providing a path to a database file, as shown in the following example:
spring.data.neo4j.uri=file://var/tmp/graph.db
Note
The Neo4j OGM embedded driver does not provide the Neo4j kernel. Users are expected to
provide this dependency manually. See the documentation for more details.
Neo4jSession
By default, if you are running a web application, the session is bound to the thread for the entire
processing of the request (that is, it uses the "Open Session in View" pattern). If you do not want this
behavior, add the following line to your application.properties file:
spring.data.neo4j.open-in-view=false
Spring Data Neo4j Repositories
Spring Data includes repository support for Neo4j.
In fact, both Spring Data JPA and Spring Data Neo4j share the same common infrastructure. You could
take the JPA example from earlier and, assuming that City is now a Neo4j OGM @NodeEntity rather
than a JPA @Entity, it works in the same way.
Tip
You can customize entity scanning locations by using the @EntityScan annotation.
To enable repository support (and optionally support for @Transactional), add the following two
annotations to your Spring configuration:
@EnableNeo4jRepositories(basePackages = "com.example.myapp.repository")
@EnableTransactionManagement
Repository Example
The following example shows an interface definition for a Neo4j repository:
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package com.example.myapp.domain;
import org.springframework.data.domain.*;
import org.springframework.data.repository.*;
public interface CityRepository extends GraphRepository<City> {
Page<City> findAll(Pageable pageable);
City findByNameAndCountry(String name, String country);
}
Tip
For complete details of Spring Data Neo4j, including its rich object mapping technologies, refer
to the reference documentation.
30.4 Gemfire
Spring Data Gemfire provides convenient Spring-friendly tools for accessing the Pivotal Gemfire data
management platform. There is a spring-boot-starter-data-gemfire “Starter” for collecting the
dependencies in a convenient way. There is currently no auto-configuration support for Gemfire, but
you can enable Spring Data Repositories with a single annotation: @EnableGemfireRepositories.
30.5 Solr
Apache Solr is a search engine. Spring Boot offers basic auto-configuration for the Solr 5 client library
and the abstractions on top of it provided by Spring Data Solr. There is a spring-boot-starter-
data-solr “Starter” for collecting the dependencies in a convenient way.
Connecting to Solr
You can inject an auto-configured SolrClient instance as you would any other Spring bean. By
default, the instance tries to connect to a server at localhost:8983/solr. The following example
shows how to inject a Solr bean:
@Component
public class MyBean {
private SolrClient solr;
@Autowired
public MyBean(SolrClient solr) {
this.solr = solr;
}
// ...
}
If you add your own @Bean of type SolrClient, it replaces the default.
Spring Data Solr Repositories
Spring Data includes repository support for Apache Solr. As with the JPA repositories discussed earlier,
the basic principle is that queries are automatically constructed for \ you based on method names.
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In fact, both Spring Data JPA and Spring Data Solr share the same common infrastructure. You could
take the JPA example from earlier and, assuming that City is now a @SolrDocument class rather
than a JPA @Entity, it works in the same way.
Tip
For complete details of Spring Data Solr, refer to the reference documentation.
30.6 Elasticsearch
Elasticsearch is an open source, distributed, real-time search and analytics engine. Spring Boot offers
basic auto-configuration for Elasticsearch and the abstractions on top of it provided by Spring Data
Elasticsearch. There is a spring-boot-starter-data-elasticsearch “Starter” for collecting the
dependencies in a convenient way. Spring Boot also supports Jest.
Connecting to Elasticsearch by Using Jest
If you have Jest on the classpath, you can inject an auto-configured JestClient that by default
targets localhost:9200. You can further tune how the client is configured, as shown in the following
example:
spring.elasticsearch.jest.uris=http://search.example.com:9200
spring.elasticsearch.jest.read-timeout=10000
spring.elasticsearch.jest.username=user
spring.elasticsearch.jest.password=secret
You can also register an arbitrary number of beans that implement
HttpClientConfigBuilderCustomizer for more advanced customizations. The following
example tunes additional HTTP settings:
static class HttpSettingsCustomizer implements HttpClientConfigBuilderCustomizer {
@Override
public void customize(HttpClientConfig.Builder builder) {
builder.maxTotalConnection(100).defaultMaxTotalConnectionPerRoute(5);
}
}
To take full control over the registration, define a JestClient bean.
Connecting to Elasticsearch by Using Spring Data
To connect to Elasticsearch, you must provide the address of one or more cluster nodes. The address
can be specified by setting the spring.data.elasticsearch.cluster-nodes property to a
comma-separated host:port list. With this configuration in place, an ElasticsearchTemplate or
TransportClient can be injected like any other Spring bean, as shown in the following example:
spring.data.elasticsearch.cluster-nodes=localhost:9300
@Component
public class MyBean {
private final ElasticsearchTemplate template;
public MyBean(ElasticsearchTemplate template) {
this.template = template;
}
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// ...
}
If you add your own ElasticsearchTemplate or TransportClient @Bean, it replaces the default.
Spring Data Elasticsearch Repositories
Spring Data includes repository support for Elasticsearch. As with the JPA repositories discussed earlier,
the basic principle is that queries are constructed for you automatically based on method names.
In fact, both Spring Data JPA and Spring Data Elasticsearch share the same common infrastructure. You
could take the JPA example from earlier and, assuming that City is now an Elasticsearch @Document
class rather than a JPA @Entity, it works in the same way.
Tip
For complete details of Spring Data Elasticsearch, refer to the reference documentation.
30.7 Cassandra
Cassandra is an open source, distributed database management system designed to handle large
amounts of data across many commodity servers. Spring Boot offers auto-configuration for Cassandra
and the abstractions on top of it provided by Spring Data Cassandra. There is a spring-boot-
starter-data-cassandra “Starter” for collecting the dependencies in a convenient way.
Connecting to Cassandra
You can inject an auto-configured CassandraTemplate or a Cassandra Session instance as you
would with any other Spring Bean. The spring.data.cassandra.* properties can be used to
customize the connection. Generally, you provide keyspace-name and contact-points properties,
as shown in the following example:
spring.data.cassandra.keyspace-name=mykeyspace
spring.data.cassandra.contact-points=cassandrahost1,cassandrahost2
The following code listing shows how to inject a Cassandra bean:
@Component
public class MyBean {
private CassandraTemplate template;
@Autowired
public MyBean(CassandraTemplate template) {
this.template = template;
}
// ...
}
If you add your own @Bean of type CassandraTemplate, it replaces the default.
Spring Data Cassandra Repositories
Spring Data includes basic repository support for Cassandra. Currently, this is more limited than the
JPA repositories discussed earlier and needs to annotate finder methods with @Query.
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Tip
For complete details of Spring Data Cassandra, refer to the reference documentation.
30.8 Couchbase
Couchbase is an open-source, distributed, multi-model NoSQL document-oriented database that
is optimized for interactive applications. Spring Boot offers auto-configuration for Couchbase
and the abstractions on top of it provided by Spring Data Couchbase. There are spring-
boot-starter-data-couchbase and spring-boot-starter-data-couchbase-reactive
“Starters” for collecting the dependencies in a convenient way.
Connecting to Couchbase
You can get a Bucket and Cluster by adding the Couchbase SDK and some configuration. The
spring.couchbase.* properties can be used to customize the connection. Generally, you provide
the bootstrap hosts, bucket name, and password, as shown in the following example:
spring.couchbase.bootstrap-hosts=my-host-1,192.168.1.123
spring.couchbase.bucket.name=my-bucket
spring.couchbase.bucket.password=secret
Tip
You need to provide at least the bootstrap host(s), in which case the bucket name
is default and the password is an empty String. Alternatively, you can define your
own org.springframework.data.couchbase.config.CouchbaseConfigurer @Bean
to take control over the whole configuration.
It is also possible to customize some of the CouchbaseEnvironment settings. For instance, the
following configuration changes the timeout to use to open a new Bucket and enables SSL support:
spring.couchbase.env.timeouts.connect=3000
spring.couchbase.env.ssl.key-store=/location/of/keystore.jks
spring.couchbase.env.ssl.key-store-password=secret
Check the spring.couchbase.env.* properties for more details.
Spring Data Couchbase Repositories
Spring Data includes repository support for Couchbase. For complete details of Spring Data Couchbase,
refer to the reference documentation.
You can inject an auto-configured CouchbaseTemplate instance as you would with any other Spring
Bean, provided a default CouchbaseConfigurer is available (which happens when you enable
Couchbase support, as explained earlier).
The following examples shows how to inject a Couchbase bean:
@Component
public class MyBean {
private final CouchbaseTemplate template;
@Autowired
public MyBean(CouchbaseTemplate template) {
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this.template = template;
}
// ...
}
There are a few beans that you can define in your own configuration to override those provided by the
auto-configuration:
• A CouchbaseTemplate @Bean with a name of couchbaseTemplate.
• An IndexManager @Bean with a name of couchbaseIndexManager.
• A CustomConversions @Bean with a name of couchbaseCustomConversions.
To avoid hard-coding those names in your own config, you can reuse BeanNames provided by Spring
Data Couchbase. For instance, you can customize the converters to use, as follows:
@Configuration
public class SomeConfiguration {
@Bean(BeanNames.COUCHBASE_CUSTOM_CONVERSIONS)
public CustomConversions myCustomConversions() {
return new CustomConversions(...);
}
// ...
}
Tip
If you want to fully bypass the auto-configuration for
Spring Data Couchbase, provide your own implementation of
org.springframework.data.couchbase.config.AbstractCouchbaseDataConfiguration.
30.9 LDAP
LDAP (Lightweight Directory Access Protocol) is an open, vendor-neutral, industry standard application
protocol for accessing and maintaining distributed directory information services over an IP network.
Spring Boot offers auto-configuration for any compliant LDAP server as well as support for the
embedded in-memory LDAP server from UnboundID.
LDAP abstractions are provided by Spring Data LDAP. There is a spring-boot-starter-data-
ldap “Starter” for collecting the dependencies in a convenient way.
Connecting to an LDAP Server
To connect to an LDAP server, make sure you declare a dependency on the spring-boot-starter-
data-ldap “Starter” or spring-ldap-core and then declare the URLs of your server in your
application.properties, as shown in the following example:
spring.ldap.urls=ldap://myserver:1235
spring.ldap.username=admin
spring.ldap.password=secret
If you need to customize connection settings, you can use the spring.ldap.base and
spring.ldap.base-environment properties.
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Spring Data LDAP Repositories
Spring Data includes repository support for LDAP. For complete details of Spring Data LDAP, refer to
the reference documentation.
You can also inject an auto-configured LdapTemplate instance as you would with any other Spring
Bean, as shown in the following example:
@Component
public class MyBean {
private final LdapTemplate template;
@Autowired
public MyBean(LdapTemplate template) {
this.template = template;
}
// ...
}
Embedded In-memory LDAP Server
For testing purposes, Spring Boot supports auto-configuration of an in-memory LDAP server from
UnboundID. To configure the server, add a dependency to com.unboundid:unboundid-ldapsdk
and declare a base-dn property, as follows:
spring.ldap.embedded.base-dn=dc=spring,dc=io
Note
It is possible to define multiple base-dn values, however, since distinguished names usually
contain commas, they must be defined using the correct notation.
In yaml files, you can use the yaml list notation:
spring.ldap.embedded.base-dn:
- dc=spring,dc=io
- dc=pivotal,dc=io
In properties files, you must include the index as part of the property name:
spring.ldap.embedded.base-dn[0]=dc=spring,dc=io
spring.ldap.embedded.base-dn[1]=dc=pivotal,dc=io
By default, the server starts on a random port and triggers the regular LDAP support. There is no need
to specify a spring.ldap.urls property.
If there is a schema.ldif file on your classpath, it is used to initialize the server. If you want to load
the initialization script from a different resource, you can also use the spring.ldap.embedded.ldif
property.
By default, a standard schema is used to validate LDIF files. You can turn off validation altogether by
setting the spring.ldap.embedded.validation.enabled property. If you have custom attributes,
you can use spring.ldap.embedded.validation.schema to define your custom attribute types
or object classes.
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30.10 InfluxDB
InfluxDB is an open-source time series database optimized for fast, high-availability storage and retrieval
of time series data in fields such as operations monitoring, application metrics, Internet-of-Things sensor
data, and real-time analytics.
Connecting to InfluxDB
Spring Boot auto-configures an InfluxDB instance, provided the influxdb-java client is on the
classpath and the URL of the database is set, as shown in the following example:
spring.influx.url=http://172.0.0.1:8086
If the connection to InfluxDB requires a user and password, you can set the spring.influx.user
and spring.influx.password properties accordingly.
InfluxDB relies on OkHttp. If you need to tune the http client InfluxDB uses behind the scenes, you
can register an OkHttpClient.Builder bean.
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31. Caching
The Spring Framework provides support for transparently adding caching to an application. At its core,
the abstraction applies caching to methods, thus reducing the number of executions based on the
information available in the cache. The caching logic is applied transparently, without any interference to
the invoker. Spring Boot auto-configures the cache infrastructure as long as caching support is enabled
via the @EnableCaching annotation.
Note
Check the relevant section of the Spring Framework reference for more details.
In a nutshell, adding caching to an operation of your service is as easy as adding the relevant annotation
to its method, as shown in the following example:
import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Component;
@Component
public class MathService {
@Cacheable("piDecimals")
public int computePiDecimal(int i) {
// ...
}
}
This example demonstrates the use of caching on a potentially costly operation. Before invoking
computePiDecimal, the abstraction looks for an entry in the piDecimals cache that matches the i
argument. If an entry is found, the content in the cache is immediately returned to the caller, and the
method is not invoked. Otherwise, the method is invoked, and the cache is updated before returning
the value.
Caution
You can also use the standard JSR-107 (JCache) annotations (such as @CacheResult)
transparently. However, we strongly advise you to not mix and match the Spring Cache and
JCache annotations.
If you do not add any specific cache library, Spring Boot auto-configures a simple provider that uses
concurrent maps in memory. When a cache is required (such as piDecimals in the preceding
example), this provider creates it for you. The simple provider is not really recommended for production
usage, but it is great for getting started and making sure that you understand the features. When you
have made up your mind about the cache provider to use, please make sure to read its documentation
to figure out how to configure the caches that your application uses. Nearly all providers require you
to explicitly configure every cache that you use in the application. Some offer a way to customize the
default caches defined by the spring.cache.cache-names property.
Tip
It is also possible to transparently update or evict data from the cache.
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31.1 Supported Cache Providers
The cache abstraction does not provide an actual store and relies on abstraction materialized by
the org.springframework.cache.Cache and org.springframework.cache.CacheManager
interfaces.
If you have not defined a bean of type CacheManager or a CacheResolver named cacheResolver
(see CachingConfigurer), Spring Boot tries to detect the following providers (in the indicated order):
1. Generic
2. JCache (JSR-107) (EhCache 3, Hazelcast, Infinispan, and others)
3. EhCache 2.x
4. Hazelcast
5. Infinispan
6. Couchbase
7. Redis
8. Caffeine
9. Simple
Tip
It is also possible to force a particular cache provider by setting the spring.cache.type
property. Use this property if you need to disable caching altogether in certain environment (such
as tests).
Tip
Use the spring-boot-starter-cache “Starter” to quickly add basic caching dependencies.
The starter brings in spring-context-support. If you add dependencies manually, you must
include spring-context-support in order to use the JCache, EhCache 2.x, or Guava support.
If the CacheManager is auto-configured by Spring Boot, you can further tune its configuration before it
is fully initialized by exposing a bean that implements the CacheManagerCustomizer interface. The
following example sets a flag to say that null values should be passed down to the underlying map:
@Bean
public CacheManagerCustomizer<ConcurrentMapCacheManager> cacheManagerCustomizer() {
return new CacheManagerCustomizer<ConcurrentMapCacheManager>() {
@Override
public void customize(ConcurrentMapCacheManager cacheManager) {
cacheManager.setAllowNullValues(false);
}
};
}
Note
In the preceding example, an auto-configured ConcurrentMapCacheManager is expected. If
that is not the case (either you provided your own config or a different cache provider was auto-
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configured), the customizer is not invoked at all. You can have as many customizers as you want,
and you can also order them by using @Order or Ordered.
Generic
Generic caching is used if the context defines at least one org.springframework.cache.Cache
bean. A CacheManager wrapping all beans of that type is created.
JCache (JSR-107)
JCache is bootstrapped through the presence of a javax.cache.spi.CachingProvider on
the classpath (that is, a JSR-107 compliant caching library exists on the classpath), and the
JCacheCacheManager is provided by the spring-boot-starter-cache “Starter”. Various
compliant libraries are available, and Spring Boot provides dependency management for Ehcache 3,
Hazelcast, and Infinispan. Any other compliant library can be added as well.
It might happen that more than one provider is present, in which case the provider must be explicitly
specified. Even if the JSR-107 standard does not enforce a standardized way to define the location of
the configuration file, Spring Boot does its best to accommodate setting a cache with implementation
details, as shown in the following example:
# Only necessary if more than one provider is present
spring.cache.jcache.provider=com.acme.MyCachingProvider
spring.cache.jcache.config=classpath:acme.xml
Note
When a cache library offers both a native implementation and JSR-107 support, Spring Boot
prefers the JSR-107 support, so that the same features are available if you switch to a different
JSR-107 implementation.
Tip
Spring Boot has general support for Hazelcast. If a single HazelcastInstance
is available, it is automatically reused for the CacheManager as well, unless the
spring.cache.jcache.config property is specified.
There are two ways to customize the underlying javax.cache.cacheManager:
• Caches can be created on startup by setting the spring.cache.cache-names property. If a custom
javax.cache.configuration.Configuration bean is defined, it is used to customize them.
•org.springframework.boot.autoconfigure.cache.JCacheManagerCustomizer beans
are invoked with the reference of the CacheManager for full customization.
Tip
If a standard javax.cache.CacheManager bean is defined, it is wrapped automatically in an
org.springframework.cache.CacheManager implementation that the abstraction expects.
No further customization is applied to it.
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EhCache 2.x
EhCache 2.x is used if a file named ehcache.xml can be found at the root of the classpath. If EhCache
2.x is found, the EhCacheCacheManager provided by the spring-boot-starter-cache “Starter”
is used to bootstrap the cache manager. An alternate configuration file can be provided as well, as
shown in the following example:
spring.cache.ehcache.config=classpath:config/another-config.xml
Hazelcast
Spring Boot has general support for Hazelcast. If a HazelcastInstance has been auto-configured,
it is automatically wrapped in a CacheManager.
Infinispan
Infinispan has no default configuration file location, so it must be specified explicitly. Otherwise, the
default bootstrap is used.
spring.cache.infinispan.config=infinispan.xml
Caches can be created on startup by setting the spring.cache.cache-names property. If a custom
ConfigurationBuilder bean is defined, it is used to customize the caches.
Note
The support of Infinispan in Spring Boot is restricted to the embedded mode and is quite basic.
If you want more options, you should use the official Infinispan Spring Boot starter instead. See
Infinispan’s documentation for more details.
Couchbase
If the Couchbase Java client and the couchbase-spring-cache implementation are available and
Couchbase is configured, a CouchbaseCacheManager is auto-configured. It is also possible to create
additional caches on startup by setting the spring.cache.cache-names property. These caches
operate on the Bucket that was auto-configured. You can also create additional caches on another
Bucket by using the customizer. Assume you need two caches (cache1 and cache2) on the "main"
Bucket and one (cache3) cache with a custom time to live of 2 seconds on the “another” Bucket.
You can create the first two caches through configuration, as follows:
spring.cache.cache-names=cache1,cache2
Then you can define a @Configuration class to configure the extra Bucket and the cache3 cache,
as follows:
@Configuration
public class CouchbaseCacheConfiguration {
private final Cluster cluster;
public CouchbaseCacheConfiguration(Cluster cluster) {
this.cluster = cluster;
}
@Bean
public Bucket anotherBucket() {
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return this.cluster.openBucket("another", "secret");
}
@Bean
public CacheManagerCustomizer<CouchbaseCacheManager> cacheManagerCustomizer() {
return c -> {
c.prepareCache("cache3", CacheBuilder.newInstance(anotherBucket())
.withExpiration(2));
};
}
}
This sample configuration reuses the Cluster that was created through auto-configuration.
Redis
If Redis is available and configured, a RedisCacheManager is auto-configured. It is possible to
create additional caches on startup by setting the spring.cache.cache-names property and cache
defaults can be configured by using spring.cache.redis.* properties. For instance, the following
configuration creates cache1 and cache2 caches with a time to live of 10 minutes:
spring.cache.cache-names=cache1,cache2
spring.cache.redis.time-to-live=600000
Note
By default, a key prefix is added so that, if two separate caches use the same key, Redis does
not have overlapping keys and cannot return invalid values. We strongly recommend keeping this
setting enabled if you create your own RedisCacheManager.
Tip
You can take full control of the configuration by adding a RedisCacheConfiguration @Bean
of your own. This can be useful if you’re looking for customizing the serialization strategy.
Caffeine
Caffeine is a Java 8 rewrite of Guava’s cache that supersedes support for Guava. If Caffeine is
present, a CaffeineCacheManager (provided by the spring-boot-starter-cache “Starter”) is
auto-configured. Caches can be created on startup by setting the spring.cache.cache-names
property and can be customized by one of the following (in the indicated order):
1. A cache spec defined by spring.cache.caffeine.spec
2. A com.github.benmanes.caffeine.cache.CaffeineSpec bean is defined
3. A com.github.benmanes.caffeine.cache.Caffeine bean is defined
For instance, the following configuration creates cache1 and cache2 caches with a maximum size of
500 and a time to live of 10 minutes
spring.cache.cache-names=cache1,cache2
spring.cache.caffeine.spec=maximumSize=500,expireAfterAccess=600s
If a com.github.benmanes.caffeine.cache.CacheLoader bean is defined, it is automatically
associated to the CaffeineCacheManager. Since the CacheLoader is going to be associated with
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all caches managed by the cache manager, it must be defined as CacheLoader<Object, Object>.
The auto-configuration ignores any other generic type.
Simple
If none of the other providers can be found, a simple implementation using a ConcurrentHashMap as
the cache store is configured. This is the default if no caching library is present in your application. By
default, caches are created as needed, but you can restrict the list of available caches by setting the
cache-names property. For instance, if you want only cache1 and cache2 caches, set the cache-
names property as follows:
spring.cache.cache-names=cache1,cache2
If you do so and your application uses a cache not listed, then it fails at runtime when the cache is
needed, but not on startup. This is similar to the way the "real" cache providers behave if you use an
undeclared cache.
None
When @EnableCaching is present in your configuration, a suitable cache configuration is expected as
well. If you need to disable caching altogether in certain environments, force the cache type to none to
use a no-op implementation, as shown in the following example:
spring.cache.type=none
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32. Messaging
The Spring Framework provides extensive support for integrating with messaging systems, from
simplified use of the JMS API using JmsTemplate to a complete infrastructure to receive messages
asynchronously. Spring AMQP provides a similar feature set for the Advanced Message Queuing
Protocol. Spring Boot also provides auto-configuration options for RabbitTemplate and RabbitMQ.
Spring WebSocket natively includes support for STOMP messaging, and Spring Boot has support for
that through starters and a small amount of auto-configuration. Spring Boot also has support for Apache
Kafka.
32.1 JMS
The javax.jms.ConnectionFactory interface provides a standard method of creating
a javax.jms.Connection for interacting with a JMS broker. Although Spring needs a
ConnectionFactory to work with JMS, you generally need not use it directly yourself and can
instead rely on higher level messaging abstractions. (See the relevant section of the Spring Framework
reference documentation for details.) Spring Boot also auto-configures the necessary infrastructure to
send and receive messages.
ActiveMQ Support
When ActiveMQ is available on the classpath, Spring Boot can also configure a ConnectionFactory.
If the broker is present, an embedded broker is automatically started and configured (provided no broker
URL is specified through configuration).
Note
If you use spring-boot-starter-activemq, the necessary dependencies to connect or
embed an ActiveMQ instance are provided, as is the Spring infrastructure to integrate with JMS.
ActiveMQ configuration is controlled by external configuration properties in spring.activemq.*. For
example, you might declare the following section in application.properties:
spring.activemq.broker-url=tcp://192.168.1.210:9876
spring.activemq.user=admin
spring.activemq.password=secret
You can also pool JMS resources by adding a dependency to org.apache.activemq:activemq-
pool and configuring the PooledConnectionFactory accordingly, as shown in the following
example:
spring.activemq.pool.enabled=true
spring.activemq.pool.max-connections=50
Tip
See ActiveMQProperties for more of the supported options. You can also register an
arbitrary number of beans that implement ActiveMQConnectionFactoryCustomizer for
more advanced customizations.
By default, ActiveMQ creates a destination if it does not yet exist so that destinations are resolved
against their provided names.
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Artemis Support
Spring Boot can auto-configure a ConnectionFactory when it detects that Artemis is available on the
classpath. If the broker is present, an embedded broker is automatically started and configured (unless
the mode property has been explicitly set). The supported modes are embedded (to make explicit that
an embedded broker is required and that an error should occur if the broker is not available on the
classpath) and native (to connect to a broker using the netty transport protocol). When the latter is
configured, Spring Boot configures a ConnectionFactory that connects to a broker running on the
local machine with the default settings.
Note
If you use spring-boot-starter-artemis, the necessary dependencies to connect to an
existing Artemis instance are provided, as well as the Spring infrastructure to integrate with
JMS. Adding org.apache.activemq:artemis-jms-server to your application lets you use
embedded mode.
Artemis configuration is controlled by external configuration properties in spring.artemis.*. For
example, you might declare the following section in application.properties:
spring.artemis.mode=native
spring.artemis.host=192.168.1.210
spring.artemis.port=9876
spring.artemis.user=admin
spring.artemis.password=secret
When embedding the broker, you can choose if you want to enable persistence and list
the destinations that should be made available. These can be specified as a comma-
separated list to create them with the default options, or you can define bean(s)
of type org.apache.activemq.artemis.jms.server.config.JMSQueueConfiguration or
org.apache.activemq.artemis.jms.server.config.TopicConfiguration, for advanced
queue and topic configurations, respectively.
See ArtemisProperties for more supported options.
No JNDI lookup is involved, and destinations are resolved against their names, using either the name
attribute in the Artemis configuration or the names provided through configuration.
Using a JNDI ConnectionFactory
If you are running your application in an application server, Spring Boot tries to locate
a JMS ConnectionFactory by using JNDI. By default, the java:/JmsXA and java:/
XAConnectionFactory location are checked. You can use the spring.jms.jndi-name property
if you need to specify an alternative location, as shown in the following example:
spring.jms.jndi-name=java:/MyConnectionFactory
Sending a Message
Spring’s JmsTemplate is auto-configured, and you can autowire it directly into your own beans, as
shown in the following example:
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jms.core.JmsTemplate;
import org.springframework.stereotype.Component;
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@Component
public class MyBean {
private final JmsTemplate jmsTemplate;
@Autowired
public MyBean(JmsTemplate jmsTemplate) {
this.jmsTemplate = jmsTemplate;
}
// ...
}
Note
JmsMessagingTemplate can be injected in a similar manner. If a DestinationResolver
or a MessageConverter bean is defined, it is associated automatically to the auto-configured
JmsTemplate.
Receiving a Message
When the JMS infrastructure is present, any bean can be annotated with @JmsListener to create
a listener endpoint. If no JmsListenerContainerFactory has been defined, a default one is
configured automatically. If a DestinationResolver or a MessageConverter beans is defined, it
is associated automatically to the default factory.
By default, the default factory is transactional. If you run in an infrastructure where a
JtaTransactionManager is present, it is associated to the listener container by default. If not, the
sessionTransacted flag is enabled. In that latter scenario, you can associate your local data store
transaction to the processing of an incoming message by adding @Transactional on your listener
method (or a delegate thereof). This ensures that the incoming message is acknowledged, once the local
transaction has completed. This also includes sending response messages that have been performed
on the same JMS session.
The following component creates a listener endpoint on the someQueue destination:
@Component
public class MyBean {
@JmsListener(destination = "someQueue")
public void processMessage(String content) {
// ...
}
}
Tip
See the Javadoc of @EnableJms for more details.
If you need to create more JmsListenerContainerFactory instances or if you want to override the
default, Spring Boot provides a DefaultJmsListenerContainerFactoryConfigurer that you
can use to initialize a DefaultJmsListenerContainerFactory with the same settings as the one
that is auto-configured.
For instance, the following example exposes another factory that uses a specific MessageConverter:
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@Configuration
static class JmsConfiguration {
@Bean
public DefaultJmsListenerContainerFactory myFactory(
DefaultJmsListenerContainerFactoryConfigurer configurer) {
DefaultJmsListenerContainerFactory factory =
new DefaultJmsListenerContainerFactory();
configurer.configure(factory, connectionFactory());
factory.setMessageConverter(myMessageConverter());
return factory;
}
}
Then you can use the factory in any @JmsListener-annotated method as follows:
@Component
public class MyBean {
@JmsListener(destination = "someQueue", containerFactory="myFactory")
public void processMessage(String content) {
// ...
}
}
32.2 AMQP
The Advanced Message Queuing Protocol (AMQP) is a platform-neutral, wire-level protocol for
message-oriented middleware. The Spring AMQP project applies core Spring concepts to the
development of AMQP-based messaging solutions. Spring Boot offers several conveniences for working
with AMQP through RabbitMQ, including the spring-boot-starter-amqp “Starter”.
RabbitMQ support
RabbitMQ is a lightweight, reliable, scalable, and portable message broker based on the AMQP protocol.
Spring uses RabbitMQ to communicate through the AMQP protocol.
RabbitMQ configuration is controlled by external configuration properties in spring.rabbitmq.*. For
example, you might declare the following section in application.properties:
spring.rabbitmq.host=localhost
spring.rabbitmq.port=5672
spring.rabbitmq.username=admin
spring.rabbitmq.password=secret
If a ConnectionNameStrategy bean exists in the context, it will be automatically used to name
connections created by the auto-configured ConnectionFactory. See RabbitProperties for more
of the supported options.
Tip
See Understanding AMQP, the protocol used by RabbitMQ for more details.
Sending a Message
Spring’s AmqpTemplate and AmqpAdmin are auto-configured, and you can autowire them directly into
your own beans, as shown in the following example:
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import org.springframework.amqp.core.AmqpAdmin;
import org.springframework.amqp.core.AmqpTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
@Component
public class MyBean {
private final AmqpAdmin amqpAdmin;
private final AmqpTemplate amqpTemplate;
@Autowired
public MyBean(AmqpAdmin amqpAdmin, AmqpTemplate amqpTemplate) {
this.amqpAdmin = amqpAdmin;
this.amqpTemplate = amqpTemplate;
}
// ...
}
Note
RabbitMessagingTemplate can be injected in a similar manner. If a MessageConverter
bean is defined, it is associated automatically to the auto-configured AmqpTemplate.
If necessary, any org.springframework.amqp.core.Queue that is defined as a bean is
automatically used to declare a corresponding queue on the RabbitMQ instance.
To retry operations, you can enable retries on the AmqpTemplate (for example, in the event that the
broker connection is lost). Retries are disabled by default.
Receiving a Message
When the Rabbit infrastructure is present, any bean can be annotated with @RabbitListener to
create a listener endpoint. If no RabbitListenerContainerFactory has been defined, a default
SimpleRabbitListenerContainerFactory is automatically configured and you can switch to a
direct container using the spring.rabbitmq.listener.type property. If a MessageConverter
or a MessageRecoverer bean is defined, it is automatically associated with the default factory.
The following sample component creates a listener endpoint on the someQueue queue:
@Component
public class MyBean {
@RabbitListener(queues = "someQueue")
public void processMessage(String content) {
// ...
}
}
Tip
See the Javadoc of @EnableRabbit for more details.
If you need to create more RabbitListenerContainerFactory instances or if you want to override
the default, Spring Boot provides a SimpleRabbitListenerContainerFactoryConfigurer
and a DirectRabbitListenerContainerFactoryConfigurer that you can
use to initialize a SimpleRabbitListenerContainerFactory and a
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DirectRabbitListenerContainerFactory with the same settings as the factories used by the
auto-configuration.
Tip
It does not matter which container type you chose. Those two beans are exposed by the auto-
configuration.
For instance, the following configuration class exposes another factory that uses a specific
MessageConverter:
@Configuration
static class RabbitConfiguration {
@Bean
public SimpleRabbitListenerContainerFactory myFactory(
SimpleRabbitListenerContainerFactoryConfigurer configurer) {
SimpleRabbitListenerContainerFactory factory =
new SimpleRabbitListenerContainerFactory();
configurer.configure(factory, connectionFactory);
factory.setMessageConverter(myMessageConverter());
return factory;
}
}
Then you can use the factory in any @RabbitListener-annotated method, as follows:
@Component
public class MyBean {
@RabbitListener(queues = "someQueue", containerFactory="myFactory")
public void processMessage(String content) {
// ...
}
}
You can enable retries to handle situations where your listener throws an exception. By default,
RejectAndDontRequeueRecoverer is used, but you can define a MessageRecoverer of your own.
When retries are exhausted, the message is rejected and either dropped or routed to a dead-letter
exchange if the broker is configured to do so. By default, retries are disabled.
Important
By default, if retries are disabled and the listener throws an exception, the
delivery is retried indefinitely. You can modify this behavior in two ways: Set the
defaultRequeueRejected property to false so that zero re-deliveries are attempted or throw
an AmqpRejectAndDontRequeueException to signal the message should be rejected. The
latter is the mechanism used when retries are enabled and the maximum number of delivery
attempts is reached.
32.3 Apache Kafka Support
Apache Kafka is supported by providing auto-configuration of the spring-kafka project.
Kafka configuration is controlled by external configuration properties in spring.kafka.*. For
example, you might declare the following section in application.properties:
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spring.kafka.bootstrap-servers=localhost:9092
spring.kafka.consumer.group-id=myGroup
Tip
To create a topic on startup, add a bean of type NewTopic. If the topic already exists, the bean
is ignored.
See KafkaProperties for more supported options.
Sending a Message
Spring’s KafkaTemplate is auto-configured, and you can autowire it directly in your own beans, as
shown in the following example:
@Component
public class MyBean {
private final KafkaTemplate kafkaTemplate;
@Autowired
public MyBean(KafkaTemplate kafkaTemplate) {
this.kafkaTemplate = kafkaTemplate;
}
// ...
}
Note
If a RecordMessageConverter bean is defined, it is automatically associated to the auto-
configured KafkaTemplate.
Receiving a Message
When the Apache Kafka infrastructure is present, any bean can be annotated with @KafkaListener
to create a listener endpoint. If no KafkaListenerContainerFactory has been defined, a
default one is automatically configured with keys defined in spring.kafka.listener.*. Also, if a
RecordMessageConverter bean is defined, it is automatically associated to the default factory.
The following component creates a listener endpoint on the someTopic topic:
@Component
public class MyBean {
@KafkaListener(topics = "someTopic")
public void processMessage(String content) {
// ...
}
}
Additional Kafka Properties
The properties supported by auto configuration are shown in Appendix A, Common application
properties. Note that, for the most part, these properties (hyphenated or camelCase) map directly to the
Apache Kafka dotted properties. Refer to the Apache Kafka documentation for details.
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The first few of these properties apply to both producers and consumers but can be specified at the
producer or consumer level if you wish to use different values for each. Apache Kafka designates
properties with an importance of HIGH, MEDIUM, or LOW. Spring Boot auto-configuration supports all
HIGH importance properties, some selected MEDIUM and LOW properties, and any properties that do
not have a default value.
Only a subset of the properties supported by Kafka are available through the KafkaProperties
class. If you wish to configure the producer or consumer with additional properties that are not directly
supported, use the following properties:
spring.kafka.properties.prop.one=first
spring.kafka.admin.properties.prop.two=second
spring.kafka.consumer.properties.prop.three=third
spring.kafka.producer.properties.prop.four=fourth
This sets the common prop.one Kafka property to first (applies to producers, consumers and
admins), the prop.two admin property to second, the prop.three consumer property to third and
the prop.four producer property to fourth.
You can also configure the Spring Kafka JsonDeserializer as follows:
spring.kafka.consumer.value-deserializer=org.springframework.kafka.support.serializer.JsonDeserializer
spring.kafka.consumer.properties.spring.json.value.default.type=com.example.Invoice
spring.kafka.consumer.properties.spring.json.trusted.packages=com.example,org.acme
Similarly, you can disable the JsonSerializer default behavior of sending type information in
headers:
spring.kafka.producer.value-serializer=org.springframework.kafka.support.serializer.JsonSerializer
spring.kafka.producer.properties.spring.json.add.type.headers=false
Important
Properties set in this way override any configuration item that Spring Boot explicitly supports.
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33. Calling REST Services with RestTemplate
If you need to call remote REST services from your application, you can use the Spring Framework’s
RestTemplate class. Since RestTemplate instances often need to be customized before being
used, Spring Boot does not provide any single auto-configured RestTemplate bean. It does,
however, auto-configure a RestTemplateBuilder, which can be used to create RestTemplate
instances when needed. The auto-configured RestTemplateBuilder ensures that sensible
HttpMessageConverters are applied to RestTemplate instances.
The following code shows a typical example:
@Service
public class MyService {
private final RestTemplate restTemplate;
public MyService(RestTemplateBuilder restTemplateBuilder) {
this.restTemplate = restTemplateBuilder.build();
}
public Details someRestCall(String name) {
return this.restTemplate.getForObject("/{name}/details", Details.class, name);
}
}
Tip
RestTemplateBuilder includes a number of useful methods that can be used to quickly
configure a RestTemplate. For example, to add BASIC auth support, you can use
builder.basicAuthorization("user", "password").build().
33.1 RestTemplate Customization
There are three main approaches to RestTemplate customization, depending on how broadly you
want the customizations to apply.
To make the scope of any customizations as narrow as possible, inject the auto-configured
RestTemplateBuilder and then call its methods as required. Each method call returns a new
RestTemplateBuilder instance, so the customizations only affect this use of the builder.
To make an application-wide, additive customization, use a RestTemplateCustomizer bean. All
such beans are automatically registered with the auto-configured RestTemplateBuilder and are
applied to any templates that are built with it.
The following example shows a customizer that configures the use of a proxy for all hosts except
192.168.0.5:
static class ProxyCustomizer implements RestTemplateCustomizer {
@Override
public void customize(RestTemplate restTemplate) {
HttpHost proxy = new HttpHost("proxy.example.com");
HttpClient httpClient = HttpClientBuilder.create()
.setRoutePlanner(new DefaultProxyRoutePlanner(proxy) {
@Override
public HttpHost determineProxy(HttpHost target,
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HttpRequest request, HttpContext context)
throws HttpException {
if (target.getHostName().equals("192.168.0.5")) {
return null;
}
return super.determineProxy(target, request, context);
}
}).build();
restTemplate.setRequestFactory(
new HttpComponentsClientHttpRequestFactory(httpClient));
}
}
Finally, the most extreme (and rarely used) option is to create your own RestTemplateBuilder
bean. Doing so switches off the auto-configuration of a RestTemplateBuilder and prevents any
RestTemplateCustomizer beans from being used.
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34. Calling REST Services with WebClient
If you have Spring WebFlux on your classpath, you can also choose to use WebClient to call remote
REST services. Compared to RestTemplate, this client has a more functional feel and is fully reactive.
You can create your own client instance with the builder, WebClient.create(). See the relevant
section on WebClient.
Spring Boot creates and pre-configures such a builder for you. For example, client HTTP codecs are
configured in the same fashion as the server ones (see WebFlux HTTP codecs auto-configuration).
The following code shows a typical example:
@Service
public class MyService {
private final WebClient webClient;
public MyService(WebClient.Builder webClientBuilder) {
this.webClient = webClientBuilder.baseUrl("http://example.org").build();
}
public Mono<Details> someRestCall(String name) {
return this.webClient.get().url("/{name}/details", name)
.retrieve().bodyToMono(Details.class);
}
}
34.1 WebClient Customization
There are three main approaches to WebClient customization, depending on how broadly you want
the customizations to apply.
To make the scope of any customizations as narrow as possible, inject the auto-configured
WebClient.Builder and then call its methods as required. WebClient.Builder instances are
stateful: Any change on the builder is reflected in all clients subsequently created with it. If you
want to create several clients with the same builder, you can also consider cloning the builder with
WebClient.Builder other = builder.clone();.
To make an application-wide, additive customization to all WebClient.Builder instances, you can
declare WebClientCustomizer beans and change the WebClient.Builder locally at the point of
injection.
Finally, you can fall back to the original API and use WebClient.create(). In that case, no auto-
configuration or WebClientCustomizer is applied.
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35. Validation
The method validation feature supported by Bean Validation 1.1 is automatically enabled as long as
a JSR-303 implementation (such as Hibernate validator) is on the classpath. This lets bean methods
be annotated with javax.validation constraints on their parameters and/or on their return value.
Target classes with such annotated methods need to be annotated with the @Validated annotation at
the type level for their methods to be searched for inline constraint annotations.
For instance, the following service triggers the validation of the first argument, making sure its size is
between 8 and 10:
@Service
@Validated
public class MyBean {
public Archive findByCodeAndAuthor(@Size(min = 8, max = 10) String code,
Author author) {
...
}
}
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36. Sending Email
The Spring Framework provides an easy abstraction for sending email by using the JavaMailSender
interface, and Spring Boot provides auto-configuration for it as well as a starter module.
Tip
See the reference documentation for a detailed explanation of how you can use
JavaMailSender.
If spring.mail.host and the relevant libraries (as defined by spring-boot-starter-mail) are
available, a default JavaMailSender is created if none exists. The sender can be further customized
by configuration items from the spring.mail namespace. See MailProperties for more details.
In particular, certain default timeout values are infinite, and you may want to change that to avoid having
a thread blocked by an unresponsive mail server, as shown in the following example:
spring.mail.properties.mail.smtp.connectiontimeout=5000
spring.mail.properties.mail.smtp.timeout=3000
spring.mail.properties.mail.smtp.writetimeout=5000
It is also possible to configure a JavaMailSender with an existing Session from JNDI:
spring.mail.jndi-name=mail/Session
When a jndi-name is set, it takes precedence over all other Session-related settings.
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37. Distributed Transactions with JTA
Spring Boot supports distributed JTA transactions across multiple XA resources by using either an
Atomikos or Bitronix embedded transaction manager. JTA transactions are also supported when
deploying to a suitable Java EE Application Server.
When a JTA environment is detected, Spring’s JtaTransactionManager is used to manage
transactions. Auto-configured JMS, DataSource, and JPA beans are upgraded to support XA
transactions. You can use standard Spring idioms, such as @Transactional, to participate in a
distributed transaction. If you are within a JTA environment and still want to use local transactions, you
can set the spring.jta.enabled property to false to disable the JTA auto-configuration.
37.1 Using an Atomikos Transaction Manager
Atomikos is a popular open source transaction manager which can be embedded into your Spring
Boot application. You can use the spring-boot-starter-jta-atomikos Starter to pull in the
appropriate Atomikos libraries. Spring Boot auto-configures Atomikos and ensures that appropriate
depends-on settings are applied to your Spring beans for correct startup and shutdown ordering.
By default, Atomikos transaction logs are written to a transaction-logs directory in your
application’s home directory (the directory in which your application jar file resides). You can
customize the location of this directory by setting a spring.jta.log-dir property in your
application.properties file. Properties starting with spring.jta.atomikos.properties
can also be used to customize the Atomikos UserTransactionServiceImp. See the
AtomikosProperties Javadoc for complete details.
Note
To ensure that multiple transaction managers can safely coordinate the same resource managers,
each Atomikos instance must be configured with a unique ID. By default, this ID is the IP address
of the machine on which Atomikos is running. To ensure uniqueness in production, you should
configure the spring.jta.transaction-manager-id property with a different value for each
instance of your application.
37.2 Using a Bitronix Transaction Manager
Bitronix is a popular open-source JTA transaction manager implementation. You can use the spring-
boot-starter-jta-bitronix starter to add the appropriate Bitronix dependencies to your project.
As with Atomikos, Spring Boot automatically configures Bitronix and post-processes your beans to
ensure that startup and shutdown ordering is correct.
By default, Bitronix transaction log files (part1.btm and part2.btm) are written to a
transaction-logs directory in your application home directory. You can customize the
location of this directory by setting the spring.jta.log-dir property. Properties starting with
spring.jta.bitronix.properties are also bound to the bitronix.tm.Configuration bean,
allowing for complete customization. See the Bitronix documentation for details.
Note
To ensure that multiple transaction managers can safely coordinate the same resource managers,
each Bitronix instance must be configured with a unique ID. By default, this ID is the IP address
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of the machine on which Bitronix is running. To ensure uniqueness in production, you should
configure the spring.jta.transaction-manager-id property with a different value for each
instance of your application.
37.3 Using a Narayana Transaction Manager
Narayana is a popular open source JTA transaction manager implementation supported by JBoss.
You can use the spring-boot-starter-jta-narayana starter to add the appropriate Narayana
dependencies to your project. As with Atomikos and Bitronix, Spring Boot automatically configures
Narayana and post-processes your beans to ensure that startup and shutdown ordering is correct.
By default, Narayana transaction logs are written to a transaction-logs directory in your application
home directory (the directory in which your application jar file resides). You can customize the location
of this directory by setting a spring.jta.log-dir property in your application.properties
file. Properties starting with spring.jta.narayana.properties can also be used to customize the
Narayana configuration. See the NarayanaProperties Javadoc for complete details.
Note
To ensure that multiple transaction managers can safely coordinate the same resource managers,
each Narayana instance must be configured with a unique ID. By default, this ID is set to 1.
To ensure uniqueness in production, you should configure the spring.jta.transaction-
manager-id property with a different value for each instance of your application.
37.4 Using a Java EE Managed Transaction Manager
If you package your Spring Boot application as a war or ear file and deploy it to a Java EE
application server, you can use your application server’s built-in transaction manager. Spring Boot
tries to auto-configure a transaction manager by looking at common JNDI locations (java:comp/
UserTransaction, java:comp/TransactionManager, and so on). If you use a transaction service
provided by your application server, you generally also want to ensure that all resources are managed
by the server and exposed over JNDI. Spring Boot tries to auto-configure JMS by looking for a
ConnectionFactory at the JNDI path (java:/JmsXA or java:/XAConnectionFactory), and you
can use the spring.datasource.jndi-name property to configure your DataSource.
37.5 Mixing XA and Non-XA JMS Connections
When using JTA, the primary JMS ConnectionFactory bean is XA-aware and participates in
distributed transactions. In some situations, you might want to process certain JMS messages by using
a non-XA ConnectionFactory. For example, your JMS processing logic might take longer than the
XA timeout.
If you want to use a non-XA ConnectionFactory, you can inject the
nonXaJmsConnectionFactory bean rather than the @Primary jmsConnectionFactory bean.
For consistency, the jmsConnectionFactory bean is also provided by using the bean alias
xaJmsConnectionFactory.
The following example shows how to inject ConnectionFactory instances:
// Inject the primary (XA aware) ConnectionFactory
@Autowired
private ConnectionFactory defaultConnectionFactory;
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// Inject the XA aware ConnectionFactory (uses the alias and injects the same as above)
@Autowired
@Qualifier("xaJmsConnectionFactory")
private ConnectionFactory xaConnectionFactory;
// Inject the non-XA aware ConnectionFactory
@Autowired
@Qualifier("nonXaJmsConnectionFactory")
private ConnectionFactory nonXaConnectionFactory;
37.6 Supporting an Alternative Embedded Transaction
Manager
The XAConnectionFactoryWrapper and XADataSourceWrapper interfaces can be used
to support alternative embedded transaction managers. The interfaces are responsible for
wrapping XAConnectionFactory and XADataSource beans and exposing them as regular
ConnectionFactory and DataSource beans, which transparently enroll in the distributed
transaction. DataSource and JMS auto-configuration use JTA variants, provided you have a
JtaTransactionManager bean and appropriate XA wrapper beans registered within your
ApplicationContext.
The BitronixXAConnectionFactoryWrapper and BitronixXADataSourceWrapper provide good examples
of how to write XA wrappers.
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38. Hazelcast
If Hazelcast is on the classpath and a suitable configuration is found, Spring Boot auto-configures a
HazelcastInstance that you can inject in your application.
If you define a com.hazelcast.config.Config bean, Spring Boot uses that. If your configuration
defines an instance name, Spring Boot tries to locate an existing instance rather than creating a new one.
You could also specify the hazelcast.xml configuration file to use through configuration, as shown
in the following example:
spring.hazelcast.config=classpath:config/my-hazelcast.xml
Otherwise, Spring Boot tries to find the Hazelcast configuration from the default locations:
hazelcast.xml in the working directory or at the root of the classpath. We also check if the
hazelcast.config system property is set. See the Hazelcast documentation for more details.
If hazelcast-client is present on the classpath, Spring Boot first attempts to create a client by
checking the following configuration options:
• The presence of a com.hazelcast.client.config.ClientConfig bean.
• A configuration file defined by the spring.hazelcast.config property.
• The presence of the hazelcast.client.config system property.
• A hazelcast-client.xml in the working directory or at the root of the classpath.
Note
Spring Boot also has explicit caching support for Hazelcast. If caching is enabled, the
HazelcastInstance is automatically wrapped in a CacheManager implementation.
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39. Quartz Scheduler
Spring Boot offers several conveniences for working with the Quartz scheduler, including the spring-
boot-starter-quartz “Starter”. If Quartz is available, a Scheduler is auto-configured (through the
SchedulerFactoryBean abstraction).
Beans of the following types are automatically picked up and associated with the Scheduler:
•JobDetail: defines a particular Job. JobDetail instances can be built with the JobBuilder API.
•Calendar.
•Trigger: defines when a particular job is triggered.
By default, an in-memory JobStore is used. However, it is possible to configure a JDBC-based store
if a DataSource bean is available in your application and if the spring.quartz.job-store-type
property is configured accordingly, as shown in the following example:
spring.quartz.job-store-type=jdbc
When the JDBC store is used, the schema can be initialized on startup, as shown in the following
example:
spring.quartz.jdbc.initialize-schema=always
Note
By default, the database is detected and initialized by using the standard scripts provided
with the Quartz library. It is also possible to provide a custom script by setting the
spring.quartz.jdbc.schema property.
Quartz Scheduler configuration can be customized by using Quartz configuration properties
()spring.quartz.properties.*) and SchedulerFactoryBeanCustomizer beans, which allow
programmatic SchedulerFactoryBean customization.
Note
In particular, an Executor bean is not associated with the scheduler as Quartz offers a way to
configure the scheduler via spring.quartz.properties. If you need to customize the task
executor, consider implementing SchedulerFactoryBeanCustomizer.
Jobs can define setters to inject data map properties. Regular beans can also be injected in a similar
manner, as shown in the following example:
public class SampleJob extends QuartzJobBean {
private MyService myService;
private String name;
// Inject "MyService" bean
public void setMyService(MyService myService) { ... }
// Inject the "name" job data property
public void setName(String name) { ... }
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@Override
protected void executeInternal(JobExecutionContext context)
throws JobExecutionException {
...
}
}
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40. Spring Integration
Spring Boot offers several conveniences for working with Spring Integration, including the spring-
boot-starter-integration “Starter”. Spring Integration provides abstractions over messaging and
also other transports such as HTTP, TCP, and others. If Spring Integration is available on your classpath,
it is initialized through the @EnableIntegration annotation.
Spring Boot also configures some features that are triggered by the presence of additional Spring
Integration modules. If spring-integration-jmx is also on the classpath, message processing
statistics are published over JMX . If spring-integration-jdbc is available, the default database
schema can be created on startup, as shown in the following line:
spring.integration.jdbc.initialize-schema=always
See the IntegrationAutoConfiguration and IntegrationProperties classes for more
details.
By default, if a Micrometer meterRegistry bean is present, Spring Integration metrics will be managed
by Micrometer. If you wish to use legacy Spring Integration metrics, add a DefaultMetricsFactory
bean to the application context.
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41. Spring Session
Spring Boot provides Spring Session auto-configuration for a wide range of data stores. When building
a Servlet web application, the following stores can be auto-configured:
• JDBC
• Redis
• Hazelcast
• MongoDB
When building a reactive web application, the following stores can be auto-configured:
• Redis
• MongoDB
If a single Spring Session module is present on the classpath, Spring Boot uses that store
implementation automatically. If you have more than one implementation, you must choose the
StoreType that you wish to use to store the sessions. For instance, to use JDBC as the back-end
store, you can configure your application as follows:
spring.session.store-type=jdbc
Tip
You can disable Spring Session by setting the store-type to none.
Each store has specific additional settings. For instance, it is possible to customize the name of the
table for the JDBC store, as shown in the following example:
spring.session.jdbc.table-name=SESSIONS
For setting the timeout of the session you can use the spring.session.timeout
property. If that property is not set, the auto-configuration falls back to the value of
server.servlet.session.timeout.
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42. Monitoring and Management over JMX
Java Management Extensions (JMX) provide a standard mechanism to monitor and manage
applications. By default, Spring Boot creates an MBeanServer bean with an ID of mbeanServer and
exposes any of your beans that are annotated with Spring JMX annotations (@ManagedResource,
@ManagedAttribute, or @ManagedOperation).
See the JmxAutoConfiguration class for more details.
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43. Testing
Spring Boot provides a number of utilities and annotations to help when testing your application. Test
support is provided by two modules: spring-boot-test contains core items, and spring-boot-
test-autoconfigure supports auto-configuration for tests.
Most developers use the spring-boot-starter-test “Starter”, which imports both Spring Boot test
modules as well as JUnit, AssertJ, Hamcrest, and a number of other useful libraries.
43.1 Test Scope Dependencies
The spring-boot-starter-test “Starter” (in the test scope) contains the following provided
libraries:
•JUnit: The de-facto standard for unit testing Java applications.
•Spring Test & Spring Boot Test: Utilities and integration test support for Spring Boot applications.
•AssertJ: A fluent assertion library.
•Hamcrest: A library of matcher objects (also known as constraints or predicates).
•Mockito: A Java mocking framework.
•JSONassert: An assertion library for JSON.
•JsonPath: XPath for JSON.
We generally find these common libraries to be useful when writing tests. If these libraries do not suit
your needs, you can add additional test dependencies of your own.
43.2 Testing Spring Applications
One of the major advantages of dependency injection is that it should make your code easier to unit
test. You can instantiate objects by using the new operator without even involving Spring. You can also
use mock objects instead of real dependencies.
Often, you need to move beyond unit testing and start integration testing (with a Spring
ApplicationContext). It is useful to be able to perform integration testing without requiring
deployment of your application or needing to connect to other infrastructure.
The Spring Framework includes a dedicated test module for such integration testing. You can
declare a dependency directly to org.springframework:spring-test or use the spring-boot-
starter-test “Starter” to pull it in transitively.
If you have not used the spring-test module before, you should start by reading the relevant section
of the Spring Framework reference documentation.
43.3 Testing Spring Boot Applications
A Spring Boot application is a Spring ApplicationContext, so nothing very special has to be done
to test it beyond what you would normally do with a vanilla Spring context.
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Note
External properties, logging, and other features of Spring Boot are installed in the context by
default only if you use SpringApplication to create it.
Spring Boot provides a @SpringBootTest annotation, which can be used as an alternative to
the standard spring-test @ContextConfiguration annotation when you need Spring Boot
features. The annotation works by creating the ApplicationContext used in your tests through
SpringApplication. In addition to @SpringBootTest a number of other annotations are also
provided for testing more specific slices of an application.
Tip
Don’t forget to also add @RunWith(SpringRunner.class) to your test, otherwise the
annotations will be ignored.
By default, @SpringBootTest will not start a server. You can use the webEnvironment attribute of
@SpringBootTest to further refine how your tests run:
•MOCK(Default) : Loads a web ApplicationContext and provides a mock web environment.
Embedded servers are not started when using this annotation. If a web environment is not
available on your classpath, this mode transparently falls back to creating a regular non-
web ApplicationContext. It can be used in conjunction with @AutoConfigureMockMvc or
@AutoConfigureWebTestClient for mock-based testing of your web application.
•RANDOM_PORT: Loads a WebServerApplicationContext and provides a real web environment.
Embedded servers are started and listen on a random port.
•DEFINED_PORT: Loads a WebServerApplicationContext and provides a real web environment.
Embedded servers are started and listen on a defined port (from your application.properties
or on the default port of 8080).
•NONE: Loads an ApplicationContext by using SpringApplication but does not provide any
web environment (mock or otherwise).
Note
If your test is @Transactional, it rolls back the transaction at the end of each test method
by default. However, as using this arrangement with either RANDOM_PORT or DEFINED_PORT
implicitly provides a real servlet environment, the HTTP client and server run in separate threads
and, thus, in separate transactions. Any transaction initiated on the server does not roll back in
this case.
Detecting Web Application Type
If Spring MVC is available, a regular MVC-based application context is configured. If you have only
Spring WebFlux, we’ll detect that and configure a WebFlux-based application context instead.
If both are present, Spring MVC takes precedence. If you want to test a reactive web application in this
scenario, you must set the spring.main.web-application-type property:
@RunWith(SpringRunner.class)
@SpringBootTest(properties = "spring.main.web-application-type=reactive")
public class MyWebFluxTests { ... }
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Detecting Test Configuration
If you are familiar with the Spring Test Framework, you may be used to using
@ContextConfiguration(classes=…) in order to specify which Spring @Configuration to load.
Alternatively, you might have often used nested @Configuration classes within your test.
When testing Spring Boot applications, this is often not required. Spring Boot’s @*Test annotations
search for your primary configuration automatically whenever you do not explicitly define one.
The search algorithm works up from the package that contains the test until it finds a class annotated
with @SpringBootApplication or @SpringBootConfiguration. As long as you structured your
code in a sensible way, your main configuration is usually found.
Note
If you use a test annotation to test a more specific slice of your application, you should avoid adding
configuration settings that are specific to a particular area on the main method’s application class.
The underlying component scan configuration of @SpringBootApplication defines exclude
filters that are used to make sure slicing works as expected. If you are using an explicit
@ComponentScan directive on your @SpringBootApplication-annotated class, be aware
that those filters will be disabled. If you are using slicing, you should define them again.
If you want to customize the primary configuration, you can use a nested @TestConfiguration class.
Unlike a nested @Configuration class, which would be used instead of your application’s primary
configuration, a nested @TestConfiguration class is used in addition to your application’s primary
configuration.
Note
Spring’s test framework caches application contexts between tests. Therefore, as long as your
tests share the same configuration (no matter how it is discovered), the potentially time-consuming
process of loading the context happens only once.
Excluding Test Configuration
If your application uses component scanning (for example, if you use @SpringBootApplication or
@ComponentScan), you may find top-level configuration classes that you created only for specific tests
accidentally get picked up everywhere.
As we have seen earlier, @TestConfiguration can be used on an inner class of a test to customize
the primary configuration. When placed on a top-level class, @TestConfiguration indicates that
classes in src/test/java should not be picked up by scanning. You can then import that class
explicitly where it is required, as shown in the following example:
@RunWith(SpringRunner.class)
@SpringBootTest
@Import(MyTestsConfiguration.class)
public class MyTests {
@Test
public void exampleTest() {
...
}
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}
Note
If you directly use @ComponentScan (that is, not through @SpringBootApplication) you
need to register the TypeExcludeFilter with it. See the Javadoc for details.
Testing with a mock environment
By default, @SpringBootTest does not start the server. If you have web endpoints that you want to
test against this mock environment, you can additionally configure MockMvc as shown in the following
example:
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.web.servlet.MockMvc;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
@RunWith(SpringRunner.class)
@SpringBootTest
@AutoConfigureMockMvc
public class MockMvcExampleTests {
@Autowired
private MockMvc mvc;
@Test
public void exampleTest() throws Exception {
this.mvc.perform(get("/")).andExpect(status().isOk())
.andExpect(content().string("Hello World"));
}
}
Tip
If you want to focus only on the web layer and not start a complete ApplicationContext,
consider using @WebMvcTest instead.
Alternatively, you can configure a WebTestClient as shown in the following example:
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.reactive.AutoConfigureWebTestClient;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.web.reactive.server.WebTestClient;
@RunWith(SpringRunner.class)
@SpringBootTest
@AutoConfigureWebTestClient
public class MockWebTestClientExampleTests {
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@Autowired
private WebTestClient webClient;
@Test
public void exampleTest() {
this.webClient.get().uri("/").exchange().expectStatus().isOk()
.expectBody(String.class).isEqualTo("Hello World");
}
}
Testing with a running server
If you need to start a full running server, we recommend that you use random ports. If you
use @SpringBootTest(webEnvironment=WebEnvironment.RANDOM_PORT), an available port
is picked at random each time your test runs.
The @LocalServerPort annotation can be used to inject the actual port used into your test. For
convenience, tests that need to make REST calls to the started server can additionally @Autowire a
WebTestClient, which resolves relative links to the running server and comes with a dedicated API
for verifying responses, as shown in the following example:
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.web.reactive.server.WebTestClient;
@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
public class RandomPortWebTestClientExampleTests {
@Autowired
private WebTestClient webClient;
@Test
public void exampleTest() {
this.webClient.get().uri("/").exchange().expectStatus().isOk()
.expectBody(String.class).isEqualTo("Hello World");
}
}
This setup requires spring-webflux on the classpath. If you can’t or won’t add webflux, Spring Boot
also provides a TestRestTemplate facility:
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
import org.springframework.boot.test.web.client.TestRestTemplate;
import org.springframework.test.context.junit4.SpringRunner;
import static org.assertj.core.api.Assertions.assertThat;
@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
public class RandomPortTestRestTemplateExampleTests {
@Autowired
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private TestRestTemplate restTemplate;
@Test
public void exampleTest() {
String body = this.restTemplate.getForObject("/", String.class);
assertThat(body).isEqualTo("Hello World");
}
}
Using JMX
As the test context framework caches context, JMX is disabled by default to prevent identical
components to register on the same domain. If such test needs access to an MBeanServer, consider
marking it dirty as well:
@RunWith(SpringRunner.class)
@SpringBootTest(properties = "spring.jmx.enabled=true")
@DirtiesContext
public class SampleJmxTests {
@Autowired
private MBeanServer mBeanServer;
@Test
public void exampleTest() {
// ...
}
}
Mocking and Spying Beans
When running tests, it is sometimes necessary to mock certain components within your application
context. For example, you may have a facade over some remote service that is unavailable during
development. Mocking can also be useful when you want to simulate failures that might be hard to
trigger in a real environment.
Spring Boot includes a @MockBean annotation that can be used to define a Mockito mock for a bean
inside your ApplicationContext. You can use the annotation to add new beans or replace a single
existing bean definition. The annotation can be used directly on test classes, on fields within your test,
or on @Configuration classes and fields. When used on a field, the instance of the created mock is
also injected. Mock beans are automatically reset after each test method.
Note
If your test uses one of Spring Boot’s test annotations (such as @SpringBootTest), this feature
is automatically enabled. To use this feature with a different arrangement, a listener must be
explicitly added, as shown in the following example:
@TestExecutionListeners(MockitoTestExecutionListener.class)
The following example replaces an existing RemoteService bean with a mock implementation:
import org.junit.*;
import org.junit.runner.*;
import org.springframework.beans.factory.annotation.*;
import org.springframework.boot.test.context.*;
import org.springframework.boot.test.mock.mockito.*;
import org.springframework.test.context.junit4.*;
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import static org.assertj.core.api.Assertions.*;
import static org.mockito.BDDMockito.*;
@RunWith(SpringRunner.class)
@SpringBootTest
public class MyTests {
@MockBean
private RemoteService remoteService;
@Autowired
private Reverser reverser;
@Test
public void exampleTest() {
// RemoteService has been injected into the reverser bean
given(this.remoteService.someCall()).willReturn("mock");
String reverse = reverser.reverseSomeCall();
assertThat(reverse).isEqualTo("kcom");
}
}
Additionally, you can use @SpyBean to wrap any existing bean with a Mockito spy. See the Javadoc
for full details.
Note
While Spring’s test framework caches application contexts between tests and reuses a context for
tests sharing the same configuration, the use of @MockBean or @SpyBean influences the cache
key, which will most likely increase the number of contexts.
Auto-configured Tests
Spring Boot’s auto-configuration system works well for applications but can sometimes be a little too
much for tests. It often helps to load only the parts of the configuration that are required to test a “slice”
of your application. For example, you might want to test that Spring MVC controllers are mapping URLs
correctly, and you do not want to involve database calls in those tests, or you might want to test JPA
entities, and you are not interested in the web layer when those tests run.
The spring-boot-test-autoconfigure module includes a number of annotations that can be
used to automatically configure such “slices”. Each of them works in a similar way, providing a @…Test
annotation that loads the ApplicationContext and one or more @AutoConfigure… annotations
that can be used to customize auto-configuration settings.
Note
Each slice loads a very restricted set of auto-configuration classes. If you need to exclude
one of them, most @…Test annotations provide an excludeAutoConfiguration attribute.
Alternatively, you can use @ImportAutoConfiguration#exclude.
Tip
It is also possible to use the @AutoConfigure… annotations with the standard
@SpringBootTest annotation. You can use this combination if you are not interested in “slicing”
your application but you want some of the auto-configured test beans.
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Auto-configured JSON Tests
To test that object JSON serialization and deserialization is working as expected, you can use the
@JsonTest annotation. @JsonTest auto-configures the available supported JSON mapper, which can
be one of the following libraries:
• Jackson ObjectMapper, any @JsonComponent beans and any Jackson Modules
•Gson
•Jsonb
If you need to configure elements of the auto-configuration, you can use the
@AutoConfigureJsonTesters annotation.
Spring Boot includes AssertJ-based helpers that work with the JSONassert and JsonPath libraries
to check that JSON appears as expected. The JacksonTester, GsonTester, JsonbTester, and
BasicJsonTester classes can be used for Jackson, Gson, Jsonb, and Strings respectively. Any
helper fields on the test class can be @Autowired when using @JsonTest. The following example
shows a test class for Jackson:
import org.junit.*;
import org.junit.runner.*;
import org.springframework.beans.factory.annotation.*;
import org.springframework.boot.test.autoconfigure.json.*;
import org.springframework.boot.test.context.*;
import org.springframework.boot.test.json.*;
import org.springframework.test.context.junit4.*;
import static org.assertj.core.api.Assertions.*;
@RunWith(SpringRunner.class)
@JsonTest
public class MyJsonTests {
@Autowired
private JacksonTester<VehicleDetails> json;
@Test
public void testSerialize() throws Exception {
VehicleDetails details = new VehicleDetails("Honda", "Civic");
// Assert against a `.json` file in the same package as the test
assertThat(this.json.write(details)).isEqualToJson("expected.json");
// Or use JSON path based assertions
assertThat(this.json.write(details)).hasJsonPathStringValue("@.make");
assertThat(this.json.write(details)).extractingJsonPathStringValue("@.make")
.isEqualTo("Honda");
}
@Test
public void testDeserialize() throws Exception {
String content = "{\"make\":\"Ford\",\"model\":\"Focus\"}";
assertThat(this.json.parse(content))
.isEqualTo(new VehicleDetails("Ford", "Focus"));
assertThat(this.json.parseObject(content).getMake()).isEqualTo("Ford");
}
}
Note
JSON helper classes can also be used directly in standard unit tests. To do so, call the
initFields method of the helper in your @Before method if you do not use @JsonTest.
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A list of the auto-configuration that is enabled by @JsonTest can be found in the appendix.
Auto-configured Spring MVC Tests
To test whether Spring MVC controllers are working as expected, use the @WebMvcTest
annotation. @WebMvcTest auto-configures the Spring MVC infrastructure and limits scanned beans
to @Controller, @ControllerAdvice, @JsonComponent, Converter, GenericConverter,
Filter, WebMvcConfigurer, and HandlerMethodArgumentResolver. Regular @Component
beans are not scanned when using this annotation.
Tip
If you need to register extra components, such as the Jackson Module, you can import additional
configuration classes by using @Import on your test.
Often, @WebMvcTest is limited to a single controller and is used in combination with @MockBean to
provide mock implementations for required collaborators.
@WebMvcTest also auto-configures MockMvc. Mock MVC offers a powerful way to quickly test MVC
controllers without needing to start a full HTTP server.
Tip
You can also auto-configure MockMvc in a non-@WebMvcTest (such as @SpringBootTest) by
annotating it with @AutoConfigureMockMvc. The following example uses MockMvc:
import org.junit.*;
import org.junit.runner.*;
import org.springframework.beans.factory.annotation.*;
import org.springframework.boot.test.autoconfigure.web.servlet.*;
import org.springframework.boot.test.mock.mockito.*;
import static org.assertj.core.api.Assertions.*;
import static org.mockito.BDDMockito.*;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.*;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;
@RunWith(SpringRunner.class)
@WebMvcTest(UserVehicleController.class)
public class MyControllerTests {
@Autowired
private MockMvc mvc;
@MockBean
private UserVehicleService userVehicleService;
@Test
public void testExample() throws Exception {
given(this.userVehicleService.getVehicleDetails("sboot"))
.willReturn(new VehicleDetails("Honda", "Civic"));
this.mvc.perform(get("/sboot/vehicle").accept(MediaType.TEXT_PLAIN))
.andExpect(status().isOk()).andExpect(content().string("Honda Civic"));
}
}
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Tip
If you need to configure elements of the auto-configuration (for example, when servlet filters should
be applied) you can use attributes in the @AutoConfigureMockMvc annotation.
If you use HtmlUnit or Selenium, auto-configuration also provides an HTMLUnit WebClient bean and/
or a WebDriver bean. The following example uses HtmlUnit:
import com.gargoylesoftware.htmlunit.*;
import org.junit.*;
import org.junit.runner.*;
import org.springframework.beans.factory.annotation.*;
import org.springframework.boot.test.autoconfigure.web.servlet.*;
import org.springframework.boot.test.mock.mockito.*;
import static org.assertj.core.api.Assertions.*;
import static org.mockito.BDDMockito.*;
@RunWith(SpringRunner.class)
@WebMvcTest(UserVehicleController.class)
public class MyHtmlUnitTests {
@Autowired
private WebClient webClient;
@MockBean
private UserVehicleService userVehicleService;
@Test
public void testExample() throws Exception {
given(this.userVehicleService.getVehicleDetails("sboot"))
.willReturn(new VehicleDetails("Honda", "Civic"));
HtmlPage page = this.webClient.getPage("/sboot/vehicle.html");
assertThat(page.getBody().getTextContent()).isEqualTo("Honda Civic");
}
}
Note
By default, Spring Boot puts WebDriver beans in a special “scope” to ensure that the driver exits
after each test and that a new instance is injected. If you do not want this behavior, you can add
@Scope("singleton") to your WebDriver @Bean definition.
A list of the auto-configuration settings that are enabled by @WebMvcTest can be found in the appendix.
Tip
Sometimes writing Spring MVC tests is not enough; Spring Boot can help you run full end-to-end
tests with an actual server.
Auto-configured Spring WebFlux Tests
To test that Spring WebFlux controllers are working as expected, you can use the
@WebFluxTest annotation. @WebFluxTest auto-configures the Spring WebFlux infrastructure and
limits scanned beans to @Controller, @ControllerAdvice, @JsonComponent, Converter,
GenericConverter, and WebFluxConfigurer. Regular @Component beans are not scanned when
the @WebFluxTest annotation is used.
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Tip
If you need to register extra components, such as Jackson Module, you can import additional
configuration classes using @Import on your test.
Often, @WebFluxTest is limited to a single controller and used in combination with the @MockBean
annotation to provide mock implementations for required collaborators.
@WebFluxTest also auto-configures WebTestClient, which offers a powerful way to quickly test
WebFlux controllers without needing to start a full HTTP server.
Tip
You can also auto-configure WebTestClient in a non-@WebFluxTest (such as
@SpringBootTest) by annotating it with @AutoConfigureWebTestClient. The following
example shows a class that uses both @WebFluxTest and a WebTestClient:
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.reactive.WebFluxTest;
import org.springframework.http.MediaType;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.web.reactive.server.WebTestClient;
@RunWith(SpringRunner.class)
@WebFluxTest(UserVehicleController.class)
public class MyControllerTests {
@Autowired
private WebTestClient webClient;
@MockBean
private UserVehicleService userVehicleService;
@Test
public void testExample() throws Exception {
given(this.userVehicleService.getVehicleDetails("sboot"))
.willReturn(new VehicleDetails("Honda", "Civic"));
this.webClient.get().uri("/sboot/vehicle").accept(MediaType.TEXT_PLAIN)
.exchange()
.expectStatus().isOk()
.expectBody(String.class).isEqualTo("Honda Civic");
}
}
Tip
This setup is only supported by WebFlux applications as using WebTestClient in a mocked
web application only works with WebFlux at the moment.
A list of the auto-configuration that is enabled by @WebFluxTest can be found in the appendix.
Note
@WebFluxTest cannot detect routes registered via the functional web framework. For testing
RouterFunction beans in the context, consider importing your RouterFunction yourself via
@Import or using @SpringBootTest.
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Tip
Sometimes writing Spring WebFlux tests is not enough; Spring Boot can help you run full end-
to-end tests with an actual server.
Auto-configured Data JPA Tests
You can use the @DataJpaTest annotation to test JPA applications. By default, it configures an in-
memory embedded database, scans for @Entity classes, and configures Spring Data JPA repositories.
Regular @Component beans are not loaded into the ApplicationContext.
By default, data JPA tests are transactional and roll back at the end of each test. See the relevant section
in the Spring Framework Reference Documentation for more details. If that is not what you want, you
can disable transaction management for a test or for the whole class as follows:
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
@RunWith(SpringRunner.class)
@DataJpaTest
@Transactional(propagation = Propagation.NOT_SUPPORTED)
public class ExampleNonTransactionalTests {
}
Data JPA tests may also inject a TestEntityManager bean, which provides an alternative
to the standard JPA EntityManager that is specifically designed for tests. If you want
to use TestEntityManager outside of @DataJpaTest instances, you can also use the
@AutoConfigureTestEntityManager annotation. A JdbcTemplate is also available if you need
that. The following example shows the @DataJpaTest annotation in use:
import org.junit.*;
import org.junit.runner.*;
import org.springframework.boot.test.autoconfigure.orm.jpa.*;
import static org.assertj.core.api.Assertions.*;
@RunWith(SpringRunner.class)
@DataJpaTest
public class ExampleRepositoryTests {
@Autowired
private TestEntityManager entityManager;
@Autowired
private UserRepository repository;
@Test
public void testExample() throws Exception {
this.entityManager.persist(new User("sboot", "1234"));
User user = this.repository.findByUsername("sboot");
assertThat(user.getUsername()).isEqualTo("sboot");
assertThat(user.getVin()).isEqualTo("1234");
}
}
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In-memory embedded databases generally work well for tests, since they are fast and do not require
any installation. If, however, you prefer to run tests against a real database you can use the
@AutoConfigureTestDatabase annotation, as shown in the following example:
@RunWith(SpringRunner.class)
@DataJpaTest
@AutoConfigureTestDatabase(replace=Replace.NONE)
public class ExampleRepositoryTests {
// ...
}
A list of the auto-configuration settings that are enabled by @DataJpaTest can be found in the
appendix.
Auto-configured JDBC Tests
@JdbcTest is similar to @DataJpaTest but is for pure JDBC-related tests. By default, it also configures
an in-memory embedded database and a JdbcTemplate. Regular @Component beans are not loaded
into the ApplicationContext.
By default, JDBC tests are transactional and roll back at the end of each test. See the relevant section
in the Spring Framework Reference Documentation for more details. If that is not what you want, you
can disable transaction management for a test or for the whole class, as follows:
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.autoconfigure.jdbc.JdbcTest;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
@RunWith(SpringRunner.class)
@JdbcTest
@Transactional(propagation = Propagation.NOT_SUPPORTED)
public class ExampleNonTransactionalTests {
}
If you prefer your test to run against a real database, you can use the @AutoConfigureTestDatabase
annotation in the same way as for DataJpaTest. (See "the section called “Auto-configured Data JPA
Tests”".)
A list of the auto-configuration that is enabled by @JdbcTest can be found in the appendix.
Auto-configured jOOQ Tests
You can use @JooqTest in a similar fashion as @JdbcTest but for jOOQ-related tests. As
jOOQ relies heavily on a Java-based schema that corresponds with the database schema, the
existing DataSource is used. If you want to replace it with an in-memory database, you can use
@AutoConfigureTestDatabase to override those settings. (For more about using jOOQ with Spring
Boot, see "Section 29.5, “Using jOOQ”", earlier in this chapter.)
@JooqTest configures a DSLContext. Regular @Component beans are not loaded into the
ApplicationContext. The following example shows the @JooqTest annotation in use:
import org.jooq.DSLContext;
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import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.autoconfigure.jooq.JooqTest;
import org.springframework.test.context.junit4.SpringRunner;
@RunWith(SpringRunner.class)
@JooqTest
public class ExampleJooqTests {
@Autowired
private DSLContext dslContext;
}
JOOQ tests are transactional and roll back at the end of each test by default. If that is not what you
want, you can disable transaction management for a test or for the whole test class as shown in the
JDBC example.
A list of the auto-configuration that is enabled by @JooqTest can be found in the appendix.
Auto-configured Data MongoDB Tests
You can use @DataMongoTest to test MongoDB applications. By default, it configures an in-memory
embedded MongoDB (if available), configures a MongoTemplate, scans for @Document classes,
and configures Spring Data MongoDB repositories. Regular @Component beans are not loaded into
the ApplicationContext. (For more about using MongoDB with Spring Boot, see "Section 30.2,
“MongoDB”", earlier in this chapter.)
The following class shows the @DataMongoTest annotation in use:
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.data.mongo.DataMongoTest;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.test.context.junit4.SpringRunner;
@RunWith(SpringRunner.class)
@DataMongoTest
public class ExampleDataMongoTests {
@Autowired
private MongoTemplate mongoTemplate;
//
}
In-memory embedded MongoDB generally works well for tests, since it is fast and does not require any
developer installation. If, however, you prefer to run tests against a real MongoDB server, you should
exclude the embedded MongoDB auto-configuration, as shown in the following example:
import org.junit.runner.RunWith;
import org.springframework.boot.autoconfigure.mongo.embedded.EmbeddedMongoAutoConfiguration;
import org.springframework.boot.test.autoconfigure.data.mongo.DataMongoTest;
import org.springframework.test.context.junit4.SpringRunner;
@RunWith(SpringRunner.class)
@DataMongoTest(excludeAutoConfiguration = EmbeddedMongoAutoConfiguration.class)
public class ExampleDataMongoNonEmbeddedTests {
}
A list of the auto-configuration settings that are enabled by @DataMongoTest can be found in the
appendix.
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Auto-configured Data Neo4j Tests
You can use @DataNeo4jTest to test Neo4j applications. By default, it uses an in-memory embedded
Neo4j (if the embedded driver is available), scans for @NodeEntity classes, and configures Spring
Data Neo4j repositories. Regular @Component beans are not loaded into the ApplicationContext.
(For more about using Neo4J with Spring Boot, see "Section 30.3, “Neo4j”", earlier in this chapter.)
The following example shows a typical setup for using Neo4J tests in Spring Boot:
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.data.neo4j.DataNeo4jTest;
import org.springframework.test.context.junit4.SpringRunner;
@RunWith(SpringRunner.class)
@DataNeo4jTest
public class ExampleDataNeo4jTests {
@Autowired
private YourRepository repository;
//
}
By default, Data Neo4j tests are transactional and roll back at the end of each test. See the relevant
section in the Spring Framework Reference Documentation for more details. If that is not what you want,
you can disable transaction management for a test or for the whole class, as follows:
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.autoconfigure.data.neo4j.DataNeo4jTest;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
@RunWith(SpringRunner.class)
@DataNeo4jTest
@Transactional(propagation = Propagation.NOT_SUPPORTED)
public class ExampleNonTransactionalTests {
}
A list of the auto-configuration settings that are enabled by @DataNeo4jTest can be found in the
appendix.
Auto-configured Data Redis Tests
You can use @DataRedisTest to test Redis applications. By default, it scans for @RedisHash classes
and configures Spring Data Redis repositories. Regular @Component beans are not loaded into the
ApplicationContext. (For more about using Redis with Spring Boot, see "Section 30.1, “Redis”",
earlier in this chapter.)
The following example shows the @DataRedisTest annotation in use:
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.data.redis.DataRedisTest;
import org.springframework.test.context.junit4.SpringRunner;
@RunWith(SpringRunner.class)
@DataRedisTest
public class ExampleDataRedisTests {
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@Autowired
private YourRepository repository;
//
}
A list of the auto-configuration settings that are enabled by @DataRedisTest can be found in the
appendix.
Auto-configured Data LDAP Tests
You can use @DataLdapTest to test LDAP applications. By default, it configures an in-memory
embedded LDAP (if available), configures an LdapTemplate, scans for @Entry classes, and
configures Spring Data LDAP repositories. Regular @Component beans are not loaded into the
ApplicationContext. (For more about using LDAP with Spring Boot, see "Section 30.9, “LDAP”",
earlier in this chapter.)
The following example shows the @DataLdapTest annotation in use:
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.data.ldap.DataLdapTest;
import org.springframework.ldap.core.LdapTemplate;
import org.springframework.test.context.junit4.SpringRunner;
@RunWith(SpringRunner.class)
@DataLdapTest
public class ExampleDataLdapTests {
@Autowired
private LdapTemplate ldapTemplate;
//
}
In-memory embedded LDAP generally works well for tests, since it is fast and does not require any
developer installation. If, however, you prefer to run tests against a real LDAP server, you should exclude
the embedded LDAP auto-configuration, as shown in the following example:
import org.junit.runner.RunWith;
import org.springframework.boot.autoconfigure.ldap.embedded.EmbeddedLdapAutoConfiguration;
import org.springframework.boot.test.autoconfigure.data.ldap.DataLdapTest;
import org.springframework.test.context.junit4.SpringRunner;
@RunWith(SpringRunner.class)
@DataLdapTest(excludeAutoConfiguration = EmbeddedLdapAutoConfiguration.class)
public class ExampleDataLdapNonEmbeddedTests {
}
A list of the auto-configuration settings that are enabled by @DataLdapTest can be found in the
appendix.
Auto-configured REST Clients
You can use the @RestClientTest annotation to test REST clients. By default, it auto-configures
Jackson, GSON, and Jsonb support, configures a RestTemplateBuilder, and adds support for
MockRestServiceServer. The specific beans that you want to test should be specified by using the
value or components attribute of @RestClientTest, as shown in the following example:
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@RunWith(SpringRunner.class)
@RestClientTest(RemoteVehicleDetailsService.class)
public class ExampleRestClientTest {
@Autowired
private RemoteVehicleDetailsService service;
@Autowired
private MockRestServiceServer server;
@Test
public void getVehicleDetailsWhenResultIsSuccessShouldReturnDetails()
throws Exception {
this.server.expect(requestTo("/greet/details"))
.andRespond(withSuccess("hello", MediaType.TEXT_PLAIN));
String greeting = this.service.callRestService();
assertThat(greeting).isEqualTo("hello");
}
}
A list of the auto-configuration settings that are enabled by @RestClientTest can be found in the
appendix.
Auto-configured Spring REST Docs Tests
You can use the @AutoConfigureRestDocs annotation to use Spring REST Docs in your tests with
Mock MVC or REST Assured. It removes the need for the JUnit rule in Spring REST Docs.
@AutoConfigureRestDocs can be used to override the default output directory (target/
generated-snippets if you are using Maven or build/generated-snippets if you are using
Gradle). It can also be used to configure the host, scheme, and port that appears in any documented
URIs.
Auto-configured Spring REST Docs Tests with Mock MVC
@AutoConfigureRestDocs customizes the MockMvc bean to use Spring REST Docs. You can inject
it by using @Autowired and use it in your tests as you normally would when using Mock MVC and
Spring REST Docs, as shown in the following example:
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
import org.springframework.http.MediaType;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.web.servlet.MockMvc;
import static org.springframework.restdocs.mockmvc.MockMvcRestDocumentation.document;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;
@RunWith(SpringRunner.class)
@WebMvcTest(UserController.class)
@AutoConfigureRestDocs
public class UserDocumentationTests {
@Autowired
private MockMvc mvc;
@Test
public void listUsers() throws Exception {
this.mvc.perform(get("/users").accept(MediaType.TEXT_PLAIN))
.andExpect(status().isOk())
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.andDo(document("list-users"));
}
}
If you require more control over Spring REST Docs configuration than offered by the attributes
of @AutoConfigureRestDocs, you can use a RestDocsMockMvcConfigurationCustomizer
bean, as shown in the following example:
@TestConfiguration
static class CustomizationConfiguration
implements RestDocsMockMvcConfigurationCustomizer {
@Override
public void customize(MockMvcRestDocumentationConfigurer configurer) {
configurer.snippets().withTemplateFormat(TemplateFormats.markdown());
}
}
If you want to make use of Spring REST Docs support for a parameterized output directory, you can
create a RestDocumentationResultHandler bean. The auto-configuration calls alwaysDo with
this result handler, thereby causing each MockMvc call to automatically generate the default snippets.
The following example shows a RestDocumentationResultHandler being defined:
@TestConfiguration
static class ResultHandlerConfiguration {
@Bean
public RestDocumentationResultHandler restDocumentation() {
return MockMvcRestDocumentation.document("{method-name}");
}
}
Auto-configured Spring REST Docs Tests with REST Assured
@AutoConfigureRestDocs makes a RequestSpecification bean, preconfigured to use Spring
REST Docs, available to your tests. You can inject it by using @Autowired and use it in your tests
as you normally would when using REST Assured and Spring REST Docs, as shown in the following
example:
import io.restassured.specification.RequestSpecification;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.restdocs.AutoConfigureRestDocs;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
import org.springframework.boot.web.server.LocalServerPort;
import org.springframework.test.context.junit4.SpringRunner;
import static io.restassured.RestAssured.given;
import static org.hamcrest.CoreMatchers.is;
import static org.springframework.restdocs.restassured3.RestAssuredRestDocumentation.document;
@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
@AutoConfigureRestDocs
public class UserDocumentationTests {
@LocalServerPort
private int port;
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@Autowired
private RequestSpecification documentationSpec;
@Test
public void listUsers() {
given(this.documentationSpec).filter(document("list-users")).when()
.port(this.port).get("/").then().assertThat().statusCode(is(200));
}
}
If you require more control over Spring REST Docs configuration than offered by the attributes of
@AutoConfigureRestDocs, a RestDocsRestAssuredConfigurationCustomizer bean can be
used, as shown in the following example:
@TestConfiguration
public static class CustomizationConfiguration
implements RestDocsRestAssuredConfigurationCustomizer {
@Override
public void customize(RestAssuredRestDocumentationConfigurer configurer) {
configurer.snippets().withTemplateFormat(TemplateFormats.markdown());
}
}
User Configuration and Slicing
If you structure your code in a sensible way, your @SpringBootApplication class is used by default
as the configuration of your tests.
It then becomes important not to litter the application’s main class with configuration settings that are
specific to a particular area of its functionality.
Assume that you are using Spring Batch and you rely on the auto-configuration for it. You could define
your @SpringBootApplication as follows:
@SpringBootApplication
@EnableBatchProcessing
public class SampleApplication { ... }
Because this class is the source configuration for the test, any slice test actually tries to start Spring
Batch, which is definitely not what you want to do. A recommended approach is to move that area-
specific configuration to a separate @Configuration class at the same level as your application, as
shown in the following example:
@Configuration
@EnableBatchProcessing
public class BatchConfiguration { ... }
Note
Depending on the complexity of your application, you may either have a single @Configuration
class for your customizations or one class per domain area. The latter approach lets you enable
it in one of your tests, if necessary, with the @Import annotation.
Another source of confusion is classpath scanning. Assume that, while you structured your code in a
sensible way, you need to scan an additional package. Your application may resemble the following
code:
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@SpringBootApplication
@ComponentScan({ "com.example.app", "org.acme.another" })
public class SampleApplication { ... }
Doing so effectively overrides the default component scan directive with the side effect of scanning those
two packages regardless of the slice that you chose. For instance, a @DataJpaTest seems to suddenly
scan components and user configurations of your application. Again, moving the custom directive to a
separate class is a good way to fix this issue.
Tip
If this is not an option for you, you can create a @SpringBootConfiguration somewhere in
the hierarchy of your test so that it is used instead. Alternatively, you can specify a source for your
test, which disables the behavior of finding a default one.
Using Spock to Test Spring Boot Applications
If you wish to use Spock to test a Spring Boot application, you should add a dependency on Spock’s
spock-spring module to your application’s build. spock-spring integrates Spring’s test framework
into Spock. It is recommended that you use Spock 1.1 or later to benefit from a number of improvements
to Spock’s Spring Framework and Spring Boot integration. See the documentation for Spock’s Spring
module for further details.
43.4 Test Utilities
A few test utility classes that are generally useful when testing your application are packaged as part
of spring-boot.
ConfigFileApplicationContextInitializer
ConfigFileApplicationContextInitializer is an ApplicationContextInitializer that
you can apply to your tests to load Spring Boot application.properties files. You can use it when
you do not need the full set of features provided by @SpringBootTest, as shown in the following
example:
@ContextConfiguration(classes = Config.class,
initializers = ConfigFileApplicationContextInitializer.class)
Note
Using ConfigFileApplicationContextInitializer alone does not provide support for
@Value("${…}") injection. Its only job is to ensure that application.properties files
are loaded into Spring’s Environment. For @Value support, you need to either additionally
configure a PropertySourcesPlaceholderConfigurer or use @SpringBootTest, which
auto-configures one for you.
TestPropertyValues
TestPropertyValues lets you quickly add properties to a ConfigurableEnvironment or
ConfigurableApplicationContext. You can call it with key=value strings, as follows:
TestPropertyValues.of("org=Spring", "name=Boot").applyTo(env);
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OutputCapture
OutputCapture is a JUnit Rule that you can use to capture System.out and System.err output.
You can declare the capture as a @Rule and then use toString() for assertions, as follows:
import org.junit.Rule;
import org.junit.Test;
import org.springframework.boot.test.rule.OutputCapture;
import static org.hamcrest.Matchers.*;
import static org.junit.Assert.*;
public class MyTest {
@Rule
public OutputCapture capture = new OutputCapture();
@Test
public void testName() throws Exception {
System.out.println("Hello World!");
assertThat(capture.toString(), containsString("World"));
}
}
TestRestTemplate
Tip
Spring Framework 5.0 provides a new WebTestClient that works for WebFlux integration tests
and both WebFlux and MVC end-to-end testing. It provides a fluent API for assertions, unlike
TestRestTemplate.
TestRestTemplate is a convenience alternative to Spring’s RestTemplate that is useful in
integration tests. You can get a vanilla template or one that sends Basic HTTP authentication (with a
username and password). In either case, the template behaves in a test-friendly way by not throwing
exceptions on server-side errors. It is recommended, but not mandatory, to use the Apache HTTP Client
(version 4.3.2 or better). If you have that on your classpath, the TestRestTemplate responds by
configuring the client appropriately. If you do use Apache’s HTTP client, some additional test-friendly
features are enabled:
• Redirects are not followed (so you can assert the response location).
• Cookies are ignored (so the template is stateless).
TestRestTemplate can be instantiated directly in your integration tests, as shown in the following
example:
public class MyTest {
private TestRestTemplate template = new TestRestTemplate();
@Test
public void testRequest() throws Exception {
HttpHeaders headers = this.template.getForEntity(
"http://myhost.example.com/example", String.class).getHeaders();
assertThat(headers.getLocation()).hasHost("other.example.com");
}
}
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Alternatively, if you use the @SpringBootTest annotation with WebEnvironment.RANDOM_PORT or
WebEnvironment.DEFINED_PORT, you can inject a fully configured TestRestTemplate and start
using it. If necessary, additional customizations can be applied through the RestTemplateBuilder
bean. Any URLs that do not specify a host and port automatically connect to the embedded server, as
shown in the following example:
@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
public class SampleWebClientTests {
@Autowired
private TestRestTemplate template;
@Test
public void testRequest() {
HttpHeaders headers = this.template.getForEntity("/example", String.class)
.getHeaders();
assertThat(headers.getLocation()).hasHost("other.example.com");
}
@TestConfiguration
static class Config {
@Bean
public RestTemplateBuilder restTemplateBuilder() {
return new RestTemplateBuilder().setConnectTimeout(1000).setReadTimeout(1000);
}
}
}
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44. WebSockets
Spring Boot provides WebSockets auto-configuration for embedded Tomcat 8.5, Jetty 9, and Undertow.
If you deploy a war file to a standalone container, Spring Boot assumes that the container is responsible
for the configuration of its WebSocket support.
Spring Framework provides rich WebSocket support that can be easily accessed through the spring-
boot-starter-websocket module.
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45. Web Services
Spring Boot provides Web Services auto-configuration so that all you must do is define your Endpoints.
The Spring Web Services features can be easily accessed with the spring-boot-starter-
webservices module.
SimpleWsdl11Definition and SimpleXsdSchema beans can be automatically created for your
WSDLs and XSDs respectively. To do so, configure their location, as shown in the following example:
spring.webservices.wsdl-locations=classpath:/wsdl
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46. Creating Your Own Auto-configuration
If you work in a company that develops shared libraries, or if you work on an open-source or commercial
library, you might want to develop your own auto-configuration. Auto-configuration classes can be
bundled in external jars and still be picked-up by Spring Boot.
Auto-configuration can be associated to a “starter” that provides the auto-configuration code as well as
the typical libraries that you would use with it. We first cover what you need to know to build your own
auto-configuration and then we move on to the typical steps required to create a custom starter.
Tip
A demo project is available to showcase how you can create a starter step-by-step.
46.1 Understanding Auto-configured Beans
Under the hood, auto-configuration is implemented with standard @Configuration classes. Additional
@Conditional annotations are used to constrain when the auto-configuration should apply. Usually,
auto-configuration classes use @ConditionalOnClass and @ConditionalOnMissingBean
annotations. This ensures that auto-configuration applies only when relevant classes are found and
when you have not declared your own @Configuration.
You can browse the source code of spring-boot-autoconfigure to see the @Configuration
classes that Spring provides (see the META-INF/spring.factories file).
46.2 Locating Auto-configuration Candidates
Spring Boot checks for the presence of a META-INF/spring.factories file within your published jar.
The file should list your configuration classes under the EnableAutoConfiguration key, as shown
in the following example:
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
com.mycorp.libx.autoconfigure.LibXAutoConfiguration,\
com.mycorp.libx.autoconfigure.LibXWebAutoConfiguration
You can use the @AutoConfigureAfter or @AutoConfigureBefore annotations if your
configuration needs to be applied in a specific order. For example, if you provide web-specific
configuration, your class may need to be applied after WebMvcAutoConfiguration.
If you want to order certain auto-configurations that should not have any direct knowledge of each other,
you can also use @AutoConfigureOrder. That annotation has the same semantic as the regular
@Order annotation but provides a dedicated order for auto-configuration classes.
Note
Auto-configurations must be loaded that way only. Make sure that they are defined in a specific
package space and that, in particular, they are never the target of component scanning.
46.3 Condition Annotations
You almost always want to include one or more @Conditional annotations on your auto-configuration
class. The @ConditionalOnMissingBean annotation is one common example that is used to allow
developers to override auto-configuration if they are not happy with your defaults.
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Spring Boot includes a number of @Conditional annotations that you can reuse in your own code by
annotating @Configuration classes or individual @Bean methods. These annotations include:
•the section called “Class Conditions”
•the section called “Bean Conditions”
•the section called “Property Conditions”
•the section called “Resource Conditions”
•the section called “Web Application Conditions”
•the section called “SpEL Expression Conditions”
Class Conditions
The @ConditionalOnClass and @ConditionalOnMissingClass annotations let configuration be
included based on the presence or absence of specific classes. Due to the fact that annotation metadata
is parsed by using ASM, you can use the value attribute to refer to the real class, even though that class
might not actually appear on the running application classpath. You can also use the name attribute if
you prefer to specify the class name by using a String value.
Tip
If you use @ConditionalOnClass or @ConditionalOnMissingClass as a part of a meta-
annotation to compose your own composed annotations, you must use name as referring to the
class in such a case is not handled.
Bean Conditions
The @ConditionalOnBean and @ConditionalOnMissingBean annotations let a bean be included
based on the presence or absence of specific beans. You can use the value attribute to specify
beans by type or name to specify beans by name. The search attribute lets you limit the
ApplicationContext hierarchy that should be considered when searching for beans.
When placed on a @Bean method, the target type defaults to the return type of the method, as shown
in the following example:
@Configuration
public class MyAutoConfiguration {
@Bean
@ConditionalOnMissingBean
public MyService myService() { ... }
}
In the preceding example, the myService bean is going to be created if no bean of type MyService
is already contained in the ApplicationContext.
Tip
You need to be very careful about the order in which bean definitions are added, as
these conditions are evaluated based on what has been processed so far. For this reason,
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we recommend using only @ConditionalOnBean and @ConditionalOnMissingBean
annotations on auto-configuration classes (since these are guaranteed to load after any user-
defined bean definitions have been added).
Note
@ConditionalOnBean and @ConditionalOnMissingBean do not prevent
@Configuration classes from being created. The only difference between using these
conditions at the class level and marking each contained @Bean method with the annotation is
that the former prevents registration of the @Configuration class as a bean if the condition
does not match.
Property Conditions
The @ConditionalOnProperty annotation lets configuration be included based on a Spring
Environment property. Use the prefix and name attributes to specify the property that should be
checked. By default, any property that exists and is not equal to false is matched. You can also create
more advanced checks by using the havingValue and matchIfMissing attributes.
Resource Conditions
The @ConditionalOnResource annotation lets configuration be included only when a specific
resource is present. Resources can be specified by using the usual Spring conventions, as shown in
the following example: file:/home/user/test.dat.
Web Application Conditions
The @ConditionalOnWebApplication and @ConditionalOnNotWebApplication annotations
let configuration be included depending on whether the application is a “web application”. A web
application is any application that uses a Spring WebApplicationContext, defines a session
scope, or has a StandardServletEnvironment.
SpEL Expression Conditions
The @ConditionalOnExpression annotation lets configuration be included based on the result of
a SpEL expression.
46.4 Testing your Auto-configuration
An auto-configuration can be affected by many factors: user configuration (@Bean definition and
Environment customization), condition evaluation (presence of a particular library), and others.
Concretely, each test should create a well defined ApplicationContext that represents a
combination of those customizations. ApplicationContextRunner provides a great way to achieve
that.
ApplicationContextRunner is usually defined as a field of the test class to gather the base,
common configuration. The following example makes sure that UserServiceAutoConfiguration
is always invoked:
private final ApplicationContextRunner contextRunner = new ApplicationContextRunner()
.withConfiguration(AutoConfigurations.of(UserServiceAutoConfiguration.class));
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Tip
If multiple auto-configurations have to be defined, there is no need to order their declarations as
they are invoked in the exact same order as when running the application.
Each test can use the runner to represent a particular use case. For instance, the sample below invokes
a user configuration (UserConfiguration) and checks that the auto-configuration backs off properly.
Invoking run provides a callback context that can be used with Assert4J.
@Test
public void defaultServiceBacksOff() {
this.contextRunner.withUserConfiguration(UserConfiguration.class)
.run((context) -> {
assertThat(context).hasSingleBean(UserService.class);
assertThat(context.getBean(UserService.class)).isSameAs(
context.getBean(UserConfiguration.class).myUserService());
});
}
@Configuration
static class UserConfiguration {
@Bean
public UserService myUserService() {
return new UserService("mine");
}
}
It is also possible to easily customize the Environment, as shown in the following example:
@Test
public void serviceNameCanBeConfigured() {
this.contextRunner.withPropertyValues("user.name=test123").run((context) -> {
assertThat(context).hasSingleBean(UserService.class);
assertThat(context.getBean(UserService.class).getName()).isEqualTo("test123");
});
}
Simulating a Web Context
If you need to test an auto-configuration that only operates in a Servlet
or Reactive web application context, use the WebApplicationContextRunner or
ReactiveWebApplicationContextRunner respectively.
Overriding the Classpath
It is also possible to test what happens when a particular class and/or package is not present at runtime.
Spring Boot ships with a FilteredClassLoader that can easily be used by the runner. In the following
example, we assert that if UserService is not present, the auto-configuration is properly disabled:
@Test
public void serviceIsIgnoredIfLibraryIsNotPresent() {
this.contextRunner.withClassLoader(new FilteredClassLoader(UserService.class))
.run((context) -> assertThat(context).doesNotHaveBean("userService"));
}
46.5 Creating Your Own Starter
A full Spring Boot starter for a library may contain the following components:
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• The autoconfigure module that contains the auto-configuration code.
• The starter module that provides a dependency to the autoconfigure module as well as the
library and any additional dependencies that are typically useful. In a nutshell, adding the starter
should provide everything needed to start using that library.
Tip
You may combine the auto-configuration code and the dependency management in a single
module if you do not need to separate those two concerns.
Naming
You should make sure to provide a proper namespace for your starter. Do not start your module names
with spring-boot, even if you use a different Maven groupId. We may offer official support for the
thing you auto-configure in the future.
As a rule of thumb, you should name a combined module after the starter. For example, assume that
you are creating a starter for "acme" and that you name the auto-configure module acme-spring-
boot-autoconfigure and the starter acme-spring-boot-starter. If you only have one module
that combines the two, name it acme-spring-boot-starter.
Also, if your starter provides configuration keys, use a unique namespace for them. In particular, do not
include your keys in the namespaces that Spring Boot uses (such as server, management, spring,
and so on). If you use the same namespace, we may modify these namespaces in the future in ways
that break your modules.
Make sure to trigger meta-data generation so that IDE assistance is available for your keys as
well. You may want to review the generated meta-data (META-INF/spring-configuration-
metadata.json) to make sure your keys are properly documented.
autoconfigure Module
The autoconfigure module contains everything that is necessary to get started with the library. It may
also contain configuration key definitions (such as @ConfigurationProperties) and any callback
interface that can be used to further customize how the components are initialized.
Tip
You should mark the dependencies to the library as optional so that you can include the
autoconfigure module in your projects more easily. If you do it that way, the library is not
provided and, by default, Spring Boot backs off.
Spring Boot uses an annotation processor to collect the conditions on auto-configurations in a metadata
file (META-INF/spring-autoconfigure-metadata.properties). If that file is present, it is used
to eagerly filter auto-configurations that do not match, which will improve startup time. It is recommended
to add the following dependency in a module that contains auto-configurations:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-autoconfigure-processor</artifactId>
<optional>true</optional>
</dependency>
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With Gradle 4.5 and earlier, the dependency should be declared in the compileOnly configuration,
as shown in the following example:
dependencies {
compileOnly "org.springframework.boot:spring-boot-autoconfigure-processor"
}
With Gradle 4.6 and later, the dependency should be declared in the annotationProcessor
configuration, as shown in the following example:
dependencies {
annotationProcessor "org.springframework.boot:spring-boot-autoconfigure-processor"
}
Starter Module
The starter is really an empty jar. Its only purpose is to provide the necessary dependencies to work
with the library. You can think of it as an opinionated view of what is required to get started.
Do not make assumptions about the project in which your starter is added. If the library you are auto-
configuring typically requires other starters, mention them as well. Providing a proper set of default
dependencies may be hard if the number of optional dependencies is high, as you should avoid including
dependencies that are unnecessary for a typical usage of the library. In other words, you should not
include optional dependencies.
Note
Either way, your starter must reference the core Spring Boot starter (spring-boot-starter)
directly or indirectly (i.e. no need to add it if your starter relies on another starter). If a project
is created with only your custom starter, Spring Boot’s core features will be honoured by the
presence of the core starter.
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47. Kotlin support
Kotlin is a statically-typed language targeting the JVM (and other platforms) which allows writing concise
and elegant code while providing interoperability with existing libraries written in Java.
Spring Boot provides Kotlin support by leveraging the support in other Spring projects such as Spring
Framework, Spring Data, and Reactor. See the Spring Framework Kotlin support documentation for
more information.
The easiest way to start with Spring Boot and Kotlin is to follow this comprehensive tutorial. You can
create new Kotlin projects via start.spring.io. Feel free to join the #spring channel of Kotlin Slack or ask
a question with the spring and kotlin tags on Stack Overflow if you need support.
47.1 Requirements
Spring Boot supports Kotlin 1.2.x. To use Kotlin, org.jetbrains.kotlin:kotlin-stdlib and
org.jetbrains.kotlin:kotlin-reflect must be present on the classpath. The kotlin-
stdlib variants kotlin-stdlib-jdk7 and kotlin-stdlib-jdk8 can also be used.
Since Kotlin classes are final by default, you are likely to want to configure kotlin-spring plugin in order
to automatically open Spring-annotated classes so that they can be proxied.
Jackson’s Kotlin module is required for serializing / deserializing JSON data in Kotlin. It is automatically
registered when found on the classpath. A warning message is logged if Jackson and Kotlin are present
but the Jackson Kotlin module is not.
Tip
These dependencies and plugins are provided by default if one bootstraps a Kotlin project on
start.spring.io.
47.2 Null-safety
One of Kotlin’s key features is null-safety. It deals with null values at compile time rather than
deferring the problem to runtime and encountering a NullPointerException. This helps to eliminate
a common source of bugs without paying the cost of wrappers like Optional. Kotlin also allows using
functional constructs with nullable values as described in this comprehensive guide to null-safety in
Kotlin.
Although Java does not allow one to express null-safety in its type system, Spring Framework, Spring
Data, and Reactor now provide null-safety of their API via tooling-friendly annotations. By default, types
from Java APIs used in Kotlin are recognized as platform types for which null-checks are relaxed. Kotlin’s
support for JSR 305 annotations combined with nullability annotations provide null-safety for the related
Spring API in Kotlin.
The JSR 305 checks can be configured by adding the -Xjsr305 compiler flag with the following options:
-Xjsr305={strict|warn|ignore}. The default behavior is the same as -Xjsr305=warn. The
strict value is required to have null-safety taken in account in Kotlin types inferred from Spring API
but should be used with the knowledge that Spring API nullability declaration could evolve even between
minor releases and more checks may be added in the future).
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Warning
Generic type arguments, varargs and array elements nullability are not yet supported. See
SPR-15942 for up-to-date information. Also be aware that Spring Boot’s own API is not yet
annotated.
47.3 Kotlin API
runApplication
Spring Boot provides an idiomatic way to run an application with
runApplication<MyApplication>(*args) as shown in the following example:
import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.boot.runApplication
@SpringBootApplication
class MyApplication
fun main(args: Array<String>) {
runApplication<MyApplication>(*args)
}
This is a drop-in replacement for SpringApplication.run(MyApplication::class.java,
*args). It also allows customization of the application as shown in the following example:
runApplication<MyApplication>(*args) {
setBannerMode(OFF)
}
Extensions
Kotlin extensions provide the ability to extend existing classes with additional functionality. The Spring
Boot Kotlin API makes use of these extensions to add new Kotlin specific conveniences to existing APIs.
TestRestTemplate extensions, similar to those provided by Spring Framework for RestOperations
in Spring Framework, are provided. Among other things, the extensions make it possible to take
advantage of Kotlin reified type parameters.
47.4 Dependency management
In order to avoid mixing different version of Kotlin dependencies on the classpath, dependency
management of the following Kotlin dependencies is provided:
•kotlin-reflect
•kotlin-runtime
•kotlin-stdlib
•kotlin-stdlib-jdk7
•kotlin-stdlib-jdk8
•kotlin-stdlib-jre7
•kotlin-stdlib-jre8
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With Maven, the Kotlin version can be customized via the kotlin.version property and
plugin management is provided for kotlin-maven-plugin. With Gradle, the Spring Boot plugin
automatically aligns the kotlin.version with the version of the Kotlin plugin.
47.5 @ConfigurationProperties
@ConfigurationProperties currently only works with lateinit or nullable var properties (the
former is recommended), since immutable classes initialized by constructors are not yet supported.
@ConfigurationProperties("example.kotlin")
class KotlinExampleProperties {
lateinit var name: String
lateinit var description: String
val myService = MyService()
class MyService {
lateinit var apiToken: String
lateinit var uri: URI
}
}
Tip
To generate your own metadata using the annotation processor, kapt should be configured with
the spring-boot-configuration-processor dependency.
47.6 Testing
While it is possible to use JUnit 4 (the default provided by spring-boot-starter-test) to test Kotlin
code, JUnit 5 is recommended. JUnit 5 enables a test class to be instantiated once and reused for all
of the class’s tests. This makes it possible to use @BeforeAll and @AfterAll annotations on non-
static methods, which is a good fit for Kotlin.
To use JUnit 5, exclude junit:junit dependency from spring-boot-starter-test, add JUnit
5 dependencies, and configure the Maven or Gradle plugin accordingly. See the JUnit 5 documentation
for more details. You also need to switch test instance lifecycle to "per-class".
47.7 Resources
Further reading
•Kotlin language reference
•Kotlin Slack (with a dedicated #spring channel)
•Stackoverflow with spring and kotlin tags
•Try Kotlin in your browser
•Kotlin blog
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•Awesome Kotlin
•Tutorial: building web applications with Spring Boot and Kotlin
•Developing Spring Boot applications with Kotlin
•A Geospatial Messenger with Kotlin, Spring Boot and PostgreSQL
•Introducing Kotlin support in Spring Framework 5.0
•Spring Framework 5 Kotlin APIs, the functional way
Examples
•spring-boot-kotlin-demo: regular Spring Boot + Spring Data JPA project
•mixit: Spring Boot 2 + WebFlux + Reactive Spring Data MongoDB
•spring-kotlin-fullstack: WebFlux Kotlin fullstack example with Kotlin2js for frontend instead of
JavaScript or TypeScript
•spring-petclinic-kotlin: Kotlin version of the Spring PetClinic Sample Application
•spring-kotlin-deepdive: a step by step migration for Boot 1.0 + Java to Boot 2.0 + Kotlin
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48. What to Read Next
If you want to learn more about any of the classes discussed in this section, you can check out the Spring
Boot API documentation or you can browse the source code directly. If you have specific questions,
take a look at the how-to section.
If you are comfortable with Spring Boot’s core features, you can continue on and read about production-
ready features.
Part V. Spring Boot Actuator:
Production-ready features
Spring Boot includes a number of additional features to help you monitor and manage your application
when you push it to production. You can choose to manage and monitor your application by using HTTP
endpoints or with JMX. Auditing, health, and metrics gathering can also be automatically applied to your
application.
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49. Enabling Production-ready Features
The spring-boot-actuator module provides all of Spring Boot’s production-ready features. The
simplest way to enable the features is to add a dependency to the spring-boot-starter-actuator
‘Starter’.
Definition of Actuator
An actuator is a manufacturing term that refers to a mechanical device for moving or controlling
something. Actuators can generate a large amount of motion from a small change.
To add the actuator to a Maven based project, add the following ‘Starter’ dependency:
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
</dependencies>
For Gradle, use the following declaration:
dependencies {
compile("org.springframework.boot:spring-boot-starter-actuator")
}
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50. Endpoints
Actuator endpoints let you monitor and interact with your application. Spring Boot includes a number
of built-in endpoints and lets you add your own. For example, the health endpoint provides basic
application health information.
Each individual endpoint can be enabled or disabled. This controls whether or not the endpoint is created
and its bean exists in the application context. To be remotely accessible an endpoint also has to be
exposed via JMX or HTTP. Most applications choose HTTP, where the ID of the endpoint along with
a prefix of /actuator is mapped to a URL. For example, by default, the health endpoint is mapped
to /actuator/health.
The following technology-agnostic endpoints are available:
ID Description Enabled by default
auditevents Exposes audit events information for the current
application.
Yes
beans Displays a complete list of all the Spring beans in your
application.
Yes
conditions Shows the conditions that were evaluated on
configuration and auto-configuration classes and the
reasons why they did or did not match.
Yes
configprops Displays a collated list of all
@ConfigurationProperties.
Yes
env Exposes properties from Spring’s
ConfigurableEnvironment.
Yes
flyway Shows any Flyway database migrations that have
been applied.
Yes
health Shows application health information. Yes
httptrace Displays HTTP trace information (by default, the last
100 HTTP request-response exchanges).
Yes
info Displays arbitrary application info. Yes
loggers Shows and modifies the configuration of loggers in the
application.
Yes
liquibase Shows any Liquibase database migrations that have
been applied.
Yes
metrics Shows ‘metrics’ information for the current application. Yes
mappings Displays a collated list of all @RequestMapping
paths.
Yes
scheduledtasks Displays the scheduled tasks in your application. Yes
sessions Allows retrieval and deletion of user sessions from a
Spring Session-backed session store. Not available
Yes
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ID Description Enabled by default
when using Spring Session’s support for reactive web
applications.
shutdown Lets the application be gracefully shutdown. No
threaddump Performs a thread dump. Yes
If your application is a web application (Spring MVC, Spring WebFlux, or Jersey), you can use the
following additional endpoints:
ID Description Enabled by default
heapdump Returns a GZip compressed hprof heap dump file. Yes
jolokia Exposes JMX beans over HTTP (when Jolokia is on
the classpath, not available for WebFlux).
Yes
logfile Returns the contents of the logfile (if logging.file
or logging.path properties have been set).
Supports the use of the HTTP Range header to
retrieve part of the log file’s content.
Yes
prometheus Exposes metrics in a format that can be scraped by a
Prometheus server.
Yes
To learn more about the Actuator’s endpoints and their request and response formats, please refer to
the separate API documentation (HTML or PDF).
50.1 Enabling Endpoints
By default, all endpoints except for shutdown are enabled. To configure the enablement of an
endpoint, use its management.endpoint.<id>.enabled property. The following example enables
the shutdown endpoint:
management.endpoint.shutdown.enabled=true
If you prefer endpoint enablement to be opt-in rather than opt-out, set the
management.endpoints.enabled-by-default property to false and use individual endpoint
enabled properties to opt back in. The following example enables the info endpoint and disables all
other endpoints:
management.endpoints.enabled-by-default=false
management.endpoint.info.enabled=true
Note
Disabled endpoints are removed entirely from the application context. If you want to change only
the technologies over which an endpoint is exposed, use the include and exclude properties
instead.
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50.2 Exposing Endpoints
Since Endpoints may contain sensitive information, careful consideration should be given about when
to expose them. The following table shows the default exposure for the built-in endpoints:
ID JMX Web
auditevents Yes No
beans Yes No
conditions Yes No
configprops Yes No
env Yes No
flyway Yes No
health Yes Yes
heapdump N/A No
httptrace Yes No
info Yes Yes
jolokia N/A No
logfile N/A No
loggers Yes No
liquibase Yes No
metrics Yes No
mappings Yes No
prometheus N/A No
scheduledtasks Yes No
sessions Yes No
shutdown Yes No
threaddump Yes No
To change which endpoints are exposed, use the following technology-specific include and exclude
properties:
Property Default
management.endpoints.jmx.exposure.exclude
management.endpoints.jmx.exposure.include *
management.endpoints.web.exposure.exclude
management.endpoints.web.exposure.include info, health
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The include property lists the IDs of the endpoints that are exposed. The exclude property lists the
IDs of the endpoints that should not be exposed. The exclude property takes precedence over the
include property. Both include and exclude properties can be configured with a list of endpoint IDs.
For example, to stop exposing all endpoints over JMX and only expose the health and info endpoints,
use the following property:
management.endpoints.jmx.exposure.include=health,info
* can be used to select all endpoints. For example, to expose everything over HTTP except the env
and beans endpoints, use the following properties:
management.endpoints.web.exposure.include=*
management.endpoints.web.exposure.exclude=env,beans
Note
* has a special meaning in YAML, so be sure to add quotes if you want to include (or exclude)
all endpoints, as shown in the following example:
management:
endpoints:
web:
exposure:
include: "*"
Note
If your application is exposed publicly, we strongly recommend that you also secure your
endpoints.
Tip
If you want to implement your own strategy for when endpoints are exposed, you can register an
EndpointFilter bean.
50.3 Securing HTTP Endpoints
You should take care to secure HTTP endpoints in the same way that you would any other sensitive
URL. If Spring Security is present, endpoints are secured by default using Spring Security’s content-
negotiation strategy. If you wish to configure custom security for HTTP endpoints, for example, only allow
users with a certain role to access them, Spring Boot provides some convenient RequestMatcher
objects that can be used in combination with Spring Security.
A typical Spring Security configuration might look something like the following example:
@Configuration
public class ActuatorSecurity extends WebSecurityConfigurerAdapter {
@Override
protected void configure(HttpSecurity http) throws Exception {
http.requestMatcher(EndpointRequest.toAnyEndpoint()).authorizeRequests()
.anyRequest().hasRole("ENDPOINT_ADMIN")
.and()
.httpBasic();
}
}
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The preceding example uses EndpointRequest.toAnyEndpoint() to match a request to any
endpoint and then ensures that all have the ENDPOINT_ADMIN role. Several other matcher methods
are also available on EndpointRequest. See the API documentation (HTML or PDF) for details.
If you deploy applications behind a firewall, you may prefer that all your actuator
endpoints can be accessed without requiring authentication. You can do so by changing the
management.endpoints.web.exposure.include property, as follows:
application.properties.
management.endpoints.web.exposure.include=*
Additionally, if Spring Security is present, you would need to add custom security configuration that
allows unauthenticated access to the endpoints as shown in the following example:
@Configuration
public class ActuatorSecurity extends WebSecurityConfigurerAdapter {
@Override
protected void configure(HttpSecurity http) throws Exception {
http.requestMatcher(EndpointRequest.toAnyEndpoint()).authorizeRequests()
.anyRequest().permitAll();
}
}
50.4 Configuring Endpoints
Endpoints automatically cache responses to read operations that do not take any parameters. To
configure the amount of time for which an endpoint will cache a response, use its cache.time-to-
live property. The following example sets the time-to-live of the beans endpoint’s cache to 10 seconds:
application.properties.
management.endpoint.beans.cache.time-to-live=10s
Note
The prefix management.endpoint.<name> is used to uniquely identify the endpoint that is
being configured.
Note
When making an authenticated HTTP request, the Principal is considered as input to the
endpoint and, therefore, the response will not be cached.
50.5 Hypermedia for Actuator Web Endpoints
A “discovery page” is added with links to all the endpoints. The “discovery page” is available on /
actuator by default.
When a custom management context path is configured, the “discovery page” automatically moves from
/actuator to the root of the management context. For example, if the management context path is /
management, then the discovery page is available from /management. When the management context
path is set to /, the discovery page is disabled to prevent the possibility of a clash with other mappings.
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50.6 Actuator Web Endpoint Paths
By default, endpoints are exposed over HTTP under the /actuator path by using the ID of the
endpoint. For example, the beans endpoint is exposed under /actuator/beans. If you want to
map endpoints to a different path, you can use the management.endpoints.web.path-mapping
property. Also, if you want change the base path, you can use management.endpoints.web.base-
path.
The following example remaps /actuator/health to /healthcheck:
application.properties.
management.endpoints.web.base-path=/
management.endpoints.web.path-mapping.health=healthcheck
50.7 CORS Support
Cross-origin resource sharing (CORS) is a W3C specification that lets you specify in a flexible way what
kind of cross-domain requests are authorized. If you use Spring MVC or Spring WebFlux, Actuator’s
web endpoints can be configured to support such scenarios.
CORS support is disabled by default and is only enabled once the
management.endpoints.web.cors.allowed-origins property has been set. The following
configuration permits GET and POST calls from the example.com domain:
management.endpoints.web.cors.allowed-origins=http://example.com
management.endpoints.web.cors.allowed-methods=GET,POST
Tip
See CorsEndpointProperties for a complete list of options.
50.8 Implementing Custom Endpoints
If you add a @Bean annotated with @Endpoint, any methods annotated with @ReadOperation,
@WriteOperation, or @DeleteOperation are automatically exposed over JMX and, in a web
application, over HTTP as well. Endpoints can be exposed over HTTP using Jersey, Spring MVC, or
Spring WebFlux.
You can also write technology-specific endpoints by using @JmxEndpoint or @WebEndpoint. These
endpoints are restricted to their respective technologies. For example, @WebEndpoint is exposed only
over HTTP and not over JMX.
You can write technology-specific extensions by using @EndpointWebExtension and
@EndpointJmxExtension. These annotations let you provide technology-specific operations to
augment an existing endpoint.
Finally, if you need access to web-framework-specific functionality, you can implement Servlet or Spring
@Controller and @RestController endpoints at the cost of them not being available over JMX or
when using a different web framework.
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Receiving Input
Operations on an endpoint receive input via their parameters. When exposed via the web, the
values for these parameters are taken from the URL’s query parameters and from the JSON request
body. When exposed via JMX, the parameters are mapped to the parameters of the MBean’s
operations. Parameters are required by default. They can be made optional by annotating them with
@org.springframework.lang.Nullable.
Note
To allow the input to be mapped to the operation method’s parameters, Java code implementing
an endpoint should be compiled with -parameters, and Kotlin code implementing an endpoint
should be compiled with -java-parameters. This will happen automatically if you are using
Spring Boot’s Gradle plugin or if you are using Maven and spring-boot-starter-parent.
Input type conversion
The parameters passed to endpoint operation methods are, if necessary, automatically converted to the
required type. Before calling an operation method, the input received via JMX or an HTTP request is
converted to the required types using an instance of ApplicationConversionService.
Custom Web Endpoints
Operations on an @Endpoint, @WebEndpoint, or @EndpointWebExtension are automatically
exposed over HTTP using Jersey, Spring MVC, or Spring WebFlux.
Web Endpoint Request Predicates
A request predicate is automatically generated for each operation on a web-exposed endpoint.
Path
The path of the predicate is determined by the ID of the endpoint and the base path of web-exposed
endpoints. The default base path is /actuator. For example, an endpoint with the ID sessions will
use /actuator/sessions as its path in the predicate.
The path can be further customized by annotating one or more parameters of the operation method with
@Selector. Such a parameter is added to the path predicate as a path variable. The variable’s value
is passed into the operation method when the endpoint operation is invoked.
HTTP method
The HTTP method of the predicate is determined by the operation type, as shown in the following table:
Operation HTTP method
@ReadOperation GET
@WriteOperation POST
@DeleteOperation DELETE
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Consumes
For a @WriteOperation (HTTP POST) that uses the request body, the consumes clause of the
predicate is application/vnd.spring-boot.actuator.v2+json, application/json. For
all other operations the consumes clause is empty.
Produces
The produces clause of the predicate can be determined by the produces attribute of the
@DeleteOperation, @ReadOperation, and @WriteOperation annotations. The attribute is
optional. If it is not used, the produces clause is determined automatically.
If the operation method returns void or Void the produces clause is empty. If the operation method
returns a org.springframework.core.io.Resource, the produces clause is application/
octet-stream. For all other operations the produces clause is application/vnd.spring-
boot.actuator.v2+json, application/json.
Web Endpoint Response Status
The default response status for an endpoint operation depends on the operation type (read, write, or
delete) and what, if anything, the operation returns.
A @ReadOperation returns a value, the response status will be 200 (OK). If it does not return a value,
the response status will be 404 (Not Found).
If a @WriteOperation or @DeleteOperation returns a value, the response status will be 200 (OK).
If it does not return a value the response status will be 204 (No Content).
If an operation is invoked without a required parameter, or with a parameter that cannot be converted
to the required type, the operation method will not be called and the response status will be 400 (Bad
Request).
Web Endpoint Range Requests
An HTTP range request can be used to request part of an HTTP resource. When using Spring
MVC or Spring Web Flux, operations that return a org.springframework.core.io.Resource
automatically support range requests.
Note
Range requests are not supported when using Jersey.
Web Endpoint Security
An operation on a web endpoint or a web-specific endpoint
extension can receive the current java.security.Principal or
org.springframework.boot.actuate.endpoint.SecurityContext as a method parameter.
The former is typically used in conjunction with @Nullable to provide different behaviour for
authenticated and unauthenticated users. The latter is typically used to perform authorization checks
using its isUserInRole(String) method.
Servlet endpoints
A Servlet can be exposed as an endpoint by implementing a class annotated with
@ServletEndpoint that also implements Supplier<EndpointServlet>. Servlet endpoints
provide deeper integration with the Servlet container but at the expense of portability. They are intended
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to be used to expose an existing Servlet as an endpoint. For new endpoints, the @Endpoint and
@WebEndpoint annotations should be preferred whenever possible.
Controller endpoints
@ControllerEndpoint and @RestControllerEndpoint can be used to implement an endpoint
that is only exposed by Spring MVC or Spring WebFlux. Methods are mapped using the standard
annotations for Spring MVC and Spring WebFlux such as @RequestMapping and @GetMapping, with
the endpoint’s ID being used as a prefix for the path. Controller endpoints provide deeper integration
with Spring’s web frameworks but at the expense of portability. The @Endpoint and @WebEndpoint
annotations should be preferred whenever possible.
50.9 Health Information
You can use health information to check the status of your running application. It is often used by
monitoring software to alert someone when a production system goes down. The information exposed
by the health endpoint depends on the management.endpoint.health.show-details property
which can be configured with one of the following values:
Name Description
never Details are never shown.
when-authorized Details are only shown to authorized users. Authorized roles can be
configured using management.endpoint.health.roles.
always Details are shown to all users.
The default value is never. A user is considered to be authorized when they are in one
or more of the endpoint’s roles. If the endpoint has no configured roles (the default) all
authenticated users are considered to be authorized. The roles can be configured using the
management.endpoint.health.roles property.
Note
If you have secured your application and wish to use always, your security configuration must
permit access to the health endpoint for both authenticated and unauthenticated users.
Health information is collected from all HealthIndicator beans defined in your
ApplicationContext. Spring Boot includes a number of auto-configured HealthIndicators, and
you can also write your own. By default, the final system state is derived by the HealthAggregator,
which sorts the statuses from each HealthIndicator based on an ordered list of statuses. The first
status in the sorted list is used as the overall health status. If no HealthIndicator returns a status
that is known to the HealthAggregator, an UNKNOWN status is used.
Auto-configured HealthIndicators
The following HealthIndicators are auto-configured by Spring Boot when appropriate:
Name Description
CassandraHealthIndicator Checks that a Cassandra database is up.
DiskSpaceHealthIndicator Checks for low disk space.
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Name Description
DataSourceHealthIndicator Checks that a connection to DataSource can be
obtained.
ElasticsearchHealthIndicator Checks that an Elasticsearch cluster is up.
InfluxDbHealthIndicator Checks that an InfluxDB server is up.
JmsHealthIndicator Checks that a JMS broker is up.
MailHealthIndicator Checks that a mail server is up.
MongoHealthIndicator Checks that a Mongo database is up.
Neo4jHealthIndicator Checks that a Neo4j server is up.
RabbitHealthIndicator Checks that a Rabbit server is up.
RedisHealthIndicator Checks that a Redis server is up.
SolrHealthIndicator Checks that a Solr server is up.
Tip
You can disable them all by setting the management.health.defaults.enabled property.
Writing Custom HealthIndicators
To provide custom health information, you can register Spring beans that implement the
HealthIndicator interface. You need to provide an implementation of the health() method
and return a Health response. The Health response should include a status and can optionally
include additional details to be displayed. The following code shows a sample HealthIndicator
implementation:
import org.springframework.boot.actuate.health.Health;
import org.springframework.boot.actuate.health.HealthIndicator;
import org.springframework.stereotype.Component;
@Component
public class MyHealthIndicator implements HealthIndicator {
@Override
public Health health() {
int errorCode = check(); // perform some specific health check
if (errorCode != 0) {
return Health.down().withDetail("Error Code", errorCode).build();
}
return Health.up().build();
}
}
Note
The identifier for a given HealthIndicator is the name of the bean without the
HealthIndicator suffix, if it exists. In the preceding example, the health information is available
in an entry named my.
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In addition to Spring Boot’s predefined Status types, it is also possible for Health to return a
custom Status that represents a new system state. In such cases, a custom implementation of the
HealthAggregator interface also needs to be provided, or the default implementation has to be
configured by using the management.health.status.order configuration property.
For example, assume a new Status with code FATAL is being used in one of your HealthIndicator
implementations. To configure the severity order, add the following property to your application
properties:
management.health.status.order=FATAL, DOWN, OUT_OF_SERVICE, UNKNOWN, UP
The HTTP status code in the response reflects the overall health status (for example, UP maps to
200, while OUT_OF_SERVICE and DOWN map to 503). You might also want to register custom status
mappings if you access the health endpoint over HTTP. For example, the following property maps FATAL
to 503 (service unavailable):
management.health.status.http-mapping.FATAL=503
Tip
If you need more control, you can define your own HealthStatusHttpMapper bean.
The following table shows the default status mappings for the built-in statuses:
Status Mapping
DOWN SERVICE_UNAVAILABLE (503)
OUT_OF_SERVICE SERVICE_UNAVAILABLE (503)
UP No mapping by default, so http status is 200
UNKNOWN No mapping by default, so http status is 200
Reactive Health Indicators
For reactive applications, such as those using Spring WebFlux, ReactiveHealthIndicator provides
a non-blocking contract for getting application health. Similar to a traditional HealthIndicator,
health information is collected from all ReactiveHealthIndicator beans defined in your
ApplicationContext. Regular HealthIndicator beans that do not check against a reactive API
are included and executed on the elastic scheduler.
To provide custom health information from a reactive API, you can register Spring beans
that implement the ReactiveHealthIndicator interface. The following code shows a sample
ReactiveHealthIndicator implementation:
@Component
public class MyReactiveHealthIndicator implements ReactiveHealthIndicator {
@Override
public Mono<Health> health() {
return doHealthCheck() //perform some specific health check that returns a Mono<Health>
.onErrorResume(ex -> Mono.just(new Health.Builder().down(ex).build())));
}
}
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Tip
To handle the error automatically, consider extending from
AbstractReactiveHealthIndicator.
Auto-configured ReactiveHealthIndicators
The following ReactiveHealthIndicators are auto-configured by Spring Boot when appropriate:
Name Description
MongoReactiveHealthIndicatorChecks that a Mongo database is up.
RedisReactiveHealthIndicatorChecks that a Redis server is up.
Tip
If necessary, reactive indicators replace the regular ones. Also, any HealthIndicator that is
not handled explicitly is wrapped automatically.
50.10 Application Information
Application information exposes various information collected from all InfoContributor beans
defined in your ApplicationContext. Spring Boot includes a number of auto-configured
InfoContributor beans, and you can write your own.
Auto-configured InfoContributors
The following InfoContributor beans are auto-configured by Spring Boot, when appropriate:
Name Description
EnvironmentInfoContributorExposes any key from the Environment under the info key.
GitInfoContributorExposes git information if a git.properties file is available.
BuildInfoContributorExposes build information if a META-INF/build-info.properties file is
available.
Tip
It is possible to disable them all by setting the management.info.defaults.enabled
property.
Custom Application Information
You can customize the data exposed by the info endpoint by setting info.* Spring properties. All
Environment properties under the info key are automatically exposed. For example, you could add
the following settings to your application.properties file:
info.app.encoding=UTF-8
info.app.java.source=1.8
info.app.java.target=1.8
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Tip
Rather than hardcoding those values, you could also expand info properties at build time.
Assuming you use Maven, you could rewrite the preceding example as follows:
info.app.encoding=@project.build.sourceEncoding@
info.app.java.source=@java.version@
info.app.java.target=@java.version@
Git Commit Information
Another useful feature of the info endpoint is its ability to publish information about the state of your
git source code repository when the project was built. If a GitProperties bean is available, the
git.branch, git.commit.id, and git.commit.time properties are exposed.
Tip
A GitProperties bean is auto-configured if a git.properties file is available at the root of
the classpath. See "Generate git information" for more details.
If you want to display the full git information (that is, the full content of git.properties), use the
management.info.git.mode property, as follows:
management.info.git.mode=full
Build Information
If a BuildProperties bean is available, the info endpoint can also publish information about your
build. This happens if a META-INF/build-info.properties file is available in the classpath.
Tip
The Maven and Gradle plugins can both generate that file. See "Generate build information" for
more details.
Writing Custom InfoContributors
To provide custom application information, you can register Spring beans that implement the
InfoContributor interface.
The following example contributes an example entry with a single value:
import java.util.Collections;
import org.springframework.boot.actuate.info.Info;
import org.springframework.boot.actuate.info.InfoContributor;
import org.springframework.stereotype.Component;
@Component
public class ExampleInfoContributor implements InfoContributor {
@Override
public void contribute(Info.Builder builder) {
builder.withDetail("example",
Collections.singletonMap("key", "value"));
}
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}
If you reach the info endpoint, you should see a response that contains the following additional entry:
{
"example": {
"key" : "value"
}
}
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51. Monitoring and Management over HTTP
If you are developing a web application, Spring Boot Actuator auto-configures all enabled endpoints
to be exposed over HTTP. The default convention is to use the id of the endpoint with a prefix of /
actuator as the URL path. For example, health is exposed as /actuator/health.
Tip
Actuator is supported natively with Spring MVC, Spring WebFlux, and Jersey.
51.1 Customizing the Management Endpoint Paths
Sometimes, it is useful to customize the prefix for the management endpoints. For example,
your application might already use /actuator for another purpose. You can use the
management.endpoints.web.base-path property to change the prefix for your management
endpoint, as shown in the following example:
management.endpoints.web.base-path=/manage
The preceding application.properties example changes the endpoint from /actuator/{id}
to /manage/{id} (for example, /manage/info).
Note
Unless the management port has been configured to expose endpoints by using a different HTTP
port, management.endpoints.web.base-path is relative to server.servlet.context-
path. If management.server.port is configured, management.endpoints.web.base-
path is relative to management.server.servlet.context-path.
51.2 Customizing the Management Server Port
Exposing management endpoints by using the default HTTP port is a sensible choice for cloud-based
deployments. If, however, your application runs inside your own data center, you may prefer to expose
endpoints by using a different HTTP port.
You can set the management.server.port property to change the HTTP port, as shown in the
following example:
management.server.port=8081
51.3 Configuring Management-specific SSL
When configured to use a custom port, the management server can also be configured with its own
SSL by using the various management.server.ssl.* properties. For example, doing so lets a
management server be available over HTTP while the main application uses HTTPS, as shown in the
following property settings:
server.port=8443
server.ssl.enabled=true
server.ssl.key-store=classpath:store.jks
server.ssl.key-password=secret
management.server.port=8080
management.server.ssl.enabled=false
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Alternatively, both the main server and the management server can use SSL but with different key
stores, as follows:
server.port=8443
server.ssl.enabled=true
server.ssl.key-store=classpath:main.jks
server.ssl.key-password=secret
management.server.port=8080
management.server.ssl.enabled=true
management.server.ssl.key-store=classpath:management.jks
management.server.ssl.key-password=secret
51.4 Customizing the Management Server Address
You can customize the address that the management endpoints are available on by setting the
management.server.address property. Doing so can be useful if you want to listen only on an
internal or ops-facing network or to listen only for connections from localhost.
Note
You can listen on a different address only when the port differs from the main server port.
The following example application.properties does not allow remote management connections:
management.server.port=8081
management.server.address=127.0.0.1
51.5 Disabling HTTP Endpoints
If you do not want to expose endpoints over HTTP, you can set the management port to -1, as shown
in the following example:
management.server.port=-1
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52. Monitoring and Management over JMX
Java Management Extensions (JMX) provide a standard mechanism to monitor and manage
applications. By default, Spring Boot exposes management endpoints as JMX MBeans under the
org.springframework.boot domain.
52.1 Customizing MBean Names
The name of the MBean is usually generated from the id of the endpoint. For example, the health
endpoint is exposed as org.springframework.boot:type=Endpoint,name=Health.
If your application contains more than one Spring ApplicationContext, you may find that names
clash. To solve this problem, you can set the management.endpoints.jmx.unique-names
property to true so that MBean names are always unique.
You can also customize the JMX domain under which endpoints are exposed. The following settings
show an example of doing so in application.properties:
management.endpoints.jmx.domain=com.example.myapp
management.endpoints.jmx.unique-names=true
52.2 Disabling JMX Endpoints
If you do not want to expose endpoints over JMX, you can set the
management.endpoints.jmx.exposure.exclude property to *, as shown in the following
example:
management.endpoints.jmx.exposure.exclude=*
52.3 Using Jolokia for JMX over HTTP
Jolokia is a JMX-HTTP bridge that provides an alternative method of accessing JMX beans. To use
Jolokia, include a dependency to org.jolokia:jolokia-core. For example, with Maven, you would
add the following dependency:
<dependency>
<groupId>org.jolokia</groupId>
<artifactId>jolokia-core</artifactId>
</dependency>
The Jolokia endpoint can then be exposed by adding jolokia or * to the
management.endpoints.web.exposure.include property. You can then access it by using /
actuator/jolokia on your management HTTP server.
Customizing Jolokia
Jolokia has a number of settings that you would traditionally configure by setting servlet parameters.
With Spring Boot, you can use your application.properties file. To do so, prefix the parameter
with management.endpoint.jolokia.config., as shown in the following example:
management.endpoint.jolokia.config.debug=true
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Disabling Jolokia
If you use Jolokia but do not want Spring Boot to configure it, set the
management.endpoint.jolokia.enabled property to false, as follows:
management.endpoint.jolokia.enabled=false
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53. Loggers
Spring Boot Actuator includes the ability to view and configure the log levels of your application at
runtime. You can view either the entire list or an individual logger’s configuration, which is made up of
both the explicitly configured logging level as well as the effective logging level given to it by the logging
framework. These levels can be one of:
•TRACE
•DEBUG
•INFO
•WARN
•ERROR
•FATAL
•OFF
•null
null indicates that there is no explicit configuration.
53.1 Configure a Logger
To configure a given logger, POST a partial entity to the resource’s URI, as shown in the following
example:
{
"configuredLevel": "DEBUG"
}
Tip
To “reset” the specific level of the logger (and use the default configuration instead), you can pass
a value of null as the configuredLevel.
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54. Metrics
Spring Boot Actuator provides dependency management and auto-configuration for Micrometer, an
application metrics facade that supports numerous monitoring systems, including:
•Atlas
•Datadog
•Ganglia
•Graphite
•Influx
•JMX
•New Relic
•Prometheus
•SignalFx
•Simple (in-memory)
•StatsD
•Wavefront
Tip
To learn more about Micrometer’s capabilities, please refer to its reference documentation, in
particular the concepts section.
54.1 Getting started
Spring Boot auto-configures a composite MeterRegistry and adds a registry to the composite
for each of the supported implementations that it finds on the classpath. Having a dependency on
micrometer-registry-{system} in your runtime classpath is enough for Spring Boot to configure
the registry.
Most registries share common features. For instance, you can disable a particular registry even if the
Micrometer registry implementation is on the classpath. For instance, to disable Datadog:
management.metrics.export.datadog.enabled=false
Spring Boot will also add any auto-configured registries to the global static composite registry on the
Metrics class unless you explicitly tell it not to:
management.metrics.use-global-registry=false
You can register any number of MeterRegistryCustomizer beans to further configure the registry,
such as applying common tags, before any meters are registered with the registry:
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@Bean
MeterRegistryCustomizer<MeterRegistry> metricsCommonTags() {
return registry -> registry.config().commonTags("region", "us-east-1");
}
You can apply customizations to particular registry implementations by being more specific about the
generic type:
@Bean
MeterRegistryCustomizer<GraphiteMeterRegistry> graphiteMetricsNamingConvention() {
return registry -> registry.config().namingConvention(MY_CUSTOM_CONVENTION);
}
With that setup in place you can inject MeterRegistry in your components and register metrics:
@Component
public class SampleBean {
private final Counter counter;
public SampleBean(MeterRegistry registry) {
this.counter = registry.counter("received.messages");
}
public void handleMessage(String message) {
this.counter.increment();
// handle message implementation
}
}
Spring Boot also configures built-in instrumentation (i.e. MeterBinder implementations) that you can
control via configuration or dedicated annotation markers.
54.2 Supported monitoring systems
Atlas
By default, metrics are exported to Atlas running on your local machine. The location of the Atlas server
to use can be provided using:
management.metrics.export.atlas.uri=http://atlas.example.com:7101/api/v1/publish
Datadog
Datadog registry pushes metrics to datadoghq periodically. To export metrics to Datadog, your API key
must be provided:
management.metrics.export.datadog.api-key=YOUR_KEY
You can also change the interval at which metrics are sent to Datadog:
management.metrics.export.datadog.step=30s
Ganglia
By default, metrics are exported to Ganglia running on your local machine. The Ganglia server host and
port to use can be provided using:
management.metrics.export.ganglia.host=ganglia.example.com
management.metrics.export.ganglia.port=9649
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Graphite
By default, metrics are exported to Graphite running on your local machine. The Graphite server host
and port to use can be provided using:
management.metrics.export.graphite.host=graphite.example.com
management.metrics.export.graphite.port=9004
Micrometer provides a default HierarchicalNameMapper that governs how a dimensional meter id
is mapped to flat hierarchical names.
Tip
To take control over this behaviour, define your GraphiteMeterRegistry and supply your
own HierarchicalNameMapper. An auto-configured GraphiteConfig and Clock beans are
provided unless you define your own:
@Bean
public GraphiteMeterRegistry graphiteMeterRegistry(GraphiteConfig config, Clock clock) {
return new GraphiteMeterRegistry(config, clock, MY_HIERARCHICAL_MAPPER);
}
Influx
By default, metrics are exported to Influx running on your local machine. The location of the Influx server
to use can be provided using:
management.metrics.export.influx.uri=http://influx.example.com:8086
JMX
Micrometer provides a hierarchical mapping to JMX, primarily as a cheap and portable way to view
metrics locally.By default, metrics are exported to the metrics JMX domain. The domain to use can
be provided provided using:
management.metrics.export.jmx.domain=com.example.app.metrics
Micrometer provides a default HierarchicalNameMapper that governs how a dimensional meter id
is mapped to flat hierarchical names.
Tip
To take control over this behaviour, define your JmxMeterRegistry and supply your own
HierarchicalNameMapper. An auto-configured JmxConfig and Clock beans are provided
unless you define your own:
@Bean
public JmxMeterRegistry jmxMeterRegistry(JmxConfig config, Clock clock) {
return new JmxMeterRegistry(config, clock, MY_HIERARCHICAL_MAPPER);
}
New Relic
New Relic registry pushes metrics to New Relic periodically. To export metrics to New Relic, your API
key and account id must be provided:
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management.metrics.export.newrelic.api-key=YOUR_KEY
management.metrics.export.newrelic.account-id=YOUR_ACCOUNT_ID
You can also change the interval at which metrics are sent to New Relic:
management.metrics.export.newrelic.step=30s
Prometheus
Prometheus expects to scrape or poll individual app instances for metrics. Spring Boot provides an
actuator endpoint available at /actuator/prometheus to present a Prometheus scrape with the
appropriate format.
Tip
The endpoint is not available by default and must be exposed, see exposing endpoints for more
details.
Here is an example scrape_config to add to prometheus.yml:
scrape_configs:
- job_name: 'spring'
metrics_path: '/actuator/prometheus'
static_configs:
- targets: ['HOST:PORT']
SignalFx
SignalFx registry pushes metrics to SignalFx periodically. To export metrics to SignalFx, your access
token must be provided:
management.metrics.export.signalfx.access-token=YOUR_ACCESS_TOKEN
You can also change the interval at which metrics are sent to SignalFx:
management.metrics.export.signalfx.step=30s
Simple
Micrometer ships with a simple, in-memory backend that is automatically used as a fallback if no other
registry is configured. This allows you to see what metrics are collected in the metrics endpoint.
The in-memory backend disables itself as soon as you’re using any of the other available backend. You
can also disable it explicitly:
management.metrics.export.simple.enabled=false
StatsD
The StatsD registry pushes metrics over UDP to a StatsD agent eagerly. By default, metrics are exported
to a StatsD agent running on your local machine. The StatsD agent host and port to use can be provided
using:
management.metrics.export.statsd.host=statsd.example.com
management.metrics.export.statsd.port=9125
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You can also change the StatsD line protocol to use (default to Datadog):
management.metrics.export.statsd.flavor=etsy
Wavefront
Wavefront registry pushes metrics to Wavefront periodically. If you are exporting metrics to Wavefront
directly, your API token must be provided:
management.metrics.export.wavefront.api-token=YOUR_API_TOKEN
Alternatively, you may use a Wavefront sidecar or an internal proxy set up in your environment that
forwards metrics data to the Wavefront API host:
management.metrics.export.wavefront.uri=proxy://localhost:2878
Tip
If publishing metrics to a Wavefront proxy (as described in the documentation), the host must be
in the proxy://HOST:PORT format.
You can also change the interval at which metrics are sent to Wavefront:
management.metrics.export.wavefront.step=30s
54.3 Supported Metrics
Spring Boot registers the following core metrics when applicable:
• JVM metrics, report utilization of:
• Various memory and buffer pools
• Statistics related to garbage collection
• Threads utilization
• Number of classes loaded/unloaded
• CPU metrics
• File descriptor metrics
• Logback metrics: record the number of events logged to Logback at each level
• Uptime metrics: report a gauge for uptime and a fixed gauge representing the application’s absolute
start time
• Tomcat metrics
•Spring Integration metrics
Spring MVC Metrics
Auto-configuration enables the instrumentation of requests handled by Spring MVC. When
management.metrics.web.server.auto-time-requests is true, this instrumentation occurs
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for all requests. Alternatively, when set to false, you can enable instrumentation by adding @Timed
to a request-handling method:
@RestController
@Timed ❶
public class MyController {
@GetMapping("/api/people")
@Timed(extraTags = { "region", "us-east-1" }) ❷
@Timed(value = "all.people", longTask = true) ❸
public List<Person> listPeople() { ... }
}
❶A controller class to enable timings on every request handler in the controller.
❷A method to enable for an individual endpoint. This is not necessary if you have it on the class, but
can be used to further customize the timer for this particular endpoint.
❸A method with longTask = true to enable a long task timer for the method. Long task timers
require a separate metric name, and can be stacked with a short task timer.
By default, metrics are generated with the name, http.server.requests. The name can
be customized by setting the management.metrics.web.server.requests-metric-name
property.
By default, Spring MVC-related metrics are tagged with the following information:
•method, the request’s method (for example, GET or POST).
•uri, the request’s URI template prior to variable substitution, if possible (for example, /api/person/
{id}).
•status, the response’s HTTP status code (for example, 200 or 500).
•exception, the simple class name of any exception that was thrown while handling the request.
To customize the tags, provide a @Bean that implements WebMvcTagsProvider.
Spring WebFlux Metrics
Auto-configuration enables the instrumentation of all requests handled by WebFlux controllers and
functional handlers.
By default, metrics are generated with the name http.server.requests. You can customize the
name by setting the management.metrics.web.server.requests-metric-name property.
By default, WebFlux-related metrics are tagged with the following information:
•method, the request’s method (for example, GET or POST).
•uri, the request’s URI template prior to variable substitution, if possible (for example, /api/person/
{id}).
•status, the response’s HTTP status code (for example, 200 or 500).
•exception, the simple class name of any exception that was thrown while handling the request.
To customize the tags, provide a @Bean that implements WebFluxTagsProvider.
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RestTemplate Metrics
The instrumentation of any RestTemplate created using the auto-configured
RestTemplateBuilder is enabled. It is also possible to apply MetricsRestTemplateCustomizer
manually.
By default, metrics are generated with the name, http.client.requests. The name can
be customized by setting the management.metrics.web.client.requests-metric-name
property.
By default, metrics generated by an instrumented RestTemplate are tagged with the following
information:
•method, the request’s method (for example, GET or POST).
•uri, the request’s URI template prior to variable substitution, if possible (for example, /api/person/
{id}).
•status, the response’s HTTP status code (for example, 200 or 500).
•clientName, the host portion of the URI.
To customize the tags, provide a @Bean that implements RestTemplateExchangeTagsProvider.
There are convenience static functions in RestTemplateExchangeTags.
Cache Metrics
Auto-configuration enables the instrumentation of all available Caches on startup with metrics prefixed
with cache. Cache instrumentation is standardized for a basic set of metrics. Additional, cache-specific
metrics are also available.
The following cache libraries are supported:
• Caffeine
• EhCache 2
• Hazelcast
• Any compliant JCache (JSR-107) implementation
Metrics are tagged by the name of the cache and by the name of the CacheManager that is derived
from the bean name.
Note
Only caches that are available on startup are bound to the registry. For caches created
on-the-fly or programmatically after the startup phase, an explicit registration is required. A
CacheMetricsRegistrar bean is made available to make that process easier.
DataSource Metrics
Auto-configuration enables the instrumentation of all available DataSource objects with a metric
named jdbc. Data source instrumentation results in gauges representing the currently active, maximum
allowed, and minimum allowed connections in the pool. Each of these gauges has a name that is prefixed
by jdbc.
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Metrics are also tagged by the name of the DataSource computed based on the bean name.
Tip
By default, Spring Boot provides metadata for all supported data sources; you can add additional
DataSourcePoolMetadataProvider beans if your favorite data source isn’t supported out of
the box. See DataSourcePoolMetadataProvidersConfiguration for examples.
Also, Hikari-specific metrics are exposed with a hikaricp prefix. Each metric is tagged by the name
of the Pool (can be controlled with spring.datasource.name).
RabbitMQ Metrics
Auto-configuration will enable the instrumentation of all available RabbitMQ connection factories with
a metric named rabbitmq.
54.4 Registering custom metrics
To register custom metrics, inject MeterRegistry into your component, as shown in the following
example:
class Dictionary {
private final List<String> words = new CopyOnWriteArrayList<>();
Dictionary(MeterRegistry registry) {
registry.gaugeCollectionSize("dictionary.size", Tags.empty(), this.words);
}
// …
}
If you find that you repeatedly instrument a suite of metrics across components or applications, you may
encapsulate this suite in a MeterBinder implementation. By default, metrics from all MeterBinder
beans will be automatically bound to the Spring-managed MeterRegistry.
54.5 Customizing individual metrics
If you need to apply customizations to specific Meter instances you can use
the io.micrometer.core.instrument.config.MeterFilter interface. By default, all
MeterFilter beans will be automatically applied to the micrometer MeterRegistry.Config.
For example, if you want to rename the mytag.region tag to mytag.area for all meter IDs beginning
with com.example, you can do the following:
@Bean
public MeterFilter renameRegionTagMeterFilter() {
return MeterFilter.renameTag("com.example", "mytag.region", "mytag.area");
}
Per-meter properties
In addition to MeterFilter beans, it’s also possible to apply a limited set of customization on a per-
meter basis using properties. Per-meter customizations apply to any all meter IDs that start with the given
name. For example, the following will disable any meters that have an ID starting with example.remote
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management.metrics.enable.example.remote=false
The following properties allow per-meter customization:
Table 54.1. Per-meter customizations
Property Description
management.metrics.enable Whether to deny meters from emitting any
metrics.
management.metrics.distribution.percentiles-
histogram
Whether to publish a histogram suitable for
computing aggregable (across dimension)
percentile approximations.
management.metrics.distribution.percentilesPublish percentile values computed in your
application
management.metrics.distribution.sla Publish a cumulative histogram with buckets
defined by your SLAs.
For more details on concepts behind percentiles-histogram, percentiles and sla refer to the
"Histograms and percentiles" section of the micrometer documentation.
54.6 Metrics endpoint
Spring Boot provides a metrics endpoint that can be used diagnostically to examine the metrics
collected by an application. The endpoint is not available by default and must be exposed, see exposing
endpoints for more details.
Navigating to /actuator/metrics displays a list of available meter names. You can drill down to view
information about a particular meter by providing its name as a selector, e.g. /actuator/metrics/
jvm.memory.max.
Tip
The name you use here should match the name used in the code, not the name after it has
been naming-convention normalized for a monitoring system it is shipped to. In other words,
if jvm.memory.max appears as jvm_memory_max in Prometheus because of its snake case
naming convention, you should still use jvm.memory.max as the selector when inspecting the
meter in the metrics endpoint.
You can also add any number of tag=KEY:VALUE query parameters to the end of the
URL to dimensionally drill down on a meter, e.g. /actuator/metrics/jvm.memory.max?
tag=area:nonheap.
Tip
The reported measurements are the sum of the statistics of all meters matching the meter
name and any tags that have been applied. So in the example above, the returned "Value"
statistic is the sum of the maximum memory footprints of "Code Cache", "Compressed Class
Space", and "Metaspace" areas of the heap. If you just wanted to see the maximum size for
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the "Metaspace", you could add an additional tag=id:Metaspace, i.e. /actuator/metrics/
jvm.memory.max?tag=area:nonheap&tag=id:Metaspace.
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55. Auditing
Once Spring Security is in play, Spring Boot Actuator has a flexible audit framework that publishes
events (by default, “authentication success”, “failure” and “access denied” exceptions). This feature
can be very useful for reporting and for implementing a lock-out policy based on authentication
failures. To customize published security events, you can provide your own implementations of
AbstractAuthenticationAuditListener and AbstractAuthorizationAuditListener.
You can also use the audit services for your own business events. To do so, either inject the
existing AuditEventRepository into your own components and use that directly or publish
an AuditApplicationEvent with the Spring ApplicationEventPublisher (by implementing
ApplicationEventPublisherAware).
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56. HTTP Tracing
Tracing is automatically enabled for all HTTP requests. You can view the httptrace endpoint and
obtain basic information about the last 100 request-response exchanges.
56.1 Custom HTTP tracing
To customize the items that are included in each trace, use the management.trace.http.include
configuration property.
By default, an InMemoryHttpTraceRepository that stores traces for the last 100 request-
response exchanges is used. If you need to expand the capacity, you can define your own
instance of the InMemoryHttpTraceRepository bean. You can also create your own alternative
HttpTraceRepository implementation.
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57. Process Monitoring
In the spring-boot module, you can find two classes to create files that are often useful for process
monitoring:
•ApplicationPidFileWriter creates a file containing the application PID (by default, in the
application directory with a file name of application.pid).
•WebServerPortFileWriter creates a file (or files) containing the ports of the running web server
(by default, in the application directory with a file name of application.port).
By default, these writers are not activated, but you can enable:
•By Extending Configuration
•Section 57.2, “Programmatically”
57.1 Extending Configuration
In the META-INF/spring.factories file, you can activate the listener(s) that writes a PID file, as
shown in the following example:
org.springframework.context.ApplicationListener=\
org.springframework.boot.context.ApplicationPidFileWriter,\
org.springframework.boot.web.context.WebServerPortFileWriter
57.2 Programmatically
You can also activate a listener by invoking the SpringApplication.addListeners(…) method
and passing the appropriate Writer object. This method also lets you customize the file name and
path in the Writer constructor.
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58. Cloud Foundry Support
Spring Boot’s actuator module includes additional support that is activated when you deploy to a
compatible Cloud Foundry instance. The /cloudfoundryapplication path provides an alternative
secured route to all @Endpoint beans.
The extended support lets Cloud Foundry management UIs (such as the web application that you can
use to view deployed applications) be augmented with Spring Boot actuator information. For example,
an application status page may include full health information instead of the typical “running” or “stopped”
status.
Note
The /cloudfoundryapplication path is not directly accessible to regular users. In order to
use the endpoint, a valid UAA token must be passed with the request.
58.1 Disabling Extended Cloud Foundry Actuator Support
If you want to fully disable the /cloudfoundryapplication endpoints, you can add the following
setting to your application.properties file:
application.properties.
management.cloudfoundry.enabled=false
58.2 Cloud Foundry Self-signed Certificates
By default, the security verification for /cloudfoundryapplication endpoints makes SSL calls to
various Cloud Foundry services. If your Cloud Foundry UAA or Cloud Controller services use self-signed
certificates, you need to set the following property:
application.properties.
management.cloudfoundry.skip-ssl-validation=true
58.3 Custom context path
If the server’s context-path has been configured to anything other then /, the Cloud Foundry endpoints
will not be available at the root of the application. For example, if server.servlet.context-path=/
app, Cloud Foundry endpoints will be available at /app/cloudfoundryapplication/*.
If you expect the Cloud Foundry endpoints to always be available at /cloudfoundryapplication/
*, regardless of the server’s context-path, you will need to explicitly configure that in your application.
The configuration will differ depending on the web server in use. For Tomcat, the following configuration
can be added:
@Bean
public TomcatServletWebServerFactory servletWebServerFactory() {
return new TomcatServletWebServerFactory() {
@Override
protected void prepareContext(Host host,
ServletContextInitializer[] initializers) {
super.prepareContext(host, initializers);
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StandardContext child = new StandardContext();
child.addLifecycleListener(new Tomcat.FixContextListener());
child.setPath("/cloudfoundryapplication");
ServletContainerInitializer initializer = getServletContextInitializer(
getContextPath());
child.addServletContainerInitializer(initializer, Collections.emptySet());
child.setCrossContext(true);
host.addChild(child);
}
};
}
private ServletContainerInitializer getServletContextInitializer(String contextPath) {
return (c, context) -> {
Servlet servlet = new GenericServlet() {
@Override
public void service(ServletRequest req, ServletResponse res)
throws ServletException, IOException {
ServletContext context = req.getServletContext()
.getContext(contextPath);
context.getRequestDispatcher("/cloudfoundryapplication").forward(req,
res);
}
};
context.addServlet("cloudfoundry", servlet).addMapping("/*");
};
}
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59. What to Read Next
If you want to explore some of the concepts discussed in this chapter, you can take a look at the actuator
sample applications. You also might want to read about graphing tools such as Graphite.
Otherwise, you can continue on, to read about ‘deployment options’ or jump ahead for some in-depth
information about Spring Boot’s build tool plugins.
Part VI. Deploying
Spring Boot Applications
Spring Boot’s flexible packaging options provide a great deal of choice when it comes to deploying your
application. You can deploy Spring Boot applications to a variety of cloud platforms, to container images
(such as Docker), or to virtual/real machines.
This section covers some of the more common deployment scenarios.
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60. Deploying to the Cloud
Spring Boot’s executable jars are ready-made for most popular cloud PaaS (Platform-as-a-Service)
providers. These providers tend to require that you “bring your own container”. They manage application
processes (not Java applications specifically), so they need an intermediary layer that adapts your
application to the cloud’s notion of a running process.
Two popular cloud providers, Heroku and Cloud Foundry, employ a “buildpack” approach. The buildpack
wraps your deployed code in whatever is needed to start your application. It might be a JDK and a
call to java, an embedded web server, or a full-fledged application server. A buildpack is pluggable,
but ideally you should be able to get by with as few customizations to it as possible. This reduces the
footprint of functionality that is not under your control. It minimizes divergence between development
and production environments.
Ideally, your application, like a Spring Boot executable jar, has everything that it needs to run packaged
within it.
In this section, we look at what it takes to get the simple application that we developed in the “Getting
Started” section up and running in the Cloud.
60.1 Cloud Foundry
Cloud Foundry provides default buildpacks that come into play if no other buildpack is specified. The
Cloud Foundry Java buildpack has excellent support for Spring applications, including Spring Boot. You
can deploy stand-alone executable jar applications as well as traditional .war packaged applications.
Once you have built your application (by using, for example, mvn clean package) and have installed
the cf command line tool, deploy your application by using the cf push command, substituting the
path to your compiled .jar. Be sure to have logged in with your cf command line client before pushing
an application. The following line shows using the cf push command to deploy an application:
$ cf push acloudyspringtime -p target/demo-0.0.1-SNAPSHOT.jar
Note
In the preceding example, we substitute acloudyspringtime for whatever value you give cf
as the name of your application.
See the cf push documentation for more options. If there is a Cloud Foundry manifest.yml file
present in the same directory, it is considered.
At this point, cf starts uploading your application, producing output similar to the following example:
Uploading acloudyspringtime... OK
Preparing to start acloudyspringtime... OK
-----> Downloaded app package (8.9M)
-----> Java Buildpack Version: v3.12 (offline) | https://github.com/cloudfoundry/java-
buildpack.git#6f25b7e
-----> Downloading Open Jdk JRE 1.8.0_121 from https://java-buildpack.cloudfoundry.org/openjdk/trusty/
x86_64/openjdk-1.8.0_121.tar.gz (found in cache)
Expanding Open Jdk JRE to .java-buildpack/open_jdk_jre (1.6s)
-----> Downloading Open JDK Like Memory Calculator 2.0.2_RELEASE from https://java-
buildpack.cloudfoundry.org/memory-calculator/trusty/x86_64/memory-calculator-2.0.2_RELEASE.tar.gz (found
in cache)
Memory Settings: -Xss349K -Xmx681574K -XX:MaxMetaspaceSize=104857K -Xms681574K -
XX:MetaspaceSize=104857K
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-----> Downloading Container Certificate Trust Store 1.0.0_RELEASE from https://java-
buildpack.cloudfoundry.org/container-certificate-trust-store/container-certificate-trust-
store-1.0.0_RELEASE.jar (found in cache)
Adding certificates to .java-buildpack/container_certificate_trust_store/truststore.jks (0.6s)
-----> Downloading Spring Auto Reconfiguration 1.10.0_RELEASE from https://java-
buildpack.cloudfoundry.org/auto-reconfiguration/auto-reconfiguration-1.10.0_RELEASE.jar (found in cache)
Checking status of app 'acloudyspringtime'...
0 of 1 instances running (1 starting)
...
0 of 1 instances running (1 starting)
...
0 of 1 instances running (1 starting)
...
1 of 1 instances running (1 running)
App started
Congratulations! The application is now live!
Once your application is live, you can verify the status of the deployed application by using the cf apps
command, as shown in the following example:
$ cf apps
Getting applications in ...
OK
name requested state instances memory disk urls
...
acloudyspringtime started 1/1 512M 1G acloudyspringtime.cfapps.io
...
Once Cloud Foundry acknowledges that your application has been deployed, you should be able
to find the application at the URI given. In the preceding example, you could find it at http://
acloudyspringtime.cfapps.io/.
Binding to Services
By default, metadata about the running application as well as service connection information is exposed
to the application as environment variables (for example: $VCAP_SERVICES). This architecture decision
is due to Cloud Foundry’s polyglot (any language and platform can be supported as a buildpack) nature.
Process-scoped environment variables are language agnostic.
Environment variables do not always make for the easiest API, so Spring Boot automatically extracts
them and flattens the data into properties that can be accessed through Spring’s Environment
abstraction, as shown in the following example:
@Component
class MyBean implements EnvironmentAware {
private String instanceId;
@Override
public void setEnvironment(Environment environment) {
this.instanceId = environment.getProperty("vcap.application.instance_id");
}
// ...
}
All Cloud Foundry properties are prefixed with vcap. You can use vcap properties to access application
information (such as the public URL of the application) and service information (such as database
credentials). See the ‘CloudFoundryVcapEnvironmentPostProcessor’ Javadoc for complete details.
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Tip
The Spring Cloud Connectors project is a better fit for tasks such as configuring a DataSource.
Spring Boot includes auto-configuration support and a spring-boot-starter-cloud-
connectors starter.
60.2 Heroku
Heroku is another popular PaaS platform. To customize Heroku builds, you provide a Procfile,
which provides the incantation required to deploy an application. Heroku assigns a port for the Java
application to use and then ensures that routing to the external URI works.
You must configure your application to listen on the correct port. The following example shows the
Procfile for our starter REST application:
web: java -Dserver.port=$PORT -jar target/demo-0.0.1-SNAPSHOT.jar
Spring Boot makes -D arguments available as properties accessible from a Spring Environment
instance. The server.port configuration property is fed to the embedded Tomcat, Jetty, or Undertow
instance, which then uses the port when it starts up. The $PORT environment variable is assigned to
us by the Heroku PaaS.
This should be everything you need. The most common deployment workflow for Heroku deployments
is to git push the code to production, as shown in the following example:
$ git push heroku master
Initializing repository, done.
Counting objects: 95, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (78/78), done.
Writing objects: 100% (95/95), 8.66 MiB | 606.00 KiB/s, done.
Total 95 (delta 31), reused 0 (delta 0)
-----> Java app detected
-----> Installing OpenJDK 1.8... done
-----> Installing Maven 3.3.1... done
-----> Installing settings.xml... done
-----> Executing: mvn -B -DskipTests=true clean install
[INFO] Scanning for projects...
Downloading: https://repo.spring.io/...
Downloaded: https://repo.spring.io/... (818 B at 1.8 KB/sec)
....
Downloaded: http://s3pository.heroku.com/jvm/... (152 KB at 595.3 KB/sec)
[INFO] Installing /tmp/build_0c35a5d2-a067-4abc-a232-14b1fb7a8229/target/...
[INFO] Installing /tmp/build_0c35a5d2-a067-4abc-a232-14b1fb7a8229/pom.xml ...
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 59.358s
[INFO] Finished at: Fri Mar 07 07:28:25 UTC 2014
[INFO] Final Memory: 20M/493M
[INFO] ------------------------------------------------------------------------
-----> Discovering process types
Procfile declares types -> web
-----> Compressing... done, 70.4MB
-----> Launching... done, v6
http://agile-sierra-1405.herokuapp.com/ deployed to Heroku
To git@heroku.com:agile-sierra-1405.git
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* [new branch] master -> master
Your application should now be up and running on Heroku.
60.3 OpenShift
OpenShift is the Red Hat public (and enterprise) extension of the Kubernetes container orchestration
platform. Similarly to Kubernetes, OpenShift has many options for installing Spring Boot based
applications.
OpenShift has many resources describing how to deploy Spring Boot applications, including:
•Using the S2I builder
•Architecture guide
•Running as a traditional web application on Wildfly
•OpenShift Commons Briefing
60.4 Amazon Web Services (AWS)
Amazon Web Services offers multiple ways to install Spring Boot-based applications, either as traditional
web applications (war) or as executable jar files with an embedded web server. The options include:
• AWS Elastic Beanstalk
• AWS Code Deploy
• AWS OPS Works
• AWS Cloud Formation
• AWS Container Registry
Each has different features and pricing models. In this document, we describe only the simplest option:
AWS Elastic Beanstalk.
AWS Elastic Beanstalk
As described in the official Elastic Beanstalk Java guide, there are two main options to deploy a Java
application. You can either use the “Tomcat Platform” or the “Java SE platform”.
Using the Tomcat Platform
This option applies to Spring Boot projects that produce a war file. No special configuration is required.
You need only follow the official guide.
Using the Java SE Platform
This option applies to Spring Boot projects that produce a jar file and run an embedded web container.
Elastic Beanstalk environments run an nginx instance on port 80 to proxy the actual application, running
on port 5000. To configure it, add the following line to your application.properties file:
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server.port=5000
Upload binaries instead of sources
By default, Elastic Beanstalk uploads sources and compiles them in AWS. However, it is
best to upload the binaries instead. To do so, add lines similar to the following to your
.elasticbeanstalk/config.yml file:
deploy:
artifact: target/demo-0.0.1-SNAPSHOT.jar
Reduce costs by setting the environment type
By default an Elastic Beanstalk environment is load balanced. The load balancer has a significant
cost. To avoid that cost, set the environment type to “Single instance”, as described in the Amazon
documentation. You can also create single instance environments by using the CLI and the
following command:
eb create -s
Summary
This is one of the easiest ways to get to AWS, but there are more things to cover, such as how to
integrate Elastic Beanstalk into any CI / CD tool, use the Elastic Beanstalk Maven plugin instead of the
CLI, and others. There is a blog post covering these topics more in detail.
60.5 Boxfuse and Amazon Web Services
Boxfuse works by turning your Spring Boot executable jar or war into a minimal VM image that can be
deployed unchanged either on VirtualBox or on AWS. Boxfuse comes with deep integration for Spring
Boot and uses the information from your Spring Boot configuration file to automatically configure ports
and health check URLs. Boxfuse leverages this information both for the images it produces as well as
for all the resources it provisions (instances, security groups, elastic load balancers, and so on).
Once you have created a Boxfuse account, connected it to your AWS account, installed the latest version
of the Boxfuse Client, and ensured that the application has been built by Maven or Gradle (by using, for
example, mvn clean package), you can deploy your Spring Boot application to AWS with a command
similar to the following:
$ boxfuse run myapp-1.0.jar -env=prod
See the boxfuse run documentation for more options. If there is a boxfuse.conf file present in the
current directory, it is considered.
Tip
By default, Boxfuse activates a Spring profile named boxfuse on startup. If your executable jar
or war contains an application-boxfuse.properties file, Boxfuse bases its configuration
on the properties it contains.
At this point, boxfuse creates an image for your application, uploads it, and configures and starts the
necessary resources on AWS, resulting in output similar to the following example:
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Fusing Image for myapp-1.0.jar ...
Image fused in 00:06.838s (53937 K) -> axelfontaine/myapp:1.0
Creating axelfontaine/myapp ...
Pushing axelfontaine/myapp:1.0 ...
Verifying axelfontaine/myapp:1.0 ...
Creating Elastic IP ...
Mapping myapp-axelfontaine.boxfuse.io to 52.28.233.167 ...
Waiting for AWS to create an AMI for axelfontaine/myapp:1.0 in eu-central-1 (this may take up to 50
seconds) ...
AMI created in 00:23.557s -> ami-d23f38cf
Creating security group boxfuse-sg_axelfontaine/myapp:1.0 ...
Launching t2.micro instance of axelfontaine/myapp:1.0 (ami-d23f38cf) in eu-central-1 ...
Instance launched in 00:30.306s -> i-92ef9f53
Waiting for AWS to boot Instance i-92ef9f53 and Payload to start at http://52.28.235.61/ ...
Payload started in 00:29.266s -> http://52.28.235.61/
Remapping Elastic IP 52.28.233.167 to i-92ef9f53 ...
Waiting 15s for AWS to complete Elastic IP Zero Downtime transition ...
Deployment completed successfully. axelfontaine/myapp:1.0 is up and running at http://myapp-
axelfontaine.boxfuse.io/
Your application should now be up and running on AWS.
See the blog post on deploying Spring Boot apps on EC2 as well as the documentation for the Boxfuse
Spring Boot integration to get started with a Maven build to run the app.
60.6 Google Cloud
Google Cloud has several options that can be used to launch Spring Boot applications. The easiest to
get started with is probably App Engine, but you could also find ways to run Spring Boot in a container
with Container Engine or on a virtual machine with Compute Engine.
To run in App Engine, you can create a project in the UI first, which sets up a unique identifier for you
and also sets up HTTP routes. Add a Java app to the project and leave it empty and then use the Google
Cloud SDK to push your Spring Boot app into that slot from the command line or CI build.
App Engine Standard requires you to use WAR packaging. Follow these steps to deploy App Engine
Standard application to Google Cloud.
Alternatively, App Engine Flex requires you to create an app.yaml file to describe the resources your
app requires. Normally, you put this file in src/main/appengine, and it should resemble the following
file:
service: default
runtime: java
env: flex
runtime_config:
jdk: openjdk8
handlers:
- url: /.*
script: this field is required, but ignored
manual_scaling:
instances: 1
health_check:
enable_health_check: False
env_variables:
ENCRYPT_KEY: your_encryption_key_here
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You can deploy the app (for example, with a Maven plugin) by adding the project ID to the build
configuration, as shown in the following example:
<plugin>
<groupId>com.google.cloud.tools</groupId>
<artifactId>appengine-maven-plugin</artifactId>
<version>1.3.0</version>
<configuration>
<project>myproject</project>
</configuration>
</plugin>
Then deploy with mvn appengine:deploy (if you need to authenticate first, the build fails).
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61. Installing Spring Boot Applications
In addition to running Spring Boot applications by using java -jar, it is also possible to make
fully executable applications for Unix systems. A fully executable jar can be executed like any other
executable binary or it can be registered with init.d or systemd. This makes it very easy to install
and manage Spring Boot applications in common production environments.
Caution
Fully executable jars work by embedding an extra script at the front of the file. Currently, some tools
do not accept this format, so you may not always be able to use this technique. For example, jar
-xf may silently fail to extract a jar or war that has been made fully executable. It is recommended
that you make your jar or war fully executable only if you intend to execute it directly, rather than
running it with java -jar or deploying it to a servlet container.
To create a ‘fully executable’ jar with Maven, use the following plugin configuration:
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<executable>true</executable>
</configuration>
</plugin>
The following example shows the equivalent Gradle configuration:
bootJar {
launchScript()
}
You can then run your application by typing ./my-application.jar (where my-application is
the name of your artifact). The directory containing the jar is used as your application’s working directory.
61.1 Supported Operating Systems
The default script supports most Linux distributions and is tested on CentOS and Ubuntu. Other
platforms, such as OS X and FreeBSD, require the use of a custom embeddedLaunchScript.
61.2 Unix/Linux Services
Spring Boot application can be easily started as Unix/Linux services by using either init.d or
systemd.
Installation as an init.d Service (System V)
If you configured Spring Boot’s Maven or Gradle plugin to generate a fully executable jar, and you do not
use a custom embeddedLaunchScript, your application can be used as an init.d service. To do
so, symlink the jar to init.d to support the standard start, stop, restart, and status commands.
The script supports the following features:
• Starts the services as the user that owns the jar file
• Tracks the application’s PID by using /var/run/<appname>/<appname>.pid
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• Writes console logs to /var/log/<appname>.log
Assuming that you have a Spring Boot application installed in /var/myapp, to install a Spring Boot
application as an init.d service, create a symlink, as follows:
$ sudo ln -s /var/myapp/myapp.jar /etc/init.d/myapp
Once installed, you can start and stop the service in the usual way. For example, on a Debian-based
system, you could start it with the following command:
$ service myapp start
Tip
If your application fails to start, check the log file written to /var/log/<appname>.log for errors.
You can also flag the application to start automatically by using your standard operating system tools.
For example, on Debian, you could use the following command:
$ update-rc.d myapp defaults <priority>
Securing an init.d Service
Note
The following is a set of guidelines on how to secure a Spring Boot application that runs as an
init.d service. It is not intended to be an exhaustive list of everything that should be done to harden
an application and the environment in which it runs.
When executed as root, as is the case when root is being used to start an init.d service, the default
executable script runs the application as the user who owns the jar file. You should never run a Spring
Boot application as root, so your application’s jar file should never be owned by root. Instead, create
a specific user to run your application and use chown to make it the owner of the jar file, as shown in
the following example:
$ chown bootapp:bootapp your-app.jar
In this case, the default executable script runs the application as the bootapp user.
Tip
To reduce the chances of the application’s user account being compromised, you should consider
preventing it from using a login shell. For example, you can set the account’s shell to /usr/
sbin/nologin.
You should also take steps to prevent the modification of your application’s jar file. Firstly, configure
its permissions so that it cannot be written and can only be read or executed by its owner, as shown
in the following example:
$ chmod 500 your-app.jar
Second, you should also take steps to limit the damage if your application or the account that’s running
it is compromised. If an attacker does gain access, they could make the jar file writable and change its
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contents. One way to protect against this is to make it immutable by using chattr, as shown in the
following example:
$ sudo chattr +i your-app.jar
This will prevent any user, including root, from modifying the jar.
If root is used to control the application’s service and you use a .conf file to customize its startup,
the .conf file is read and evaluated by the root user. It should be secured accordingly. Use chmod
so that the file can only be read by the owner and use chown to make root the owner, as shown in
the following example:
$ chmod 400 your-app.conf
$ sudo chown root:root your-app.conf
Installation as a systemd Service
systemd is the successor of the System V init system and is now being used by many modern Linux
distributions. Although you can continue to use init.d scripts with systemd, it is also possible to
launch Spring Boot applications by using systemd ‘service’ scripts.
Assuming that you have a Spring Boot application installed in /var/myapp, to install a Spring Boot
application as a systemd service, create a script named myapp.service and place it in /etc/
systemd/system directory. The following script offers an example:
[Unit]
Description=myapp
After=syslog.target
[Service]
User=myapp
ExecStart=/var/myapp/myapp.jar
SuccessExitStatus=143
[Install]
WantedBy=multi-user.target
Important
Remember to change the Description, User, and ExecStart fields for your application.
Note
The ExecStart field does not declare the script action command, which means that the run
command is used by default.
Note that, unlike when running as an init.d service, the user that runs the application, the PID file,
and the console log file are managed by systemd itself and therefore must be configured by using
appropriate fields in the ‘service’ script. Consult the service unit configuration man page for more details.
To flag the application to start automatically on system boot, use the following command:
$ systemctl enable myapp.service
Refer to man systemctl for more details.
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Customizing the Startup Script
The default embedded startup script written by the Maven or Gradle plugin can be customized
in a number of ways. For most people, using the default script along with a few customizations
is usually enough. If you find you cannot customize something that you need to, use the
embeddedLaunchScript option to write your own file entirely.
Customizing the Start Script when It Is Written
It often makes sense to customize elements of the start script as it is written into the jar file. For example,
init.d scripts can provide a “description”. Since you know the description up front (and it need not
change), you may as well provide it when the jar is generated.
To customize written elements, use the embeddedLaunchScriptProperties option of the Spring
Boot Maven or Gradle plugins.
The following property substitutions are supported with the default script:
Name Description
mode The script mode. Defaults to auto.
initInfoProvidesThe Provides section of “INIT INFO”. Defaults to spring-boot-application for
Gradle and to ${project.artifactId} for Maven.
initInfoRequiredStartThe Required-Start section of “INIT INFO”. Defaults to $remote_fs $syslog
$network.
initInfoRequiredStopThe Required-Stop section of “INIT INFO”. Defaults to $remote_fs $syslog
$network.
initInfoDefaultStartThe Default-Start section of “INIT INFO”. Defaults to 2 3 4 5.
initInfoDefaultStopThe Default-Stop section of “INIT INFO”. Defaults to 0 1 6.
initInfoShortDescriptionThe Short-Description section of “INIT INFO”. Defaults to Spring Boot
Application for Gradle and to ${project.name} for Maven.
initInfoDescriptionThe Description section of “INIT INFO”. Defaults to Spring Boot
Application for Gradle and to ${project.description} (falling back to
${project.name}) for Maven.
initInfoChkconfigThe chkconfig section of “INIT INFO”. Defaults to 2345 99 01.
confFolder The default value for CONF_FOLDER. Defaults to the folder containing the jar.
inlinedConfScriptReference to a file script that should be inlined in the default launch script. This can
be used to set environmental variables such as JAVA_OPTS before any external
config files are loaded.
logFolder The default value for LOG_FOLDER. Only valid for an init.d service.
logFilenameThe default value for LOG_FILENAME. Only valid for an init.d service.
pidFolder The default value for PID_FOLDER. Only valid for an init.d service.
pidFilenameThe default value for the name of the PID file in PID_FOLDER. Only valid for an
init.d service.
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Name Description
useStartStopDaemonWhether the start-stop-daemon command, when it’s available, should be used to
control the process. Defaults to true.
stopWaitTimeThe default value for STOP_WAIT_TIME. Only valid for an init.d service. Defaults
to 60 seconds.
Customizing a Script When It Runs
For items of the script that need to be customized after the jar has been written, you can use environment
variables or a config file.
The following environment properties are supported with the default script:
Variable Description
MODE The “mode” of operation. The default depends on the way the jar was built but
is usually auto (meaning it tries to guess if it is an init script by checking if it is a
symlink in a directory called init.d). You can explicitly set it to service so that the
stop|start|status|restart commands work or to run if you want to run the
script in the foreground.
USE_START_STOP_DAEMONWhether the start-stop-daemon command, when it’s available, should be used to
control the process. Defaults to true.
PID_FOLDER The root name of the pid folder (/var/run by default).
LOG_FOLDER The name of the folder in which to put log files (/var/log by default).
CONF_FOLDERThe name of the folder from which to read .conf files (same folder as jar-file by
default).
LOG_FILENAMEThe name of the log file in the LOG_FOLDER (<appname>.log by default).
APP_NAME The name of the app. If the jar is run from a symlink, the script guesses the app
name. If it is not a symlink or you want to explicitly set the app name, this can be
useful.
RUN_ARGS The arguments to pass to the program (the Spring Boot app).
JAVA_HOME The location of the java executable is discovered by using the PATH by default, but
you can set it explicitly if there is an executable file at $JAVA_HOME/bin/java.
JAVA_OPTS Options that are passed to the JVM when it is launched.
JARFILE The explicit location of the jar file, in case the script is being used to launch a jar that
it is not actually embedded.
DEBUG If not empty, sets the -x flag on the shell process, making it easy to see the logic in
the script.
STOP_WAIT_TIMEThe time in seconds to wait when stopping the application before forcing a shutdown
(60 by default).
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Note
The PID_FOLDER, LOG_FOLDER, and LOG_FILENAME variables are only valid for an init.d
service. For systemd, the equivalent customizations are made by using the ‘service’ script. See
the service unit configuration man page for more details.
With the exception of JARFILE and APP_NAME, the settings listed in the preceding section can be
configured by using a .conf file. The file is expected to be next to the jar file and have the same name
but suffixed with .conf rather than .jar. For example, a jar named /var/myapp/myapp.jar uses
the configuration file named /var/myapp/myapp.conf, as shown in the following example:
myapp.conf.
JAVA_OPTS=-Xmx1024M
LOG_FOLDER=/custom/log/folder
Tip
If you do not like having the config file next to the jar file, you can set a CONF_FOLDER environment
variable to customize the location of the config file.
To learn about securing this file appropriately, see the guidelines for securing an init.d service.
61.3 Microsoft Windows Services
A Spring Boot application can be started as a Windows service by using winsw.
A (separately maintained sample) describes step-by-step how you can create a Windows service for
your Spring Boot application.
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62. What to Read Next
Check out the Cloud Foundry, Heroku, OpenShift, and Boxfuse web sites for more information about
the kinds of features that a PaaS can offer. These are just four of the most popular Java PaaS providers.
Since Spring Boot is so amenable to cloud-based deployment, you can freely consider other providers
as well.
The next section goes on to cover the Spring Boot CLI, or you can jump ahead to read about build
tool plugins.
Part VII. Spring Boot CLI
The Spring Boot CLI is a command line tool that you can use if you want to quickly develop a Spring
application. It lets you run Groovy scripts, which means that you have a familiar Java-like syntax without
so much boilerplate code. You can also bootstrap a new project or write your own command for it.
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63. Installing the CLI
The Spring Boot CLI (Command-Line Interface) can be installed manually by using SDKMAN! (the SDK
Manager) or by using Homebrew or MacPorts if you are an OSX user. See Section 10.2, “Installing the
Spring Boot CLI” in the “Getting started” section for comprehensive installation instructions.
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64. Using the CLI
Once you have installed the CLI, you can run it by typing spring and pressing Enter at the command
line. If you run spring without any arguments, a simple help screen is displayed, as follows:
$ spring
usage: spring [--help] [--version]
<command> [<args>]
Available commands are:
run [options] <files> [--] [args]
Run a spring groovy script
... more command help is shown here
You can type spring help to get more details about any of the supported commands, as shown in
the following example:
$ spring help run
spring run - Run a spring groovy script
usage: spring run [options] <files> [--] [args]
Option Description
------ -----------
--autoconfigure [Boolean] Add autoconfigure compiler
transformations (default: true)
--classpath, -cp Additional classpath entries
-e, --edit Open the file with the default system
editor
--no-guess-dependencies Do not attempt to guess dependencies
--no-guess-imports Do not attempt to guess imports
-q, --quiet Quiet logging
-v, --verbose Verbose logging of dependency
resolution
--watch Watch the specified file for changes
The version command provides a quick way to check which version of Spring Boot you are using,
as follows:
$ spring version
Spring CLI v2.0.4.RELEASE
64.1 Running Applications with the CLI
You can compile and run Groovy source code by using the run command. The Spring Boot CLI is
completely self-contained, so you do not need any external Groovy installation.
The following example shows a “hello world” web application written in Groovy:
hello.groovy.
@RestController
class WebApplication {
@RequestMapping("/")
String home() {
"Hello World!"
}
}
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To compile and run the application, type the following command:
$ spring run hello.groovy
To pass command-line arguments to the application, use -- to separate the commands from the “spring”
command arguments, as shown in the following example:
$ spring run hello.groovy -- --server.port=9000
To set JVM command line arguments, you can use the JAVA_OPTS environment variable, as shown
in the following example:
$ JAVA_OPTS=-Xmx1024m spring run hello.groovy
Note
When setting JAVA_OPTS on Microsoft Windows, make sure to quote the entire instruction, such
as set "JAVA_OPTS=-Xms256m -Xmx2048m". Doing so ensures the values are properly
passed to the process.
Deduced “grab” Dependencies
Standard Groovy includes a @Grab annotation, which lets you declare dependencies on third-party
libraries. This useful technique lets Groovy download jars in the same way as Maven or Gradle would
but without requiring you to use a build tool.
Spring Boot extends this technique further and tries to deduce which libraries to “grab” based on your
code. For example, since the WebApplication code shown previously uses @RestController
annotations, Spring Boot grabs "Tomcat" and "Spring MVC".
The following items are used as “grab hints”:
Items Grabs
JdbcTemplate,
NamedParameterJdbcTemplate,
DataSource
JDBC Application.
@EnableJms JMS Application.
@EnableCaching Caching abstraction.
@Test JUnit.
@EnableRabbit RabbitMQ.
extends Specification Spock test.
@EnableBatchProcessing Spring Batch.
@MessageEndpoint @EnableIntegration Spring Integration.
@Controller @RestController
@EnableWebMvc
Spring MVC + Embedded Tomcat.
@EnableWebSecurity Spring Security.
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Items Grabs
@EnableTransactionManagement Spring Transaction Management.
Tip
See subclasses of CompilerAutoConfiguration in the Spring Boot CLI source code to
understand exactly how customizations are applied.
Deduced “grab” Coordinates
Spring Boot extends Groovy’s standard @Grab support by letting you specify a dependency without
a group or version (for example, @Grab('freemarker')). Doing so consults Spring Boot’s default
dependency metadata to deduce the artifact’s group and version.
Note
The default metadata is tied to the version of the CLI that you use. it changes only when you move
to a new version of the CLI, putting you in control of when the versions of your dependencies
may change. A table showing the dependencies and their versions that are included in the default
metadata can be found in the appendix.
Default Import Statements
To help reduce the size of your Groovy code, several import statements are automatically
included. Notice how the preceding example refers to @Component, @RestController, and
@RequestMapping without needing to use fully-qualified names or import statements.
Tip
Many Spring annotations work without using import statements. Try running your application to
see what fails before adding imports.
Automatic Main Method
Unlike the equivalent Java application, you do not need to include a public static void
main(String[] args) method with your Groovy scripts. A SpringApplication is automatically
created, with your compiled code acting as the source.
Custom Dependency Management
By default, the CLI uses the dependency management declared in spring-boot-dependencies
when resolving @Grab dependencies. Additional dependency management, which overrides the default
dependency management, can be configured by using the @DependencyManagementBom annotation.
The annotation’s value should specify the coordinates (groupId:artifactId:version) of one or
more Maven BOMs.
For example, consider the following declaration:
@DependencyManagementBom("com.example.custom-bom:1.0.0")
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The preceding declaration picks up custom-bom-1.0.0.pom in a Maven repository under com/
example/custom-versions/1.0.0/.
When you specify multiple BOMs, they are applied in the order in which you declare them, as shown
in the following example:
@DependencyManagementBom(["com.example.custom-bom:1.0.0",
"com.example.another-bom:1.0.0"])
The preceding example indicates that the dependency management in another-bom overrides the
dependency management in custom-bom.
You can use @DependencyManagementBom anywhere that you can use @Grab. However, to ensure
consistent ordering of the dependency management, you can use @DependencyManagementBom at
most once in your application. A useful source of dependency management (which is a superset of
Spring Boot’s dependency management) is the Spring IO Platform, which you might include with the
following line:
@DependencyManagementBom('io.spring.platform:platform-bom:1.1.2.RELEASE')
64.2 Applications with Multiple Source Files
You can use “shell globbing” with all commands that accept file input. Doing so lets you use multiple
files from a single directory, as shown in the following example:
$ spring run *.groovy
64.3 Packaging Your Application
You can use the jar command to package your application into a self-contained executable jar file, as
shown in the following example:
$ spring jar my-app.jar *.groovy
The resulting jar contains the classes produced by compiling the application and all of the application’s
dependencies so that it can then be run by using java -jar. The jar file also contains entries from
the application’s classpath. You can add and remove explicit paths to the jar by using --include and
--exclude. Both are comma-separated, and both accept prefixes, in the form of “+” and “-”, to signify
that they should be removed from the defaults. The default includes are as follows:
public/**, resources/**, static/**, templates/**, META-INF/**, *
The default excludes are as follows:
.*, repository/**, build/**, target/**, **/*.jar, **/*.groovy
Type spring help jar on the command line for more information.
64.4 Initialize a New Project
The init command lets you create a new project by using start.spring.io without leaving the shell, as
shown in the following example:
$ spring init --dependencies=web,data-jpa my-project
Using service at https://start.spring.io
Project extracted to '/Users/developer/example/my-project'
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The preceding example creates a my-project directory with a Maven-based project that uses
spring-boot-starter-web and spring-boot-starter-data-jpa. You can list the capabilities
of the service by using the --list flag, as shown in the following example:
$ spring init --list
=======================================
Capabilities of https://start.spring.io
=======================================
Available dependencies:
-----------------------
actuator - Actuator: Production ready features to help you monitor and manage your application
...
web - Web: Support for full-stack web development, including Tomcat and spring-webmvc
websocket - Websocket: Support for WebSocket development
ws - WS: Support for Spring Web Services
Available project types:
------------------------
gradle-build - Gradle Config [format:build, build:gradle]
gradle-project - Gradle Project [format:project, build:gradle]
maven-build - Maven POM [format:build, build:maven]
maven-project - Maven Project [format:project, build:maven] (default)
...
The init command supports many options. See the help output for more details. For instance, the
following command creates a Gradle project that uses Java 8 and war packaging:
$ spring init --build=gradle --java-version=1.8 --dependencies=websocket --packaging=war sample-app.zip
Using service at https://start.spring.io
Content saved to 'sample-app.zip'
64.5 Using the Embedded Shell
Spring Boot includes command-line completion scripts for the BASH and zsh shells. If you do not use
either of these shells (perhaps you are a Windows user), you can use the shell command to launch
an integrated shell, as shown in the following example:
$ spring shell
Spring Boot (v2.0.4.RELEASE)
Hit TAB to complete. Type \'help' and hit RETURN for help, and \'exit' to quit.
From inside the embedded shell, you can run other commands directly:
$ version
Spring CLI v2.0.4.RELEASE
The embedded shell supports ANSI color output as well as tab completion. If you need to run a native
command, you can use the ! prefix. To exit the embedded shell, press ctrl-c.
64.6 Adding Extensions to the CLI
You can add extensions to the CLI by using the install command. The command takes one or
more sets of artifact coordinates in the format group:artifact:version, as shown in the following
example:
$ spring install com.example:spring-boot-cli-extension:1.0.0.RELEASE
In addition to installing the artifacts identified by the coordinates you supply, all of the artifacts'
dependencies are also installed.
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To uninstall a dependency, use the uninstall command. As with the install command, it takes
one or more sets of artifact coordinates in the format of group:artifact:version, as shown in the
following example:
$ spring uninstall com.example:spring-boot-cli-extension:1.0.0.RELEASE
It uninstalls the artifacts identified by the coordinates you supply and their dependencies.
To uninstall all additional dependencies, you can use the --all option, as shown in the following
example:
$ spring uninstall --all
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65. Developing Applications with the Groovy Beans
DSL
Spring Framework 4.0 has native support for a beans{} “DSL” (borrowed from Grails), and you can
embed bean definitions in your Groovy application scripts by using the same format. This is sometimes a
good way to include external features like middleware declarations, as shown in the following example:
@Configuration
class Application implements CommandLineRunner {
@Autowired
SharedService service
@Override
void run(String... args) {
println service.message
}
}
import my.company.SharedService
beans {
service(SharedService) {
message = "Hello World"
}
}
You can mix class declarations with beans{} in the same file as long as they stay at the top level, or,
if you prefer, you can put the beans DSL in a separate file.
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66. Configuring the CLI with settings.xml
The Spring Boot CLI uses Aether, Maven’s dependency resolution engine, to resolve dependencies.
The CLI makes use of the Maven configuration found in ~/.m2/settings.xml to configure Aether.
The following configuration settings are honored by the CLI:
• Offline
• Mirrors
• Servers
• Proxies
• Profiles
• Activation
• Repositories
• Active profiles
See Maven’s settings documentation for further information.
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67. What to Read Next
There are some sample groovy scripts available from the GitHub repository that you can use to try out
the Spring Boot CLI. There is also extensive Javadoc throughout the source code.
If you find that you reach the limit of the CLI tool, you probably want to look at converting your application
to a full Gradle or Maven built “Groovy project”. The next section covers Spring Boot’s "Build tool plugins",
which you can use with Gradle or Maven.
Part VIII. Build tool plugins
Spring Boot provides build tool plugins for Maven and Gradle. The plugins offer a variety of features,
including the packaging of executable jars. This section provides more details on both plugins as well
as some help should you need to extend an unsupported build system. If you are just getting started,
you might want to read “Chapter 13, Build Systems” from the “Part III, “Using Spring Boot”” section first.
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68. Spring Boot Maven Plugin
The Spring Boot Maven Plugin provides Spring Boot support in Maven, letting you package executable
jar or war archives and run an application “in-place”. To use it, you must use Maven 3.2 (or later).
Note
See the Spring Boot Maven Plugin Site for complete plugin documentation.
68.1 Including the Plugin
To use the Spring Boot Maven Plugin, include the appropriate XML in the plugins section of your
pom.xml, as shown in the following example:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<!-- ... -->
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>2.0.4.RELEASE</version>
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
The preceding configuration repackages a jar or war that is built during the package phase of the
Maven lifecycle. The following example shows both the repackaged jar as well as the original jar in the
target directory:
$ mvn package
$ ls target/*.jar
target/myproject-1.0.0.jar target/myproject-1.0.0.jar.original
If you do not include the <execution/> configuration, as shown in the prior example, you can run the
plugin on its own (but only if the package goal is used as well), as shown in the following example:
$ mvn package spring-boot:repackage
$ ls target/*.jar
target/myproject-1.0.0.jar target/myproject-1.0.0.jar.original
If you use a milestone or snapshot release, you also need to add the appropriate pluginRepository
elements, as shown in the following listing:
<pluginRepositories>
<pluginRepository>
<id>spring-snapshots</id>
<url>https://repo.spring.io/snapshot</url>
</pluginRepository>
<pluginRepository>
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<id>spring-milestones</id>
<url>https://repo.spring.io/milestone</url>
</pluginRepository>
</pluginRepositories>
68.2 Packaging Executable Jar and War Files
Once spring-boot-maven-plugin has been included in your pom.xml, it automatically tries to
rewrite archives to make them executable by using the spring-boot:repackage goal. You should
configure your project to build a jar or war (as appropriate) by using the usual packaging element, as
shown in the following example:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<!-- ... -->
<packaging>jar</packaging>
<!-- ... -->
</project>
Your existing archive is enhanced by Spring Boot during the package phase. The main class that you
want to launch can be specified either by using a configuration option or by adding a Main-Class
attribute to the manifest in the usual way. If you do not specify a main class, the plugin searches for a
class with a public static void main(String[] args) method.
To build and run a project artifact, you can type the following:
$ mvn package
$ java -jar target/mymodule-0.0.1-SNAPSHOT.jar
To build a war file that is both executable and deployable into an external container, you need to mark
the embedded container dependencies as “provided”, as shown in the following example:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<!-- ... -->
<packaging>war</packaging>
<!-- ... -->
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
<scope>provided</scope>
</dependency>
<!-- ... -->
</dependencies>
</project>
Tip
See the “Section 88.1, “Create a Deployable War File”” section for more details on how to create
a deployable war file.
Advanced configuration options and examples are available in the plugin info page.
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69. Spring Boot Gradle Plugin
The Spring Boot Gradle Plugin provides Spring Boot support in Gradle, letting you package executable
jar or war archives, run Spring Boot applications, and use the dependency management provided
by spring-boot-dependencies. It requires Gradle 4.0 or later. Please refer to the plugin’s
documentation to learn more:
• Reference (HTML and PDF)
•API
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70. Spring Boot AntLib Module
The Spring Boot AntLib module provides basic Spring Boot support for Apache Ant. You can use the
module to create executable jars. To use the module, you need to declare an additional spring-boot
namespace in your build.xml, as shown in the following example:
<project xmlns:ivy="antlib:org.apache.ivy.ant"
xmlns:spring-boot="antlib:org.springframework.boot.ant"
name="myapp" default="build">
...
</project>
You need to remember to start Ant using the -lib option, as shown in the following example:
$ ant -lib <folder containing spring-boot-antlib-2.0.4.RELEASE.jar>
Tip
The “Using Spring Boot” section includes a more complete example of using Apache Ant with
spring-boot-antlib.
70.1 Spring Boot Ant Tasks
Once the spring-boot-antlib namespace has been declared, the following additional tasks are
available:
•the section called “spring-boot:exejar”
•Section 70.2, “spring-boot:findmainclass”
spring-boot:exejar
You can use the exejar task to create a Spring Boot executable jar. The following attributes are
supported by the task:
Attribute Description Required
destfile The destination jar file to create Yes
classes The root directory of Java class files Yes
start-class The main application class to run No (the default is the first class found
that declares a main method)
The following nested elements can be used with the task:
Element Description
resources One or more Resource Collections describing a set of Resources that should
be added to the content of the created jar file.
lib One or more Resource Collections that should be added to the set of jar
libraries that make up the runtime dependency classpath of the application.
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Examples
This section shows two examples of Ant tasks.
Specify start-class.
<spring-boot:exejar destfile="target/my-application.jar"
classes="target/classes" start-class="com.example.MyApplication">
<resources>
<fileset dir="src/main/resources" />
</resources>
<lib>
<fileset dir="lib" />
</lib>
</spring-boot:exejar>
Detect start-class.
<exejar destfile="target/my-application.jar" classes="target/classes">
<lib>
<fileset dir="lib" />
</lib>
</exejar>
70.2 spring-boot:findmainclass
The findmainclass task is used internally by exejar to locate a class declaring a main. If necessary,
you can also use this task directly in your build. The following attributes are supported:
Attribute Description Required
classesroot The root directory of Java class files Yes (unless mainclass is specified)
mainclass Can be used to short-circuit the main
class search
No
property The Ant property that should be set
with the result
No (result will be logged if unspecified)
Examples
This section contains three examples of using findmainclass.
Find and log.
<findmainclass classesroot="target/classes" />
Find and set.
<findmainclass classesroot="target/classes" property="main-class" />
Override and set.
<findmainclass mainclass="com.example.MainClass" property="main-class" />
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71. Supporting Other Build Systems
If you want to use a build tool other than Maven, Gradle, or Ant, you likely need to develop your own
plugin. Executable jars need to follow a specific format and certain entries need to be written in an
uncompressed form (see the “executable jar format” section in the appendix for details).
The Spring Boot Maven and Gradle plugins both make use of spring-boot-loader-tools to
actually generate jars. If you need to, you may use this library directly.
71.1 Repackaging Archives
To repackage an existing archive so that it becomes a self-contained executable archive, use
org.springframework.boot.loader.tools.Repackager. The Repackager class takes a
single constructor argument that refers to an existing jar or war archive. Use one of the two available
repackage() methods to either replace the original file or write to a new destination. Various settings
can also be configured on the repackager before it is run.
71.2 Nested Libraries
When repackaging an archive, you can include references to dependency files by using the
org.springframework.boot.loader.tools.Libraries interface. We do not provide any
concrete implementations of Libraries here as they are usually build-system-specific.
If your archive already includes libraries, you can use Libraries.NONE.
71.3 Finding a Main Class
If you do not use Repackager.setMainClass() to specify a main class, the repackager uses ASM
to read class files and tries to find a suitable class with a public static void main(String[]
args) method. An exception is thrown if more than one candidate is found.
71.4 Example Repackage Implementation
The following example shows a typical repackage implementation:
Repackager repackager = new Repackager(sourceJarFile);
repackager.setBackupSource(false);
repackager.repackage(new Libraries() {
@Override
public void doWithLibraries(LibraryCallback callback) throws IOException {
// Build system specific implementation, callback for each dependency
// callback.library(new Library(nestedFile, LibraryScope.COMPILE));
}
});
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72. What to Read Next
If you are interested in how the build tool plugins work, you can look at the spring-boot-tools
module on GitHub. More technical details of the executable jar format are covered in the appendix.
If you have specific build-related questions, you can check out the “how-to” guides.
Part IX. ‘How-to’ guides
This section provides answers to some common ‘how do I do that…’ questions that often arise when
using Spring Boot. Its coverage is not exhaustive, but it does cover quite a lot.
If you have a specific problem that we do not cover here, you might want to check out stackoverflow.com
to see if someone has already provided an answer. This is also a great place to ask new questions
(please use the spring-boot tag).
We are also more than happy to extend this section. If you want to add a ‘how-to’, send us a pull request.
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73. Spring Boot Application
This section includes topics relating directly to Spring Boot applications.
73.1 Create Your Own FailureAnalyzer
FailureAnalyzer is a great way to intercept an exception on startup and turn it into a human-readable
message, wrapped in a FailureAnalysis. Spring Boot provides such an analyzer for application-
context-related exceptions, JSR-303 validations, and more. You can also create your own.
AbstractFailureAnalyzer is a convenient extension of FailureAnalyzer that checks the
presence of a specified exception type in the exception to handle. You can extend from that so that your
implementation gets a chance to handle the exception only when it is actually present. If, for whatever
reason, you cannot handle the exception, return null to give another implementation a chance to
handle the exception.
FailureAnalyzer implementations must be registered in META-INF/spring.factories. The
following example registers ProjectConstraintViolationFailureAnalyzer:
org.springframework.boot.diagnostics.FailureAnalyzer=\
com.example.ProjectConstraintViolationFailureAnalyzer
Note
If you need access to the BeanFactory or the Environment, your FailureAnalyzer can
simply implement BeanFactoryAware or EnvironmentAware respectively.
73.2 Troubleshoot Auto-configuration
The Spring Boot auto-configuration tries its best to “do the right thing”, but sometimes things fail, and
it can be hard to tell why.
There is a really useful ConditionEvaluationReport available in any Spring Boot
ApplicationContext. You can see it if you enable DEBUG logging output. If you use the spring-
boot-actuator (see the Actuator chapter), there is also a conditions endpoint that renders the
report in JSON. Use that endpoint to debug the application and see what features have been added
(and which have not been added) by Spring Boot at runtime.
Many more questions can be answered by looking at the source code and the Javadoc. When reading
the code, remember the following rules of thumb:
• Look for classes called *AutoConfiguration and read their sources. Pay special attention to the
@Conditional* annotations to find out what features they enable and when. Add --debug to the
command line or a System property -Ddebug to get a log on the console of all the auto-configuration
decisions that were made in your app. In a running Actuator app, look at the conditions endpoint
(/actuator/conditions or the JMX equivalent) for the same information.
• Look for classes that are @ConfigurationProperties (such as ServerProperties) and
read from there the available external configuration options. The @ConfigurationProperties
annotation has a name attribute that acts as a prefix to external properties. Thus,
ServerProperties has prefix="server" and its configuration properties are server.port,
server.address, and others. In a running Actuator app, look at the configprops endpoint.
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• Look for uses of the bind method on the Binder to pull configuration values explicitly out of the
Environment in a relaxed manner. It is often used with a prefix.
• Look for @Value annotations that bind directly to the Environment.
• Look for @ConditionalOnExpression annotations that switch features on and off in response to
SpEL expressions, normally evaluated with placeholders resolved from the Environment.
73.3 Customize the Environment or ApplicationContext Before
It Starts
A SpringApplication has ApplicationListeners and ApplicationContextInitializers
that are used to apply customizations to the context or environment. Spring Boot loads a number of
such customizations for use internally from META-INF/spring.factories. There is more than one
way to register additional customizations:
• Programmatically, per application, by calling the addListeners and addInitializers methods
on SpringApplication before you run it.
• Declaratively, per application, by setting the context.initializer.classes or
context.listener.classes properties.
• Declaratively, for all applications, by adding a META-INF/spring.factories and packaging a jar
file that the applications all use as a library.
The SpringApplication sends some special ApplicationEvents to the listeners (some
even before the context is created) and then registers the listeners for events published by the
ApplicationContext as well. See “Section 23.5, “Application Events and Listeners”” in the ‘Spring
Boot features’ section for a complete list.
It is also possible to customize the Environment before the application context is refreshed by
using EnvironmentPostProcessor. Each implementation should be registered in META-INF/
spring.factories, as shown in the following example:
org.springframework.boot.env.EnvironmentPostProcessor=com.example.YourEnvironmentPostProcessor
The implementation can load arbitrary files and add them to the Environment. For instance, the
following example loads a YAML configuration file from the classpath:
public class EnvironmentPostProcessorExample implements EnvironmentPostProcessor {
private final YamlPropertySourceLoader loader = new YamlPropertySourceLoader();
@Override
public void postProcessEnvironment(ConfigurableEnvironment environment,
SpringApplication application) {
Resource path = new ClassPathResource("com/example/myapp/config.yml");
PropertySource<?> propertySource = loadYaml(path);
environment.getPropertySources().addLast(propertySource);
}
private PropertySource<?> loadYaml(Resource path) {
if (!path.exists()) {
throw new IllegalArgumentException("Resource " + path + " does not exist");
}
try {
return this.loader.load("custom-resource", path).get(0);
}
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catch (IOException ex) {
throw new IllegalStateException(
"Failed to load yaml configuration from " + path, ex);
}
}
}
Tip
The Environment has already been prepared with all the usual property sources that Spring
Boot loads by default. It is therefore possible to get the location of the file from the environment.
The preceding example adds the custom-resource property source at the end of the list so
that a key defined in any of the usual other locations takes precedence. A custom implementation
may define another order.
Caution
While using @PropertySource on your @SpringBootApplication may seem to be a
convenient and easy way to load a custom resource in the Environment, we do not recommend
it, because Spring Boot prepares the Environment before the ApplicationContext is
refreshed. Any key defined with @PropertySource is loaded too late to have any effect on auto-
configuration.
73.4 Build an ApplicationContext Hierarchy (Adding a Parent or
Root Context)
You can use the ApplicationBuilder class to create parent/child ApplicationContext
hierarchies. See “Section 23.4, “Fluent Builder API”” in the ‘Spring Boot features’ section for more
information.
73.5 Create a Non-web Application
Not all Spring applications have to be web applications (or web services). If you want to execute
some code in a main method but also bootstrap a Spring application to set up the infrastructure
to use, you can use the SpringApplication features of Spring Boot. A SpringApplication
changes its ApplicationContext class, depending on whether it thinks it needs a web application
or not. The first thing you can do to help it is to leave server-related dependencies (e.g. servlet API)
off the classpath. If you cannot do that (for example, you run two applications from the same code
base) then you can explicitly call setWebApplicationType(WebApplicationType.NONE) on your
SpringApplication instance or set the applicationContextClass property (through the Java
API or with external properties). Application code that you want to run as your business logic can be
implemented as a CommandLineRunner and dropped into the context as a @Bean definition.
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74. Properties and Configuration
This section includes topics about setting and reading properties and configuration settings and their
interaction with Spring Boot applications.
74.1 Automatically Expand Properties at Build Time
Rather than hardcoding some properties that are also specified in your project’s build configuration,
you can automatically expand them by instead using the existing build configuration. This is possible
in both Maven and Gradle.
Automatic Property Expansion Using Maven
You can automatically expand properties from the Maven project by using resource filtering. If you use
the spring-boot-starter-parent, you can then refer to your Maven ‘project properties’ with @..@
placeholders, as shown in the following example:
app.encoding=@project.build.sourceEncoding@
app.java.version=@java.version@
Note
Only production configuration is filtered that way (in other words, no filtering is applied on src/
test/resources).
Tip
If you enable the addResources flag, the spring-boot:run goal can add src/main/
resources directly to the classpath (for hot reloading purposes). Doing so circumvents the
resource filtering and this feature. Instead, you can use the exec:java goal or customize the
plugin’s configuration. See the plugin usage page for more details.
If you do not use the starter parent, you need to include the following element inside the <build/>
element of your pom.xml:
<resources>
<resource>
<directory>src/main/resources</directory>
<filtering>true</filtering>
</resource>
</resources>
You also need to include the following element inside <plugins/>:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-resources-plugin</artifactId>
<version>2.7</version>
<configuration>
<delimiters>
<delimiter>@</delimiter>
</delimiters>
<useDefaultDelimiters>false</useDefaultDelimiters>
</configuration>
</plugin>
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Note
The useDefaultDelimiters property is important if you use standard Spring placeholders
(such as ${placeholder}) in your configuration. If that property is not set to false, these may
be expanded by the build.
Automatic Property Expansion Using Gradle
You can automatically expand properties from the Gradle project by configuring the Java plugin’s
processResources task to do so, as shown in the following example:
processResources {
expand(project.properties)
}
You can then refer to your Gradle project’s properties by using placeholders, as shown in the following
example:
app.name=${name}
app.description=${description}
Note
Gradle’s expand method uses Groovy’s SimpleTemplateEngine, which transforms ${..}
tokens. The ${..} style conflicts with Spring’s own property placeholder mechanism. To use
Spring property placeholders together with automatic expansion, escape the Spring property
placeholders as follows: \${..}.
74.2 Externalize the Configuration of SpringApplication
A SpringApplication has bean properties (mainly setters), so you can use its Java API as you
create the application to modify its behavior. Alternatively, you can externalize the configuration by
setting properties in spring.main.*. For example, in application.properties, you might have
the following settings:
spring.main.web-application-type=none
spring.main.banner-mode=off
Then the Spring Boot banner is not printed on startup, and the application is not starting an embedded
web server.
Properties defined in external configuration override the values specified with the Java API, with the
notable exception of the sources used to create the ApplicationContext. Consider the following
application:
new SpringApplicationBuilder()
.bannerMode(Banner.Mode.OFF)
.sources(demo.MyApp.class)
.run(args);
Now consider the following configuration:
spring.main.sources=com.acme.Config,com.acme.ExtraConfig
spring.main.banner-mode=console
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The actual application now shows the banner (as overridden by configuration) and uses three
sources for the ApplicationContext (in the following order): demo.MyApp, com.acme.Config,
and com.acme.ExtraConfig.
74.3 Change the Location of External Properties of an
Application
By default, properties from different sources are added to the Spring Environment in a defined order
(see “Chapter 24, Externalized Configuration” in the ‘Spring Boot features’ section for the exact order).
A nice way to augment and modify this ordering is to add @PropertySource annotations to your
application sources. Classes passed to the SpringApplication static convenience methods and
those added using setSources() are inspected to see if they have @PropertySources. If they
do, those properties are added to the Environment early enough to be used in all phases of the
ApplicationContext lifecycle. Properties added in this way have lower priority than any added by
using the default locations (such as application.properties), system properties, environment
variables, or the command line.
You can also provide the following System properties (or environment variables) to change the behavior:
•spring.config.name (SPRING_CONFIG_NAME): Defaults to application as the root of the file
name.
•spring.config.location (SPRING_CONFIG_LOCATION): The file to load (such as a classpath
resource or a URL). A separate Environment property source is set up for this document and it can
be overridden by system properties, environment variables, or the command line.
No matter what you set in the environment, Spring Boot always loads application.properties as
described above. By default, if YAML is used, then files with the ‘.yml’ extension are also added to the list.
Spring Boot logs the configuration files that are loaded at the DEBUG level and the candidates it has
not found at TRACE level.
See ConfigFileApplicationListener for more detail.
74.4 Use ‘Short’ Command Line Arguments
Some people like to use (for example) --port=9000 instead of --server.port=9000 to set
configuration properties on the command line. You can enable this behavior by using placeholders in
application.properties, as shown in the following example:
server.port=${port:8080}
Tip
If you inherit from the spring-boot-starter-parent POM, the default filter token of the
maven-resources-plugins has been changed from ${*} to @ (that is, @maven.token@
instead of ${maven.token}) to prevent conflicts with Spring-style placeholders. If you have
enabled Maven filtering for the application.properties directly, you may want to also
change the default filter token to use other delimiters.
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Note
In this specific case, the port binding works in a PaaS environment such as Heroku or Cloud
Foundry. In those two platforms, the PORT environment variable is set automatically and Spring
can bind to capitalized synonyms for Environment properties.
74.5 Use YAML for External Properties
YAML is a superset of JSON and, as such, is a convenient syntax for storing external properties in a
hierarchical format, as shown in the following example:
spring:
application:
name: cruncher
datasource:
driverClassName: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost/test
server:
port: 9000
Create a file called application.yml and put it in the root of your classpath. Then add snakeyaml
to your dependencies (Maven coordinates org.yaml:snakeyaml, already included if you use the
spring-boot-starter). A YAML file is parsed to a Java Map<String,Object> (like a JSON
object), and Spring Boot flattens the map so that it is one level deep and has period-separated keys, as
many people are used to with Properties files in Java.
The preceding example YAML corresponds to the following application.properties file:
spring.application.name=cruncher
spring.datasource.driverClassName=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost/test
server.port=9000
See “Section 24.6, “Using YAML Instead of Properties”” in the ‘Spring Boot features’ section for more
information about YAML.
74.6 Set the Active Spring Profiles
The Spring Environment has an API for this, but you would normally set a System property
(spring.profiles.active) or an OS environment variable (SPRING_PROFILES_ACTIVE). Also,
you can launch your application with a -D argument (remember to put it before the main class or jar
archive), as follows:
$ java -jar -Dspring.profiles.active=production demo-0.0.1-SNAPSHOT.jar
In Spring Boot, you can also set the active profile in application.properties, as shown in the
following example:
spring.profiles.active=production
A value set this way is replaced by the System property or environment variable setting but not by
the SpringApplicationBuilder.profiles() method. Thus, the latter Java API can be used to
augment the profiles without changing the defaults.
See “Chapter 25, Profiles” in the “Spring Boot features” section for more information.
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74.7 Change Configuration Depending on the Environment
A YAML file is actually a sequence of documents separated by --- lines, and each document is parsed
separately to a flattened map.
If a YAML document contains a spring.profiles key, then the profiles value (a comma-separated
list of profiles) is fed into the Spring Environment.acceptsProfiles() method. If any of those
profiles is active, that document is included in the final merge (otherwise, it is not), as shown in the
following example:
server:
port: 9000
---
spring:
profiles: development
server:
port: 9001
---
spring:
profiles: production
server:
port: 0
In the preceding example, the default port is 9000. However, if the Spring profile called ‘development’
is active, then the port is 9001. If ‘production’ is active, then the port is 0.
Note
The YAML documents are merged in the order in which they are encountered. Later values
override earlier values.
To do the same thing with properties files, you can use application-${profile}.properties to
specify profile-specific values.
74.8 Discover Built-in Options for External Properties
Spring Boot binds external properties from application.properties (or .yml files and other
places) into an application at runtime. There is not (and technically cannot be) an exhaustive list of all
supported properties in a single location, because contributions can come from additional jar files on
your classpath.
A running application with the Actuator features has a configprops endpoint that shows all the bound
and bindable properties available through @ConfigurationProperties.
The appendix includes an application.properties example with a list of the most common
properties supported by Spring Boot. The definitive list comes from searching the source code for
@ConfigurationProperties and @Value annotations as well as the occasional use of Binder.
For more about the exact ordering of loading properties, see "Chapter 24, Externalized Configuration".
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75. Embedded Web Servers
Each Spring Boot web application includes an embedded web server. This feature leads to a number of
how-to questions, including how to change the embedded server and how to configure the embedded
server. This section answers those questions.
75.1 Use Another Web Server
Many Spring Boot starters include default embedded containers.
• For servlet stack applications, the spring-boot-starter-web includes Tomcat by including
spring-boot-starter-tomcat, but you can use spring-boot-starter-jetty or spring-
boot-starter-undertow instead.
• For reactive stack applications, the spring-boot-starter-webflux includes Reactor Netty by
including spring-boot-starter-reactor-netty, but you can use spring-boot-starter-
tomcat, spring-boot-starter-jetty, or spring-boot-starter-undertow instead.
When switching to a different HTTP server, you need to exclude the default dependencies in addition
to including the one you need. Spring Boot provides separate starters for HTTP servers to help make
this process as easy as possible.
The following Maven example shows how to exclude Tomcat and include Jetty for Spring MVC:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<!-- Exclude the Tomcat dependency -->
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</exclusion>
</exclusions>
</dependency>
<!-- Use Jetty instead -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jetty</artifactId>
</dependency>
The following Gradle example shows how to exclude Netty and include Undertow for Spring WebFlux:
configurations {
// exclude Reactor Netty
compile.exclude module: 'spring-boot-starter-reactor-netty'
}
dependencies {
compile 'org.springframework.boot:spring-boot-starter-webflux'
// Use Undertow instead
compile 'org.springframework.boot:spring-boot-starter-undertow'
// ...
}
Note
spring-boot-starter-reactor-netty is required to use the WebClient class, so you may
need to keep a dependency on Netty even when you need to include a different HTTP server.
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75.2 Disabling the Web Server
If your classpath contains the necessary bits to start a web server, Spring Boot will automatically start it.
To disable this behaviour configure the WebApplicationType in your application.properties,
as shown in the following example:
spring.main.web-application-type=none
75.3 Change the HTTP Port
In a standalone application, the main HTTP port defaults to 8080 but can be set with server.port
(for example, in application.properties or as a System property). Thanks to relaxed binding of
Environment values, you can also use SERVER_PORT (for example, as an OS environment variable).
To switch off the HTTP endpoints completely but still create a WebApplicationContext, use
server.port=-1. (Doing so is sometimes useful for testing.)
For more details, see “the section called “Customizing Embedded Servlet Containers”” in the ‘Spring
Boot features’ section, or the ServerProperties source code.
75.4 Use a Random Unassigned HTTP Port
To scan for a free port (using OS natives to prevent clashes) use server.port=0.
75.5 Discover the HTTP Port at Runtime
You can access the port the server is running on from log output or from
the ServletWebServerApplicationContext through its WebServer. The best way to
get that and be sure that it has been initialized is to add a @Bean of type
ApplicationListener<ServletWebServerInitializedEvent> and pull the container out of
the event when it is published.
Tests that use @SpringBootTest(webEnvironment=WebEnvironment.RANDOM_PORT) can also
inject the actual port into a field by using the @LocalServerPort annotation, as shown in the following
example:
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(webEnvironment=WebEnvironment.RANDOM_PORT)
public class MyWebIntegrationTests {
@Autowired
ServletWebServerApplicationContext server;
@LocalServerPort
int port;
// ...
}
Note
@LocalServerPort is a meta-annotation for @Value("${local.server.port}"). Do not
try to inject the port in a regular application. As we just saw, the value is set only after the container
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has been initialized. Contrary to a test, application code callbacks are processed early (before
the value is actually available).
75.6 Enable HTTP Response Compression
HTTP response compression is supported by Jetty, Tomcat, and Undertow. It can be enabled in
application.properties, as follows:
server.compression.enabled=true
By default, responses must be at least 2048 bytes in length for compression to be performed. You can
configure this behavior by setting the server.compression.min-response-size property.
By default, responses are compressed only if their content type is one of the following:
•text/html
•text/xml
•text/plain
•text/css
You can configure this behavior by setting the server.compression.mime-types property.
75.7 Configure SSL
SSL can be configured declaratively by setting the various server.ssl.* properties, typically
in application.properties or application.yml. The following example shows setting SSL
properties in application.properties:
server.port=8443
server.ssl.key-store=classpath:keystore.jks
server.ssl.key-store-password=secret
server.ssl.key-password=another-secret
See Ssl for details of all of the supported properties.
Using configuration such as the preceding example means the application no longer supports a plain
HTTP connector at port 8080. Spring Boot does not support the configuration of both an HTTP connector
and an HTTPS connector through application.properties. If you want to have both, you need
to configure one of them programmatically. We recommend using application.properties to
configure HTTPS, as the HTTP connector is the easier of the two to configure programmatically. See
the spring-boot-sample-tomcat-multi-connectors sample project for an example.
75.8 Configure HTTP/2
You can enable HTTP/2 support in your Spring Boot application with the server.http2.enabled
configuration property. This support depends on the chosen web server and the application environment,
since that protocol is not supported out-of-the-box by JDK8.
Note
Spring Boot does not support h2c, the cleartext version of the HTTP/2 protocol. So you must
configure SSL first.
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HTTP/2 with Undertow
As of Undertow 1.4.0+, HTTP/2 is supported without any additional requirement on JDK8.
HTTP/2 with Jetty
As of Jetty 9.4.8, HTTP/2 is also supported with the Conscrypt library. To enable that support,
your application needs to have two additional dependencies: org.eclipse.jetty:jetty-alpn-
conscrypt-server and org.eclipse.jetty.http2:http2-server.
HTTP/2 with Tomcat
Spring Boot ships by default with Tomcat 8.5.x. With that version, HTTP/2 is only supported if the
libtcnative library and its dependencies are installed on the host operating system.
The library folder must be made available, if not already, to the JVM library path. You can do so with
a JVM argument such as -Djava.library.path=/usr/local/opt/tomcat-native/lib. More
on this in the official Tomcat documentation.
Starting Tomcat 8.5.x without that native support logs the following error:
ERROR 8787 --- [ main] o.a.coyote.http11.Http11NioProtocol : The upgrade handler
[org.apache.coyote.http2.Http2Protocol] for [h2] only supports upgrade via ALPN but has been configured
for the ["https-jsse-nio-8443"] connector that does not support ALPN.
This error is not fatal, and the application still starts with HTTP/1.1 SSL support.
Running your application with Tomcat 9.0.x and JDK9 does not require any native library to be installed.
To use Tomcat 9, you can override the tomcat.version build property with the version of your choice.
75.9 Configure the Web Server
Generally, you should first consider using one of the many available configuration keys and customize
your web server by adding new entries in your application.properties (or application.yml,
or environment, etc. see “Section 74.8, “Discover Built-in Options for External Properties””). The
server.* namespace is quite useful here, and it includes namespaces like server.tomcat.*,
server.jetty.* and others, for server-specific features. See the list of Appendix A, Common
application properties.
The previous sections covered already many common use cases, such as compression, SSL or
HTTP/2. However, if a configuration key doesn’t exist for your use case, you should then look at
WebServerFactoryCustomizer. You can declare such a component and get access to the server
factory relevant to your choice: you should select the variant for the chosen Server (Tomcat, Jetty,
Reactor Netty, Undertow) and the chosen web stack (Servlet or Reactive).
The example below is for Tomcat with the spring-boot-starter-web (Servlet stack):
@Component
public class MyTomcatWebServerCustomizer
implements WebServerFactoryCustomizer<TomcatServletWebServerFactory> {
@Override
public void customize(TomcatServletWebServerFactory factory) {
// customize the factory here
}
}
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In addition Spring Boot provides:
Server Servlet stack Reactive stack
Tomcat TomcatServletWebServerFactory TomcatReactiveWebServerFactory
Jetty JettyServletWebServerFactory JettyReactiveWebServerFactory
Undertow UndertowServletWebServerFactoryUndertowReactiveWebServerFactory
Reactor N/A NettyReactiveWebServerFactory
Once you’ve got access to a WebServerFactory, you can often add customizers to it to configure
specific parts, like connectors, server resources, or the server itself - all using server-specific APIs.
As a last resort, you can also declare your own WebServerFactory component, which will override
the one provided by Spring Boot. In this case, you can’t rely on configuration properties in the server
namespace anymore.
75.10 Add a Servlet, Filter, or Listener to an Application
In a servlet stack application, i.e. with the spring-boot-starter-web, there are two ways to add
Servlet, Filter, ServletContextListener, and the other listeners supported by the Servlet API
to your application:
•the section called “Add a Servlet, Filter, or Listener by Using a Spring Bean”
•the section called “Add Servlets, Filters, and Listeners by Using Classpath Scanning”
Add a Servlet, Filter, or Listener by Using a Spring Bean
To add a Servlet, Filter, or Servlet *Listener by using a Spring bean, you must provide a @Bean
definition for it. Doing so can be very useful when you want to inject configuration or dependencies.
However, you must be very careful that they do not cause eager initialization of too many other beans,
because they have to be installed in the container very early in the application lifecycle. (For example,
it is not a good idea to have them depend on your DataSource or JPA configuration.) You can work
around such restrictions by initializing the beans lazily when first used instead of on initialization.
In the case of Filters and Servlets, you can also add mappings and init parameters by adding
a FilterRegistrationBean or a ServletRegistrationBean instead of or in addition to the
underlying component.
Note
If no dispatcherType is specified on a filter registration, REQUEST is used. This aligns with the
Servlet Specification’s default dispatcher type.
Like any other Spring bean, you can define the order of Servlet filter beans; please make sure to check
the “the section called “Registering Servlets, Filters, and Listeners as Spring Beans”” section.
Disable Registration of a Servlet or Filter
As described earlier, any Servlet or Filter beans are registered with the servlet container
automatically. To disable registration of a particular Filter or Servlet bean, create a registration
bean for it and mark it as disabled, as shown in the following example:
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@Bean
public FilterRegistrationBean registration(MyFilter filter) {
FilterRegistrationBean registration = new FilterRegistrationBean(filter);
registration.setEnabled(false);
return registration;
}
Add Servlets, Filters, and Listeners by Using Classpath Scanning
@WebServlet, @WebFilter, and @WebListener annotated classes can be automatically
registered with an embedded servlet container by annotating a @Configuration class with
@ServletComponentScan and specifying the package(s) containing the components that you want
to register. By default, @ServletComponentScan scans from the package of the annotated class.
75.11 Configure Access Logging
Access logs can be configured for Tomcat, Undertow, and Jetty through their respective namespaces.
For instance, the following settings log access on Tomcat with a custom pattern.
server.tomcat.basedir=my-tomcat
server.tomcat.accesslog.enabled=true
server.tomcat.accesslog.pattern=%t %a "%r" %s (%D ms)
Note
The default location for logs is a logs directory relative to the Tomcat base directory. By default,
the logs directory is a temporary directory, so you may want to fix Tomcat’s base directory or use
an absolute path for the logs. In the preceding example, the logs are available in my-tomcat/
logs relative to the working directory of the application.
Access logging for Undertow can be configured in a similar fashion, as shown in the following example:
server.undertow.accesslog.enabled=true
server.undertow.accesslog.pattern=%t %a "%r" %s (%D ms)
Logs are stored in a logs directory relative to the working directory of the application. You can customize
this location by setting the server.undertow.accesslog.directory property.
Finally, access logging for Jetty can also be configured as follows:
server.jetty.accesslog.enabled=true
server.jetty.accesslog.filename=/var/log/jetty-access.log
By default, logs are redirected to System.err. For more details, see the Jetty documentation.
75.12 Running Behind a Front-end Proxy Server
Your application might need to send 302 redirects or render content with absolute links back to itself.
When running behind a proxy, the caller wants a link to the proxy and not to the physical address of
the machine hosting your app. Typically, such situations are handled through a contract with the proxy,
which adds headers to tell the back end how to construct links to itself.
If the proxy adds conventional X-Forwarded-For and X-Forwarded-Proto headers (most proxy
servers do so), the absolute links should be rendered correctly, provided server.use-forward-
headers is set to true in your application.properties.
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Note
If your application runs in Cloud Foundry or Heroku, the server.use-forward-headers
property defaults to true. In all other instances, it defaults to false.
Customize Tomcat’s Proxy Configuration
If you use Tomcat, you can additionally configure the names of the headers used to carry “forwarded”
information, as shown in the following example:
server.tomcat.remote-ip-header=x-your-remote-ip-header
server.tomcat.protocol-header=x-your-protocol-header
Tomcat is also configured with a default regular expression that matches internal proxies that are to
be trusted. By default, IP addresses in 10/8, 192.168/16, 169.254/16 and 127/8 are trusted. You
can customize the valve’s configuration by adding an entry to application.properties, as shown
in the following example:
server.tomcat.internal-proxies=192\\.168\\.\\d{1,3}\\.\\d{1,3}
Note
The double backslashes are required only when you use a properties file for configuration. If you
use YAML, single backslashes are sufficient, and a value equivalent to that shown in the preceding
example would be 192\.168\.\d{1,3}\.\d{1,3}.
Note
You can trust all proxies by setting the internal-proxies to empty (but do not do so in
production).
You can take complete control of the configuration of Tomcat’s RemoteIpValve by switching the
automatic one off (to do so, set server.use-forward-headers=false) and adding a new valve
instance in a TomcatServletWebServerFactory bean.
75.13 Enable Multiple Connectors with Tomcat
You can add an org.apache.catalina.connector.Connector to the
TomcatServletWebServerFactory, which can allow multiple connectors, including HTTP and
HTTPS connectors, as shown in the following example:
@Bean
public ServletWebServerFactory servletContainer() {
TomcatServletWebServerFactory tomcat = new TomcatServletWebServerFactory();
tomcat.addAdditionalTomcatConnectors(createSslConnector());
return tomcat;
}
private Connector createSslConnector() {
Connector connector = new Connector("org.apache.coyote.http11.Http11NioProtocol");
Http11NioProtocol protocol = (Http11NioProtocol) connector.getProtocolHandler();
try {
File keystore = new ClassPathResource("keystore").getFile();
File truststore = new ClassPathResource("keystore").getFile();
connector.setScheme("https");
connector.setSecure(true);
connector.setPort(8443);
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protocol.setSSLEnabled(true);
protocol.setKeystoreFile(keystore.getAbsolutePath());
protocol.setKeystorePass("changeit");
protocol.setTruststoreFile(truststore.getAbsolutePath());
protocol.setTruststorePass("changeit");
protocol.setKeyAlias("apitester");
return connector;
}
catch (IOException ex) {
throw new IllegalStateException("can't access keystore: [" + "keystore"
+ "] or truststore: [" + "keystore" + "]", ex);
}
}
75.14 Use Tomcat’s LegacyCookieProcessor
By default, the embedded Tomcat used by Spring Boot does not support "Version 0" of the Cookie
format, so you may see the following error:
java.lang.IllegalArgumentException: An invalid character [32] was present in the Cookie value
If at all possible, you should consider updating your code to only store values compliant with later
Cookie specifications. If, however, you cannot change the way that cookies are written, you can instead
configure Tomcat to use a LegacyCookieProcessor. To switch to the LegacyCookieProcessor,
use an WebServerFactoryCustomizer bean that adds a TomcatContextCustomizer, as shown
in the following example:
@Bean
public WebServerFactoryCustomizer<TomcatServletWebServerFactory> cookieProcessorCustomizer() {
return (factory) -> factory.addContextCustomizers(
(context) -> context.setCookieProcessor(new LegacyCookieProcessor()));
}
75.15 Enable Multiple Listeners with Undertow
Add an UndertowBuilderCustomizer to the UndertowServletWebServerFactory and add a
listener to the Builder, as shown in the following example:
@Bean
public UndertowServletWebServerFactory servletWebServerFactory() {
UndertowServletWebServerFactory factory = new UndertowServletWebServerFactory();
factory.addBuilderCustomizers(new UndertowBuilderCustomizer() {
@Override
public void customize(Builder builder) {
builder.addHttpListener(8080, "0.0.0.0");
}
});
return factory;
}
75.16 Create WebSocket Endpoints Using @ServerEndpoint
If you want to use @ServerEndpoint in a Spring Boot application that used an embedded container,
you must declare a single ServerEndpointExporter @Bean, as shown in the following example:
@Bean
public ServerEndpointExporter serverEndpointExporter() {
return new ServerEndpointExporter();
}
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The bean shown in the preceding example registers any @ServerEndpoint annotated beans with
the underlying WebSocket container. When deployed to a standalone servlet container, this role is
performed by a servlet container initializer, and the ServerEndpointExporter bean is not required.
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76. Spring MVC
Spring Boot has a number of starters that include Spring MVC. Note that some starters include a
dependency on Spring MVC rather than include it directly. This section answers common questions
about Spring MVC and Spring Boot.
76.1 Write a JSON REST Service
Any Spring @RestController in a Spring Boot application should render JSON response by default
as long as Jackson2 is on the classpath, as shown in the following example:
@RestController
public class MyController {
@RequestMapping("/thing")
public MyThing thing() {
return new MyThing();
}
}
As long as MyThing can be serialized by Jackson2 (true for a normal POJO or Groovy object), then
localhost:8080/thing serves a JSON representation of it by default. Note that, in a browser, you
might sometimes see XML responses, because browsers tend to send accept headers that prefer XML.
76.2 Write an XML REST Service
If you have the Jackson XML extension (jackson-dataformat-xml) on the classpath, you can use
it to render XML responses. The previous example that we used for JSON would work. To use the
Jackson XML renderer, add the following dependency to your project:
<dependency>
<groupId>com.fasterxml.jackson.dataformat</groupId>
<artifactId>jackson-dataformat-xml</artifactId>
</dependency>
You may also want to add a dependency on Woodstox. It is faster than the default StAX implementation
provided by the JDK and also adds pretty-print support and improved namespace handling. The
following listing shows how to include a dependency on Woodstox:
<dependency>
<groupId>org.codehaus.woodstox</groupId>
<artifactId>woodstox-core-asl</artifactId>
</dependency>
If Jackson’s XML extension is not available, JAXB (provided by default in the JDK) is used, with the
additional requirement of having MyThing annotated as @XmlRootElement, as shown in the following
example:
@XmlRootElement
public class MyThing {
private String name;
// .. getters and setters
}
To get the server to render XML instead of JSON, you might have to send an Accept: text/xml
header (or use a browser).
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76.3 Customize the Jackson ObjectMapper
Spring MVC (client and server side) uses HttpMessageConverters to negotiate content conversion
in an HTTP exchange. If Jackson is on the classpath, you already get the default converter(s) provided
by Jackson2ObjectMapperBuilder, an instance of which is auto-configured for you.
The ObjectMapper (or XmlMapper for Jackson XML converter) instance (created by default) has the
following customized properties:
•MapperFeature.DEFAULT_VIEW_INCLUSION is disabled
•DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES is disabled
•SerializationFeature.WRITE_DATES_AS_TIMESTAMPS is disabled
Spring Boot also has some features to make it easier to customize this behavior.
You can configure the ObjectMapper and XmlMapper instances by using the environment. Jackson
provides an extensive suite of simple on/off features that can be used to configure various aspects of
its processing. These features are described in six enums (in Jackson) that map onto properties in the
environment:
Enum Property Values
com.fasterxml.jackson.databind.DeserializationFeaturespring.jackson.deserialization.<feature_name>true, false
com.fasterxml.jackson.core.JsonGenerator.Featurespring.jackson.generator.<feature_name>true, false
com.fasterxml.jackson.databind.MapperFeaturespring.jackson.mapper.<feature_name>true, false
com.fasterxml.jackson.core.JsonParser.Featurespring.jackson.parser.<feature_name>true, false
com.fasterxml.jackson.databind.SerializationFeaturespring.jackson.serialization.<feature_name>true, false
com.fasterxml.jackson.annotation.JsonInclude.Includespring.jackson.default-
property-inclusion
always, non_null,
non_absent, non_default,
non_empty
For example, to enable pretty print, set
spring.jackson.serialization.indent_output=true. Note that, thanks to the use of relaxed
binding, the case of indent_output does not have to match the case of the corresponding enum
constant, which is INDENT_OUTPUT.
This environment-based configuration is applied to the auto-configured
Jackson2ObjectMapperBuilder bean and applies to any mappers created by using the builder,
including the auto-configured ObjectMapper bean.
The context’s Jackson2ObjectMapperBuilder can be customized by one or more
Jackson2ObjectMapperBuilderCustomizer beans. Such customizer beans can be ordered
(Boot’s own customizer has an order of 0), letting additional customization be applied both before and
after Boot’s customization.
Any beans of type com.fasterxml.jackson.databind.Module are automatically registered
with the auto-configured Jackson2ObjectMapperBuilder and are applied to any ObjectMapper
instances that it creates. This provides a global mechanism for contributing custom modules when you
add new features to your application.
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If you want to replace the default ObjectMapper completely, either define a @Bean of
that type and mark it as @Primary or, if you prefer the builder-based approach, define a
Jackson2ObjectMapperBuilder @Bean. Note that, in either case, doing so disables all auto-
configuration of the ObjectMapper.
If you provide any @Beans of type MappingJackson2HttpMessageConverter, they replace the
default value in the MVC configuration. Also, a convenience bean of type HttpMessageConverters is
provided (and is always available if you use the default MVC configuration). It has some useful methods
to access the default and user-enhanced message converters.
See the “Section 76.4, “Customize the @ResponseBody Rendering”” section and the
WebMvcAutoConfiguration source code for more details.
76.4 Customize the @ResponseBody Rendering
Spring uses HttpMessageConverters to render @ResponseBody (or responses from
@RestController). You can contribute additional converters by adding beans of the appropriate type
in a Spring Boot context. If a bean you add is of a type that would have been included by default anyway
(such as MappingJackson2HttpMessageConverter for JSON conversions), it replaces the default
value. A convenience bean of type HttpMessageConverters is provided and is always available if
you use the default MVC configuration. It has some useful methods to access the default and user-
enhanced message converters (For example, it can be useful if you want to manually inject them into
a custom RestTemplate).
As in normal MVC usage, any WebMvcConfigurer beans that you provide can also contribute
converters by overriding the configureMessageConverters method. However, unlike with normal
MVC, you can supply only additional converters that you need (because Spring Boot uses the same
mechanism to contribute its defaults). Finally, if you opt out of the Spring Boot default MVC configuration
by providing your own @EnableWebMvc configuration, you can take control completely and do
everything manually by using getMessageConverters from WebMvcConfigurationSupport.
See the WebMvcAutoConfiguration source code for more details.
76.5 Handling Multipart File Uploads
Spring Boot embraces the Servlet 3 javax.servlet.http.Part API to support uploading files. By
default, Spring Boot configures Spring MVC with a maximum size of 1MB per file and a maximum of
10MB of file data in a single request. You may override these values, the location to which intermediate
data is stored (for example, to the /tmp directory), and the threshold past which data is flushed to disk by
using the properties exposed in the MultipartProperties class. For example, if you want to specify
that files be unlimited, set the spring.servlet.multipart.max-file-size property to -1.
The multipart support is helpful when you want to receive multipart encoded file data as a
@RequestParam-annotated parameter of type MultipartFile in a Spring MVC controller handler
method.
See the MultipartAutoConfiguration source for more details.
76.6 Switch Off the Spring MVC DispatcherServlet
Spring Boot wants to serve all content from the root of your application (/) down. If you would rather
map your own servlet to that URL, you can do it. However, you may lose some of the other Boot MVC
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features. To add your own servlet and map it to the root resource, declare a @Bean of type Servlet
and give it the special bean name, dispatcherServlet. (You can also create a bean of a different
type with that name if you want to switch it off and not replace it.)
76.7 Switch off the Default MVC Configuration
The easiest way to take complete control over MVC configuration is to provide your own
@Configuration with the @EnableWebMvc annotation. Doing so leaves all MVC configuration in your
hands.
76.8 Customize ViewResolvers
A ViewResolver is a core component of Spring MVC, translating view names in @Controller
to actual View implementations. Note that ViewResolvers are mainly used in UI applications,
rather than REST-style services (a View is not used to render a @ResponseBody). There are many
implementations of ViewResolver to choose from, and Spring on its own is not opinionated about
which ones you should use. Spring Boot, on the other hand, installs one or two for you, depending on
what it finds on the classpath and in the application context. The DispatcherServlet uses all the
resolvers it finds in the application context, trying each one in turn until it gets a result, so, if you add
your own, you have to be aware of the order and in which position your resolver is added.
WebMvcAutoConfiguration adds the following ViewResolvers to your context:
• An InternalResourceViewResolver named ‘defaultViewResolver’. This one locates physical
resources that can be rendered by using the DefaultServlet (including static resources and JSP
pages, if you use those). It applies a prefix and a suffix to the view name and then looks for a
physical resource with that path in the servlet context (the defaults are both empty but are accessible
for external configuration through spring.mvc.view.prefix and spring.mvc.view.suffix).
You can override it by providing a bean of the same type.
• A BeanNameViewResolver named ‘beanNameViewResolver’. This is a useful member of the view
resolver chain and picks up any beans with the same name as the View being resolved. It should
not be necessary to override or replace it.
• A ContentNegotiatingViewResolver named ‘viewResolver’ is added only if there are actually
beans of type View present. This is a ‘master’ resolver, delegating to all the others and
attempting to find a match to the ‘Accept’ HTTP header sent by the client. There is a useful
blog about ContentNegotiatingViewResolver that you might like to study to learn more,
and you might also look at the source code for detail. You can switch off the auto-configured
ContentNegotiatingViewResolver by defining a bean named ‘viewResolver’.
• If you use Thymeleaf, you also have a ThymeleafViewResolver named ‘thymeleafViewResolver’.
It looks for resources by surrounding the view name with a prefix and suffix. The prefix is
spring.thymeleaf.prefix, and the suffix is spring.thymeleaf.suffix. The values of
the prefix and suffix default to ‘classpath:/templates/’ and ‘.html’, respectively. You can override
ThymeleafViewResolver by providing a bean of the same name.
• If you use FreeMarker, you also have a FreeMarkerViewResolver named
‘freeMarkerViewResolver’. It looks for resources in a loader path (which is externalized to
spring.freemarker.templateLoaderPath and has a default value of ‘classpath:/templates/’)
by surrounding the view name with a prefix and a suffix. The prefix is externalized to
spring.freemarker.prefix, and the suffix is externalized to spring.freemarker.suffix.
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The default values of the prefix and suffix are empty and ‘.ftl’, respectively. You can override
FreeMarkerViewResolver by providing a bean of the same name.
• If you use Groovy templates (actually, if groovy-templates is on your classpath), you also
have a GroovyMarkupViewResolver named ‘groovyMarkupViewResolver’. It looks for resources
in a loader path by surrounding the view name with a prefix and suffix (externalized to
spring.groovy.template.prefix and spring.groovy.template.suffix). The prefix and
suffix have default values of ‘classpath:/templates/’ and ‘.tpl’, respectively. You can override
GroovyMarkupViewResolver by providing a bean of the same name.
For more detail, see the following sections:
•WebMvcAutoConfiguration
•ThymeleafAutoConfiguration
•FreeMarkerAutoConfiguration
•GroovyTemplateAutoConfiguration
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77. Jersey
77.1 Secure Jersey endpoints with Spring Security
Spring Security can be used to secure a Jersey-based web application in much the same way as
it can be used to secure a Spring MVC-based web application. However, if you want to use Spring
Security’s method-level security with Jersey, you must configure Jersey to use setStatus(int) rather
sendError(int). This prevents Jersey from committing the response before Spring Security has had
an opportunity to report an authentication or authorization failure to the client.
The jersey.config.server.response.setStatusOverSendError property must be set to
true on the application’s ResourceConfig bean, as shown in the following example:
@Component
public class JerseyConfig extends ResourceConfig {
public JerseyConfig() {
register(Endpoint.class);
setProperties(Collections.singletonMap(
"jersey.config.server.response.setStatusOverSendError", true));
}
}
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78. HTTP Clients
Spring Boot offers a number of starters that work with HTTP clients. This section answers questions
related to using them.
78.1 Configure RestTemplate to Use a Proxy
As described in Section 33.1, “RestTemplate Customization”, you can use a
RestTemplateCustomizer with RestTemplateBuilder to build a customized RestTemplate.
This is the recommended approach for creating a RestTemplate configured to use a proxy.
The exact details of the proxy configuration depend on the underlying client request factory that is
being used. The following example configures HttpComponentsClientRequestFactory with an
HttpClient that uses a proxy for all hosts except 192.168.0.5:
static class ProxyCustomizer implements RestTemplateCustomizer {
@Override
public void customize(RestTemplate restTemplate) {
HttpHost proxy = new HttpHost("proxy.example.com");
HttpClient httpClient = HttpClientBuilder.create()
.setRoutePlanner(new DefaultProxyRoutePlanner(proxy) {
@Override
public HttpHost determineProxy(HttpHost target,
HttpRequest request, HttpContext context)
throws HttpException {
if (target.getHostName().equals("192.168.0.5")) {
return null;
}
return super.determineProxy(target, request, context);
}
}).build();
restTemplate.setRequestFactory(
new HttpComponentsClientHttpRequestFactory(httpClient));
}
}
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79. Logging
Spring Boot has no mandatory logging dependency, except for the Commons Logging API, which is
typically provided by Spring Framework’s spring-jcl module. To use Logback, you need to include
it and spring-jcl on the classpath. The simplest way to do that is through the starters, which all
depend on spring-boot-starter-logging. For a web application, you need only spring-boot-
starter-web, since it depends transitively on the logging starter. If you use Maven, the following
dependency adds logging for you:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
Spring Boot has a LoggingSystem abstraction that attempts to configure logging based on the content
of the classpath. If Logback is available, it is the first choice.
If the only change you need to make to logging is to set the levels of various loggers, you can do so in
application.properties by using the "logging.level" prefix, as shown in the following example:
logging.level.org.springframework.web=DEBUG
logging.level.org.hibernate=ERROR
You can also set the location of a file to which to write the log (in addition to the console) by using
"logging.file".
To configure the more fine-grained settings of a logging system, you need to use the native configuration
format supported by the LoggingSystem in question. By default, Spring Boot picks up the native
configuration from its default location for the system (such as classpath:logback.xml for Logback),
but you can set the location of the config file by using the "logging.config" property.
79.1 Configure Logback for Logging
If you put a logback.xml in the root of your classpath, it is picked up from there (or from logback-
spring.xml, to take advantage of the templating features provided by Boot). Spring Boot provides
a default base configuration that you can include if you want to set levels, as shown in the following
example:
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<include resource="org/springframework/boot/logging/logback/base.xml"/>
<logger name="org.springframework.web" level="DEBUG"/>
</configuration>
If you look at base.xml in the spring-boot jar, you can see that it uses some useful System properties
that the LoggingSystem takes care of creating for you:
•${PID}: The current process ID.
•${LOG_FILE}: Whether logging.file was set in Boot’s external configuration.
•${LOG_PATH}: Whether logging.path (representing a directory for log files to live in) was set in
Boot’s external configuration.
•${LOG_EXCEPTION_CONVERSION_WORD}: Whether logging.exception-conversion-word
was set in Boot’s external configuration.
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Spring Boot also provides some nice ANSI color terminal output on a console (but not in a log file) by
using a custom Logback converter. See the default base.xml configuration for details.
If Groovy is on the classpath, you should be able to configure Logback with logback.groovy as well.
If present, this setting is given preference.
Configure Logback for File-only Output
If you want to disable console logging and write output only to a file, you need a custom logback-
spring.xml that imports file-appender.xml but not console-appender.xml, as shown in the
following example:
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<include resource="org/springframework/boot/logging/logback/defaults.xml" />
<property name="LOG_FILE" value="${LOG_FILE:-${LOG_PATH:-${LOG_TEMP:-${java.io.tmpdir:-/
tmp}}/}spring.log}"/>
<include resource="org/springframework/boot/logging/logback/file-appender.xml" />
<root level="INFO">
<appender-ref ref="FILE" />
</root>
</configuration>
You also need to add logging.file to your application.properties, as shown in the following
example:
logging.file=myapplication.log
79.2 Configure Log4j for Logging
Spring Boot supports Log4j 2 for logging configuration if it is on the classpath. If you use the starters for
assembling dependencies, you have to exclude Logback and then include log4j 2 instead. If you do not
use the starters, you need to provide (at least) spring-jcl in addition to Log4j 2.
The simplest path is probably through the starters, even though it requires some jiggling with excludes.
The following example shows how to set up the starters in Maven:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-log4j2</artifactId>
</dependency>
And the following example shows one way to set up the starters in Gradle:
dependencies {
compile 'org.springframework.boot:spring-boot-starter-web'
compile 'org.springframework.boot:spring-boot-starter-log4j2'
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}
configurations {
all {
exclude group: 'org.springframework.boot', module: 'spring-boot-starter-logging'
}
}
Note
The Log4j starters gather together the dependencies for common logging requirements (such
as having Tomcat use java.util.logging but configuring the output using Log4j 2). See the
Actuator Log4j 2 samples for more detail and to see it in action.
Note
To ensure that debug logging performed using java.util.logging is routed into Log4j
2, configure its JDK logging adapter by setting the java.util.logging.manager system
property to org.apache.logging.log4j.jul.LogManager.
Use YAML or JSON to Configure Log4j 2
In addition to its default XML configuration format, Log4j 2 also supports YAML and JSON configuration
files. To configure Log4j 2 to use an alternative configuration file format, add the appropriate
dependencies to the classpath and name your configuration files to match your chosen file format, as
shown in the following example:
Format Dependencies File names
YAML com.fasterxml.jackson.core:jackson-databind
com.fasterxml.jackson.dataformat:jackson-dataformat-
yaml
log4j2.yaml
log4j2.yml
JSON com.fasterxml.jackson.core:jackson-databind log4j2.json
log4j2.jsn
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80. Data Access
Spring Boot includes a number of starters for working with data sources. This section answers questions
related to doing so.
80.1 Configure a Custom DataSource
To configure your own DataSource, define a @Bean of that type in your configuration. Spring Boot
reuses your DataSource anywhere one is required, including database initialization. If you need to
externalize some settings, you can bind your DataSource to the environment (see “the section called
“Third-party Configuration””).
The following example shows how to define a data source in a bean:
@Bean
@ConfigurationProperties(prefix="app.datasource")
public DataSource dataSource() {
return new FancyDataSource();
}
The following example shows how to define a data source by setting properties:
app.datasource.url=jdbc:h2:mem:mydb
app.datasource.username=sa
app.datasource.pool-size=30
Assuming that your FancyDataSource has regular JavaBean properties for the URL, the username,
and the pool size, these settings are bound automatically before the DataSource is made available
to other components. The regular database initialization also happens (so the relevant sub-set of
spring.datasource.* can still be used with your custom configuration).
You can apply the same principle if you configure a custom JNDI DataSource, as shown in the following
example:
@Bean(destroyMethod="")
@ConfigurationProperties(prefix="app.datasource")
public DataSource dataSource() throws Exception {
JndiDataSourceLookup dataSourceLookup = new JndiDataSourceLookup();
return dataSourceLookup.getDataSource("java:comp/env/jdbc/YourDS");
}
Spring Boot also provides a utility builder class, called DataSourceBuilder, that can be used to create
one of the standard data sources (if it is on the classpath). The builder can detect the one to use based
on what’s available on the classpath. It also auto-detects the driver based on the JDBC URL.
The following example shows how to create a data source by using a DataSourceBuilder:
@Bean
@ConfigurationProperties("app.datasource")
public DataSource dataSource() {
return DataSourceBuilder.create().build();
}
To run an app with that DataSource, all you need is the connection information. Pool-specific settings
can also be provided. Check the implementation that is going to be used at runtime for more details.
The following example shows how to define a JDBC data source by setting properties:
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app.datasource.url=jdbc:mysql://localhost/test
app.datasource.username=dbuser
app.datasource.password=dbpass
app.datasource.pool-size=30
However, there is a catch. Because the actual type of the connection pool is not exposed, no keys
are generated in the metadata for your custom DataSource and no completion is available in your
IDE (because the DataSource interface exposes no properties). Also, if you happen to have Hikari on
the classpath, this basic setup does not work, because Hikari has no url property (but does have a
jdbcUrl property). In that case, you must rewrite your configuration as follows:
app.datasource.jdbc-url=jdbc:mysql://localhost/test
app.datasource.username=dbuser
app.datasource.password=dbpass
app.datasource.maximum-pool-size=30
You can fix that by forcing the connection pool to use and return a dedicated implementation rather than
DataSource. You cannot change the implementation at runtime, but the list of options will be explicit.
The following example shows how create a HikariDataSource with DataSourceBuilder:
@Bean
@ConfigurationProperties("app.datasource")
public HikariDataSource dataSource() {
return DataSourceBuilder.create().type(HikariDataSource.class).build();
}
You can even go further by leveraging what DataSourceProperties does for you — that is, by
providing a default embedded database with a sensible username and password if no URL is provided.
You can easily initialize a DataSourceBuilder from the state of any DataSourceProperties
object, so you could also inject the DataSource that Spring Boot creates automatically. However, that
would split your configuration into two namespaces: url, username, password, type, and driver
on spring.datasource and the rest on your custom namespace (app.datasource). To avoid that,
you can redefine a custom DataSourceProperties on your custom namespace, as shown in the
following example:
@Bean
@Primary
@ConfigurationProperties("app.datasource")
public DataSourceProperties dataSourceProperties() {
return new DataSourceProperties();
}
@Bean
@ConfigurationProperties("app.datasource")
public HikariDataSource dataSource(DataSourceProperties properties) {
return properties.initializeDataSourceBuilder().type(HikariDataSource.class)
.build();
}
This setup puts you in sync with what Spring Boot does for you by default, except that a dedicated
connection pool is chosen (in code) and its settings are exposed in the same namespace. Because
DataSourceProperties is taking care of the url/jdbcUrl translation for you, you can configure
it as follows:
app.datasource.url=jdbc:mysql://localhost/test
app.datasource.username=dbuser
app.datasource.password=dbpass
app.datasource.maximum-pool-size=30
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Note
Because your custom configuration chooses to go with Hikari, app.datasource.type has no
effect. In practice, the builder is initialized with whatever value you might set there and then
overridden by the call to .type().
See “Section 29.1, “Configure a DataSource”” in the “Spring Boot features” section and the
DataSourceAutoConfiguration class for more details.
80.2 Configure Two DataSources
If you need to configure multiple data sources, you can apply the same tricks that are described in the
previous section. You must, however, mark one of the DataSource instances as @Primary, because
various auto-configurations down the road expect to be able to get one by type.
If you create your own DataSource, the auto-configuration backs off. In the following example, we
provide the exact same feature set as the auto-configuration provides on the primary data source:
@Bean
@Primary
@ConfigurationProperties("app.datasource.first")
public DataSourceProperties firstDataSourceProperties() {
return new DataSourceProperties();
}
@Bean
@Primary
@ConfigurationProperties("app.datasource.first")
public DataSource firstDataSource() {
return firstDataSourceProperties().initializeDataSourceBuilder().build();
}
@Bean
@ConfigurationProperties("app.datasource.second")
public BasicDataSource secondDataSource() {
return DataSourceBuilder.create().type(BasicDataSource.class).build();
}
Tip
firstDataSourceProperties has to be flagged as @Primary so that the database initializer
feature uses your copy (if you use the initializer).
Both data sources are also bound for advanced customizations. For instance, you could configure them
as follows:
app.datasource.first.type=com.zaxxer.hikari.HikariDataSource
app.datasource.first.maximum-pool-size=30
app.datasource.second.url=jdbc:mysql://localhost/test
app.datasource.second.username=dbuser
app.datasource.second.password=dbpass
app.datasource.second.max-total=30
You can apply the same concept to the secondary DataSource as well, as shown in the following
example:
@Bean
@Primary
@ConfigurationProperties("app.datasource.first")
public DataSourceProperties firstDataSourceProperties() {
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return new DataSourceProperties();
}
@Bean
@Primary
@ConfigurationProperties("app.datasource.first")
public DataSource firstDataSource() {
return firstDataSourceProperties().initializeDataSourceBuilder().build();
}
@Bean
@ConfigurationProperties("app.datasource.second")
public DataSourceProperties secondDataSourceProperties() {
return new DataSourceProperties();
}
@Bean
@ConfigurationProperties("app.datasource.second")
public DataSource secondDataSource() {
return secondDataSourceProperties().initializeDataSourceBuilder().build();
}
The preceding example configures two data sources on custom namespaces with the same logic as
Spring Boot would use in auto-configuration.
80.3 Use Spring Data Repositories
Spring Data can create implementations of @Repository interfaces of various flavors. Spring Boot
handles all of that for you, as long as those @Repositories are included in the same package (or a
sub-package) of your @EnableAutoConfiguration class.
For many applications, all you need is to put the right Spring Data dependencies on your classpath (there
is a spring-boot-starter-data-jpa for JPA and a spring-boot-starter-data-mongodb
for Mongodb) and create some repository interfaces to handle your @Entity objects. Examples are in
the JPA sample and the Mongodb sample.
Spring Boot tries to guess the location of your @Repository definitions, based on the
@EnableAutoConfiguration it finds. To get more control, use the @EnableJpaRepositories
annotation (from Spring Data JPA).
For more about Spring Data, see the Spring Data project page.
80.4 Separate @Entity Definitions from Spring Configuration
Spring Boot tries to guess the location of your @Entity definitions, based on the
@EnableAutoConfiguration it finds. To get more control, you can use the @EntityScan
annotation, as shown in the following example:
@Configuration
@EnableAutoConfiguration
@EntityScan(basePackageClasses=City.class)
public class Application {
//...
}
80.5 Configure JPA Properties
Spring Data JPA already provides some vendor-independent configuration options (such as those
for SQL logging), and Spring Boot exposes those options and a few more for Hibernate as external
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configuration properties. Some of them are automatically detected according to the context so you
should not have to set them.
The spring.jpa.hibernate.ddl-auto is a special case, because, depending on runtime
conditions, it has different defaults. If an embedded database is used and no schema manager (such
as Liquibase or Flyway) is handling the DataSource, it defaults to create-drop. In all other cases,
it defaults to none.
The dialect to use is also automatically detected based on the current DataSource, but you can set
spring.jpa.database yourself if you want to be explicit and bypass that check on startup.
Note
Specifying a database leads to the configuration of a well-defined Hibernate dialect. Several
databases have more than one Dialect, and this may not suit your needs. In that case, you
can either set spring.jpa.database to default to let Hibernate figure things out or set the
dialect by setting the spring.jpa.database-platform property.
The most common options to set are shown in the following example:
spring.jpa.hibernate.naming.physical-strategy=com.example.MyPhysicalNamingStrategy
spring.jpa.show-sql=true
In addition, all properties in spring.jpa.properties.* are passed through as normal JPA
properties (with the prefix stripped) when the local EntityManagerFactory is created.
Tip
If you need to apply advanced customization to Hibernate properties, consider registering
a HibernatePropertiesCustomizer bean that will be invoked prior to creating the
EntityManagerFactory. This takes precedence to anything that is applied by the auto-
configuration.
80.6 Configure Hibernate Naming Strategy
Hibernate uses two different naming strategies to map names from the object model to the
corresponding database names. The fully qualified class name of the physical and the implicit strategy
implementations can be configured by setting the spring.jpa.hibernate.naming.physical-
strategy and spring.jpa.hibernate.naming.implicit-strategy properties, respectively.
Alternatively, if ImplicitNamingStrategy or PhysicalNamingStrategy beans are available in
the application context, Hibernate will be automatically configured to use them.
By default, Spring Boot configures the physical naming strategy with
SpringPhysicalNamingStrategy. This implementation provides the same table structure as
Hibernate 4: all dots are replaced by underscores and camel casing is replaced by underscores as well.
By default, all table names are generated in lower case, but it is possible to override that flag if your
schema requires it.
For example, a TelephoneNumber entity is mapped to the telephone_number table.
If you prefer to use Hibernate 5’s default instead, set the following property:
spring.jpa.hibernate.naming.physical-
strategy=org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl
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Alternatively, you can configure the following bean:
@Bean
public PhysicalNamingStrategy physicalNamingStrategy() {
return new PhysicalNamingStrategyStandardImpl();
}
See HibernateJpaAutoConfiguration and JpaBaseConfiguration for more details.
80.7 Use a Custom EntityManagerFactory
To take full control of the configuration of the EntityManagerFactory, you need to add a @Bean
named ‘entityManagerFactory’. Spring Boot auto-configuration switches off its entity manager in the
presence of a bean of that type.
80.8 Use Two EntityManagers
Even if the default EntityManagerFactory works fine, you need to define a new one. Otherwise,
the presence of the second bean of that type switches off the default. To make it easy to do, you
can use the convenient EntityManagerBuilder provided by Spring Boot. Alternatively, you can
just the LocalContainerEntityManagerFactoryBean directly from Spring ORM, as shown in the
following example:
// add two data sources configured as above
@Bean
public LocalContainerEntityManagerFactoryBean customerEntityManagerFactory(
EntityManagerFactoryBuilder builder) {
return builder
.dataSource(customerDataSource())
.packages(Customer.class)
.persistenceUnit("customers")
.build();
}
@Bean
public LocalContainerEntityManagerFactoryBean orderEntityManagerFactory(
EntityManagerFactoryBuilder builder) {
return builder
.dataSource(orderDataSource())
.packages(Order.class)
.persistenceUnit("orders")
.build();
}
The configuration above almost works on its own. To complete the picture, you need to configure
TransactionManagers for the two EntityManagers as well. If you mark one of them as @Primary,
it could be picked up by the default JpaTransactionManager in Spring Boot. The other would have
to be explicitly injected into a new instance. Alternatively, you might be able to use a JTA transaction
manager that spans both.
If you use Spring Data, you need to configure @EnableJpaRepositories accordingly, as shown in
the following example:
@Configuration
@EnableJpaRepositories(basePackageClasses = Customer.class,
entityManagerFactoryRef = "customerEntityManagerFactory")
public class CustomerConfiguration {
...
}
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@Configuration
@EnableJpaRepositories(basePackageClasses = Order.class,
entityManagerFactoryRef = "orderEntityManagerFactory")
public class OrderConfiguration {
...
}
80.9 Use a Traditional persistence.xml File
Spring Boot will not search for or use a META-INF/persistence.xml by default. If you
prefer to use a traditional persistence.xml, you need to define your own @Bean of type
LocalEntityManagerFactoryBean (with an ID of ‘entityManagerFactory’) and set the persistence
unit name there.
See JpaBaseConfiguration for the default settings.
80.10 Use Spring Data JPA and Mongo Repositories
Spring Data JPA and Spring Data Mongo can both automatically create Repository implementations
for you. If they are both present on the classpath, you might have to do some extra configuration to tell
Spring Boot which repositories to create. The most explicit way to do that is to use the standard Spring
Data @EnableJpaRepositories and @EnableMongoRepositories annotations and provide the
location of your Repository interfaces.
There are also flags (spring.data.*.repositories.enabled and
spring.data.*.repositories.type) that you can use to switch the auto-configured repositories
on and off in external configuration. Doing so is useful, for instance, in case you want to switch off the
Mongo repositories and still use the auto-configured MongoTemplate.
The same obstacle and the same features exist for other auto-configured Spring Data repository types
(Elasticsearch, Solr, and others). To work with them, change the names of the annotations and flags
accordingly.
80.11 Expose Spring Data Repositories as REST Endpoint
Spring Data REST can expose the Repository implementations as REST endpoints for you, provided
Spring MVC has been enabled for the application.
Spring Boot exposes a set of useful properties (from the spring.data.rest namespace) that
customize the RepositoryRestConfiguration. If you need to provide additional customization,
you should use a RepositoryRestConfigurer bean.
Note
If you do not specify any order on your custom RepositoryRestConfigurer, it runs after the
one Spring Boot uses internally. If you need to specify an order, make sure it is higher than 0.
80.12 Configure a Component that is Used by JPA
If you want to configure a component that JPA uses, then you need to ensure that the component is
initialized before JPA. When the component is auto-configured, Spring Boot takes care of this for you.
For example, when Flyway is auto-configured, Hibernate is configured to depend upon Flyway so that
Flyway has a chance to initialize the database before Hibernate tries to use it.
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If you are configuring a component yourself, you can use an
EntityManagerFactoryDependsOnPostProcessor subclass as a convenient way of setting
up the necessary dependencies. For example, if you use Hibernate Search with Elasticsearch as
its index manager, any EntityManagerFactory beans must be configured to depend on the
elasticsearchClient bean, as shown in the following example:
/**
* {@link EntityManagerFactoryDependsOnPostProcessor} that ensures that
* {@link EntityManagerFactory} beans depend on the {@code elasticsearchClient} bean.
*/
@Configuration
static class ElasticsearchJpaDependencyConfiguration
extends EntityManagerFactoryDependsOnPostProcessor {
ElasticsearchJpaDependencyConfiguration() {
super("elasticsearchClient");
}
}
80.13 Configure jOOQ with Two DataSources
If you need to use jOOQ with multiple data sources, you should create your own DSLContext for each
one. Refer to JooqAutoConfiguration for more details.
Tip
In particular, JooqExceptionTranslator and SpringTransactionProvider can be
reused to provide similar features to what the auto-configuration does with a single DataSource.
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81. Database Initialization
An SQL database can be initialized in different ways depending on what your stack is. Of course, you
can also do it manually, provided the database is a separate process.
81.1 Initialize a Database Using JPA
JPA has features for DDL generation, and these can be set up to run on startup against the database.
This is controlled through two external properties:
•spring.jpa.generate-ddl (boolean) switches the feature on and off and is vendor independent.
•spring.jpa.hibernate.ddl-auto (enum) is a Hibernate feature that controls the behavior in a
more fine-grained way. This feature is described in more detail later in this guide.
81.2 Initialize a Database Using Hibernate
You can set spring.jpa.hibernate.ddl-auto explicitly and the standard Hibernate property
values are none, validate, update, create, and create-drop. Spring Boot chooses a default
value for you based on whether it thinks your database is embedded. It defaults to create-drop if no
schema manager has been detected or none in all other cases. An embedded database is detected
by looking at the Connection type. hsqldb, h2, and derby are embedded, and others are not. Be
careful when switching from in-memory to a ‘real’ database that you do not make assumptions about
the existence of the tables and data in the new platform. You either have to set ddl-auto explicitly or
use one of the other mechanisms to initialize the database.
Note
You can output the schema creation by enabling the org.hibernate.SQL logger. This is done
for you automatically if you enable the debug mode.
In addition, a file named import.sql in the root of the classpath is executed on startup if Hibernate
creates the schema from scratch (that is, if the ddl-auto property is set to create or create-drop).
This can be useful for demos and for testing if you are careful but is probably not something you want
to be on the classpath in production. It is a Hibernate feature (and has nothing to do with Spring).
81.3 Initialize a Database
Spring Boot can automatically create the schema (DDL scripts) of your DataSource
and initialize it (DML scripts). It loads SQL from the standard root classpath locations:
schema.sql and data.sql, respectively. In addition, Spring Boot processes the schema-
${platform}.sql and data-${platform}.sql files (if present), where platform is the value of
spring.datasource.platform. This allows you to switch to database-specific scripts if necessary.
For example, you might choose to set it to the vendor name of the database (hsqldb, h2, oracle,
mysql, postgresql, and so on).
Note
Spring Boot automatically creates the schema of an embedded DataSource. This behaviour
can be customized by using the spring.datasource.initialization-mode property. For
instance, if you want to always initialize the DataSource regardless of its type:
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spring.datasource.initialization-mode=always
By default, Spring Boot enables the fail-fast feature of the Spring JDBC initializer. This means that,
if the scripts cause exceptions, the application fails to start. You can tune that behavior by setting
spring.datasource.continue-on-error.
Note
In a JPA-based app, you can choose to let Hibernate create the schema or use schema.sql,
but you cannot do both. Make sure to disable spring.jpa.hibernate.ddl-auto if you use
schema.sql.
81.4 Initialize a Spring Batch Database
If you use Spring Batch, it comes pre-packaged with SQL initialization scripts for most popular database
platforms. Spring Boot can detect your database type and execute those scripts on startup. If you use an
embedded database, this happens by default. You can also enable it for any database type, as shown
in the following example:
spring.batch.initialize-schema=always
You can also switch off the initialization explicitly by setting spring.batch.initialize-
schema=never.
81.5 Use a Higher-level Database Migration Tool
Spring Boot supports two higher-level migration tools: Flyway and Liquibase.
Execute Flyway Database Migrations on Startup
To automatically run Flyway database migrations on startup, add the org.flywaydb:flyway-core
to your classpath.
The migrations are scripts in the form V<VERSION>__<NAME>.sql (with <VERSION> an underscore-
separated version, such as ‘1’ or ‘2_1’). By default, they are in a folder called classpath:db/
migration, but you can modify that location by setting spring.flyway.locations. This is a
comma-separated list of one or more classpath: or filesystem: locations. For example, the
following configuration would search for scripts in both the default classpath location and the /opt/
migration directory:
spring.flyway.locations=classpath:db/migration,filesystem:/opt/migration
You can also add a special {vendor} placeholder to use vendor-specific scripts. Assume the following:
spring.flyway.locations=db/migration/{vendor}
Rather than using db/migration, the preceding configuration sets the folder to use according to the
type of the database (such as db/migration/mysql for MySQL). The list of supported databases is
available in DatabaseDriver.
See the Flyway class from flyway-core for details of available settings such as schemas and others.
In addition, Spring Boot provides a small set of properties (in FlywayProperties) that can be used
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to disable the migrations or switch off the location checking. Spring Boot calls Flyway.migrate()
to perform the database migration. If you would like more control, provide a @Bean that implements
FlywayMigrationStrategy.
Flyway supports SQL and Java callbacks. To use SQL-based callbacks, place the callback scripts
in the classpath:db/migration folder. To use Java-based callbacks, create one or more beans
that implement FlywayCallback or, preferably, extend BaseFlywayCallback. Any such beans
are automatically registered with Flyway. They can be ordered by using @Order or by implementing
Ordered.
By default, Flyway autowires the (@Primary) DataSource in your context and uses that
for migrations. If you like to use a different DataSource, you can create one and mark
its @Bean as @FlywayDataSource. If you do so and want two data sources, remember
to create another one and mark it as @Primary. Alternatively, you can use Flyway’s native
DataSource by setting spring.flyway.[url,user,password] in external properties. Setting
either spring.flyway.url or spring.flyway.user is sufficient to cause Flyway to use its
own DataSource. If any of the three properties has not be set, the value of its equivalent
spring.datasource property will be used.
There is a Flyway sample so that you can see how to set things up.
You can also use Flyway to provide data for specific scenarios. For example, you can place test-
specific migrations in src/test/resources and they are run only when your application starts for
testing. Also, you can use profile-specific configuration to customize spring.flyway.locations
so that certain migrations run only when a particular profile is active. For example, in application-
dev.properties, you might specify the following setting:
spring.flyway.locations=classpath:/db/migration,classpath:/dev/db/migration
With that setup, migrations in dev/db/migration run only when the dev profile is active.
Execute Liquibase Database Migrations on Startup
To automatically run Liquibase database migrations on startup, add the
org.liquibase:liquibase-core to your classpath.
By default, the master change log is read from db/changelog/db.changelog-master.yaml, but
you can change the location by setting spring.liquibase.change-log. In addition to YAML,
Liquibase also supports JSON, XML, and SQL change log formats.
By default, Liquibase autowires the (@Primary) DataSource in your context and uses that
for migrations. If you need to use a different DataSource, you can create one and mark its
@Bean as @LiquibaseDataSource. If you do so and you want two data sources, remember
to create another one and mark it as @Primary. Alternatively, you can use Liquibase’s native
DataSource by setting spring.liquibase.[url,user,password] in external properties. Setting
either spring.liquibase.url or spring.liquibase.user is sufficient to cause Liquibase to
use its own DataSource. If any of the three properties has not be set, the value of its equivalent
spring.datasource property will be used.
See LiquibaseProperties for details about available settings such as contexts, the default schema,
and others.
There is a Liquibase sample so that you can see how to set things up.
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82. Messaging
Spring Boot offers a number of starters that include messaging. This section answers questions that
arise from using messaging with Spring Boot.
82.1 Disable Transacted JMS Session
If your JMS broker does not support transacted sessions, you have to disable the support
of transactions altogether. If you create your own JmsListenerContainerFactory, there
is nothing to do, since, by default it cannot be transacted. If you want to use the
DefaultJmsListenerContainerFactoryConfigurer to reuse Spring Boot’s default, you can
disable transacted sessions, as follows:
@Bean
public DefaultJmsListenerContainerFactory jmsListenerContainerFactory(
ConnectionFactory connectionFactory,
DefaultJmsListenerContainerFactoryConfigurer configurer) {
DefaultJmsListenerContainerFactory listenerFactory =
new DefaultJmsListenerContainerFactory();
configurer.configure(listenerFactory, connectionFactory);
listenerFactory.setTransactionManager(null);
listenerFactory.setSessionTransacted(false);
return listenerFactory;
}
The preceding example overrides the default factory, and it should be applied to any other factory that
your application defines, if any.
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83. Batch Applications
This section answers questions that arise from using Spring Batch with Spring Boot.
Note
By default, batch applications require a DataSource to store job details. If you want
to deviate from that, you need to implement BatchConfigurer. See The Javadoc of
@EnableBatchProcessing for more details.
For more about Spring Batch, see the Spring Batch project page.
83.1 Execute Spring Batch Jobs on Startup
Spring Batch auto-configuration is enabled by adding @EnableBatchProcessing (from Spring Batch)
somewhere in your context.
By default, it executes all Jobs in the application context on startup (see
JobLauncherCommandLineRunner for details). You can narrow down to a specific job or jobs by
specifying spring.batch.job.names (which takes a comma-separated list of job name patterns).
If the application context includes a JobRegistry, the jobs in spring.batch.job.names are looked
up in the registry instead of being autowired from the context. This is a common pattern with more
complex systems, where multiple jobs are defined in child contexts and registered centrally.
See BatchAutoConfiguration and @EnableBatchProcessing for more details.
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84. Actuator
Spring Boot includes the Spring Boot Actuator. This section answers questions that often arise from
its use.
84.1 Change the HTTP Port or Address of the Actuator
Endpoints
In a standalone application, the Actuator HTTP port defaults to the same as the main
HTTP port. To make the application listen on a different port, set the external property:
management.server.port. To listen on a completely different network address (such as when you
have an internal network for management and an external one for user applications), you can also set
management.server.address to a valid IP address to which the server is able to bind.
For more detail, see the ManagementServerProperties source code and “Section 51.2,
“Customizing the Management Server Port”” in the “Production-ready features” section.
84.2 Customize the ‘whitelabel’ Error Page
Spring Boot installs a ‘whitelabel’ error page that you see in a browser client if you encounter a server
error (machine clients consuming JSON and other media types should see a sensible response with
the right error code).
Note
Set server.error.whitelabel.enabled=false to switch the default error page off. Doing
so restores the default of the servlet container that you are using. Note that Spring Boot still tries
to resolve the error view, so you should probably add your own error page rather than disabling
it completely.
Overriding the error page with your own depends on the templating technology that you use. For
example, if you use Thymeleaf, you can add an error.html template. If you use FreeMarker, you can
add an error.ftl template. In general, you need a View that resolves with a name of error or a
@Controller that handles the /error path. Unless you replaced some of the default configuration,
you should find a BeanNameViewResolver in your ApplicationContext, so a @Bean named
error would be a simple way of doing that. See ErrorMvcAutoConfiguration for more options.
See also the section on “Error Handling” for details of how to register handlers in the servlet container.
84.3 Sanitize sensible values
Information returned by the env and configprops endpoints can be somewhat sensitive so keys
matching a certain pattern are sanitized by default (i.e. their values are replaced by ).
Spring Boot uses sensible defaults for such keys: for instance, any key ending with the word "password",
"secret", "key" or "token" is sanitized. It is also possible to use a regular expression instead, such as
credentials. to sanitize any key that holds the word credentials as part of the key.
The patterns to use can be customized using the management.endpoint.env.keys-to-sanitize
and management.endpoint.configprops.keys-to-sanitize respectively.
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85. Security
This section addresses questions about security when working with Spring Boot, including questions
that arise from using Spring Security with Spring Boot.
For more about Spring Security, see the Spring Security project page.
85.1 Switch off the Spring Boot Security Configuration
If you define a @Configuration with a WebSecurityConfigurerAdapter in your application, it
switches off the default webapp security settings in Spring Boot.
85.2 Change the UserDetailsService and Add User Accounts
If you provide a @Bean of type AuthenticationManager, AuthenticationProvider, or
UserDetailsService, the default @Bean for InMemoryUserDetailsManager is not created, so
you have the full feature set of Spring Security available (such as various authentication options).
The easiest way to add user accounts is to provide your own UserDetailsService bean.
85.3 Enable HTTPS When Running behind a Proxy Server
Ensuring that all your main endpoints are only available over HTTPS is an important chore for
any application. If you use Tomcat as a servlet container, then Spring Boot adds Tomcat’s own
RemoteIpValve automatically if it detects some environment settings, and you should be able to
rely on the HttpServletRequest to report whether it is secure or not (even downstream of a proxy
server that handles the real SSL termination). The standard behavior is determined by the presence or
absence of certain request headers (x-forwarded-for and x-forwarded-proto), whose names
are conventional, so it should work with most front-end proxies. You can switch on the valve by adding
some entries to application.properties, as shown in the following example:
server.tomcat.remote-ip-header=x-forwarded-for
server.tomcat.protocol-header=x-forwarded-proto
(The presence of either of those properties switches on the valve. Alternatively, you can add the
RemoteIpValve by adding a TomcatServletWebServerFactory bean.)
To configure Spring Security to require a secure channel for all (or some) requests, consider adding
your own WebSecurityConfigurerAdapter that adds the following HttpSecurity configuration:
@Configuration
public class SslWebSecurityConfigurerAdapter extends WebSecurityConfigurerAdapter {
@Override
protected void configure(HttpSecurity http) throws Exception {
// Customize the application security
http.requiresChannel().anyRequest().requiresSecure();
}
}
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86. Hot Swapping
Spring Boot supports hot swapping. This section answers questions about how it works.
86.1 Reload Static Content
There are several options for hot reloading. The recommended approach is to use spring-boot-
devtools, as it provides additional development-time features, such as support for fast application
restarts and LiveReload as well as sensible development-time configuration (such as template caching).
Devtools works by monitoring the classpath for changes. This means that static resource changes must
be "built" for the change to take affect. By default, this happens automatically in Eclipse when you save
your changes. In IntelliJ IDEA, the Make Project command triggers the necessary build. Due to the
default restart exclusions, changes to static resources do not trigger a restart of your application. They
do, however, trigger a live reload.
Alternatively, running in an IDE (especially with debugging on) is a good way to do development (all
modern IDEs allow reloading of static resources and usually also allow hot-swapping of Java class
changes).
Finally, the Maven and Gradle plugins can be configured (see the addResources property) to support
running from the command line with reloading of static files directly from source. You can use that with
an external css/js compiler process if you are writing that code with higher-level tools.
86.2 Reload Templates without Restarting the Container
Most of the templating technologies supported by Spring Boot include a configuration option to disable
caching (described later in this document). If you use the spring-boot-devtools module, these
properties are automatically configured for you at development time.
Thymeleaf Templates
If you use Thymeleaf, set spring.thymeleaf.cache to false. See
ThymeleafAutoConfiguration for other Thymeleaf customization options.
FreeMarker Templates
If you use FreeMarker, set spring.freemarker.cache to false. See
FreeMarkerAutoConfiguration for other FreeMarker customization options.
Groovy Templates
If you use Groovy templates, set spring.groovy.template.cache to false. See
GroovyTemplateAutoConfiguration for other Groovy customization options.
86.3 Fast Application Restarts
The spring-boot-devtools module includes support for automatic application restarts. While not
as fast as technologies such as JRebel it is usually significantly faster than a “cold start”. You should
probably give it a try before investigating some of the more complex reload options discussed later in
this document.
For more details, see the Chapter 20, Developer Tools section.
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86.4 Reload Java Classes without Restarting the Container
Many modern IDEs (Eclipse, IDEA, and others) support hot swapping of bytecode. Consequently, if
you make a change that does not affect class or method signatures, it should reload cleanly with no
side effects.
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87. Build
Spring Boot includes build plugins for Maven and Gradle. This section answers common questions
about these plugins.
87.1 Generate Build Information
Both the Maven plugin and the Gradle plugin allow generating build information containing the
coordinates, name, and version of the project. The plugins can also be configured to add additional
properties through configuration. When such a file is present, Spring Boot auto-configures a
BuildProperties bean.
To generate build information with Maven, add an execution for the build-info goal, as shown in
the following example:
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>2.0.4.RELEASE</version>
<executions>
<execution>
<goals>
<goal>build-info</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
Tip
See the Spring Boot Maven Plugin documentation for more details.
The following example does the same with Gradle:
springBoot {
buildInfo()
}
Tip
See the Spring Boot Gradle Plugin documentation for more details.
87.2 Generate Git Information
Both Maven and Gradle allow generating a git.properties file containing information about the state
of your git source code repository when the project was built.
For Maven users, the spring-boot-starter-parent POM includes a pre-configured plugin to
generate a git.properties file. To use it, add the following declaration to your POM:
<build>
<plugins>
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<plugin>
<groupId>pl.project13.maven</groupId>
<artifactId>git-commit-id-plugin</artifactId>
</plugin>
</plugins>
</build>
Gradle users can achieve the same result by using the gradle-git-properties plugin, as shown
in the following example:
plugins {
id "com.gorylenko.gradle-git-properties" version "1.5.1"
}
Tip
The commit time in git.properties is expected to match the following format: yyyy-MM-
dd’T’HH:mm:ssZ. This is the default format for both plugins listed above. Using this format lets
the time be parsed into a Date and its format, when serialized to JSON, to be controlled by
Jackson’s date serialization configuration settings.
87.3 Customize Dependency Versions
If you use a Maven build that inherits directly or indirectly from spring-boot-dependencies
(for instance, spring-boot-starter-parent) but you want to override a specific third-party
dependency, you can add appropriate <properties> elements. Browse the spring-boot-
dependencies POM for a complete list of properties. For example, to pick a different slf4j version,
you would add the following property:
<properties>
<slf4j.version>1.7.5<slf4j.version>
</properties>
Note
Doing so only works if your Maven project inherits (directly or indirectly) from spring-
boot-dependencies. If you have added spring-boot-dependencies in your own
dependencyManagement section with <scope>import</scope>, you have to redefine the
artifact yourself instead of overriding the property.
Warning
Each Spring Boot release is designed and tested against this specific set of third-party
dependencies. Overriding versions may cause compatibility issues.
To override dependency versions in Gradle, see this section of the Gradle plugin’s documentation.
87.4 Create an Executable JAR with Maven
The spring-boot-maven-plugin can be used to create an executable “fat” JAR. If you use the
spring-boot-starter-parent POM, you can declare the plugin and your jars are repackaged as
follows:
<build>
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<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
If you do not use the parent POM, you can still use the plugin. However, you must additionally add an
<executions> section, as follows:
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>2.0.4.RELEASE</version>
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
See the plugin documentation for full usage details.
87.5 Use a Spring Boot Application as a Dependency
Like a war file, a Spring Boot application is not intended to be used as a dependency. If your application
contains classes that you want to share with other projects, the recommended approach is to move that
code into a separate module. The separate module can then be depended upon by your application
and other projects.
If you cannot rearrange your code as recommended above, Spring Boot’s Maven and Gradle plugins
must be configured to produce a separate artifact that is suitable for use as a dependency. The
executable archive cannot be used as a dependency as the executable jar format packages application
classes in BOOT-INF/classes. This means that they cannot be found when the executable jar is used
as a dependency.
To produce the two artifacts, one that can be used as a dependency and one that is executable, a
classifier must be specified. This classifier is applied to the name of the executable archive, leaving the
default archive for use as a dependency.
To configure a classifier of exec in Maven, you can use the following configuration:
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<classifier>exec</classifier>
</configuration>
</plugin>
</plugins>
</build>
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87.6 Extract Specific Libraries When an Executable Jar Runs
Most nested libraries in an executable jar do not need to be unpacked in order to run. However, certain
libraries can have problems. For example, JRuby includes its own nested jar support, which assumes
that the jruby-complete.jar is always directly available as a file in its own right.
To deal with any problematic libraries, you can flag that specific nested jars should be automatically
unpacked to the “temp folder” when the executable jar first runs.
For example, to indicate that JRuby should be flagged for unpacking by using the Maven Plugin, you
would add the following configuration:
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<requiresUnpack>
<dependency>
<groupId>org.jruby</groupId>
<artifactId>jruby-complete</artifactId>
</dependency>
</requiresUnpack>
</configuration>
</plugin>
</plugins>
</build>
87.7 Create a Non-executable JAR with Exclusions
Often, if you have an executable and a non-executable jar as two separate build products, the
executable version has additional configuration files that are not needed in a library jar. For example,
the application.yml configuration file might by excluded from the non-executable JAR.
In Maven, the executable jar must be the main artifact and you can add a classified jar for the library,
as follows:
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<artifactId>maven-jar-plugin</artifactId>
<executions>
<execution>
<id>lib</id>
<phase>package</phase>
<goals>
<goal>jar</goal>
</goals>
<configuration>
<classifier>lib</classifier>
<excludes>
<exclude>application.yml</exclude>
</excludes>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
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87.8 Remote Debug a Spring Boot Application Started with
Maven
To attach a remote debugger to a Spring Boot application that was started with Maven, you can use the
jvmArguments property of the maven plugin.
See this example for more details.
87.9 Build an Executable Archive from Ant without Using
spring-boot-antlib
To build with Ant, you need to grab dependencies, compile, and then create a jar or war archive. To
make it executable, you can either use the spring-boot-antlib module or you can follow these
instructions:
1. If you are building a jar, package the application’s classes and resources in a nested BOOT-INF/
classes directory. If you are building a war, package the application’s classes in a nested WEB-
INF/classes directory as usual.
2. Add the runtime dependencies in a nested BOOT-INF/lib directory for a jar or WEB-INF/lib for
a war. Remember not to compress the entries in the archive.
3. Add the provided (embedded container) dependencies in a nested BOOT-INF/lib directory for a
jar or WEB-INF/lib-provided for a war. Remember not to compress the entries in the archive.
4. Add the spring-boot-loader classes at the root of the archive (so that the Main-Class is
available).
5. Use the appropriate launcher (such as JarLauncher for a jar file) as a Main-Class attribute in
the manifest and specify the other properties it needs as manifest entries — principally, by setting a
Start-Class property.
The following example shows how to build an executable archive with Ant:
<target name="build" depends="compile">
<jar destfile="target/${ant.project.name}-${spring-boot.version}.jar" compress="false">
<mappedresources>
<fileset dir="target/classes" />
<globmapper from="*" to="BOOT-INF/classes/*"/>
</mappedresources>
<mappedresources>
<fileset dir="src/main/resources" erroronmissingdir="false"/>
<globmapper from="*" to="BOOT-INF/classes/*"/>
</mappedresources>
<mappedresources>
<fileset dir="${lib.dir}/runtime" />
<globmapper from="*" to="BOOT-INF/lib/*"/>
</mappedresources>
<zipfileset src="${lib.dir}/loader/spring-boot-loader-jar-${spring-boot.version}.jar" />
<manifest>
<attribute name="Main-Class" value="org.springframework.boot.loader.JarLauncher" />
<attribute name="Start-Class" value="${start-class}" />
</manifest>
</jar>
</target>
The Ant Sample has a build.xml file with a manual task that should work if you run it with the following
command:
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$ ant -lib <folder containing ivy-2.2.jar> clean manual
Then you can run the application with the following command:
$ java -jar target/*.jar
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88. Traditional Deployment
Spring Boot supports traditional deployment as well as more modern forms of deployment. This section
answers common questions about traditional deployment.
88.1 Create a Deployable War File
Warning
Because Spring WebFlux does not strictly depend on the Servlet API and applications are
deployed by default on an embedded Reactor Netty server, War deployment is not supported for
WebFlux applications.
The first step in producing a deployable war file is to provide a SpringBootServletInitializer
subclass and override its configure method. Doing so makes use of Spring Framework’s Servlet 3.0
support and lets you configure your application when it is launched by the servlet container. Typically,
you should update your application’s main class to extend SpringBootServletInitializer, as
shown in the following example:
@SpringBootApplication
public class Application extends SpringBootServletInitializer {
@Override
protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
return application.sources(Application.class);
}
public static void main(String[] args) throws Exception {
SpringApplication.run(Application.class, args);
}
}
The next step is to update your build configuration such that your project produces a war file rather
than a jar file. If you use Maven and spring-boot-starter-parent (which configures Maven’s war
plugin for you), all you need to do is to modify pom.xml to change the packaging to war, as follows:
<packaging>war</packaging>
If you use Gradle, you need to modify build.gradle to apply the war plugin to the project, as follows:
apply plugin: 'war'
The final step in the process is to ensure that the embedded servlet container does not interfere with the
servlet container to which the war file is deployed. To do so, you need to mark the embedded servlet
container dependency as being provided.
If you use Maven, the following example marks the servlet container (Tomcat, in this case) as being
provided:
<dependencies>
<!-- … -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
<scope>provided</scope>
</dependency>
<!-- … -->
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</dependencies>
If you use Gradle, the following example marks the servlet container (Tomcat, in this case) as being
provided:
dependencies {
// …
providedRuntime 'org.springframework.boot:spring-boot-starter-tomcat'
// …
}
Tip
providedRuntime is preferred to Gradle’s compileOnly configuration. Among other
limitations, compileOnly dependencies are not on the test classpath, so any web-based
integration tests fail.
If you use the Spring Boot build tools, marking the embedded servlet container dependency as provided
produces an executable war file with the provided dependencies packaged in a lib-provided
directory. This means that, in addition to being deployable to a servlet container, you can also run your
application by using java -jar on the command line.
Tip
Take a look at Spring Boot’s sample applications for a Maven-based example of the previously
described configuration.
88.2 Convert an Existing Application to Spring Boot
For a non-web application, it should be easy to convert an existing Spring application to a Spring Boot
application. To do so, throw away the code that creates your ApplicationContext and replace it
with calls to SpringApplication or SpringApplicationBuilder. Spring MVC web applications
are generally amenable to first creating a deployable war application and then migrating it later to an
executable war or jar. See the Getting Started Guide on Converting a jar to a war.
To create a deployable war by extending SpringBootServletInitializer (for example, in a class
called Application) and adding the Spring Boot @SpringBootApplication annotation, use code
similar to that shown in the following example:
@SpringBootApplication
public class Application extends SpringBootServletInitializer {
@Override
protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
// Customize the application or call application.sources(...) to add sources
// Since our example is itself a @Configuration class (via @SpringBootApplication)
// we actually don't need to override this method.
return application;
}
}
Remember that, whatever you put in the sources is merely a Spring ApplicationContext.
Normally, anything that already works should work here. There might be some beans you can remove
later and let Spring Boot provide its own defaults for them, but it should be possible to get something
working before you need to do that.
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Static resources can be moved to /public (or /static or /resources or /META-INF/resources)
in the classpath root. The same applies to messages.properties (which Spring Boot automatically
detects in the root of the classpath).
Vanilla usage of Spring DispatcherServlet and Spring Security should require no further changes.
If you have other features in your application (for instance, using other servlets or filters), you may
need to add some configuration to your Application context, by replacing those elements from the
web.xml, as follows:
• A @Bean of type Servlet or ServletRegistrationBean installs that bean in the container as if
it were a <servlet/> and <servlet-mapping/> in web.xml.
• A @Bean of type Filter or FilterRegistrationBean behaves similarly (as a <filter/> and
<filter-mapping/>).
• An ApplicationContext in an XML file can be added through an @ImportResource in your
Application. Alternatively, simple cases where annotation configuration is heavily used already
can be recreated in a few lines as @Bean definitions.
Once the war file is working, you can make it executable by adding a main method to your
Application, as shown in the following example:
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
Note
If you intend to start your application as a war or as an executable application, you
need to share the customizations of the builder in a method that is both available to the
SpringBootServletInitializer callback and in the main method in a class similar to the
following:
@SpringBootApplication
public class Application extends SpringBootServletInitializer {
@Override
protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
return configureApplication(builder);
}
public static void main(String[] args) {
configureApplication(new SpringApplicationBuilder()).run(args);
}
private static SpringApplicationBuilder configureApplication(SpringApplicationBuilder builder) {
return builder.sources(Application.class).bannerMode(Banner.Mode.OFF);
}
}
Applications can fall into more than one category:
• Servlet 3.0+ applications with no web.xml.
• Applications with a web.xml.
• Applications with a context hierarchy.
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• Applications without a context hierarchy.
All of these should be amenable to translation, but each might require slightly different techniques.
Servlet 3.0+ applications might translate pretty easily if they already use the Spring Servlet 3.0+
initializer support classes. Normally, all the code from an existing WebApplicationInitializer
can be moved into a SpringBootServletInitializer. If your existing application has more than
one ApplicationContext (for example, if it uses AbstractDispatcherServletInitializer)
then you might be able to combine all your context sources into a single SpringApplication. The
main complication you might encounter is if combining does not work and you need to maintain the
context hierarchy. See the entry on building a hierarchy for examples. An existing parent context that
contains web-specific features usually needs to be broken up so that all the ServletContextAware
components are in the child context.
Applications that are not already Spring applications might be convertible to Spring Boot applications,
and the previously mentioned guidance may help. However, you may yet encounter problems. In that
case, we suggest asking questions on Stack Overflow with a tag of spring-boot.
88.3 Deploying a WAR to WebLogic
To deploy a Spring Boot application to WebLogic, you must ensure that your servlet initializer directly
implements WebApplicationInitializer (even if you extend from a base class that already
implements it).
A typical initializer for WebLogic should resemble the following example:
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;
import org.springframework.web.WebApplicationInitializer;
@SpringBootApplication
public class MyApplication extends SpringBootServletInitializer implements WebApplicationInitializer {
}
If you use Logback, you also need to tell WebLogic to prefer the packaged version rather than the
version that was pre-installed with the server. You can do so by adding a WEB-INF/weblogic.xml
file with the following contents:
<?xml version="1.0" encoding="UTF-8"?>
<wls:weblogic-web-app
xmlns:wls="http://xmlns.oracle.com/weblogic/weblogic-web-app"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/ejb-jar_3_0.xsd
http://xmlns.oracle.com/weblogic/weblogic-web-app
http://xmlns.oracle.com/weblogic/weblogic-web-app/1.4/weblogic-web-app.xsd">
<wls:container-descriptor>
<wls:prefer-application-packages>
<wls:package-name>org.slf4j</wls:package-name>
</wls:prefer-application-packages>
</wls:container-descriptor>
</wls:weblogic-web-app>
88.4 Use Jedis Instead of Lettuce
By default, the Spring Boot starter (spring-boot-starter-data-redis) uses Lettuce. You need to
exclude that dependency and include the Jedis one instead. Spring Boot manages these dependencies
to help make this process as easy as possible.
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The following example shows how to do so in Maven:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis</artifactId>
<exclusions>
<exclusion>
<groupId>io.lettuce</groupId>
<artifactId>lettuce-core</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>redis.clients</groupId>
<artifactId>jedis</artifactId>
</dependency>
The following example shows how to do so in Gradle:
configurations {
compile.exclude module: "lettuce"
}
dependencies {
compile("redis.clients:jedis")
// ...
}
Part X. Appendices
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Appendix A. Common application
properties
Various properties can be specified inside your application.properties file, inside your
application.yml file, or as command line switches. This appendix provides a list of common Spring
Boot properties and references to the underlying classes that consume them.
Note
Property contributions can come from additional jar files on your classpath, so you should not
consider this an exhaustive list. Also, you can define your own properties.
Warning
This sample file is meant as a guide only. Do not copy and paste the entire content into your
application. Rather, pick only the properties that you need.
# ===================================================================
# COMMON SPRING BOOT PROPERTIES
#
# This sample file is provided as a guideline. Do NOT copy it in its
# entirety to your own application. ^^^
# ===================================================================
# ----------------------------------------
# CORE PROPERTIES
# ----------------------------------------
debug=false # Enable debug logs.
trace=false # Enable trace logs.
# LOGGING
logging.config= # Location of the logging configuration file. For instance, `classpath:logback.xml` for
Logback.
logging.exception-conversion-word=%wEx # Conversion word used when logging exceptions.
logging.file= # Log file name (for instance, `myapp.log`). Names can be an exact location or relative to
the current directory.
logging.file.max-history=0 # Maximum of archive log files to keep. Only supported with the default
logback setup.
logging.file.max-size=10MB # Maximum log file size. Only supported with the default logback setup.
logging.level.*= # Log levels severity mapping. For instance, `logging.level.org.springframework=DEBUG`.
logging.path= # Location of the log file. For instance, `/var/log`.
logging.pattern.console= # Appender pattern for output to the console. Supported only with the default
Logback setup.
logging.pattern.dateformat=yyyy-MM-dd HH:mm:ss.SSS # Appender pattern for log date format. Supported
only with the default Logback setup.
logging.pattern.file= # Appender pattern for output to a file. Supported only with the default Logback
setup.
logging.pattern.level=%5p # Appender pattern for log level. Supported only with the default Logback
setup.
logging.register-shutdown-hook=false # Register a shutdown hook for the logging system when it is
initialized.
# AOP
spring.aop.auto=true # Add @EnableAspectJAutoProxy.
spring.aop.proxy-target-class=true # Whether subclass-based (CGLIB) proxies are to be created (true), as
opposed to standard Java interface-based proxies (false).
# IDENTITY (ContextIdApplicationContextInitializer)
spring.application.name= # Application name.
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# ADMIN (SpringApplicationAdminJmxAutoConfiguration)
spring.application.admin.enabled=false # Whether to enable admin features for the application.
spring.application.admin.jmx-name=org.springframework.boot:type=Admin,name=SpringApplication # JMX name
of the application admin MBean.
# AUTO-CONFIGURATION
spring.autoconfigure.exclude= # Auto-configuration classes to exclude.
# BANNER
spring.banner.charset=UTF-8 # Banner file encoding.
spring.banner.location=classpath:banner.txt # Banner text resource location.
spring.banner.image.location=classpath:banner.gif # Banner image file location (jpg or png can also be
used).
spring.banner.image.width=76 # Width of the banner image in chars.
spring.banner.image.height= # Height of the banner image in chars (default based on image height).
spring.banner.image.margin=2 # Left hand image margin in chars.
spring.banner.image.invert=false # Whether images should be inverted for dark terminal themes.
# SPRING CORE
spring.beaninfo.ignore=true # Whether to skip search of BeanInfo classes.
# SPRING CACHE (CacheProperties)
spring.cache.cache-names= # Comma-separated list of cache names to create if supported by the underlying
cache manager.
spring.cache.caffeine.spec= # The spec to use to create caches. See CaffeineSpec for more details on the
spec format.
spring.cache.couchbase.expiration=0ms # Entry expiration. By default the entries never expire. Note that
this value is ultimately converted to seconds.
spring.cache.ehcache.config= # The location of the configuration file to use to initialize EhCache.
spring.cache.infinispan.config= # The location of the configuration file to use to initialize
Infinispan.
spring.cache.jcache.config= # The location of the configuration file to use to initialize the cache
manager.
spring.cache.jcache.provider= # Fully qualified name of the CachingProvider implementation to use to
retrieve the JSR-107 compliant cache manager. Needed only if more than one JSR-107 implementation is
available on the classpath.
spring.cache.redis.cache-null-values=true # Allow caching null values.
spring.cache.redis.key-prefix= # Key prefix.
spring.cache.redis.time-to-live=0ms # Entry expiration. By default the entries never expire.
spring.cache.redis.use-key-prefix=true # Whether to use the key prefix when writing to Redis.
spring.cache.type= # Cache type. By default, auto-detected according to the environment.
# SPRING CONFIG - using environment property only (ConfigFileApplicationListener)
spring.config.additional-location= # Config file locations used in addition to the defaults.
spring.config.location= # Config file locations that replace the defaults.
spring.config.name=application # Config file name.
# HAZELCAST (HazelcastProperties)
spring.hazelcast.config= # The location of the configuration file to use to initialize Hazelcast.
# PROJECT INFORMATION (ProjectInfoProperties)
spring.info.build.location=classpath:META-INF/build-info.properties # Location of the generated build-
info.properties file.
spring.info.git.location=classpath:git.properties # Location of the generated git.properties file.
# JMX
spring.jmx.default-domain= # JMX domain name.
spring.jmx.enabled=true # Expose management beans to the JMX domain.
spring.jmx.server=mbeanServer # MBeanServer bean name.
# Email (MailProperties)
spring.mail.default-encoding=UTF-8 # Default MimeMessage encoding.
spring.mail.host= # SMTP server host. For instance, `smtp.example.com`.
spring.mail.jndi-name= # Session JNDI name. When set, takes precedence over other Session settings.
spring.mail.password= # Login password of the SMTP server.
spring.mail.port= # SMTP server port.
spring.mail.properties.*= # Additional JavaMail Session properties.
spring.mail.protocol=smtp # Protocol used by the SMTP server.
spring.mail.test-connection=false # Whether to test that the mail server is available on startup.
spring.mail.username= # Login user of the SMTP server.
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# APPLICATION SETTINGS (SpringApplication)
spring.main.banner-mode=console # Mode used to display the banner when the application runs.
spring.main.sources= # Sources (class names, package names, or XML resource locations) to include in the
ApplicationContext.
spring.main.web-application-type= # Flag to explicitly request a specific type of web application. If
not set, auto-detected based on the classpath.
# FILE ENCODING (FileEncodingApplicationListener)
spring.mandatory-file-encoding= # Expected character encoding the application must use.
# INTERNATIONALIZATION (MessageSourceProperties)
spring.messages.always-use-message-format=false # Whether to always apply the MessageFormat rules,
parsing even messages without arguments.
spring.messages.basename=messages # Comma-separated list of basenames (essentially a fully-qualified
classpath location), each following the ResourceBundle convention with relaxed support for slash based
locations.
spring.messages.cache-duration= # Loaded resource bundle files cache duration. When not set, bundles are
cached forever. If a duration suffix is not specified, seconds will be used.
spring.messages.encoding=UTF-8 # Message bundles encoding.
spring.messages.fallback-to-system-locale=true # Whether to fall back to the system Locale if no files
for a specific Locale have been found.
spring.messages.use-code-as-default-message=false # Whether to use the message code as the default
message instead of throwing a "NoSuchMessageException". Recommended during development only.
# OUTPUT
spring.output.ansi.enabled=detect # Configures the ANSI output.
# PID FILE (ApplicationPidFileWriter)
spring.pid.fail-on-write-error= # Fails if ApplicationPidFileWriter is used but it cannot write the PID
file.
spring.pid.file= # Location of the PID file to write (if ApplicationPidFileWriter is used).
# PROFILES
spring.profiles.active= # Comma-separated list of active profiles. Can be overridden by a command line
switch.
spring.profiles.include= # Unconditionally activate the specified comma-separated list of profiles (or
list of profiles if using YAML).
# QUARTZ SCHEDULER (QuartzProperties)
spring.quartz.jdbc.comment-prefix=-- # Prefix for single-line comments in SQL initialization scripts.
spring.quartz.jdbc.initialize-schema=embedded # Database schema initialization mode.
spring.quartz.jdbc.schema=classpath:org/quartz/impl/jdbcjobstore/tables_@@platform@@.sql # Path to the
SQL file to use to initialize the database schema.
spring.quartz.job-store-type=memory # Quartz job store type.
spring.quartz.properties.*= # Additional Quartz Scheduler properties.
# REACTOR (ReactorCoreProperties)
spring.reactor.stacktrace-mode.enabled=false # Whether Reactor should collect stacktrace information at
runtime.
# SENDGRID (SendGridAutoConfiguration)
spring.sendgrid.api-key= # SendGrid API key.
spring.sendgrid.proxy.host= # SendGrid proxy host.
spring.sendgrid.proxy.port= # SendGrid proxy port.
# ----------------------------------------
# WEB PROPERTIES
# ----------------------------------------
# EMBEDDED SERVER CONFIGURATION (ServerProperties)
server.address= # Network address to which the server should bind.
server.compression.enabled=false # Whether response compression is enabled.
server.compression.excluded-user-agents= # List of user-agents to exclude from compression.
server.compression.mime-types=text/html,text/xml,text/plain,text/css,text/javascript,application/
javascript # Comma-separated list of MIME types that should be compressed.
server.compression.min-response-size=2048 # Minimum "Content-Length" value that is required for
compression to be performed.
server.connection-timeout= # Time that connectors wait for another HTTP request before closing the
connection. When not set, the connector's container-specific default is used. Use a value of -1 to
indicate no (that is, an infinite) timeout.
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server.error.include-exception=false # Include the "exception" attribute.
server.error.include-stacktrace=never # When to include a "stacktrace" attribute.
server.error.path=/error # Path of the error controller.
server.error.whitelabel.enabled=true # Whether to enable the default error page displayed in browsers in
case of a server error.
server.http2.enabled=false # Whether to enable HTTP/2 support, if the current environment supports it.
server.jetty.acceptors= # Number of acceptor threads to use.
server.jetty.accesslog.append=false # Append to log.
server.jetty.accesslog.date-format=dd/MMM/yyyy:HH:mm:ss Z # Timestamp format of the request log.
server.jetty.accesslog.enabled=false # Enable access log.
server.jetty.accesslog.extended-format=false # Enable extended NCSA format.
server.jetty.accesslog.file-date-format= # Date format to place in log file name.
server.jetty.accesslog.filename= # Log filename. If not specified, logs redirect to "System.err".
server.jetty.accesslog.locale= # Locale of the request log.
server.jetty.accesslog.log-cookies=false # Enable logging of the request cookies.
server.jetty.accesslog.log-latency=false # Enable logging of request processing time.
server.jetty.accesslog.log-server=false # Enable logging of the request hostname.
server.jetty.accesslog.retention-period=31 # Number of days before rotated log files are deleted.
server.jetty.accesslog.time-zone=GMT # Timezone of the request log.
server.jetty.max-http-post-size=0 # Maximum size, in bytes, of the HTTP post or put content.
server.jetty.selectors= # Number of selector threads to use.
server.max-http-header-size=0 # Maximum size, in bytes, of the HTTP message header.
server.port=8080 # Server HTTP port.
server.server-header= # Value to use for the Server response header (if empty, no header is sent).
server.use-forward-headers= # Whether X-Forwarded-* headers should be applied to the HttpRequest.
server.servlet.context-parameters.*= # Servlet context init parameters.
server.servlet.context-path= # Context path of the application.
server.servlet.application-display-name=application # Display name of the application.
server.servlet.jsp.class-name=org.apache.jasper.servlet.JspServlet # The class name of the JSP servlet.
server.servlet.jsp.init-parameters.*= # Init parameters used to configure the JSP servlet.
server.servlet.jsp.registered=true # Whether the JSP servlet is registered.
server.servlet.path=/ # Path of the main dispatcher servlet.
server.servlet.session.cookie.comment= # Comment for the session cookie.
server.servlet.session.cookie.domain= # Domain for the session cookie.
server.servlet.session.cookie.http-only= # "HttpOnly" flag for the session cookie.
server.servlet.session.cookie.max-age= # Maximum age of the session cookie. If a duration suffix is not
specified, seconds will be used.
server.servlet.session.cookie.name= # Session cookie name.
server.servlet.session.cookie.path= # Path of the session cookie.
server.servlet.session.cookie.secure= # "Secure" flag for the session cookie.
server.servlet.session.persistent=false # Whether to persist session data between restarts.
server.servlet.session.store-dir= # Directory used to store session data.
server.servlet.session.timeout= # Session timeout. If a duration suffix is not specified, seconds will
be used.
server.servlet.session.tracking-modes= # Session tracking modes (one or more of the following: "cookie",
"url", "ssl").
server.ssl.ciphers= # Supported SSL ciphers.
server.ssl.client-auth= # Whether client authentication is wanted ("want") or needed ("need"). Requires
a trust store.
server.ssl.enabled= # Enable SSL support.
server.ssl.enabled-protocols= # Enabled SSL protocols.
server.ssl.key-alias= # Alias that identifies the key in the key store.
server.ssl.key-password= # Password used to access the key in the key store.
server.ssl.key-store= # Path to the key store that holds the SSL certificate (typically a jks file).
server.ssl.key-store-password= # Password used to access the key store.
server.ssl.key-store-provider= # Provider for the key store.
server.ssl.key-store-type= # Type of the key store.
server.ssl.protocol=TLS # SSL protocol to use.
server.ssl.trust-store= # Trust store that holds SSL certificates.
server.ssl.trust-store-password= # Password used to access the trust store.
server.ssl.trust-store-provider= # Provider for the trust store.
server.ssl.trust-store-type= # Type of the trust store.
server.tomcat.accept-count=0 # Maximum queue length for incoming connection requests when all possible
request processing threads are in use.
server.tomcat.accesslog.buffered=true # Whether to buffer output such that it is flushed only
periodically.
server.tomcat.accesslog.directory=logs # Directory in which log files are created. Can be absolute or
relative to the Tomcat base dir.
server.tomcat.accesslog.enabled=false # Enable access log.
server.tomcat.accesslog.file-date-format=.yyyy-MM-dd # Date format to place in the log file name.
server.tomcat.accesslog.pattern=common # Format pattern for access logs.
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server.tomcat.accesslog.prefix=access_log # Log file name prefix.
server.tomcat.accesslog.rename-on-rotate=false # Whether to defer inclusion of the date stamp in the
file name until rotate time.
server.tomcat.accesslog.request-attributes-enabled=false # Set request attributes for the IP address,
Hostname, protocol, and port used for the request.
server.tomcat.accesslog.rotate=true # Whether to enable access log rotation.
server.tomcat.accesslog.suffix=.log # Log file name suffix.
server.tomcat.additional-tld-skip-patterns= # Comma-separated list of additional patterns that match
jars to ignore for TLD scanning.
server.tomcat.background-processor-delay=30s # Delay between the invocation of backgroundProcess
methods. If a duration suffix is not specified, seconds will be used.
server.tomcat.basedir= # Tomcat base directory. If not specified, a temporary directory is used.
server.tomcat.internal-proxies=10\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}|\\
192\\.168\\.\\d{1,3}\\.\\d{1,3}|\\
169\\.254\\.\\d{1,3}\\.\\d{1,3}|\\
127\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}|\\
172\\.1[6-9]{1}\\.\\d{1,3}\\.\\d{1,3}|\\
172\\.2[0-9]{1}\\.\\d{1,3}\\.\\d{1,3}|\\
172\\.3[0-1]{1}\\.\\d{1,3}\\.\\d{1,3} # Regular expression matching trusted IP addresses.
server.tomcat.max-connections=0 # Maximum number of connections that the server accepts and processes at
any given time.
server.tomcat.max-http-header-size=0 # Maximum size, in bytes, of the HTTP message header.
server.tomcat.max-http-post-size=0 # Maximum size, in bytes, of the HTTP post content.
server.tomcat.max-threads=0 # Maximum number of worker threads.
server.tomcat.min-spare-threads=0 # Minimum number of worker threads.
server.tomcat.port-header=X-Forwarded-Port # Name of the HTTP header used to override the original port
value.
server.tomcat.protocol-header= # Header that holds the incoming protocol, usually named "X-Forwarded-
Proto".
server.tomcat.protocol-header-https-value=https # Value of the protocol header indicating whether the
incoming request uses SSL.
server.tomcat.redirect-context-root= # Whether requests to the context root should be redirected by
appending a / to the path.
server.tomcat.remote-ip-header= # Name of the HTTP header from which the remote IP is extracted. For
instance, `X-FORWARDED-FOR`.
server.tomcat.resource.cache-ttl= # Time-to-live of the static resource cache.
server.tomcat.uri-encoding=UTF-8 # Character encoding to use to decode the URI.
server.tomcat.use-relative-redirects= # Whether HTTP 1.1 and later location headers generated by a call
to sendRedirect will use relative or absolute redirects.
server.undertow.accesslog.dir= # Undertow access log directory.
server.undertow.accesslog.enabled=false # Whether to enable the access log.
server.undertow.accesslog.pattern=common # Format pattern for access logs.
server.undertow.accesslog.prefix=access_log. # Log file name prefix.
server.undertow.accesslog.rotate=true # Whether to enable access log rotation.
server.undertow.accesslog.suffix=log # Log file name suffix.
server.undertow.buffer-size= # Size of each buffer, in bytes.
server.undertow.direct-buffers= # Whether to allocate buffers outside the Java heap.
server.undertow.io-threads= # Number of I/O threads to create for the worker.
server.undertow.eager-filter-init=true # Whether servlet filters should be initialized on startup.
server.undertow.max-http-post-size=0 # Maximum size, in bytes, of the HTTP post content.
server.undertow.worker-threads= # Number of worker threads.
# FREEMARKER (FreeMarkerProperties)
spring.freemarker.allow-request-override=false # Whether HttpServletRequest attributes are allowed to
override (hide) controller generated model attributes of the same name.
spring.freemarker.allow-session-override=false # Whether HttpSession attributes are allowed to override
(hide) controller generated model attributes of the same name.
spring.freemarker.cache=false # Whether to enable template caching.
spring.freemarker.charset=UTF-8 # Template encoding.
spring.freemarker.check-template-location=true # Whether to check that the templates location exists.
spring.freemarker.content-type=text/html # Content-Type value.
spring.freemarker.enabled=true # Whether to enable MVC view resolution for this technology.
spring.freemarker.expose-request-attributes=false # Whether all request attributes should be added to
the model prior to merging with the template.
spring.freemarker.expose-session-attributes=false # Whether all HttpSession attributes should be added
to the model prior to merging with the template.
spring.freemarker.expose-spring-macro-helpers=true # Whether to expose a RequestContext for use by
Spring's macro library, under the name "springMacroRequestContext".
spring.freemarker.prefer-file-system-access=true # Whether to prefer file system access for template
loading. File system access enables hot detection of template changes.
spring.freemarker.prefix= # Prefix that gets prepended to view names when building a URL.
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spring.freemarker.request-context-attribute= # Name of the RequestContext attribute for all views.
spring.freemarker.settings.*= # Well-known FreeMarker keys which are passed to FreeMarker's
Configuration.
spring.freemarker.suffix=.ftl # Suffix that gets appended to view names when building a URL.
spring.freemarker.template-loader-path=classpath:/templates/ # Comma-separated list of template paths.
spring.freemarker.view-names= # White list of view names that can be resolved.
# GROOVY TEMPLATES (GroovyTemplateProperties)
spring.groovy.template.allow-request-override=false # Whether HttpServletRequest attributes are allowed
to override (hide) controller generated model attributes of the same name.
spring.groovy.template.allow-session-override=false # Whether HttpSession attributes are allowed to
override (hide) controller generated model attributes of the same name.
spring.groovy.template.cache=false # Whether to enable template caching.
spring.groovy.template.charset=UTF-8 # Template encoding.
spring.groovy.template.check-template-location=true # Whether to check that the templates location
exists.
spring.groovy.template.configuration.*= # See GroovyMarkupConfigurer
spring.groovy.template.content-type=text/html # Content-Type value.
spring.groovy.template.enabled=true # Whether to enable MVC view resolution for this technology.
spring.groovy.template.expose-request-attributes=false # Whether all request attributes should be added
to the model prior to merging with the template.
spring.groovy.template.expose-session-attributes=false # Whether all HttpSession attributes should be
added to the model prior to merging with the template.
spring.groovy.template.expose-spring-macro-helpers=true # Whether to expose a RequestContext for use by
Spring's macro library, under the name "springMacroRequestContext".
spring.groovy.template.prefix= # Prefix that gets prepended to view names when building a URL.
spring.groovy.template.request-context-attribute= # Name of the RequestContext attribute for all views.
spring.groovy.template.resource-loader-path=classpath:/templates/ # Template path.
spring.groovy.template.suffix=.tpl # Suffix that gets appended to view names when building a URL.
spring.groovy.template.view-names= # White list of view names that can be resolved.
# SPRING HATEOAS (HateoasProperties)
spring.hateoas.use-hal-as-default-json-media-type=true # Whether application/hal+json responses should
be sent to requests that accept application/json.
# HTTP message conversion
spring.http.converters.preferred-json-mapper= # Preferred JSON mapper to use for HTTP message
conversion. By default, auto-detected according to the environment.
# HTTP encoding (HttpEncodingProperties)
spring.http.encoding.charset=UTF-8 # Charset of HTTP requests and responses. Added to the "Content-Type"
header if not set explicitly.
spring.http.encoding.enabled=true # Whether to enable http encoding support.
spring.http.encoding.force= # Whether to force the encoding to the configured charset on HTTP requests
and responses.
spring.http.encoding.force-request= # Whether to force the encoding to the configured charset on HTTP
requests. Defaults to true when "force" has not been specified.
spring.http.encoding.force-response= # Whether to force the encoding to the configured charset on HTTP
responses.
spring.http.encoding.mapping= # Locale in which to encode mapping.
# MULTIPART (MultipartProperties)
spring.servlet.multipart.enabled=true # Whether to enable support of multipart uploads.
spring.servlet.multipart.file-size-threshold=0 # Threshold after which files are written to disk. Values
can use the suffixes "MB" or "KB" to indicate megabytes or kilobytes, respectively.
spring.servlet.multipart.location= # Intermediate location of uploaded files.
spring.servlet.multipart.max-file-size=1MB # Max file size. Values can use the suffixes "MB" or "KB" to
indicate megabytes or kilobytes, respectively.
spring.servlet.multipart.max-request-size=10MB # Max request size. Values can use the suffixes "MB" or
"KB" to indicate megabytes or kilobytes, respectively.
spring.servlet.multipart.resolve-lazily=false # Whether to resolve the multipart request lazily at the
time of file or parameter access.
# JACKSON (JacksonProperties)
spring.jackson.date-format= # Date format string or a fully-qualified date format class name. For
instance, `yyyy-MM-dd HH:mm:ss`.
spring.jackson.default-property-inclusion= # Controls the inclusion of properties during serialization.
Configured with one of the values in Jackson's JsonInclude.Include enumeration.
spring.jackson.deserialization.*= # Jackson on/off features that affect the way Java objects are
deserialized.
spring.jackson.generator.*= # Jackson on/off features for generators.
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spring.jackson.joda-date-time-format= # Joda date time format string. If not configured, "date-format"
is used as a fallback if it is configured with a format string.
spring.jackson.locale= # Locale used for formatting.
spring.jackson.mapper.*= # Jackson general purpose on/off features.
spring.jackson.parser.*= # Jackson on/off features for parsers.
spring.jackson.property-naming-strategy= # One of the constants on Jackson's PropertyNamingStrategy. Can
also be a fully-qualified class name of a PropertyNamingStrategy subclass.
spring.jackson.serialization.*= # Jackson on/off features that affect the way Java objects are
serialized.
spring.jackson.time-zone= # Time zone used when formatting dates. For instance, "America/Los_Angeles"
or "GMT+10".
# GSON (GsonProperties)
spring.gson.date-format= # Format to use when serializing Date objects.
spring.gson.disable-html-escaping= # Whether to disable the escaping of HTML characters such as '<',
'>', etc.
spring.gson.disable-inner-class-serialization= # Whether to exclude inner classes during serialization.
spring.gson.enable-complex-map-key-serialization= # Whether to enable serialization of complex map keys
(i.e. non-primitives).
spring.gson.exclude-fields-without-expose-annotation= # Whether to exclude all fields from consideration
for serialization or deserialization that do not have the "Expose" annotation.
spring.gson.field-naming-policy= # Naming policy that should be applied to an object's field during
serialization and deserialization.
spring.gson.generate-non-executable-json= # Whether to generate non executable JSON by prefixing the
output with some special text.
spring.gson.lenient= # Whether to be lenient about parsing JSON that doesn't conform to RFC 4627.
spring.gson.long-serialization-policy= # Serialization policy for Long and long types.
spring.gson.pretty-printing= # Whether to output serialized JSON that fits in a page for pretty
printing.
spring.gson.serialize-nulls= # Whether to serialize null fields.
# JERSEY (JerseyProperties)
spring.jersey.application-path= # Path that serves as the base URI for the application. If specified,
overrides the value of "@ApplicationPath".
spring.jersey.filter.order=0 # Jersey filter chain order.
spring.jersey.init.*= # Init parameters to pass to Jersey through the servlet or filter.
spring.jersey.servlet.load-on-startup=-1 # Load on startup priority of the Jersey servlet.
spring.jersey.type=servlet # Jersey integration type.
# SPRING LDAP (LdapProperties)
spring.ldap.anonymous-read-only=false # Whether read-only operations should use an anonymous
environment.
spring.ldap.base= # Base suffix from which all operations should originate.
spring.ldap.base-environment.*= # LDAP specification settings.
spring.ldap.password= # Login password of the server.
spring.ldap.urls= # LDAP URLs of the server.
spring.ldap.username= # Login username of the server.
# EMBEDDED LDAP (EmbeddedLdapProperties)
spring.ldap.embedded.base-dn= # List of base DNs.
spring.ldap.embedded.credential.username= # Embedded LDAP username.
spring.ldap.embedded.credential.password= # Embedded LDAP password.
spring.ldap.embedded.ldif=classpath:schema.ldif # Schema (LDIF) script resource reference.
spring.ldap.embedded.port=0 # Embedded LDAP port.
spring.ldap.embedded.validation.enabled=true # Whether to enable LDAP schema validation.
spring.ldap.embedded.validation.schema= # Path to the custom schema.
# MUSTACHE TEMPLATES (MustacheAutoConfiguration)
spring.mustache.allow-request-override=false # Whether HttpServletRequest attributes are allowed to
override (hide) controller generated model attributes of the same name.
spring.mustache.allow-session-override=false # Whether HttpSession attributes are allowed to override
(hide) controller generated model attributes of the same name.
spring.mustache.cache=false # Whether to enable template caching.
spring.mustache.charset=UTF-8 # Template encoding.
spring.mustache.check-template-location=true # Whether to check that the templates location exists.
spring.mustache.content-type=text/html # Content-Type value.
spring.mustache.enabled=true # Whether to enable MVC view resolution for this technology.
spring.mustache.expose-request-attributes=false # Whether all request attributes should be added to the
model prior to merging with the template.
spring.mustache.expose-session-attributes=false # Whether all HttpSession attributes should be added to
the model prior to merging with the template.
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spring.mustache.expose-spring-macro-helpers=true # Whether to expose a RequestContext for use by
Spring's macro library, under the name "springMacroRequestContext".
spring.mustache.prefix=classpath:/templates/ # Prefix to apply to template names.
spring.mustache.request-context-attribute= # Name of the RequestContext attribute for all views.
spring.mustache.suffix=.mustache # Suffix to apply to template names.
spring.mustache.view-names= # White list of view names that can be resolved.
# SPRING MVC (WebMvcProperties)
spring.mvc.async.request-timeout= # Amount of time before asynchronous request handling times out.
spring.mvc.contentnegotiation.favor-parameter=false # Whether a request parameter ("format" by default)
should be used to determine the requested media type.
spring.mvc.contentnegotiation.favor-path-extension=false # Whether the path extension in the URL path
should be used to determine the requested media type.
spring.mvc.contentnegotiation.media-types.*= # Map file extensions to media types for content
negotiation. For instance, yml to text/yaml.
spring.mvc.contentnegotiation.parameter-name= # Query parameter name to use when "favor-parameter" is
enabled.
spring.mvc.date-format= # Date format to use. For instance, `dd/MM/yyyy`.
spring.mvc.dispatch-trace-request=false # Whether to dispatch TRACE requests to the FrameworkServlet
doService method.
spring.mvc.dispatch-options-request=true # Whether to dispatch OPTIONS requests to the FrameworkServlet
doService method.
spring.mvc.favicon.enabled=true # Whether to enable resolution of favicon.ico.
spring.mvc.formcontent.putfilter.enabled=true # Whether to enable Spring's HttpPutFormContentFilter.
spring.mvc.ignore-default-model-on-redirect=true # Whether the content of the "default" model should be
ignored during redirect scenarios.
spring.mvc.locale= # Locale to use. By default, this locale is overridden by the "Accept-Language"
header.
spring.mvc.locale-resolver=accept-header # Define how the locale should be resolved.
spring.mvc.log-resolved-exception=false # Whether to enable warn logging of exceptions resolved by a
"HandlerExceptionResolver".
spring.mvc.message-codes-resolver-format= # Formatting strategy for message codes. For instance,
`PREFIX_ERROR_CODE`.
spring.mvc.pathmatch.use-registered-suffix-pattern=false # Whether suffix pattern matching should work
only against extensions registered with "spring.mvc.contentnegotiation.media-types.*".
spring.mvc.pathmatch.use-suffix-pattern=false # Whether to use suffix pattern match (".*") when matching
patterns to requests.
spring.mvc.servlet.load-on-startup=-1 # Load on startup priority of the dispatcher servlet.
spring.mvc.static-path-pattern=/** # Path pattern used for static resources.
spring.mvc.throw-exception-if-no-handler-found=false # Whether a "NoHandlerFoundException" should be
thrown if no Handler was found to process a request.
spring.mvc.view.prefix= # Spring MVC view prefix.
spring.mvc.view.suffix= # Spring MVC view suffix.
# SPRING RESOURCES HANDLING (ResourceProperties)
spring.resources.add-mappings=true # Whether to enable default resource handling.
spring.resources.cache.cachecontrol.cache-private= # Indicate that the response message is intended for
a single user and must not be stored by a shared cache.
spring.resources.cache.cachecontrol.cache-public= # Indicate that any cache may store the response.
spring.resources.cache.cachecontrol.max-age= # Maximum time the response should be cached, in seconds if
no duration suffix is not specified.
spring.resources.cache.cachecontrol.must-revalidate= # Indicate that once it has become stale, a cache
must not use the response without re-validating it with the server.
spring.resources.cache.cachecontrol.no-cache= # Indicate that the cached response can be reused only if
re-validated with the server.
spring.resources.cache.cachecontrol.no-store= # Indicate to not cache the response in any case.
spring.resources.cache.cachecontrol.no-transform= # Indicate intermediaries (caches and others) that
they should not transform the response content.
spring.resources.cache.cachecontrol.proxy-revalidate= # Same meaning as the "must-revalidate" directive,
except that it does not apply to private caches.
spring.resources.cache.cachecontrol.s-max-age= # Maximum time the response should be cached by shared
caches, in seconds if no duration suffix is not specified.
spring.resources.cache.cachecontrol.stale-if-error= # Maximum time the response may be used when errors
are encountered, in seconds if no duration suffix is not specified.
spring.resources.cache.cachecontrol.stale-while-revalidate= # Maximum time the response can be served
after it becomes stale, in seconds if no duration suffix is not specified.
spring.resources.cache.period= # Cache period for the resources served by the resource handler. If a
duration suffix is not specified, seconds will be used.
spring.resources.chain.cache=true # Whether to enable caching in the Resource chain.
spring.resources.chain.enabled= # Whether to enable the Spring Resource Handling chain. By default,
disabled unless at least one strategy has been enabled.
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spring.resources.chain.gzipped=false # Whether to enable resolution of already gzipped resources.
spring.resources.chain.html-application-cache=false # Whether to enable HTML5 application cache manifest
rewriting.
spring.resources.chain.strategy.content.enabled=false # Whether to enable the content Version Strategy.
spring.resources.chain.strategy.content.paths=/** # Comma-separated list of patterns to apply to the
content Version Strategy.
spring.resources.chain.strategy.fixed.enabled=false # Whether to enable the fixed Version Strategy.
spring.resources.chain.strategy.fixed.paths=/** # Comma-separated list of patterns to apply to the fixed
Version Strategy.
spring.resources.chain.strategy.fixed.version= # Version string to use for the fixed Version Strategy.
spring.resources.static-locations=classpath:/META-INF/resources/,classpath:/resources/,classpath:/
static/,classpath:/public/ # Locations of static resources.
# SPRING SESSION (SessionProperties)
spring.session.store-type= # Session store type.
spring.session.timeout= # Session timeout. If a duration suffix is not specified, seconds will be used.
spring.session.servlet.filter-order=-2147483598 # Session repository filter order.
spring.session.servlet.filter-dispatcher-types=async,error,request # Session repository filter
dispatcher types.
# SPRING SESSION HAZELCAST (HazelcastSessionProperties)
spring.session.hazelcast.flush-mode=on-save # Sessions flush mode.
spring.session.hazelcast.map-name=spring:session:sessions # Name of the map used to store sessions.
# SPRING SESSION JDBC (JdbcSessionProperties)
spring.session.jdbc.cleanup-cron=0 * * * * * # Cron expression for expired session cleanup job.
spring.session.jdbc.initialize-schema=embedded # Database schema initialization mode.
spring.session.jdbc.schema=classpath:org/springframework/session/jdbc/schema-@@platform@@.sql # Path to
the SQL file to use to initialize the database schema.
spring.session.jdbc.table-name=SPRING_SESSION # Name of the database table used to store sessions.
# SPRING SESSION MONGODB (MongoSessionProperties)
spring.session.mongodb.collection-name=sessions # Collection name used to store sessions.
# SPRING SESSION REDIS (RedisSessionProperties)
spring.session.redis.cleanup-cron=0 * * * * * # Cron expression for expired session cleanup job.
spring.session.redis.flush-mode=on-save # Sessions flush mode.
spring.session.redis.namespace=spring:session # Namespace for keys used to store sessions.
# THYMELEAF (ThymeleafAutoConfiguration)
spring.thymeleaf.cache=true # Whether to enable template caching.
spring.thymeleaf.check-template=true # Whether to check that the template exists before rendering it.
spring.thymeleaf.check-template-location=true # Whether to check that the templates location exists.
spring.thymeleaf.enabled=true # Whether to enable Thymeleaf view resolution for Web frameworks.
spring.thymeleaf.enable-spring-el-compiler=false # Enable the SpringEL compiler in SpringEL expressions.
spring.thymeleaf.encoding=UTF-8 # Template files encoding.
spring.thymeleaf.excluded-view-names= # Comma-separated list of view names (patterns allowed) that
should be excluded from resolution.
spring.thymeleaf.mode=HTML # Template mode to be applied to templates. See also Thymeleaf's TemplateMode
enum.
spring.thymeleaf.prefix=classpath:/templates/ # Prefix that gets prepended to view names when building a
URL.
spring.thymeleaf.reactive.chunked-mode-view-names= # Comma-separated list of view names (patterns
allowed) that should be the only ones executed in CHUNKED mode when a max chunk size is set.
spring.thymeleaf.reactive.full-mode-view-names= # Comma-separated list of view names (patterns allowed)
that should be executed in FULL mode even if a max chunk size is set.
spring.thymeleaf.reactive.max-chunk-size=0 # Maximum size of data buffers used for writing to the
response, in bytes.
spring.thymeleaf.reactive.media-types= # Media types supported by the view technology.
spring.thymeleaf.servlet.content-type=text/html # Content-Type value written to HTTP responses.
spring.thymeleaf.suffix=.html # Suffix that gets appended to view names when building a URL.
spring.thymeleaf.template-resolver-order= # Order of the template resolver in the chain.
spring.thymeleaf.view-names= # Comma-separated list of view names (patterns allowed) that can be
resolved.
# SPRING WEBFLUX (WebFluxProperties)
spring.webflux.date-format= # Date format to use. For instance, `dd/MM/yyyy`.
spring.webflux.static-path-pattern=/** # Path pattern used for static resources.
# SPRING WEB SERVICES (WebServicesProperties)
spring.webservices.path=/services # Path that serves as the base URI for the services.
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spring.webservices.servlet.init= # Servlet init parameters to pass to Spring Web Services.
spring.webservices.servlet.load-on-startup=-1 # Load on startup priority of the Spring Web Services
servlet.
spring.webservices.wsdl-locations= # Comma-separated list of locations of WSDLs and accompanying XSDs to
be exposed as beans.
# ----------------------------------------
# SECURITY PROPERTIES
# ----------------------------------------
# SECURITY (SecurityProperties)
spring.security.filter.order=-100 # Security filter chain order.
spring.security.filter.dispatcher-types=async,error,request # Security filter chain dispatcher types.
spring.security.user.name=user # Default user name.
spring.security.user.password= # Password for the default user name.
spring.security.user.roles= # Granted roles for the default user name.
# SECURITY OAUTH2 CLIENT (OAuth2ClientProperties)
spring.security.oauth2.client.provider.*= # OAuth provider details.
spring.security.oauth2.client.registration.*= # OAuth client registrations.
# ----------------------------------------
# DATA PROPERTIES
# ----------------------------------------
# FLYWAY (FlywayProperties)
spring.flyway.baseline-description= #
spring.flyway.baseline-on-migrate= #
spring.flyway.baseline-version=1 # Version to start migration
spring.flyway.check-location=true # Whether to check that migration scripts location exists.
spring.flyway.clean-disabled= #
spring.flyway.clean-on-validation-error= #
spring.flyway.dry-run-output= #
spring.flyway.enabled=true # Whether to enable flyway.
spring.flyway.encoding= #
spring.flyway.error-handlers= #
spring.flyway.group= #
spring.flyway.ignore-future-migrations= #
spring.flyway.ignore-missing-migrations= #
spring.flyway.init-sqls= # SQL statements to execute to initialize a connection immediately after
obtaining it.
spring.flyway.installed-by= #
spring.flyway.locations=classpath:db/migration # The locations of migrations scripts.
spring.flyway.mixed= #
spring.flyway.out-of-order= #
spring.flyway.password= # JDBC password to use if you want Flyway to create its own DataSource.
spring.flyway.placeholder-prefix= #
spring.flyway.placeholder-replacement= #
spring.flyway.placeholder-suffix= #
spring.flyway.placeholders.*= #
spring.flyway.repeatable-sql-migration-prefix= #
spring.flyway.schemas= # schemas to update
spring.flyway.skip-default-callbacks= #
spring.flyway.skip-default-resolvers= #
spring.flyway.sql-migration-prefix=V #
spring.flyway.sql-migration-separator= #
spring.flyway.sql-migration-suffix=.sql #
spring.flyway.sql-migration-suffixes= #
spring.flyway.table= #
spring.flyway.target= #
spring.flyway.undo-sql-migration-prefix= #
spring.flyway.url= # JDBC url of the database to migrate. If not set, the primary configured data source
is used.
spring.flyway.user= # Login user of the database to migrate.
spring.flyway.validate-on-migrate= #
# LIQUIBASE (LiquibaseProperties)
spring.liquibase.change-log=classpath:/db/changelog/db.changelog-master.yaml # Change log configuration
path.
spring.liquibase.check-change-log-location=true # Whether to check that the change log location exists.
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spring.liquibase.contexts= # Comma-separated list of runtime contexts to use.
spring.liquibase.default-schema= # Default database schema.
spring.liquibase.drop-first=false # Whether to first drop the database schema.
spring.liquibase.enabled=true # Whether to enable Liquibase support.
spring.liquibase.labels= # Comma-separated list of runtime labels to use.
spring.liquibase.parameters.*= # Change log parameters.
spring.liquibase.password= # Login password of the database to migrate.
spring.liquibase.rollback-file= # File to which rollback SQL is written when an update is performed.
spring.liquibase.url= # JDBC URL of the database to migrate. If not set, the primary configured data
source is used.
spring.liquibase.user= # Login user of the database to migrate.
# COUCHBASE (CouchbaseProperties)
spring.couchbase.bootstrap-hosts= # Couchbase nodes (host or IP address) to bootstrap from.
spring.couchbase.bucket.name=default # Name of the bucket to connect to.
spring.couchbase.bucket.password= # Password of the bucket.
spring.couchbase.env.endpoints.key-value=1 # Number of sockets per node against the key/value service.
spring.couchbase.env.endpoints.queryservice.min-endpoints=1 # Minimum number of sockets per node.
spring.couchbase.env.endpoints.queryservice.max-endpoints=1 # Maximum number of sockets per node.
spring.couchbase.env.endpoints.viewservice.min-endpoints=1 # Minimum number of sockets per node.
spring.couchbase.env.endpoints.viewservice.max-endpoints=1 # Maximum number of sockets per node.
spring.couchbase.env.ssl.enabled= # Whether to enable SSL support. Enabled automatically if a "keyStore"
is provided unless specified otherwise.
spring.couchbase.env.ssl.key-store= # Path to the JVM key store that holds the certificates.
spring.couchbase.env.ssl.key-store-password= # Password used to access the key store.
spring.couchbase.env.timeouts.connect=5000ms # Bucket connections timeouts.
spring.couchbase.env.timeouts.key-value=2500ms # Blocking operations performed on a specific key
timeout.
spring.couchbase.env.timeouts.query=7500ms # N1QL query operations timeout.
spring.couchbase.env.timeouts.socket-connect=1000ms # Socket connect connections timeout.
spring.couchbase.env.timeouts.view=7500ms # Regular and geospatial view operations timeout.
# DAO (PersistenceExceptionTranslationAutoConfiguration)
spring.dao.exceptiontranslation.enabled=true # Whether to enable the
PersistenceExceptionTranslationPostProcessor.
# CASSANDRA (CassandraProperties)
spring.data.cassandra.cluster-name= # Name of the Cassandra cluster.
spring.data.cassandra.compression=none # Compression supported by the Cassandra binary protocol.
spring.data.cassandra.connect-timeout= # Socket option: connection time out.
spring.data.cassandra.consistency-level= # Queries consistency level.
spring.data.cassandra.contact-points=localhost # Cluster node addresses.
spring.data.cassandra.fetch-size= # Queries default fetch size.
spring.data.cassandra.keyspace-name= # Keyspace name to use.
spring.data.cassandra.load-balancing-policy= # Class name of the load balancing policy.
spring.data.cassandra.port= # Port of the Cassandra server.
spring.data.cassandra.password= # Login password of the server.
spring.data.cassandra.pool.heartbeat-interval=30s # Heartbeat interval after which a message is sent on
an idle connection to make sure it's still alive. If a duration suffix is not specified, seconds will
be used.
spring.data.cassandra.pool.idle-timeout=120s # Idle timeout before an idle connection is removed. If a
duration suffix is not specified, seconds will be used.
spring.data.cassandra.pool.max-queue-size=256 # Maximum number of requests that get queued if no
connection is available.
spring.data.cassandra.pool.pool-timeout=5000ms # Pool timeout when trying to acquire a connection from a
host's pool.
spring.data.cassandra.read-timeout= # Socket option: read time out.
spring.data.cassandra.reconnection-policy= # Reconnection policy class.
spring.data.cassandra.repositories.type=auto # Type of Cassandra repositories to enable.
spring.data.cassandra.retry-policy= # Class name of the retry policy.
spring.data.cassandra.serial-consistency-level= # Queries serial consistency level.
spring.data.cassandra.schema-action=none # Schema action to take at startup.
spring.data.cassandra.ssl=false # Enable SSL support.
spring.data.cassandra.username= # Login user of the server.
# DATA COUCHBASE (CouchbaseDataProperties)
spring.data.couchbase.auto-index=false # Automatically create views and indexes.
spring.data.couchbase.consistency=read-your-own-writes # Consistency to apply by default on generated
queries.
spring.data.couchbase.repositories.type=auto # Type of Couchbase repositories to enable.
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# ELASTICSEARCH (ElasticsearchProperties)
spring.data.elasticsearch.cluster-name=elasticsearch # Elasticsearch cluster name.
spring.data.elasticsearch.cluster-nodes= # Comma-separated list of cluster node addresses.
spring.data.elasticsearch.properties.*= # Additional properties used to configure the client.
spring.data.elasticsearch.repositories.enabled=true # Whether to enable Elasticsearch repositories.
# DATA LDAP
spring.data.ldap.repositories.enabled=true # Whether to enable LDAP repositories.
# MONGODB (MongoProperties)
spring.data.mongodb.authentication-database= # Authentication database name.
spring.data.mongodb.database= # Database name.
spring.data.mongodb.field-naming-strategy= # Fully qualified name of the FieldNamingStrategy to use.
spring.data.mongodb.grid-fs-database= # GridFS database name.
spring.data.mongodb.host= # Mongo server host. Cannot be set with URI.
spring.data.mongodb.password= # Login password of the mongo server. Cannot be set with URI.
spring.data.mongodb.port= # Mongo server port. Cannot be set with URI.
spring.data.mongodb.repositories.type=auto # Type of Mongo repositories to enable.
spring.data.mongodb.uri=mongodb://localhost/test # Mongo database URI. Cannot be set with host, port and
credentials.
spring.data.mongodb.username= # Login user of the mongo server. Cannot be set with URI.
# DATA REDIS
spring.data.redis.repositories.enabled=true # Whether to enable Redis repositories.
# NEO4J (Neo4jProperties)
spring.data.neo4j.auto-index=none # Auto index mode.
spring.data.neo4j.embedded.enabled=true # Whether to enable embedded mode if the embedded driver is
available.
spring.data.neo4j.open-in-view=true # Register OpenSessionInViewInterceptor. Binds a Neo4j Session to
the thread for the entire processing of the request.
spring.data.neo4j.password= # Login password of the server.
spring.data.neo4j.repositories.enabled=true # Whether to enable Neo4j repositories.
spring.data.neo4j.uri= # URI used by the driver. Auto-detected by default.
spring.data.neo4j.username= # Login user of the server.
# DATA REST (RepositoryRestProperties)
spring.data.rest.base-path= # Base path to be used by Spring Data REST to expose repository resources.
spring.data.rest.default-media-type= # Content type to use as a default when none is specified.
spring.data.rest.default-page-size= # Default size of pages.
spring.data.rest.detection-strategy=default # Strategy to use to determine which repositories get
exposed.
spring.data.rest.enable-enum-translation= # Whether to enable enum value translation through the Spring
Data REST default resource bundle.
spring.data.rest.limit-param-name= # Name of the URL query string parameter that indicates how many
results to return at once.
spring.data.rest.max-page-size= # Maximum size of pages.
spring.data.rest.page-param-name= # Name of the URL query string parameter that indicates what page to
return.
spring.data.rest.return-body-on-create= # Whether to return a response body after creating an entity.
spring.data.rest.return-body-on-update= # Whether to return a response body after updating an entity.
spring.data.rest.sort-param-name= # Name of the URL query string parameter that indicates what direction
to sort results.
# SOLR (SolrProperties)
spring.data.solr.host=http://127.0.0.1:8983/solr # Solr host. Ignored if "zk-host" is set.
spring.data.solr.repositories.enabled=true # Whether to enable Solr repositories.
spring.data.solr.zk-host= # ZooKeeper host address in the form HOST:PORT.
# DATA WEB (SpringDataWebProperties)
spring.data.web.pageable.default-page-size=20 # Default page size.
spring.data.web.pageable.max-page-size=2000 # Maximum page size to be accepted.
spring.data.web.pageable.one-indexed-parameters=false # Whether to expose and assume 1-based page number
indexes.
spring.data.web.pageable.page-parameter=page # Page index parameter name.
spring.data.web.pageable.prefix= # General prefix to be prepended to the page number and page size
parameters.
spring.data.web.pageable.qualifier-delimiter=_ # Delimiter to be used between the qualifier and the
actual page number and size properties.
spring.data.web.pageable.size-parameter=size # Page size parameter name.
spring.data.web.sort.sort-parameter=sort # Sort parameter name.
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# DATASOURCE (DataSourceAutoConfiguration & DataSourceProperties)
spring.datasource.continue-on-error=false # Whether to stop if an error occurs while initializing the
database.
spring.datasource.data= # Data (DML) script resource references.
spring.datasource.data-username= # Username of the database to execute DML scripts (if different).
spring.datasource.data-password= # Password of the database to execute DML scripts (if different).
spring.datasource.dbcp2.*= # Commons DBCP2 specific settings
spring.datasource.driver-class-name= # Fully qualified name of the JDBC driver. Auto-detected based on
the URL by default.
spring.datasource.generate-unique-name=false # Whether to generate a random datasource name.
spring.datasource.hikari.*= # Hikari specific settings
spring.datasource.initialization-mode=embedded # Initialize the datasource with available DDL and DML
scripts.
spring.datasource.jmx-enabled=false # Whether to enable JMX support (if provided by the underlying
pool).
spring.datasource.jndi-name= # JNDI location of the datasource. Class, url, username & password are
ignored when set.
spring.datasource.name= # Name of the datasource. Default to "testdb" when using an embedded database.
spring.datasource.password= # Login password of the database.
spring.datasource.platform=all # Platform to use in the DDL or DML scripts (such as schema-
${platform}.sql or data-${platform}.sql).
spring.datasource.schema= # Schema (DDL) script resource references.
spring.datasource.schema-username= # Username of the database to execute DDL scripts (if different).
spring.datasource.schema-password= # Password of the database to execute DDL scripts (if different).
spring.datasource.separator=; # Statement separator in SQL initialization scripts.
spring.datasource.sql-script-encoding= # SQL scripts encoding.
spring.datasource.tomcat.*= # Tomcat datasource specific settings
spring.datasource.type= # Fully qualified name of the connection pool implementation to use. By default,
it is auto-detected from the classpath.
spring.datasource.url= # JDBC URL of the database.
spring.datasource.username= # Login username of the database.
spring.datasource.xa.data-source-class-name= # XA datasource fully qualified name.
spring.datasource.xa.properties= # Properties to pass to the XA data source.
# JEST (Elasticsearch HTTP client) (JestProperties)
spring.elasticsearch.jest.connection-timeout=3s # Connection timeout.
spring.elasticsearch.jest.multi-threaded=true # Whether to enable connection requests from multiple
execution threads.
spring.elasticsearch.jest.password= # Login password.
spring.elasticsearch.jest.proxy.host= # Proxy host the HTTP client should use.
spring.elasticsearch.jest.proxy.port= # Proxy port the HTTP client should use.
spring.elasticsearch.jest.read-timeout=3s # Read timeout.
spring.elasticsearch.jest.uris=http://localhost:9200 # Comma-separated list of the Elasticsearch
instances to use.
spring.elasticsearch.jest.username= # Login username.
# H2 Web Console (H2ConsoleProperties)
spring.h2.console.enabled=false # Whether to enable the console.
spring.h2.console.path=/h2-console # Path at which the console is available.
spring.h2.console.settings.trace=false # Whether to enable trace output.
spring.h2.console.settings.web-allow-others=false # Whether to enable remote access.
# InfluxDB (InfluxDbProperties)
spring.influx.password= # Login password.
spring.influx.url= # URL of the InfluxDB instance to which to connect.
spring.influx.user= # Login user.
# JOOQ (JooqProperties)
spring.jooq.sql-dialect= # SQL dialect to use. Auto-detected by default.
# JDBC (JdbcProperties)
spring.jdbc.template.fetch-size=-1 # Number of rows that should be fetched from the database when more
rows are needed.
spring.jdbc.template.max-rows=-1 # Maximum number of rows.
spring.jdbc.template.query-timeout= # Query timeout. Default is to use the JDBC driver's default
configuration. If a duration suffix is not specified, seconds will be used.
# JPA (JpaBaseConfiguration, HibernateJpaAutoConfiguration)
spring.data.jpa.repositories.enabled=true # Whether to enable JPA repositories.
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spring.jpa.database= # Target database to operate on, auto-detected by default. Can be alternatively set
using the "databasePlatform" property.
spring.jpa.database-platform= # Name of the target database to operate on, auto-detected by default. Can
be alternatively set using the "Database" enum.
spring.jpa.generate-ddl=false # Whether to initialize the schema on startup.
spring.jpa.hibernate.ddl-auto= # DDL mode. This is actually a shortcut for the "hibernate.hbm2ddl.auto"
property. Defaults to "create-drop" when using an embedded database and no schema manager was detected.
Otherwise, defaults to "none".
spring.jpa.hibernate.naming.implicit-strategy= # Fully qualified name of the implicit naming strategy.
spring.jpa.hibernate.naming.physical-strategy= # Fully qualified name of the physical naming strategy.
spring.jpa.hibernate.use-new-id-generator-mappings= # Whether to use Hibernate's newer
IdentifierGenerator for AUTO, TABLE and SEQUENCE.
spring.jpa.mapping-resources= # Mapping resources (equivalent to "mapping-file" entries in
persistence.xml).
spring.jpa.open-in-view=true # Register OpenEntityManagerInViewInterceptor. Binds a JPA EntityManager to
the thread for the entire processing of the request.
spring.jpa.properties.*= # Additional native properties to set on the JPA provider.
spring.jpa.show-sql=false # Whether to enable logging of SQL statements.
# JTA (JtaAutoConfiguration)
spring.jta.enabled=true # Whether to enable JTA support.
spring.jta.log-dir= # Transaction logs directory.
spring.jta.transaction-manager-id= # Transaction manager unique identifier.
# ATOMIKOS (AtomikosProperties)
spring.jta.atomikos.connectionfactory.borrow-connection-timeout=30 # Timeout, in seconds, for borrowing
connections from the pool.
spring.jta.atomikos.connectionfactory.ignore-session-transacted-flag=true # Whether to ignore the
transacted flag when creating session.
spring.jta.atomikos.connectionfactory.local-transaction-mode=false # Whether local transactions are
desired.
spring.jta.atomikos.connectionfactory.maintenance-interval=60 # The time, in seconds, between runs of
the pool's maintenance thread.
spring.jta.atomikos.connectionfactory.max-idle-time=60 # The time, in seconds, after which connections
are cleaned up from the pool.
spring.jta.atomikos.connectionfactory.max-lifetime=0 # The time, in seconds, that a connection can be
pooled for before being destroyed. 0 denotes no limit.
spring.jta.atomikos.connectionfactory.max-pool-size=1 # The maximum size of the pool.
spring.jta.atomikos.connectionfactory.min-pool-size=1 # The minimum size of the pool.
spring.jta.atomikos.connectionfactory.reap-timeout=0 # The reap timeout, in seconds, for borrowed
connections. 0 denotes no limit.
spring.jta.atomikos.connectionfactory.unique-resource-name=jmsConnectionFactory # The unique name used
to identify the resource during recovery.
spring.jta.atomikos.connectionfactory.xa-connection-factory-class-name= # Vendor-specific implementation
of XAConnectionFactory.
spring.jta.atomikos.connectionfactory.xa-properties= # Vendor-specific XA properties.
spring.jta.atomikos.datasource.borrow-connection-timeout=30 # Timeout, in seconds, for borrowing
connections from the pool.
spring.jta.atomikos.datasource.concurrent-connection-validation= # Whether to use concurrent connection
validation.
spring.jta.atomikos.datasource.default-isolation-level= # Default isolation level of connections
provided by the pool.
spring.jta.atomikos.datasource.login-timeout= # Timeout, in seconds, for establishing a database
connection.
spring.jta.atomikos.datasource.maintenance-interval=60 # The time, in seconds, between runs of the
pool's maintenance thread.
spring.jta.atomikos.datasource.max-idle-time=60 # The time, in seconds, after which connections are
cleaned up from the pool.
spring.jta.atomikos.datasource.max-lifetime=0 # The time, in seconds, that a connection can be pooled
for before being destroyed. 0 denotes no limit.
spring.jta.atomikos.datasource.max-pool-size=1 # The maximum size of the pool.
spring.jta.atomikos.datasource.min-pool-size=1 # The minimum size of the pool.
spring.jta.atomikos.datasource.reap-timeout=0 # The reap timeout, in seconds, for borrowed connections.
0 denotes no limit.
spring.jta.atomikos.datasource.test-query= # SQL query or statement used to validate a connection before
returning it.
spring.jta.atomikos.datasource.unique-resource-name=dataSource # The unique name used to identify the
resource during recovery.
spring.jta.atomikos.datasource.xa-data-source-class-name= # Vendor-specific implementation of
XAConnectionFactory.
spring.jta.atomikos.datasource.xa-properties= # Vendor-specific XA properties.
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spring.jta.atomikos.properties.allow-sub-transactions=true # Specify whether sub-transactions are
allowed.
spring.jta.atomikos.properties.checkpoint-interval=500 # Interval between checkpoints, expressed as the
number of log writes between two checkpoints.
spring.jta.atomikos.properties.default-jta-timeout=10000ms # Default timeout for JTA transactions.
spring.jta.atomikos.properties.default-max-wait-time-on-shutdown=9223372036854775807 # How long should
normal shutdown (no-force) wait for transactions to complete.
spring.jta.atomikos.properties.enable-logging=true # Whether to enable disk logging.
spring.jta.atomikos.properties.force-shutdown-on-vm-exit=false # Whether a VM shutdown should trigger
forced shutdown of the transaction core.
spring.jta.atomikos.properties.log-base-dir= # Directory in which the log files should be stored.
spring.jta.atomikos.properties.log-base-name=tmlog # Transactions log file base name.
spring.jta.atomikos.properties.max-actives=50 # Maximum number of active transactions.
spring.jta.atomikos.properties.max-timeout=300000ms # Maximum timeout that can be allowed for
transactions.
spring.jta.atomikos.properties.recovery.delay=10000ms # Delay between two recovery scans.
spring.jta.atomikos.properties.recovery.forget-orphaned-log-entries-delay=86400000ms # Delay after which
recovery can cleanup pending ('orphaned') log entries.
spring.jta.atomikos.properties.recovery.max-retries=5 # Number of retry attempts to commit the
transaction before throwing an exception.
spring.jta.atomikos.properties.recovery.retry-interval=10000ms # Delay between retry attempts.
spring.jta.atomikos.properties.serial-jta-transactions=true # Whether sub-transactions should be joined
when possible.
spring.jta.atomikos.properties.service= # Transaction manager implementation that should be started.
spring.jta.atomikos.properties.threaded-two-phase-commit=false # Whether to use different (and
concurrent) threads for two-phase commit on the participating resources.
spring.jta.atomikos.properties.transaction-manager-unique-name= # The transaction manager's unique name.
# BITRONIX
spring.jta.bitronix.connectionfactory.acquire-increment=1 # Number of connections to create when growing
the pool.
spring.jta.bitronix.connectionfactory.acquisition-interval=1 # Time, in seconds, to wait before trying
to acquire a connection again after an invalid connection was acquired.
spring.jta.bitronix.connectionfactory.acquisition-timeout=30 # Timeout, in seconds, for acquiring
connections from the pool.
spring.jta.bitronix.connectionfactory.allow-local-transactions=true # Whether the transaction manager
should allow mixing XA and non-XA transactions.
spring.jta.bitronix.connectionfactory.apply-transaction-timeout=false # Whether the transaction timeout
should be set on the XAResource when it is enlisted.
spring.jta.bitronix.connectionfactory.automatic-enlisting-enabled=true # Whether resources should be
enlisted and delisted automatically.
spring.jta.bitronix.connectionfactory.cache-producers-consumers=true # Whether producers and consumers
should be cached.
spring.jta.bitronix.connectionfactory.class-name= # Underlying implementation class name of the XA
resource.
spring.jta.bitronix.connectionfactory.defer-connection-release=true # Whether the provider can run many
transactions on the same connection and supports transaction interleaving.
spring.jta.bitronix.connectionfactory.disabled= # Whether this resource is disabled, meaning it's
temporarily forbidden to acquire a connection from its pool.
spring.jta.bitronix.connectionfactory.driver-properties= # Properties that should be set on the
underlying implementation.
spring.jta.bitronix.connectionfactory.failed= # Mark this resource producer as failed.
spring.jta.bitronix.connectionfactory.ignore-recovery-failures=false # Whether recovery failures should
be ignored.
spring.jta.bitronix.connectionfactory.max-idle-time=60 # The time, in seconds, after which connections
are cleaned up from the pool.
spring.jta.bitronix.connectionfactory.max-pool-size=10 # The maximum size of the pool. 0 denotes no
limit.
spring.jta.bitronix.connectionfactory.min-pool-size=0 # The minimum size of the pool.
spring.jta.bitronix.connectionfactory.password= # The password to use to connect to the JMS provider.
spring.jta.bitronix.connectionfactory.share-transaction-connections=false # Whether connections in the
ACCESSIBLE state can be shared within the context of a transaction.
spring.jta.bitronix.connectionfactory.test-connections=true # Whether connections should be tested when
acquired from the pool.
spring.jta.bitronix.connectionfactory.two-pc-ordering-position=1 # The position that this
resource should take during two-phase commit (always first is Integer.MIN_VALUE, always last is
Integer.MAX_VALUE).
spring.jta.bitronix.connectionfactory.unique-name=jmsConnectionFactory # The unique name used to
identify the resource during recovery.
spring.jta.bitronix.connectionfactory.use-tm-join=true # Whether TMJOIN should be used when starting
XAResources.
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spring.jta.bitronix.connectionfactory.user= # The user to use to connect to the JMS provider.
spring.jta.bitronix.datasource.acquire-increment=1 # Number of connections to create when growing the
pool.
spring.jta.bitronix.datasource.acquisition-interval=1 # Time, in seconds, to wait before trying to
acquire a connection again after an invalid connection was acquired.
spring.jta.bitronix.datasource.acquisition-timeout=30 # Timeout, in seconds, for acquiring connections
from the pool.
spring.jta.bitronix.datasource.allow-local-transactions=true # Whether the transaction manager should
allow mixing XA and non-XA transactions.
spring.jta.bitronix.datasource.apply-transaction-timeout=false # Whether the transaction timeout should
be set on the XAResource when it is enlisted.
spring.jta.bitronix.datasource.automatic-enlisting-enabled=true # Whether resources should be enlisted
and delisted automatically.
spring.jta.bitronix.datasource.class-name= # Underlying implementation class name of the XA resource.
spring.jta.bitronix.datasource.cursor-holdability= # The default cursor holdability for connections.
spring.jta.bitronix.datasource.defer-connection-release=true # Whether the database can run many
transactions on the same connection and supports transaction interleaving.
spring.jta.bitronix.datasource.disabled= # Whether this resource is disabled, meaning it's temporarily
forbidden to acquire a connection from its pool.
spring.jta.bitronix.datasource.driver-properties= # Properties that should be set on the underlying
implementation.
spring.jta.bitronix.datasource.enable-jdbc4-connection-test= # Whether Connection.isValid() is called
when acquiring a connection from the pool.
spring.jta.bitronix.datasource.failed= # Mark this resource producer as failed.
spring.jta.bitronix.datasource.ignore-recovery-failures=false # Whether recovery failures should be
ignored.
spring.jta.bitronix.datasource.isolation-level= # The default isolation level for connections.
spring.jta.bitronix.datasource.local-auto-commit= # The default auto-commit mode for local transactions.
spring.jta.bitronix.datasource.login-timeout= # Timeout, in seconds, for establishing a database
connection.
spring.jta.bitronix.datasource.max-idle-time=60 # The time, in seconds, after which connections are
cleaned up from the pool.
spring.jta.bitronix.datasource.max-pool-size=10 # The maximum size of the pool. 0 denotes no limit.
spring.jta.bitronix.datasource.min-pool-size=0 # The minimum size of the pool.
spring.jta.bitronix.datasource.prepared-statement-cache-size=0 # The target size of the prepared
statement cache. 0 disables the cache.
spring.jta.bitronix.datasource.share-transaction-connections=false # Whether connections in the
ACCESSIBLE state can be shared within the context of a transaction.
spring.jta.bitronix.datasource.test-query= # SQL query or statement used to validate a connection before
returning it.
spring.jta.bitronix.datasource.two-pc-ordering-position=1 # The position that this resource should take
during two-phase commit (always first is Integer.MIN_VALUE, and always last is Integer.MAX_VALUE).
spring.jta.bitronix.datasource.unique-name=dataSource # The unique name used to identify the resource
during recovery.
spring.jta.bitronix.datasource.use-tm-join=true # Whether TMJOIN should be used when starting
XAResources.
spring.jta.bitronix.properties.allow-multiple-lrc=false # Whether to allow multiple LRC resources to be
enlisted into the same transaction.
spring.jta.bitronix.properties.asynchronous2-pc=false # Whether to enable asynchronously execution of
two phase commit.
spring.jta.bitronix.properties.background-recovery-interval-seconds=60 # Interval in seconds at which to
run the recovery process in the background.
spring.jta.bitronix.properties.current-node-only-recovery=true # Whether to recover only the current
node.
spring.jta.bitronix.properties.debug-zero-resource-transaction=false # Whether to log the creation and
commit call stacks of transactions executed without a single enlisted resource.
spring.jta.bitronix.properties.default-transaction-timeout=60 # Default transaction timeout, in seconds.
spring.jta.bitronix.properties.disable-jmx=false # Whether to enable JMX support.
spring.jta.bitronix.properties.exception-analyzer= # Set the fully qualified name of the exception
analyzer implementation to use.
spring.jta.bitronix.properties.filter-log-status=false # Whether to enable filtering of logs so that
only mandatory logs are written.
spring.jta.bitronix.properties.force-batching-enabled=true # Whether disk forces are batched.
spring.jta.bitronix.properties.forced-write-enabled=true # Whether logs are forced to disk.
spring.jta.bitronix.properties.graceful-shutdown-interval=60 # Maximum amount of seconds the TM waits
for transactions to get done before aborting them at shutdown time.
spring.jta.bitronix.properties.jndi-transaction-synchronization-registry-name= # JNDI name of the
TransactionSynchronizationRegistry.
spring.jta.bitronix.properties.jndi-user-transaction-name= # JNDI name of the UserTransaction.
spring.jta.bitronix.properties.journal=disk # Name of the journal. Can be 'disk', 'null', or a class
name.
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spring.jta.bitronix.properties.log-part1-filename=btm1.tlog # Name of the first fragment of the journal.
spring.jta.bitronix.properties.log-part2-filename=btm2.tlog # Name of the second fragment of the
journal.
spring.jta.bitronix.properties.max-log-size-in-mb=2 # Maximum size in megabytes of the journal
fragments.
spring.jta.bitronix.properties.resource-configuration-filename= # ResourceLoader configuration file
name.
spring.jta.bitronix.properties.server-id= # ASCII ID that must uniquely identify this TM instance.
Defaults to the machine's IP address.
spring.jta.bitronix.properties.skip-corrupted-logs=false # Skip corrupted transactions log entries.
spring.jta.bitronix.properties.warn-about-zero-resource-transaction=true # Whether to log a warning for
transactions executed without a single enlisted resource.
# NARAYANA (NarayanaProperties)
spring.jta.narayana.default-timeout=60s # Transaction timeout. If a duration suffix is not specified,
seconds will be used.
spring.jta.narayana.expiry-
scanners=com.arjuna.ats.internal.arjuna.recovery.ExpiredTransactionStatusManagerScanner # Comma-
separated list of expiry scanners.
spring.jta.narayana.log-dir= # Transaction object store directory.
spring.jta.narayana.one-phase-commit=true # Whether to enable one phase commit optimization.
spring.jta.narayana.periodic-recovery-period=120s # Interval in which periodic recovery scans are
performed. If a duration suffix is not specified, seconds will be used.
spring.jta.narayana.recovery-backoff-period=10s # Back off period between first and second phases of the
recovery scan. If a duration suffix is not specified, seconds will be used.
spring.jta.narayana.recovery-db-pass= # Database password to be used by the recovery manager.
spring.jta.narayana.recovery-db-user= # Database username to be used by the recovery manager.
spring.jta.narayana.recovery-jms-pass= # JMS password to be used by the recovery manager.
spring.jta.narayana.recovery-jms-user= # JMS username to be used by the recovery manager.
spring.jta.narayana.recovery-modules= # Comma-separated list of recovery modules.
spring.jta.narayana.transaction-manager-id=1 # Unique transaction manager id.
spring.jta.narayana.xa-resource-orphan-filters= # Comma-separated list of orphan filters.
# EMBEDDED MONGODB (EmbeddedMongoProperties)
spring.mongodb.embedded.features=sync_delay # Comma-separated list of features to enable.
spring.mongodb.embedded.storage.database-dir= # Directory used for data storage.
spring.mongodb.embedded.storage.oplog-size= # Maximum size of the oplog, in megabytes.
spring.mongodb.embedded.storage.repl-set-name= # Name of the replica set.
spring.mongodb.embedded.version=3.2.2 # Version of Mongo to use.
# REDIS (RedisProperties)
spring.redis.cluster.max-redirects= # Maximum number of redirects to follow when executing commands
across the cluster.
spring.redis.cluster.nodes= # Comma-separated list of "host:port" pairs to bootstrap from.
spring.redis.database=0 # Database index used by the connection factory.
spring.redis.url= # Connection URL. Overrides host, port, and password. User is ignored. Example:
redis://user:password@example.com:6379
spring.redis.host=localhost # Redis server host.
spring.redis.jedis.pool.max-active=8 # Maximum number of connections that can be allocated by the pool
at a given time. Use a negative value for no limit.
spring.redis.jedis.pool.max-idle=8 # Maximum number of "idle" connections in the pool. Use a negative
value to indicate an unlimited number of idle connections.
spring.redis.jedis.pool.max-wait=-1ms # Maximum amount of time a connection allocation should block
before throwing an exception when the pool is exhausted. Use a negative value to block indefinitely.
spring.redis.jedis.pool.min-idle=0 # Target for the minimum number of idle connections to maintain in
the pool. This setting only has an effect if it is positive.
spring.redis.lettuce.pool.max-active=8 # Maximum number of connections that can be allocated by the pool
at a given time. Use a negative value for no limit.
spring.redis.lettuce.pool.max-idle=8 # Maximum number of "idle" connections in the pool. Use a negative
value to indicate an unlimited number of idle connections.
spring.redis.lettuce.pool.max-wait=-1ms # Maximum amount of time a connection allocation should block
before throwing an exception when the pool is exhausted. Use a negative value to block indefinitely.
spring.redis.lettuce.pool.min-idle=0 # Target for the minimum number of idle connections to maintain in
the pool. This setting only has an effect if it is positive.
spring.redis.lettuce.shutdown-timeout=100ms # Shutdown timeout.
spring.redis.password= # Login password of the redis server.
spring.redis.port=6379 # Redis server port.
spring.redis.sentinel.master= # Name of the Redis server.
spring.redis.sentinel.nodes= # Comma-separated list of "host:port" pairs.
spring.redis.ssl=false # Whether to enable SSL support.
spring.redis.timeout= # Connection timeout.
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# TRANSACTION (TransactionProperties)
spring.transaction.default-timeout= # Default transaction timeout. If a duration suffix is not
specified, seconds will be used.
spring.transaction.rollback-on-commit-failure= # Whether to roll back on commit failures.
# ----------------------------------------
# INTEGRATION PROPERTIES
# ----------------------------------------
# ACTIVEMQ (ActiveMQProperties)
spring.activemq.broker-url= # URL of the ActiveMQ broker. Auto-generated by default.
spring.activemq.close-timeout=15s # Time to wait before considering a close complete.
spring.activemq.in-memory=true # Whether the default broker URL should be in memory. Ignored if an
explicit broker has been specified.
spring.activemq.non-blocking-redelivery=false # Whether to stop message delivery before re-delivering
messages from a rolled back transaction. This implies that message order is not preserved when this is
enabled.
spring.activemq.password= # Login password of the broker.
spring.activemq.send-timeout=0ms # Time to wait on message sends for a response. Set it to 0 to wait
forever.
spring.activemq.user= # Login user of the broker.
spring.activemq.packages.trust-all= # Whether to trust all packages.
spring.activemq.packages.trusted= # Comma-separated list of specific packages to trust (when not
trusting all packages).
spring.activemq.pool.block-if-full=true # Whether to block when a connection is requested and the pool
is full. Set it to false to throw a "JMSException" instead.
spring.activemq.pool.block-if-full-timeout=-1ms # Blocking period before throwing an exception if the
pool is still full.
spring.activemq.pool.create-connection-on-startup=true # Whether to create a connection on startup. Can
be used to warm up the pool on startup.
spring.activemq.pool.enabled=false # Whether a PooledConnectionFactory should be created, instead of a
regular ConnectionFactory.
spring.activemq.pool.expiry-timeout=0ms # Connection expiration timeout.
spring.activemq.pool.idle-timeout=30s # Connection idle timeout.
spring.activemq.pool.max-connections=1 # Maximum number of pooled connections.
spring.activemq.pool.maximum-active-session-per-connection=500 # Maximum number of active sessions per
connection.
spring.activemq.pool.reconnect-on-exception=true # Reset the connection when a "JMSException" occurs.
spring.activemq.pool.time-between-expiration-check=-1ms # Time to sleep between runs of the idle
connection eviction thread. When negative, no idle connection eviction thread runs.
spring.activemq.pool.use-anonymous-producers=true # Whether to use only one anonymous "MessageProducer"
instance. Set it to false to create one "MessageProducer" every time one is required.
# ARTEMIS (ArtemisProperties)
spring.artemis.embedded.cluster-password= # Cluster password. Randomly generated on startup by default.
spring.artemis.embedded.data-directory= # Journal file directory. Not necessary if persistence is turned
off.
spring.artemis.embedded.enabled=true # Whether to enable embedded mode if the Artemis server APIs are
available.
spring.artemis.embedded.persistent=false # Whether to enable persistent store.
spring.artemis.embedded.queues= # Comma-separated list of queues to create on startup.
spring.artemis.embedded.server-id= # Server ID. By default, an auto-incremented counter is used.
spring.artemis.embedded.topics= # Comma-separated list of topics to create on startup.
spring.artemis.host=localhost # Artemis broker host.
spring.artemis.mode= # Artemis deployment mode, auto-detected by default.
spring.artemis.password= # Login password of the broker.
spring.artemis.port=61616 # Artemis broker port.
spring.artemis.user= # Login user of the broker.
# SPRING BATCH (BatchProperties)
spring.batch.initialize-schema=embedded # Database schema initialization mode.
spring.batch.job.enabled=true # Execute all Spring Batch jobs in the context on startup.
spring.batch.job.names= # Comma-separated list of job names to execute on startup (for instance,
`job1,job2`). By default, all Jobs found in the context are executed.
spring.batch.schema=classpath:org/springframework/batch/core/schema-@@platform@@.sql # Path to the SQL
file to use to initialize the database schema.
spring.batch.table-prefix= # Table prefix for all the batch meta-data tables.
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# SPRING INTEGRATION (IntegrationProperties)
spring.integration.jdbc.initialize-schema=embedded # Database schema initialization mode.
spring.integration.jdbc.schema=classpath:org/springframework/integration/jdbc/schema-@@platform@@.sql #
Path to the SQL file to use to initialize the database schema.
# JMS (JmsProperties)
spring.jms.jndi-name= # Connection factory JNDI name. When set, takes precedence to others connection
factory auto-configurations.
spring.jms.listener.acknowledge-mode= # Acknowledge mode of the container. By default, the listener is
transacted with automatic acknowledgment.
spring.jms.listener.auto-startup=true # Start the container automatically on startup.
spring.jms.listener.concurrency= # Minimum number of concurrent consumers.
spring.jms.listener.max-concurrency= # Maximum number of concurrent consumers.
spring.jms.pub-sub-domain=false # Whether the default destination type is topic.
spring.jms.template.default-destination= # Default destination to use on send and receive operations
that do not have a destination parameter.
spring.jms.template.delivery-delay= # Delivery delay to use for send calls.
spring.jms.template.delivery-mode= # Delivery mode. Enables QoS (Quality of Service) when set.
spring.jms.template.priority= # Priority of a message when sending. Enables QoS (Quality of Service)
when set.
spring.jms.template.qos-enabled= # Whether to enable explicit QoS (Quality of Service) when sending a
message.
spring.jms.template.receive-timeout= # Timeout to use for receive calls.
spring.jms.template.time-to-live= # Time-to-live of a message when sending. Enables QoS (Quality of
Service) when set.
# APACHE KAFKA (KafkaProperties)
spring.kafka.admin.client-id= # ID to pass to the server when making requests. Used for server-side
logging.
spring.kafka.admin.fail-fast=false # Whether to fail fast if the broker is not available on startup.
spring.kafka.admin.properties.*= # Additional admin-specific properties used to configure the client.
spring.kafka.admin.ssl.key-password= # Password of the private key in the key store file.
spring.kafka.admin.ssl.keystore-location= # Location of the key store file.
spring.kafka.admin.ssl.keystore-password= # Store password for the key store file.
spring.kafka.admin.ssl.keystore-type= # Type of the key store.
spring.kafka.admin.ssl.protocol= # SSL protocol to use.
spring.kafka.admin.ssl.truststore-location= # Location of the trust store file.
spring.kafka.admin.ssl.truststore-password= # Store password for the trust store file.
spring.kafka.admin.ssl.truststore-type= # Type of the trust store.
spring.kafka.bootstrap-servers= # Comma-delimited list of host:port pairs to use for establishing the
initial connection to the Kafka cluster.
spring.kafka.client-id= # ID to pass to the server when making requests. Used for server-side logging.
spring.kafka.consumer.auto-commit-interval= # Frequency with which the consumer offsets are auto-
committed to Kafka if 'enable.auto.commit' is set to true.
spring.kafka.consumer.auto-offset-reset= # What to do when there is no initial offset in Kafka or if the
current offset no longer exists on the server.
spring.kafka.consumer.bootstrap-servers= # Comma-delimited list of host:port pairs to use for
establishing the initial connection to the Kafka cluster.
spring.kafka.consumer.client-id= # ID to pass to the server when making requests. Used for server-side
logging.
spring.kafka.consumer.enable-auto-commit= # Whether the consumer's offset is periodically committed in
the background.
spring.kafka.consumer.fetch-max-wait= # Maximum amount of time the server blocks before answering
the fetch request if there isn't sufficient data to immediately satisfy the requirement given by
"fetch.min.bytes".
spring.kafka.consumer.fetch-min-size= # Minimum amount of data, in bytes, the server should return for a
fetch request.
spring.kafka.consumer.group-id= # Unique string that identifies the consumer group to which this
consumer belongs.
spring.kafka.consumer.heartbeat-interval= # Expected time between heartbeats to the consumer
coordinator.
spring.kafka.consumer.key-deserializer= # Deserializer class for keys.
spring.kafka.consumer.max-poll-records= # Maximum number of records returned in a single call to poll().
spring.kafka.consumer.properties.*= # Additional consumer-specific properties used to configure the
client.
spring.kafka.consumer.ssl.key-password= # Password of the private key in the key store file.
spring.kafka.consumer.ssl.keystore-location= # Location of the key store file.
spring.kafka.consumer.ssl.keystore-password= # Store password for the key store file.
spring.kafka.consumer.ssl.keystore-type= # Type of the key store.
spring.kafka.consumer.ssl.protocol= # SSL protocol to use.
spring.kafka.consumer.ssl.truststore-location= # Location of the trust store file.
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spring.kafka.consumer.ssl.truststore-password= # Store password for the trust store file.
spring.kafka.consumer.ssl.truststore-type= # Type of the trust store.
spring.kafka.consumer.value-deserializer= # Deserializer class for values.
spring.kafka.jaas.control-flag=required # Control flag for login configuration.
spring.kafka.jaas.enabled=false # Whether to enable JAAS configuration.
spring.kafka.jaas.login-module=com.sun.security.auth.module.Krb5LoginModule # Login module.
spring.kafka.jaas.options= # Additional JAAS options.
spring.kafka.listener.ack-count= # Number of records between offset commits when ackMode is "COUNT" or
"COUNT_TIME".
spring.kafka.listener.ack-mode= # Listener AckMode. See the spring-kafka documentation.
spring.kafka.listener.ack-time= # Time between offset commits when ackMode is "TIME" or "COUNT_TIME".
spring.kafka.listener.client-id= # Prefix for the listener's consumer client.id property.
spring.kafka.listener.concurrency= # Number of threads to run in the listener containers.
spring.kafka.listener.idle-event-interval= # Time between publishing idle consumer events (no data
received).
spring.kafka.listener.log-container-config= # Whether to log the container configuration during
initialization (INFO level).
spring.kafka.listener.monitor-interval= # Time between checks for non-responsive consumers. If a
duration suffix is not specified, seconds will be used.
spring.kafka.listener.no-poll-threshold= # Multiplier applied to "pollTimeout" to determine if a
consumer is non-responsive.
spring.kafka.listener.poll-timeout= # Timeout to use when polling the consumer.
spring.kafka.listener.type=single # Listener type.
spring.kafka.producer.acks= # Number of acknowledgments the producer requires the leader to have
received before considering a request complete.
spring.kafka.producer.batch-size= # Default batch size in bytes.
spring.kafka.producer.bootstrap-servers= # Comma-delimited list of host:port pairs to use for
establishing the initial connection to the Kafka cluster.
spring.kafka.producer.buffer-memory= # Total bytes of memory the producer can use to buffer records
waiting to be sent to the server.
spring.kafka.producer.client-id= # ID to pass to the server when making requests. Used for server-side
logging.
spring.kafka.producer.compression-type= # Compression type for all data generated by the producer.
spring.kafka.producer.key-serializer= # Serializer class for keys.
spring.kafka.producer.properties.*= # Additional producer-specific properties used to configure the
client.
spring.kafka.producer.retries= # When greater than zero, enables retrying of failed sends.
spring.kafka.producer.ssl.key-password= # Password of the private key in the key store file.
spring.kafka.producer.ssl.keystore-location= # Location of the key store file.
spring.kafka.producer.ssl.keystore-password= # Store password for the key store file.
spring.kafka.producer.ssl.keystore-type= # Type of the key store.
spring.kafka.producer.ssl.protocol= # SSL protocol to use.
spring.kafka.producer.ssl.truststore-location= # Location of the trust store file.
spring.kafka.producer.ssl.truststore-password= # Store password for the trust store file.
spring.kafka.producer.ssl.truststore-type= # Type of the trust store.
spring.kafka.producer.transaction-id-prefix= # When non empty, enables transaction support for producer.
spring.kafka.producer.value-serializer= # Serializer class for values.
spring.kafka.properties.*= # Additional properties, common to producers and consumers, used to configure
the client.
spring.kafka.ssl.key-password= # Password of the private key in the key store file.
spring.kafka.ssl.keystore-location= # Location of the key store file.
spring.kafka.ssl.keystore-password= # Store password for the key store file.
spring.kafka.ssl.keystore-type= # Type of the key store.
spring.kafka.ssl.protocol= # SSL protocol to use.
spring.kafka.ssl.truststore-location= # Location of the trust store file.
spring.kafka.ssl.truststore-password= # Store password for the trust store file.
spring.kafka.ssl.truststore-type= # Type of the trust store.
spring.kafka.template.default-topic= # Default topic to which messages are sent.
# RABBIT (RabbitProperties)
spring.rabbitmq.addresses= # Comma-separated list of addresses to which the client should connect.
spring.rabbitmq.cache.channel.checkout-timeout= # Duration to wait to obtain a channel if the cache size
has been reached.
spring.rabbitmq.cache.channel.size= # Number of channels to retain in the cache.
spring.rabbitmq.cache.connection.mode=channel # Connection factory cache mode.
spring.rabbitmq.cache.connection.size= # Number of connections to cache.
spring.rabbitmq.connection-timeout= # Connection timeout. Set it to zero to wait forever.
spring.rabbitmq.dynamic=true # Whether to create an AmqpAdmin bean.
spring.rabbitmq.host=localhost # RabbitMQ host.
spring.rabbitmq.listener.direct.acknowledge-mode= # Acknowledge mode of container.
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spring.rabbitmq.listener.direct.auto-startup=true # Whether to start the container automatically on
startup.
spring.rabbitmq.listener.direct.consumers-per-queue= # Number of consumers per queue.
spring.rabbitmq.listener.direct.default-requeue-rejected= # Whether rejected deliveries are re-queued by
default.
spring.rabbitmq.listener.direct.idle-event-interval= # How often idle container events should be
published.
spring.rabbitmq.listener.direct.prefetch= # Number of messages to be handled in a single request. It
should be greater than or equal to the transaction size (if used).
spring.rabbitmq.listener.direct.retry.enabled=false # Whether publishing retries are enabled.
spring.rabbitmq.listener.direct.retry.initial-interval=1000ms # Duration between the first and second
attempt to deliver a message.
spring.rabbitmq.listener.direct.retry.max-attempts=3 # Maximum number of attempts to deliver a message.
spring.rabbitmq.listener.direct.retry.max-interval=10000ms # Maximum duration between attempts.
spring.rabbitmq.listener.direct.retry.multiplier=1 # Multiplier to apply to the previous retry interval.
spring.rabbitmq.listener.direct.retry.stateless=true # Whether retries are stateless or stateful.
spring.rabbitmq.listener.simple.acknowledge-mode= # Acknowledge mode of container.
spring.rabbitmq.listener.simple.auto-startup=true # Whether to start the container automatically on
startup.
spring.rabbitmq.listener.simple.concurrency= # Minimum number of listener invoker threads.
spring.rabbitmq.listener.simple.default-requeue-rejected= # Whether rejected deliveries are re-queued by
default.
spring.rabbitmq.listener.simple.idle-event-interval= # How often idle container events should be
published.
spring.rabbitmq.listener.simple.max-concurrency= # Maximum number of listener invoker threads.
spring.rabbitmq.listener.simple.prefetch= # Number of messages to be handled in a single request. It
should be greater than or equal to the transaction size (if used).
spring.rabbitmq.listener.simple.retry.enabled=false # Whether publishing retries are enabled.
spring.rabbitmq.listener.simple.retry.initial-interval=1000ms # Duration between the first and second
attempt to deliver a message.
spring.rabbitmq.listener.simple.retry.max-attempts=3 # Maximum number of attempts to deliver a message.
spring.rabbitmq.listener.simple.retry.max-interval=10000ms # Maximum duration between attempts.
spring.rabbitmq.listener.simple.retry.multiplier=1 # Multiplier to apply to the previous retry interval.
spring.rabbitmq.listener.simple.retry.stateless=true # Whether retries are stateless or stateful.
spring.rabbitmq.listener.simple.transaction-size= # Number of messages to be processed in a transaction.
That is, the number of messages between acks. For best results, it should be less than or equal to the
prefetch count.
spring.rabbitmq.listener.type=simple # Listener container type.
spring.rabbitmq.password=guest # Login to authenticate against the broker.
spring.rabbitmq.port=5672 # RabbitMQ port.
spring.rabbitmq.publisher-confirms=false # Whether to enable publisher confirms.
spring.rabbitmq.publisher-returns=false # Whether to enable publisher returns.
spring.rabbitmq.requested-heartbeat= # Requested heartbeat timeout; zero for none. If a duration suffix
is not specified, seconds will be used.
spring.rabbitmq.ssl.enabled=false # Whether to enable SSL support.
spring.rabbitmq.ssl.key-store= # Path to the key store that holds the SSL certificate.
spring.rabbitmq.ssl.key-store-password= # Password used to access the key store.
spring.rabbitmq.ssl.key-store-type=PKCS12 # Key store type.
spring.rabbitmq.ssl.trust-store= # Trust store that holds SSL certificates.
spring.rabbitmq.ssl.trust-store-password= # Password used to access the trust store.
spring.rabbitmq.ssl.trust-store-type=JKS # Trust store type.
spring.rabbitmq.ssl.algorithm= # SSL algorithm to use. By default, configured by the Rabbit client
library.
spring.rabbitmq.template.exchange= # Name of the default exchange to use for send operations.
spring.rabbitmq.template.mandatory= # Whether to enable mandatory messages.
spring.rabbitmq.template.receive-timeout= # Timeout for `receive()` operations.
spring.rabbitmq.template.reply-timeout= # Timeout for `sendAndReceive()` operations.
spring.rabbitmq.template.retry.enabled=false # Whether publishing retries are enabled.
spring.rabbitmq.template.retry.initial-interval=1000ms # Duration between the first and second attempt
to deliver a message.
spring.rabbitmq.template.retry.max-attempts=3 # Maximum number of attempts to deliver a message.
spring.rabbitmq.template.retry.max-interval=10000ms # Maximum duration between attempts.
spring.rabbitmq.template.retry.multiplier=1 # Multiplier to apply to the previous retry interval.
spring.rabbitmq.template.routing-key= # Value of a default routing key to use for send operations.
spring.rabbitmq.username=guest # Login user to authenticate to the broker.
spring.rabbitmq.virtual-host= # Virtual host to use when connecting to the broker.
# ----------------------------------------
# ACTUATOR PROPERTIES
# ----------------------------------------
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# MANAGEMENT HTTP SERVER (ManagementServerProperties)
management.server.add-application-context-header=false # Add the "X-Application-Context" HTTP header in
each response.
management.server.address= # Network address to which the management endpoints should bind. Requires a
custom management.server.port.
management.server.port= # Management endpoint HTTP port (uses the same port as the application by
default). Configure a different port to use management-specific SSL.
management.server.servlet.context-path= # Management endpoint context-path (for instance, `/
management`). Requires a custom management.server.port.
management.server.ssl.ciphers= # Supported SSL ciphers. Requires a custom management.port.
management.server.ssl.client-auth= # Whether client authentication is wanted ("want") or needed
("need"). Requires a trust store. Requires a custom management.server.port.
management.server.ssl.enabled= # Whether to enable SSL support. Requires a custom
management.server.port.
management.server.ssl.enabled-protocols= # Enabled SSL protocols. Requires a custom
management.server.port.
management.server.ssl.key-alias= # Alias that identifies the key in the key store. Requires a custom
management.server.port.
management.server.ssl.key-password= # Password used to access the key in the key store. Requires a
custom management.server.port.
management.server.ssl.key-store= # Path to the key store that holds the SSL certificate (typically a jks
file). Requires a custom management.server.port.
management.server.ssl.key-store-password= # Password used to access the key store. Requires a custom
management.server.port.
management.server.ssl.key-store-provider= # Provider for the key store. Requires a custom
management.server.port.
management.server.ssl.key-store-type= # Type of the key store. Requires a custom management.server.port.
management.server.ssl.protocol=TLS # SSL protocol to use. Requires a custom management.server.port.
management.server.ssl.trust-store= # Trust store that holds SSL certificates. Requires a custom
management.server.port.
management.server.ssl.trust-store-password= # Password used to access the trust store. Requires a custom
management.server.port.
management.server.ssl.trust-store-provider= # Provider for the trust store. Requires a custom
management.server.port.
management.server.ssl.trust-store-type= # Type of the trust store. Requires a custom
management.server.port.
# CLOUDFOUNDRY
management.cloudfoundry.enabled=true # Whether to enable extended Cloud Foundry actuator endpoints.
management.cloudfoundry.skip-ssl-validation=false # Whether to skip SSL verification for Cloud Foundry
actuator endpoint security calls.
# ENDPOINTS GENERAL CONFIGURATION
management.endpoints.enabled-by-default= # Whether to enable or disable all endpoints by default.
# ENDPOINTS JMX CONFIGURATION (JmxEndpointProperties)
management.endpoints.jmx.domain=org.springframework.boot # Endpoints JMX domain name. Fallback to
'spring.jmx.default-domain' if set.
management.endpoints.jmx.exposure.include=* # Endpoint IDs that should be included or '*' for all.
management.endpoints.jmx.exposure.exclude= # Endpoint IDs that should be excluded or '*' for all.
management.endpoints.jmx.static-names= # Additional static properties to append to all ObjectNames of
MBeans representing Endpoints.
management.endpoints.jmx.unique-names=false # Whether to ensure that ObjectNames are modified in case of
conflict.
# ENDPOINTS WEB CONFIGURATION (WebEndpointProperties)
management.endpoints.web.exposure.include=health,info # Endpoint IDs that should be included or '*' for
all.
management.endpoints.web.exposure.exclude= # Endpoint IDs that should be excluded or '*' for all.
management.endpoints.web.base-path=/actuator # Base path for Web endpoints. Relative to
server.servlet.context-path or management.server.servlet.context-path if management.server.port is
configured.
management.endpoints.web.path-mapping= # Mapping between endpoint IDs and the path that should expose
them.
# ENDPOINTS CORS CONFIGURATION (CorsEndpointProperties)
management.endpoints.web.cors.allow-credentials= # Whether credentials are supported. When not set,
credentials are not supported.
management.endpoints.web.cors.allowed-headers= # Comma-separated list of headers to allow in a request.
'*' allows all headers.
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management.endpoints.web.cors.allowed-methods= # Comma-separated list of methods to allow. '*' allows
all methods. When not set, defaults to GET.
management.endpoints.web.cors.allowed-origins= # Comma-separated list of origins to allow. '*' allows
all origins. When not set, CORS support is disabled.
management.endpoints.web.cors.exposed-headers= # Comma-separated list of headers to include in a
response.
management.endpoints.web.cors.max-age=1800s # How long the response from a pre-flight request can be
cached by clients. If a duration suffix is not specified, seconds will be used.
# AUDIT EVENTS ENDPOINT (AuditEventsEndpoint)
management.endpoint.auditevents.cache.time-to-live=0ms # Maximum time that a response can be cached.
management.endpoint.auditevents.enabled=true # Whether to enable the auditevents endpoint.
# BEANS ENDPOINT (BeansEndpoint)
management.endpoint.beans.cache.time-to-live=0ms # Maximum time that a response can be cached.
management.endpoint.beans.enabled=true # Whether to enable the beans endpoint.
# CONDITIONS REPORT ENDPOINT (ConditionsReportEndpoint)
management.endpoint.conditions.cache.time-to-live=0ms # Maximum time that a response can be cached.
management.endpoint.conditions.enabled=true # Whether to enable the conditions endpoint.
# CONFIGURATION PROPERTIES REPORT ENDPOINT
(ConfigurationPropertiesReportEndpoint, ConfigurationPropertiesReportEndpointProperties)
management.endpoint.configprops.cache.time-to-live=0ms # Maximum time that a response can be cached.
management.endpoint.configprops.enabled=true # Whether to enable the configprops endpoint.
management.endpoint.configprops.keys-to-
sanitize=password,secret,key,token,.*credentials.*,vcap_services,sun.java.command # Keys that should be
sanitized. Keys can be simple strings that the property ends with or regular expressions.
# ENVIRONMENT ENDPOINT (EnvironmentEndpoint, EnvironmentEndpointProperties)
management.endpoint.env.cache.time-to-live=0ms # Maximum time that a response can be cached.
management.endpoint.env.enabled=true # Whether to enable the env endpoint.
management.endpoint.env.keys-to-
sanitize=password,secret,key,token,.*credentials.*,vcap_services,sun.java.command # Keys that should be
sanitized. Keys can be simple strings that the property ends with or regular expressions.
# FLYWAY ENDPOINT (FlywayEndpoint)
management.endpoint.flyway.cache.time-to-live=0ms # Maximum time that a response can be cached.
management.endpoint.flyway.enabled=true # Whether to enable the flyway endpoint.
# HEALTH ENDPOINT (HealthEndpoint, HealthEndpointProperties)
management.endpoint.health.cache.time-to-live=0ms # Maximum time that a response can be cached.
management.endpoint.health.enabled=true # Whether to enable the health endpoint.
management.endpoint.health.roles= # Roles used to determine whether or not a user is authorized to be
shown details. When empty, all authenticated users are authorized.
management.endpoint.health.show-details=never # When to show full health details.
# HEAP DUMP ENDPOINT (HeapDumpWebEndpoint)
management.endpoint.heapdump.cache.time-to-live=0ms # Maximum time that a response can be cached.
management.endpoint.heapdump.enabled=true # Whether to enable the heapdump endpoint.
# HTTP TRACE ENDPOINT (HttpTraceEndpoint)
management.endpoint.httptrace.cache.time-to-live=0ms # Maximum time that a response can be cached.
management.endpoint.httptrace.enabled=true # Whether to enable the httptrace endpoint.
# INFO ENDPOINT (InfoEndpoint)
info= # Arbitrary properties to add to the info endpoint.
management.endpoint.info.cache.time-to-live=0ms # Maximum time that a response can be cached.
management.endpoint.info.enabled=true # Whether to enable the info endpoint.
# JOLOKIA ENDPOINT (JolokiaProperties)
management.endpoint.jolokia.config.*= # Jolokia settings. Refer to the documentation of Jolokia for more
details.
management.endpoint.jolokia.enabled=true # Whether to enable the jolokia endpoint.
# LIQUIBASE ENDPOINT (LiquibaseEndpoint)
management.endpoint.liquibase.cache.time-to-live=0ms # Maximum time that a response can be cached.
management.endpoint.liquibase.enabled=true # Whether to enable the liquibase endpoint.
# LOG FILE ENDPOINT (LogFileWebEndpoint, LogFileWebEndpointProperties)
management.endpoint.logfile.cache.time-to-live=0ms # Maximum time that a response can be cached.
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management.endpoint.logfile.enabled=true # Whether to enable the logfile endpoint.
management.endpoint.logfile.external-file= # External Logfile to be accessed. Can be used if the logfile
is written by output redirect and not by the logging system itself.
# LOGGERS ENDPOINT (LoggersEndpoint)
management.endpoint.loggers.cache.time-to-live=0ms # Maximum time that a response can be cached.
management.endpoint.loggers.enabled=true # Whether to enable the loggers endpoint.
# REQUEST MAPPING ENDPOINT (MappingsEndpoint)
management.endpoint.mappings.cache.time-to-live=0ms # Maximum time that a response can be cached.
management.endpoint.mappings.enabled=true # Whether to enable the mappings endpoint.
# METRICS ENDPOINT (MetricsEndpoint)
management.endpoint.metrics.cache.time-to-live=0ms # Maximum time that a response can be cached.
management.endpoint.metrics.enabled=true # Whether to enable the metrics endpoint.
# PROMETHEUS ENDPOINT (PrometheusScrapeEndpoint)
management.endpoint.prometheus.cache.time-to-live=0ms # Maximum time that a response can be cached.
management.endpoint.prometheus.enabled=true # Whether to enable the prometheus endpoint.
# SCHEDULED TASKS ENDPOINT (ScheduledTasksEndpoint)
management.endpoint.scheduledtasks.cache.time-to-live=0ms # Maximum time that a response can be cached.
management.endpoint.scheduledtasks.enabled=true # Whether to enable the scheduledtasks endpoint.
# SESSIONS ENDPOINT (SessionsEndpoint)
management.endpoint.sessions.enabled=true # Whether to enable the sessions endpoint.
# SHUTDOWN ENDPOINT (ShutdownEndpoint)
management.endpoint.shutdown.enabled=false # Whether to enable the shutdown endpoint.
# THREAD DUMP ENDPOINT (ThreadDumpEndpoint)
management.endpoint.threaddump.cache.time-to-live=0ms # Maximum time that a response can be cached.
management.endpoint.threaddump.enabled=true # Whether to enable the threaddump endpoint.
# HEALTH INDICATORS
management.health.db.enabled=true # Whether to enable database health check.
management.health.cassandra.enabled=true # Whether to enable Cassandra health check.
management.health.couchbase.enabled=true # Whether to enable Couchbase health check.
management.health.defaults.enabled=true # Whether to enable default health indicators.
management.health.diskspace.enabled=true # Whether to enable disk space health check.
management.health.diskspace.path= # Path used to compute the available disk space.
management.health.diskspace.threshold=0 # Minimum disk space, in bytes, that should be available.
management.health.elasticsearch.enabled=true # Whether to enable Elasticsearch health check.
management.health.elasticsearch.indices= # Comma-separated index names.
management.health.elasticsearch.response-timeout=100ms # Time to wait for a response from the cluster.
management.health.influxdb.enabled=true # Whether to enable InfluxDB health check.
management.health.jms.enabled=true # Whether to enable JMS health check.
management.health.ldap.enabled=true # Whether to enable LDAP health check.
management.health.mail.enabled=true # Whether to enable Mail health check.
management.health.mongo.enabled=true # Whether to enable MongoDB health check.
management.health.neo4j.enabled=true # Whether to enable Neo4j health check.
management.health.rabbit.enabled=true # Whether to enable RabbitMQ health check.
management.health.redis.enabled=true # Whether to enable Redis health check.
management.health.solr.enabled=true # Whether to enable Solr health check.
management.health.status.http-mapping= # Mapping of health statuses to HTTP status codes. By default,
registered health statuses map to sensible defaults (for example, UP maps to 200).
management.health.status.order=DOWN,OUT_OF_SERVICE,UP,UNKNOWN # Comma-separated list of health statuses
in order of severity.
# HTTP TRACING (HttpTraceProperties)
management.trace.http.enabled=true # Whether to enable HTTP request-response tracing.
management.trace.http.include=request-headers,response-headers,cookies,errors # Items to be included in
the trace.
# INFO CONTRIBUTORS (InfoContributorProperties)
management.info.build.enabled=true # Whether to enable build info.
management.info.defaults.enabled=true # Whether to enable default info contributors.
management.info.env.enabled=true # Whether to enable environment info.
management.info.git.enabled=true # Whether to enable git info.
management.info.git.mode=simple # Mode to use to expose git information.
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# METRICS
management.metrics.binders.files.enabled=true # Whether to enable files metrics.
management.metrics.binders.integration.enabled=true # Whether to enable Spring Integration metrics.
management.metrics.binders.jvm.enabled=true # Whether to enable JVM metrics.
management.metrics.binders.logback.enabled=true # Whether to enable Logback metrics.
management.metrics.binders.processor.enabled=true # Whether to enable processor metrics.
management.metrics.binders.uptime.enabled=true # Whether to enable uptime metrics.
management.metrics.distribution.percentiles-histogram.*= # Whether meter IDs starting-with the specified
name should be publish percentile histograms.
management.metrics.distribution.percentiles.*= # Specific computed non-aggregable percentiles to ship to
the backend for meter IDs starting-with the specified name.
management.metrics.distribution.sla.*= # Specific SLA boundaries for meter IDs starting-with the
specified name. The longest match wins, the key `all` can also be used to configure all meters.
management.metrics.enable.*= # Whether meter IDs starting-with the specified name should be enabled. The
longest match wins, the key `all` can also be used to configure all meters.
management.metrics.export.atlas.batch-size=10000 # Number of measurements per request to use for this
backend. If more measurements are found, then multiple requests will be made.
management.metrics.export.atlas.config-refresh-frequency=10s # Frequency for refreshing config settings
from the LWC service.
management.metrics.export.atlas.config-time-to-live=150s # Time to live for subscriptions from the LWC
service.
management.metrics.export.atlas.config-uri=http://localhost:7101/lwc/api/v1/expressions/local-dev # URI
for the Atlas LWC endpoint to retrieve current subscriptions.
management.metrics.export.atlas.connect-timeout=1s # Connection timeout for requests to this backend.
management.metrics.export.atlas.enabled=true # Whether exporting of metrics to this backend is enabled.
management.metrics.export.atlas.eval-uri=http://localhost:7101/lwc/api/v1/evaluate # URI for the Atlas
LWC endpoint to evaluate the data for a subscription.
management.metrics.export.atlas.lwc-enabled=false # Whether to enable streaming to Atlas LWC.
management.metrics.export.atlas.meter-time-to-live=15m # Time to live for meters that do not have any
activity. After this period the meter will be considered expired and will not get reported.
management.metrics.export.atlas.num-threads=2 # Number of threads to use with the metrics publishing
scheduler.
management.metrics.export.atlas.read-timeout=10s # Read timeout for requests to this backend.
management.metrics.export.atlas.step=1m # Step size (i.e. reporting frequency) to use.
management.metrics.export.atlas.uri=http://localhost:7101/api/v1/publish # URI of the Atlas server.
management.metrics.export.datadog.api-key= # Datadog API key.
management.metrics.export.datadog.application-key= # Datadog application key. Not strictly required, but
improves the Datadog experience by sending meter descriptions, types, and base units to Datadog.
management.metrics.export.datadog.batch-size=10000 # Number of measurements per request to use for this
backend. If more measurements are found, then multiple requests will be made.
management.metrics.export.datadog.connect-timeout=1s # Connection timeout for requests to this backend.
management.metrics.export.datadog.descriptions=true # Whether to publish descriptions metadata to
Datadog. Turn this off to minimize the amount of metadata sent.
management.metrics.export.datadog.enabled=true # Whether exporting of metrics to this backend is
enabled.
management.metrics.export.datadog.host-tag=instance # Tag that will be mapped to "host" when shipping
metrics to Datadog.
management.metrics.export.datadog.num-threads=2 # Number of threads to use with the metrics publishing
scheduler.
management.metrics.export.datadog.read-timeout=10s # Read timeout for requests to this backend.
management.metrics.export.datadog.step=1m # Step size (i.e. reporting frequency) to use.
management.metrics.export.datadog.uri=https://app.datadoghq.com # URI to ship metrics to. If you need to
publish metrics to an internal proxy en-route to Datadog, you can define the location of the proxy with
this.
management.metrics.export.ganglia.addressing-mode=multicast # UDP addressing mode, either unicast or
multicast.
management.metrics.export.ganglia.duration-units=milliseconds # Base time unit used to report durations.
management.metrics.export.ganglia.enabled=true # Whether exporting of metrics to Ganglia is enabled.
management.metrics.export.ganglia.host=localhost # Host of the Ganglia server to receive exported
metrics.
management.metrics.export.ganglia.port=8649 # Port of the Ganglia server to receive exported metrics.
management.metrics.export.ganglia.protocol-version=3.1 # Ganglia protocol version. Must be either 3.1 or
3.0.
management.metrics.export.ganglia.rate-units=seconds # Base time unit used to report rates.
management.metrics.export.ganglia.step=1m # Step size (i.e. reporting frequency) to use.
management.metrics.export.ganglia.time-to-live=1 # Time to live for metrics on Ganglia. Set the multi-
cast Time-To-Live to be one greater than the number of hops (routers) between the hosts.
management.metrics.export.graphite.duration-units=milliseconds # Base time unit used to report
durations.
management.metrics.export.graphite.enabled=true # Whether exporting of metrics to Graphite is enabled.
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management.metrics.export.graphite.host=localhost # Host of the Graphite server to receive exported
metrics.
management.metrics.export.graphite.port=2004 # Port of the Graphite server to receive exported metrics.
management.metrics.export.graphite.protocol=pickled # Protocol to use while shipping data to Graphite.
management.metrics.export.graphite.rate-units=seconds # Base time unit used to report rates.
management.metrics.export.graphite.step=1m # Step size (i.e. reporting frequency) to use.
management.metrics.export.graphite.tags-as-prefix= # For the default naming convention, turn the
specified tag keys into part of the metric prefix.
management.metrics.export.influx.auto-create-db=true # Whether to create the Influx database if it does
not exist before attempting to publish metrics to it.
management.metrics.export.influx.batch-size=10000 # Number of measurements per request to use for this
backend. If more measurements are found, then multiple requests will be made.
management.metrics.export.influx.compressed=true # Whether to enable GZIP compression of metrics batches
published to Influx.
management.metrics.export.influx.connect-timeout=1s # Connection timeout for requests to this backend.
management.metrics.export.influx.consistency=one # Write consistency for each point.
management.metrics.export.influx.db=mydb # Tag that will be mapped to "host" when shipping metrics to
Influx.
management.metrics.export.influx.enabled=true # Whether exporting of metrics to this backend is enabled.
management.metrics.export.influx.num-threads=2 # Number of threads to use with the metrics publishing
scheduler.
management.metrics.export.influx.password= # Login password of the Influx server.
management.metrics.export.influx.read-timeout=10s # Read timeout for requests to this backend.
management.metrics.export.influx.retention-duration= # Time period for which Influx should retain data
in the current database.
management.metrics.export.influx.retention-shard-duration= # Time range covered by a shard group.
management.metrics.export.influx.retention-policy= # Retention policy to use (Influx writes to the
DEFAULT retention policy if one is not specified).
management.metrics.export.influx.retention-replication-factor= # How many copies of the data are stored
in the cluster.
management.metrics.export.influx.step=1m # Step size (i.e. reporting frequency) to use.
management.metrics.export.influx.uri=http://localhost:8086 # URI of the Influx server.
management.metrics.export.influx.user-name= # Login user of the Influx server.
management.metrics.export.jmx.domain=metrics # Metrics JMX domain name.
management.metrics.export.jmx.enabled=true # Whether exporting of metrics to JMX is enabled.
management.metrics.export.jmx.step=1m # Step size (i.e. reporting frequency) to use.
management.metrics.export.newrelic.account-id= # New Relic account ID.
management.metrics.export.newrelic.api-key= # New Relic API key.
management.metrics.export.newrelic.batch-size=10000 # Number of measurements per request to use for this
backend. If more measurements are found, then multiple requests will be made.
management.metrics.export.newrelic.connect-timeout=1s # Connection timeout for requests to this backend.
management.metrics.export.newrelic.enabled=true # Whether exporting of metrics to this backend is
enabled.
management.metrics.export.newrelic.num-threads=2 # Number of threads to use with the metrics publishing
scheduler.
management.metrics.export.newrelic.read-timeout=10s # Read timeout for requests to this backend.
management.metrics.export.newrelic.step=1m # Step size (i.e. reporting frequency) to use.
management.metrics.export.newrelic.uri=https://insights-collector.newrelic.com # URI to ship metrics to.
management.metrics.export.prometheus.descriptions=true # Whether to enable publishing descriptions as
part of the scrape payload to Prometheus. Turn this off to minimize the amount of data sent on each
scrape.
management.metrics.export.prometheus.enabled=true # Whether exporting of metrics to Prometheus is
enabled.
management.metrics.export.prometheus.step=1m # Step size (i.e. reporting frequency) to use.
management.metrics.export.signalfx.access-token= # SignalFX access token.
management.metrics.export.signalfx.batch-size=10000 # Number of measurements per request to use for this
backend. If more measurements are found, then multiple requests will be made.
management.metrics.export.signalfx.connect-timeout=1s # Connection timeout for requests to this backend.
management.metrics.export.signalfx.enabled=true # Whether exporting of metrics to this backend is
enabled.
management.metrics.export.signalfx.num-threads=2 # Number of threads to use with the metrics publishing
scheduler.
management.metrics.export.signalfx.read-timeout=10s # Read timeout for requests to this backend.
management.metrics.export.signalfx.source= # Uniquely identifies the app instance that is publishing
metrics to SignalFx. Defaults to the local host name.
management.metrics.export.signalfx.step=10s # Step size (i.e. reporting frequency) to use.
management.metrics.export.signalfx.uri=https://ingest.signalfx.com # URI to ship metrics to.
management.metrics.export.simple.enabled=true # Whether, in the absence of any other exporter, exporting
of metrics to an in-memory backend is enabled.
management.metrics.export.simple.mode=cumulative # Counting mode.
management.metrics.export.simple.step=1m # Step size (i.e. reporting frequency) to use.
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management.metrics.export.statsd.enabled=true # Whether exporting of metrics to StatsD is enabled.
management.metrics.export.statsd.flavor=datadog # StatsD line protocol to use.
management.metrics.export.statsd.host=localhost # Host of the StatsD server to receive exported metrics.
management.metrics.export.statsd.max-packet-length=1400 # Total length of a single payload should be
kept within your network's MTU.
management.metrics.export.statsd.polling-frequency=10s # How often gauges will be polled. When a gauge
is polled, its value is recalculated and if the value has changed (or publishUnchangedMeters is true),
it is sent to the StatsD server.
management.metrics.export.statsd.port=8125 # Port of the StatsD server to receive exported metrics.
management.metrics.export.statsd.publish-unchanged-meters=true # Whether to send unchanged meters to the
StatsD server.
management.metrics.export.wavefront.api-token= # API token used when publishing metrics directly to the
Wavefront API host.
management.metrics.export.wavefront.batch-size=10000 # Number of measurements per request to use for
this backend. If more measurements are found, then multiple requests will be made.
management.metrics.export.wavefront.connect-timeout=1s # Connection timeout for requests to this
backend.
management.metrics.export.wavefront.enabled=true # Whether exporting of metrics to this backend is
enabled.
management.metrics.export.wavefront.global-prefix= # Global prefix to separate metrics originating from
this app's white box instrumentation from those originating from other Wavefront integrations when
viewed in the Wavefront UI.
management.metrics.export.wavefront.num-threads=2 # Number of threads to use with the metrics publishing
scheduler.
management.metrics.export.wavefront.read-timeout=10s # Read timeout for requests to this backend.
management.metrics.export.wavefront.source= # Unique identifier for the app instance that is the source
of metrics being published to Wavefront. Defaults to the local host name.
management.metrics.export.wavefront.step=10s # Step size (i.e. reporting frequency) to use.
management.metrics.export.wavefront.uri=https://longboard.wavefront.com # URI to ship metrics to.
management.metrics.use-global-registry=true # Whether auto-configured MeterRegistry implementations
should be bound to the global static registry on Metrics.
management.metrics.web.client.max-uri-tags=100 # Maximum number of unique URI tag values allowed. After
the max number of tag values is reached, metrics with additional tag values are denied by filter.
management.metrics.web.client.requests-metric-name=http.client.requests # Name of the metric for sent
requests.
management.metrics.web.server.auto-time-requests=true # Whether requests handled by Spring MVC or
WebFlux should be automatically timed.
management.metrics.web.server.requests-metric-name=http.server.requests # Name of the metric for
received requests.
# ----------------------------------------
# DEVTOOLS PROPERTIES
# ----------------------------------------
# DEVTOOLS (DevToolsProperties)
spring.devtools.livereload.enabled=true # Whether to enable a livereload.com-compatible server.
spring.devtools.livereload.port=35729 # Server port.
spring.devtools.restart.additional-exclude= # Additional patterns that should be excluded from
triggering a full restart.
spring.devtools.restart.additional-paths= # Additional paths to watch for changes.
spring.devtools.restart.enabled=true # Whether to enable automatic restart.
spring.devtools.restart.exclude=META-INF/maven/**,META-INF/resources/**,resources/**,static/**,public/
**,templates/**,**/*Test.class,**/*Tests.class,git.properties,META-INF/build-info.properties # Patterns
that should be excluded from triggering a full restart.
spring.devtools.restart.log-condition-evaluation-delta=true # Whether to log the condition evaluation
delta upon restart.
spring.devtools.restart.poll-interval=1s # Amount of time to wait between polling for classpath changes.
spring.devtools.restart.quiet-period=400ms # Amount of quiet time required without any classpath changes
before a restart is triggered.
spring.devtools.restart.trigger-file= # Name of a specific file that, when changed, triggers the restart
check. If not specified, any classpath file change triggers the restart.
# REMOTE DEVTOOLS (RemoteDevToolsProperties)
spring.devtools.remote.context-path=/.~~spring-boot!~ # Context path used to handle the remote
connection.
spring.devtools.remote.proxy.host= # The host of the proxy to use to connect to the remote application.
spring.devtools.remote.proxy.port= # The port of the proxy to use to connect to the remote application.
spring.devtools.remote.restart.enabled=true # Whether to enable remote restart.
spring.devtools.remote.secret= # A shared secret required to establish a connection (required to enable
remote support).
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spring.devtools.remote.secret-header-name=X-AUTH-TOKEN # HTTP header used to transfer the shared secret.
# ----------------------------------------
# TESTING PROPERTIES
# ----------------------------------------
spring.test.database.replace=any # Type of existing DataSource to replace.
spring.test.mockmvc.print=default # MVC Print option.
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Appendix B. Configuration Metadata
Spring Boot jars include metadata files that provide details of all supported configuration properties.
The files are designed to let IDE developers offer contextual help and “code completion” as users are
working with application.properties or application.yml files.
The majority of the metadata file is generated automatically at compile time by processing all items
annotated with @ConfigurationProperties. However, it is possible to write part of the metadata
manually for corner cases or more advanced use cases.
B.1 Metadata Format
Configuration metadata files are located inside jars under META-INF/spring-configuration-
metadata.json They use a simple JSON format with items categorized under either “groups” or
“properties” and additional values hints categorized under "hints", as shown in the following example:
{"groups": [
{
"name": "server",
"type": "org.springframework.boot.autoconfigure.web.ServerProperties",
"sourceType": "org.springframework.boot.autoconfigure.web.ServerProperties"
},
{
"name": "spring.jpa.hibernate",
"type": "org.springframework.boot.autoconfigure.orm.jpa.JpaProperties$Hibernate",
"sourceType": "org.springframework.boot.autoconfigure.orm.jpa.JpaProperties",
"sourceMethod": "getHibernate()"
}
...
],"properties": [
{
"name": "server.port",
"type": "java.lang.Integer",
"sourceType": "org.springframework.boot.autoconfigure.web.ServerProperties"
},
{
"name": "server.servlet.path",
"type": "java.lang.String",
"sourceType": "org.springframework.boot.autoconfigure.web.ServerProperties",
"defaultValue": "/"
},
{
"name": "spring.jpa.hibernate.ddl-auto",
"type": "java.lang.String",
"description": "DDL mode. This is actually a shortcut for the \"hibernate.hbm2ddl.auto\" property.",
"sourceType": "org.springframework.boot.autoconfigure.orm.jpa.JpaProperties$Hibernate"
}
...
],"hints": [
{
"name": "spring.jpa.hibernate.ddl-auto",
"values": [
{
"value": "none",
"description": "Disable DDL handling."
},
{
"value": "validate",
"description": "Validate the schema, make no changes to the database."
},
{
"value": "update",
"description": "Update the schema if necessary."
},
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{
"value": "create",
"description": "Create the schema and destroy previous data."
},
{
"value": "create-drop",
"description": "Create and then destroy the schema at the end of the session."
}
]
}
]}
Each “property” is a configuration item that the user specifies with a given value. For example,
server.port and server.servlet.path might be specified in application.properties, as
follows:
server.port=9090
server.servlet.path=/home
The “groups” are higher level items that do not themselves specify a value but instead provide a
contextual grouping for properties. For example, the server.port and server.servlet.path
properties are part of the server group.
Note
It is not required that every “property” has a “group”. Some properties might exist in their own right.
Finally, “hints” are additional information used to assist the user in configuring a given property. For
example, when a developer is configuring the spring.jpa.hibernate.ddl-auto property, a tool
can use the hints to offer some auto-completion help for the none, validate, update, create, and
create-drop values.
Group Attributes
The JSON object contained in the groups array can contain the attributes shown in the following table:
Name Type Purpose
name String The full name of the group. This attribute is mandatory.
type String The class name of the data type of the group. For example,
if the group were based on a class annotated with
@ConfigurationProperties, the attribute would contain the
fully qualified name of that class. If it were based on a @Bean
method, it would be the return type of that method. If the type is
not known, the attribute may be omitted.
description String A short description of the group that can be displayed to users. If
not description is available, it may be omitted. It is recommended
that descriptions be short paragraphs, with the first line providing
a concise summary. The last line in the description should end
with a period (.).
sourceType String The class name of the source that contributed this group. For
example, if the group were based on a @Bean method annotated
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Name Type Purpose
with @ConfigurationProperties, this attribute would contain
the fully qualified name of the @Configuration class that
contains the method. If the source type is not known, the attribute
may be omitted.
sourceMethod String The full name of the method (include parenthesis and argument
types) that contributed this group (for example, the name of a
@ConfigurationProperties annotated @Bean method). If the
source method is not known, it may be omitted.
Property Attributes
The JSON object contained in the properties array can contain the attributes described in the
following table:
Name Type Purpose
name String The full name of the property. Names are in lower-case period-
separated form (for example, server.servlet.path). This
attribute is mandatory.
type String The full signature of the data type of the property (for example,
java.lang.String) but also a full generic type (such as
java.util.Map<java.util.String,acme.MyEnum>). You
can use this attribute to guide the user as to the types of values
that they can enter. For consistency, the type of a primitive is
specified by using its wrapper counterpart (for example, boolean
becomes java.lang.Boolean). Note that this class may be a
complex type that gets converted from a String as values are
bound. If the type is not known, it may be omitted.
description String A short description of the group that can be displayed to users. If
no description is available, it may be omitted. It is recommended
that descriptions be short paragraphs, with the first line providing
a concise summary. The last line in the description should end
with a period (.).
sourceType String The class name of the source that contributed this property.
For example, if the property were from a class annotated with
@ConfigurationProperties, this attribute would contain the
fully qualified name of that class. If the source type is unknown, it
may be omitted.
defaultValue Object The default value, which is used if the property is not specified. If
the type of the property is an array, it can be an array of value(s).
If the default value is unknown, it may be omitted.
deprecation Deprecation Specify whether the property is deprecated. If the field is not
deprecated or if that information is not known, it may be omitted.
The next table offers more detail about the deprecation
attribute.
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The JSON object contained in the deprecation attribute of each properties element can contain
the following attributes:
Name Type Purpose
level String The level of deprecation, which can be either warning (the
default) or error. When a property has a warning deprecation
level, it should still be bound in the environment. However, when
it has an error deprecation level, the property is no longer
managed and is not bound.
reason String A short description of the reason why the property was
deprecated. If no reason is available, it may be omitted. It is
recommended that descriptions be short paragraphs, with the first
line providing a concise summary. The last line in the description
should end with a period (.).
replacement String The full name of the property that replaces this deprecated
property. If there is no replacement for this property, it may be
omitted.
Note
Prior to Spring Boot 1.3, a single deprecated boolean attribute can be used instead of the
deprecation element. This is still supported in a deprecated fashion and should no longer be
used. If no reason and replacement are available, an empty deprecation object should be set.
Deprecation can also be specified declaratively in code by adding the
@DeprecatedConfigurationProperty annotation to the getter exposing the deprecated property.
For instance, assume that the app.acme.target property was confusing and was renamed to
app.acme.name. The following example shows how to handle that situation:
@ConfigurationProperties("app.acme")
public class AcmeProperties {
private String name;
public String getName() { ... }
public void setName(String name) { ... }
@DeprecatedConfigurationProperty(replacement = "app.acme.name")
@Deprecated
public String getTarget() {
return getName();
}
@Deprecated
public void setTarget(String target) {
setName(target);
}
}
Note
There is no way to set a level. warning is always assumed, since code is still handling the
property.
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The preceding code makes sure that the deprecated property still works (delegating to the name property
behind the scenes). Once the getTarget and setTarget methods can be removed from your public
API, the automatic deprecation hint in the metadata goes away as well. If you want to keep a hint,
adding manual metadata with an error deprecation level ensures that users are still informed about
that property. Doing so is particularly useful when a replacement is provided.
Hint Attributes
The JSON object contained in the hints array can contain the attributes shown in the following table:
Name Type Purpose
name String The full name of the property to which this hint refers.
Names are in lower-case period-separated form (such as
server.servlet.path). If the property refers to a map
(such as system.contexts), the hint either applies to the
keys of the map (system.context.keys) or the values
(system.context.values) of the map. This attribute is
mandatory.
values ValueHint[] A list of valid values as defined by the ValueHint object
(described in the next table). Each entry defines the value and
may have a description.
providers ValueProvider[] A list of providers as defined by the ValueProvider object
(described later in this document). Each entry defines the name of
the provider and its parameters, if any.
The JSON object contained in the values attribute of each hint element can contain the attributes
described in the following table:
Name Type Purpose
value Object A valid value for the element to which the hint refers. If the type of
the property is an array, it can also be an array of value(s). This
attribute is mandatory.
description String A short description of the value that can be displayed to users. If
no description is available, it may be omitted . It is recommended
that descriptions be short paragraphs, with the first line providing
a concise summary. The last line in the description should end
with a period (.).
The JSON object contained in the providers attribute of each hint element can contain the attributes
described in the following table:
Name Type Purpose
name String The name of the provider to use to offer additional content
assistance for the element to which the hint refers.
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Name Type Purpose
parameters JSON object Any additional parameter that the provider supports (check the
documentation of the provider for more details).
Repeated Metadata Items
Objects with the same “property” and “group” name can appear multiple times within a metadata file.
For example, you could bind two separate classes to the same prefix, with each having potentially
overlapping property names. While the same names appearing in the metadata multiple times should
not be common, consumers of metadata should take care to ensure that they support it.
B.2 Providing Manual Hints
To improve the user experience and further assist the user in configuring a given property, you can
provide additional metadata that:
• Describes the list of potential values for a property.
• Associates a provider, to attach a well defined semantic to a property, so that a tool can discover the
list of potential values based on the project’s context.
Value Hint
The name attribute of each hint refers to the name of a property. In the initial example shown earlier, we
provide five values for the spring.jpa.hibernate.ddl-auto property: none, validate, update,
create, and create-drop. Each value may have a description as well.
If your property is of type Map, you can provide hints for both the keys and the values (but not for the map
itself). The special .keys and .values suffixes must refer to the keys and the values, respectively.
Assume a sample.contexts maps magic String values to an integer, as shown in the following
example:
@ConfigurationProperties("sample")
public class SampleProperties {
private Map<String,Integer> contexts;
// getters and setters
}
The magic values are (in this example) are sample1 and sample2. In order to offer additional content
assistance for the keys, you could add the following JSON to the manual metadata of the module:
{"hints": [
{
"name": "sample.contexts.keys",
"values": [
{
"value": "sample1"
},
{
"value": "sample2"
}
]
}
]}
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Tip
We recommend that you use an Enum for those two values instead. If your IDE supports it, this
is by far the most effective approach to auto-completion.
Value Providers
Providers are a powerful way to attach semantics to a property. In this section, we define the official
providers that you can use for your own hints. However, your favorite IDE may implement some of these
or none of them. Also, it could eventually provide its own.
Note
As this is a new feature, IDE vendors must catch up with how it works. Adoption times naturally
vary.
The following table summarizes the list of supported providers:
Name Description
any Permits any additional value to be provided.
class-reference Auto-completes the classes available in the project. Usually
constrained by a base class that is specified by the target
parameter.
handle-as Handles the property as if it were defined by the type defined by
the mandatory target parameter.
logger-name Auto-completes valid logger names. Typically, package and class
names available in the current project can be auto-completed.
spring-bean-reference Auto-completes the available bean names in the current project.
Usually constrained by a base class that is specified by the
target parameter.
spring-profile-name Auto-completes the available Spring profile names in the project.
Tip
Only one provider can be active for a given property, but you can specify several providers if they
can all manage the property in some way. Make sure to place the most powerful provider first, as
the IDE must use the first one in the JSON section that it can handle. If no provider for a given
property is supported, no special content assistance is provided, either.
Any
The special any provider value permits any additional values to be provided. Regular value validation
based on the property type should be applied if this is supported.
This provider is typically used if you have a list of values and any extra values should still be considered
as valid.
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The following example offers on and off as auto-completion values for system.state:
{"hints": [
{
"name": "system.state",
"values": [
{
"value": "on"
},
{
"value": "off"
}
],
"providers": [
{
"name": "any"
}
]
}
]}
Note that, in the preceding example, any other value is also allowed.
Class Reference
The class-reference provider auto-completes classes available in the project. This provider supports
the following parameters:
Parameter Type Default value Description
target String
(Class)
none The fully qualified name of the class that should
be assignable to the chosen value. Typically
used to filter out-non candidate classes. Note
that this information can be provided by the type
itself by exposing a class with the appropriate
upper bound.
concrete boolean true Specify whether only concrete classes are to be
considered as valid candidates.
The following metadata snippet corresponds to the standard server.servlet.jsp.class-name
property that defines the JspServlet class name to use:
{"hints": [
{
"name": "server.servlet.jsp.class-name",
"providers": [
{
"name": "class-reference",
"parameters": {
"target": "javax.servlet.http.HttpServlet"
}
}
]
}
]}
Handle As
The handle-as provider lets you substitute the type of the property to a more high-level type. This
typically happens when the property has a java.lang.String type, because you do not want your
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configuration classes to rely on classes that may not be on the classpath. This provider supports the
following parameters:
Parameter Type Default value Description
target String
(Class)
none The fully qualified name of the type to consider
for the property. This parameter is mandatory.
The following types can be used:
• Any java.lang.Enum: Lists the possible values for the property. (We recommend defining the
property with the Enum type, as no further hint should be required for the IDE to auto-complete the
values.)
•java.nio.charset.Charset: Supports auto-completion of charset/encoding values (such as
UTF-8)
•java.util.Locale: auto-completion of locales (such as en_US)
•org.springframework.util.MimeType: Supports auto-completion of content type values (such
as text/plain)
•org.springframework.core.io.Resource: Supports auto-completion of Spring’s Resource
abstraction to refer to a file on the filesystem or on the classpath. (such as classpath:/
sample.properties)
Tip
If multiple values can be provided, use a Collection or Array type to teach the IDE about it.
The following metadata snippet corresponds to the standard spring.liquibase.change-log
property that defines the path to the changelog to use. It is actually used internally as a
org.springframework.core.io.Resource but cannot be exposed as such, because we need to
keep the original String value to pass it to the Liquibase API.
{"hints": [
{
"name": "spring.liquibase.change-log",
"providers": [
{
"name": "handle-as",
"parameters": {
"target": "org.springframework.core.io.Resource"
}
}
]
}
]}
Logger Name
The logger-name provider auto-completes valid logger names. Typically, package and class names
available in the current project can be auto-completed. Specific frameworks may have extra magic
logger names that can be supported as well.
Since a logger name can be any arbitrary name, this provider should allow any value but could highlight
valid package and class names that are not available in the project’s classpath.
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The following metadata snippet corresponds to the standard logging.level property. Keys are logger
names, and values correspond to the standard log levels or any custom level.
{"hints": [
{
"name": "logging.level.keys",
"values": [
{
"value": "root",
"description": "Root logger used to assign the default logging level."
}
],
"providers": [
{
"name": "logger-name"
}
]
},
{
"name": "logging.level.values",
"values": [
{
"value": "trace"
},
{
"value": "debug"
},
{
"value": "info"
},
{
"value": "warn"
},
{
"value": "error"
},
{
"value": "fatal"
},
{
"value": "off"
}
],
"providers": [
{
"name": "any"
}
]
}
]}
Spring Bean Reference
The spring-bean-reference provider auto-completes the beans that are defined in the configuration of
the current project. This provider supports the following parameters:
Parameter Type Default value Description
target String
(Class)
none The fully qualified name of the bean class that
should be assignable to the candidate. Typically
used to filter out non-candidate beans.
The following metadata snippet corresponds to the standard spring.jmx.server property that
defines the name of the MBeanServer bean to use:
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{"hints": [
{
"name": "spring.jmx.server",
"providers": [
{
"name": "spring-bean-reference",
"parameters": {
"target": "javax.management.MBeanServer"
}
}
]
}
]}
Note
The binder is not aware of the metadata. If you provide that hint, you still need to transform the
bean name into an actual Bean reference using by the ApplicationContext.
Spring Profile Name
The spring-profile-name provider auto-completes the Spring profiles that are defined in the
configuration of the current project.
The following metadata snippet corresponds to the standard spring.profiles.active property that
defines the name of the Spring profile(s) to enable:
{"hints": [
{
"name": "spring.profiles.active",
"providers": [
{
"name": "spring-profile-name"
}
]
}
]}
B.3 Generating Your Own Metadata by Using the Annotation
Processor
You can easily generate your own configuration metadata file from items annotated with
@ConfigurationProperties by using the spring-boot-configuration-processor jar. The
jar includes a Java annotation processor which is invoked as your project is compiled. To use the
processor, include a dependency on spring-boot-configuration-processor.
With Maven the dependency should be declared as optional, as shown in the following example:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-configuration-processor</artifactId>
<optional>true</optional>
</dependency>
With Gradle 4.5 and earlier, the dependency should be declared in the compileOnly configuration,
as shown in the following example:
dependencies {
compileOnly "org.springframework.boot:spring-boot-configuration-processor"
}
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With Gradle 4.6 and later, the dependency should be declared in the annotationProcessor
configuration, as shown in the following example:
dependencies {
annotationProcessor "org.springframework.boot:spring-boot-configuration-processor"
}
If you are using an additional-spring-configuration-metadata.json file, the
compileJava task should be configured to depend on the processResources task, as shown in the
following example:
compileJava.dependsOn(processResources)
This dependency ensures that the additional metadata is available when the annotation processor runs
during compilation.
The processor picks up both classes and methods that are annotated with
@ConfigurationProperties. The Javadoc for field values within configuration classes is used to
populate the description attribute.
Note
You should only use simple text with @ConfigurationProperties field Javadoc, since they
are not processed before being added to the JSON.
Properties are discovered through the presence of standard getters and setters with special handling
for collection types (that is detected even if only a getter is present). The annotation processor also
supports the use of the @Data, @Getter, and @Setter lombok annotations.
Note
If you are using AspectJ in your project, you need to make sure that the annotation processor runs
only once. There are several ways to do this. With Maven, you can configure the maven-apt-
plugin explicitly and add the dependency to the annotation processor only there. You could also
let the AspectJ plugin run all the processing and disable annotation processing in the maven-
compiler-plugin configuration, as follows:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<proc>none</proc>
</configuration>
</plugin>
Nested Properties
The annotation processor automatically considers inner classes as nested properties. Consider the
following class:
@ConfigurationProperties(prefix="server")
public class ServerProperties {
private String name;
private Host host;
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// ... getter and setters
public static class Host {
private String ip;
private int port;
// ... getter and setters
}
}
The preceding example produces metadata information for server.name, server.host.ip, and
server.host.port properties. You can use the @NestedConfigurationProperty annotation on
a field to indicate that a regular (non-inner) class should be treated as if it were nested.
Tip
This has no effect on collections and maps, as those types are automatically identified, and a
single metadata property is generated for each of them.
Adding Additional Metadata
Spring Boot’s configuration file handling is quite flexible, and it is often the case that properties may
exist that are not bound to a @ConfigurationProperties bean. You may also need to tune some
attributes of an existing key. To support such cases and let you provide custom "hints", the annotation
processor automatically merges items from META-INF/additional-spring-configuration-
metadata.json into the main metadata file.
If you refer to a property that has been detected automatically, the description, default value, and
deprecation information are overridden, if specified. If the manual property declaration is not identified
in the current module, it is added as a new property.
The format of the additional-spring-configuration-metadata.json file is exactly the same
as the regular spring-configuration-metadata.json. The additional properties file is optional.
If you do not have any additional properties, do not add the file.
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Appendix C. Auto-configuration
classes
Here is a list of all auto-configuration classes provided by Spring Boot, with links to documentation and
source code. Remember to also look at the conditions report in your application for more details of
which features are switched on. (To do so, start the app with --debug or -Ddebug or, in an Actuator
application, use the conditions endpoint).
C.1 From the “spring-boot-autoconfigure” module
The following auto-configuration classes are from the spring-boot-autoconfigure module:
Configuration Class Links
ActiveMQAutoConfiguration javadoc
AopAutoConfiguration javadoc
ArtemisAutoConfiguration javadoc
BatchAutoConfiguration javadoc
CacheAutoConfiguration javadoc
CassandraAutoConfiguration javadoc
CassandraDataAutoConfiguration javadoc
CassandraReactiveDataAutoConfiguration javadoc
CassandraReactiveRepositoriesAutoConfiguration javadoc
CassandraRepositoriesAutoConfiguration javadoc
CloudAutoConfiguration javadoc
CodecsAutoConfiguration javadoc
ConfigurationPropertiesAutoConfiguration javadoc
CouchbaseAutoConfiguration javadoc
CouchbaseDataAutoConfiguration javadoc
CouchbaseReactiveDataAutoConfiguration javadoc
CouchbaseReactiveRepositoriesAutoConfiguration javadoc
CouchbaseRepositoriesAutoConfiguration javadoc
DataSourceAutoConfiguration javadoc
DataSourceTransactionManagerAutoConfiguration javadoc
DispatcherServletAutoConfiguration javadoc
ElasticsearchAutoConfiguration javadoc
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Configuration Class Links
ElasticsearchDataAutoConfiguration javadoc
ElasticsearchRepositoriesAutoConfiguration javadoc
EmbeddedLdapAutoConfiguration javadoc
EmbeddedMongoAutoConfiguration javadoc
EmbeddedWebServerFactoryCustomizerAutoConfiguration javadoc
ErrorMvcAutoConfiguration javadoc
ErrorWebFluxAutoConfiguration javadoc
FlywayAutoConfiguration javadoc
FreeMarkerAutoConfiguration javadoc
GroovyTemplateAutoConfiguration javadoc
GsonAutoConfiguration javadoc
H2ConsoleAutoConfiguration javadoc
HazelcastAutoConfiguration javadoc
HazelcastJpaDependencyAutoConfiguration javadoc
HibernateJpaAutoConfiguration javadoc
HttpEncodingAutoConfiguration javadoc
HttpHandlerAutoConfiguration javadoc
HttpMessageConvertersAutoConfiguration javadoc
HypermediaAutoConfiguration javadoc
InfluxDbAutoConfiguration javadoc
IntegrationAutoConfiguration javadoc
JacksonAutoConfiguration javadoc
JdbcTemplateAutoConfiguration javadoc
JerseyAutoConfiguration javadoc
JestAutoConfiguration javadoc
JmsAutoConfiguration javadoc
JmxAutoConfiguration javadoc
JndiConnectionFactoryAutoConfiguration javadoc
JndiDataSourceAutoConfiguration javadoc
JooqAutoConfiguration javadoc
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Configuration Class Links
JpaRepositoriesAutoConfiguration javadoc
JsonbAutoConfiguration javadoc
JtaAutoConfiguration javadoc
KafkaAutoConfiguration javadoc
LdapAutoConfiguration javadoc
LdapDataAutoConfiguration javadoc
LdapRepositoriesAutoConfiguration javadoc
LiquibaseAutoConfiguration javadoc
MailSenderAutoConfiguration javadoc
MailSenderValidatorAutoConfiguration javadoc
MessageSourceAutoConfiguration javadoc
MongoAutoConfiguration javadoc
MongoDataAutoConfiguration javadoc
MongoReactiveAutoConfiguration javadoc
MongoReactiveDataAutoConfiguration javadoc
MongoReactiveRepositoriesAutoConfiguration javadoc
MongoRepositoriesAutoConfiguration javadoc
MultipartAutoConfiguration javadoc
MustacheAutoConfiguration javadoc
Neo4jDataAutoConfiguration javadoc
Neo4jRepositoriesAutoConfiguration javadoc
OAuth2ClientAutoConfiguration javadoc
PersistenceExceptionTranslationAutoConfiguration javadoc
ProjectInfoAutoConfiguration javadoc
PropertyPlaceholderAutoConfiguration javadoc
QuartzAutoConfiguration javadoc
RabbitAutoConfiguration javadoc
ReactiveSecurityAutoConfiguration javadoc
ReactiveUserDetailsServiceAutoConfiguration javadoc
ReactiveWebServerFactoryAutoConfiguration javadoc
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Configuration Class Links
ReactorCoreAutoConfiguration javadoc
RedisAutoConfiguration javadoc
RedisReactiveAutoConfiguration javadoc
RedisRepositoriesAutoConfiguration javadoc
RepositoryRestMvcAutoConfiguration javadoc
RestTemplateAutoConfiguration javadoc
SecurityAutoConfiguration javadoc
SecurityFilterAutoConfiguration javadoc
SendGridAutoConfiguration javadoc
ServletWebServerFactoryAutoConfiguration javadoc
SessionAutoConfiguration javadoc
SolrAutoConfiguration javadoc
SolrRepositoriesAutoConfiguration javadoc
SpringApplicationAdminJmxAutoConfiguration javadoc
SpringDataWebAutoConfiguration javadoc
ThymeleafAutoConfiguration javadoc
TransactionAutoConfiguration javadoc
UserDetailsServiceAutoConfiguration javadoc
ValidationAutoConfiguration javadoc
WebClientAutoConfiguration javadoc
WebFluxAutoConfiguration javadoc
WebMvcAutoConfiguration javadoc
WebServicesAutoConfiguration javadoc
WebSocketMessagingAutoConfiguration javadoc
WebSocketReactiveAutoConfiguration javadoc
WebSocketServletAutoConfiguration javadoc
XADataSourceAutoConfiguration javadoc
C.2 From the “spring-boot-actuator-autoconfigure” module
The following auto-configuration classes are from the spring-boot-actuator-autoconfigure
module:
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Configuration Class Links
AtlasMetricsExportAutoConfiguration javadoc
AuditAutoConfiguration javadoc
AuditEventsEndpointAutoConfiguration javadoc
BeansEndpointAutoConfiguration javadoc
CacheMetricsAutoConfiguration javadoc
CassandraHealthIndicatorAutoConfiguration javadoc
CloudFoundryActuatorAutoConfiguration javadoc
CompositeMeterRegistryAutoConfiguration javadoc
ConditionsReportEndpointAutoConfiguration javadoc
ConfigurationPropertiesReportEndpointAutoConfiguration javadoc
CouchbaseHealthIndicatorAutoConfiguration javadoc
DataSourceHealthIndicatorAutoConfiguration javadoc
DataSourcePoolMetricsAutoConfiguration javadoc
DatadogMetricsExportAutoConfiguration javadoc
DiskSpaceHealthIndicatorAutoConfiguration javadoc
ElasticsearchHealthIndicatorAutoConfiguration javadoc
EndpointAutoConfiguration javadoc
EnvironmentEndpointAutoConfiguration javadoc
FlywayEndpointAutoConfiguration javadoc
GangliaMetricsExportAutoConfiguration javadoc
GraphiteMetricsExportAutoConfiguration javadoc
HealthEndpointAutoConfiguration javadoc
HealthIndicatorAutoConfiguration javadoc
HeapDumpWebEndpointAutoConfiguration javadoc
HttpTraceAutoConfiguration javadoc
HttpTraceEndpointAutoConfiguration javadoc
InfluxDbHealthIndicatorAutoConfiguration javadoc
InfluxMetricsExportAutoConfiguration javadoc
InfoContributorAutoConfiguration javadoc
InfoEndpointAutoConfiguration javadoc
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Configuration Class Links
JmsHealthIndicatorAutoConfiguration javadoc
JmxEndpointAutoConfiguration javadoc
JmxMetricsExportAutoConfiguration javadoc
JolokiaEndpointAutoConfiguration javadoc
LdapHealthIndicatorAutoConfiguration javadoc
LiquibaseEndpointAutoConfiguration javadoc
LogFileWebEndpointAutoConfiguration javadoc
LoggersEndpointAutoConfiguration javadoc
MailHealthIndicatorAutoConfiguration javadoc
ManagementContextAutoConfiguration javadoc
MappingsEndpointAutoConfiguration javadoc
MetricsAutoConfiguration javadoc
MetricsEndpointAutoConfiguration javadoc
MongoHealthIndicatorAutoConfiguration javadoc
Neo4jHealthIndicatorAutoConfiguration javadoc
NewRelicMetricsExportAutoConfiguration javadoc
PrometheusMetricsExportAutoConfiguration javadoc
RabbitHealthIndicatorAutoConfiguration javadoc
RabbitMetricsAutoConfiguration javadoc
ReactiveCloudFoundryActuatorAutoConfiguration javadoc
ReactiveManagementContextAutoConfiguration javadoc
RedisHealthIndicatorAutoConfiguration javadoc
RestTemplateMetricsAutoConfiguration javadoc
ScheduledTasksEndpointAutoConfiguration javadoc
ServletManagementContextAutoConfiguration javadoc
SessionsEndpointAutoConfiguration javadoc
ShutdownEndpointAutoConfiguration javadoc
SignalFxMetricsExportAutoConfiguration javadoc
SimpleMetricsExportAutoConfiguration javadoc
SolrHealthIndicatorAutoConfiguration javadoc
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Configuration Class Links
StatsdMetricsExportAutoConfiguration javadoc
ThreadDumpEndpointAutoConfiguration javadoc
TomcatMetricsAutoConfiguration javadoc
WavefrontMetricsExportAutoConfiguration javadoc
WebEndpointAutoConfiguration javadoc
WebFluxMetricsAutoConfiguration javadoc
WebMvcMetricsAutoConfiguration javadoc
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Appendix D. Test auto-configuration
annotations
The following table lists the various @…Test annotations that can be used to test slices of your application
and the auto-configuration that they import by default:
Test slice Imported auto-configuration
@DataJpaTest org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration
org.springframework.boot.autoconfigure.data.jpa.JpaRepositoriesAutoConfiguration
org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration
org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration
org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration
org.springframework.boot.autoconfigure.jdbc.JdbcTemplateAutoConfiguration
org.springframework.boot.autoconfigure.liquibase.LiquibaseAutoConfiguration
org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration
org.springframework.boot.autoconfigure.transaction.TransactionAutoConfiguration
org.springframework.boot.test.autoconfigure.jdbc.TestDatabaseAutoConfiguration
org.springframework.boot.test.autoconfigure.orm.jpa.TestEntityManagerAutoConfiguration
@DataLdapTest org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration
org.springframework.boot.autoconfigure.data.ldap.LdapDataAutoConfiguration
org.springframework.boot.autoconfigure.data.ldap.LdapRepositoriesAutoConfiguration
org.springframework.boot.autoconfigure.ldap.LdapAutoConfiguration
org.springframework.boot.autoconfigure.ldap.embedded.EmbeddedLdapAutoConfiguration
@DataMongoTest org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration
org.springframework.boot.autoconfigure.data.mongo.MongoDataAutoConfiguration
org.springframework.boot.autoconfigure.data.mongo.MongoReactiveDataAutoConfiguration
org.springframework.boot.autoconfigure.data.mongo.MongoReactiveRepositoriesAutoConfiguration
org.springframework.boot.autoconfigure.data.mongo.MongoRepositoriesAutoConfiguration
org.springframework.boot.autoconfigure.mongo.MongoAutoConfiguration
org.springframework.boot.autoconfigure.mongo.MongoReactiveAutoConfiguration
org.springframework.boot.autoconfigure.mongo.embedded.EmbeddedMongoAutoConfiguration
@DataNeo4jTest org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration
org.springframework.boot.autoconfigure.data.neo4j.Neo4jDataAutoConfiguration
org.springframework.boot.autoconfigure.data.neo4j.Neo4jRepositoriesAutoConfiguration
org.springframework.boot.autoconfigure.transaction.TransactionAutoConfiguration
@DataRedisTest org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration
org.springframework.boot.autoconfigure.data.redis.RedisAutoConfiguration
org.springframework.boot.autoconfigure.data.redis.RedisRepositoriesAutoConfiguration
@JdbcTest org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration
org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration
org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration
org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration
org.springframework.boot.autoconfigure.jdbc.JdbcTemplateAutoConfiguration
org.springframework.boot.autoconfigure.liquibase.LiquibaseAutoConfiguration
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Test slice Imported auto-configuration
org.springframework.boot.autoconfigure.transaction.TransactionAutoConfiguration
org.springframework.boot.test.autoconfigure.jdbc.TestDatabaseAutoConfiguration
@JooqTest org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration
org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration
org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration
org.springframework.boot.autoconfigure.jooq.JooqAutoConfiguration
org.springframework.boot.autoconfigure.liquibase.LiquibaseAutoConfiguration
org.springframework.boot.autoconfigure.transaction.TransactionAutoConfiguration
@JsonTest org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration
org.springframework.boot.autoconfigure.gson.GsonAutoConfiguration
org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration
org.springframework.boot.autoconfigure.jsonb.JsonbAutoConfiguration
org.springframework.boot.test.autoconfigure.json.JsonTestersAutoConfiguration
@RestClientTest org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration
org.springframework.boot.autoconfigure.gson.GsonAutoConfiguration
org.springframework.boot.autoconfigure.http.HttpMessageConvertersAutoConfiguration
org.springframework.boot.autoconfigure.http.codec.CodecsAutoConfiguration
org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration
org.springframework.boot.autoconfigure.jsonb.JsonbAutoConfiguration
org.springframework.boot.autoconfigure.web.client.RestTemplateAutoConfiguration
org.springframework.boot.autoconfigure.web.reactive.function.client.WebClientAutoConfiguration
org.springframework.boot.test.autoconfigure.web.client.MockRestServiceServerAutoConfiguration
org.springframework.boot.test.autoconfigure.web.client.WebClientRestTemplateAutoConfiguration
@WebFluxTest org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration
org.springframework.boot.autoconfigure.context.MessageSourceAutoConfiguration
org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration
org.springframework.boot.autoconfigure.web.reactive.WebFluxAutoConfiguration
org.springframework.boot.test.autoconfigure.web.reactive.WebTestClientAutoConfiguration
@WebMvcTest org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration
org.springframework.boot.autoconfigure.context.MessageSourceAutoConfiguration
org.springframework.boot.autoconfigure.freemarker.FreeMarkerAutoConfiguration
org.springframework.boot.autoconfigure.groovy.template.GroovyTemplateAutoConfiguration
org.springframework.boot.autoconfigure.gson.GsonAutoConfiguration
org.springframework.boot.autoconfigure.hateoas.HypermediaAutoConfiguration
org.springframework.boot.autoconfigure.http.HttpMessageConvertersAutoConfiguration
org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration
org.springframework.boot.autoconfigure.jsonb.JsonbAutoConfiguration
org.springframework.boot.autoconfigure.mustache.MustacheAutoConfiguration
org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration
org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration
org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration
org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration
org.springframework.boot.test.autoconfigure.web.servlet.MockMvcAutoConfiguration
org.springframework.boot.test.autoconfigure.web.servlet.MockMvcSecurityAutoConfiguration
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Test slice Imported auto-configuration
org.springframework.boot.test.autoconfigure.web.servlet.MockMvcWebClientAutoConfiguration
org.springframework.boot.test.autoconfigure.web.servlet.MockMvcWebDriverAutoConfiguration
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Appendix E. The Executable Jar
Format
The spring-boot-loader modules lets Spring Boot support executable jar and war files. If you use
the Maven plugin or the Gradle plugin, executable jars are automatically generated, and you generally
do not need to know the details of how they work.
If you need to create executable jars from a different build system or if you are just curious about the
underlying technology, this section provides some background.
E.1 Nested JARs
Java does not provide any standard way to load nested jar files (that is, jar files that are themselves
contained within a jar). This can be problematic if you need to distribute a self-contained application that
can be run from the command line without unpacking.
To solve this problem, many developers use “shaded” jars. A shaded jar packages all classes, from all
jars, into a single “uber jar”. The problem with shaded jars is that it becomes hard to see which libraries
are actually in your application. It can also be problematic if the same filename is used (but with different
content) in multiple jars. Spring Boot takes a different approach and lets you actually nest jars directly.
The Executable Jar File Structure
Spring Boot Loader-compatible jar files should be structured in the following way:
example.jar
|
+-META-INF
| +-MANIFEST.MF
+-org
| +-springframework
| +-boot
| +-loader
| +-<spring boot loader classes>
+-BOOT-INF
+-classes
| +-mycompany
| +-project
| +-YourClasses.class
+-lib
+-dependency1.jar
+-dependency2.jar
Application classes should be placed in a nested BOOT-INF/classes directory. Dependencies should
be placed in a nested BOOT-INF/lib directory.
The Executable War File Structure
Spring Boot Loader-compatible war files should be structured in the following way:
example.war
|
+-META-INF
| +-MANIFEST.MF
+-org
| +-springframework
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| +-boot
| +-loader
| +-<spring boot loader classes>
+-WEB-INF
+-classes
| +-com
| +-mycompany
| +-project
| +-YourClasses.class
+-lib
| +-dependency1.jar
| +-dependency2.jar
+-lib-provided
+-servlet-api.jar
+-dependency3.jar
Dependencies should be placed in a nested WEB-INF/lib directory. Any dependencies that are
required when running embedded but are not required when deploying to a traditional web container
should be placed in WEB-INF/lib-provided.
E.2 Spring Boot’s “JarFile” Class
The core class used to support loading nested jars is
org.springframework.boot.loader.jar.JarFile. It lets you load jar content from a standard
jar file or from nested child jar data. When first loaded, the location of each JarEntry is mapped to a
physical file offset of the outer jar, as shown in the following example:
myapp.jar
+-------------------+-------------------------+
| /BOOT-INF/classes | /BOOT-INF/lib/mylib.jar |
|+-----------------+||+-----------+----------+|
|| A.class ||| B.class | C.class ||
|+-----------------+||+-----------+----------+|
+-------------------+-------------------------+
^ ^ ^
0063 3452 3980
The preceding example shows how A.class can be found in /BOOT-INF/classes in myapp.jar
at position 0063. B.class from the nested jar can actually be found in myapp.jar at position 3452,
and C.class is at position 3980.
Armed with this information, we can load specific nested entries by seeking to the appropriate part of the
outer jar. We do not need to unpack the archive, and we do not need to read all entry data into memory.
Compatibility with the Standard Java “JarFile”
Spring Boot Loader strives to remain compatible with existing code and libraries.
org.springframework.boot.loader.jar.JarFile extends from java.util.jar.JarFile
and should work as a drop-in replacement. The getURL() method returns a URL that opens
a connection compatible with java.net.JarURLConnection and can be used with Java’s
URLClassLoader.
E.3 Launching Executable Jars
The org.springframework.boot.loader.Launcher class is a special bootstrap class that is
used as an executable jar’s main entry point. It is the actual Main-Class in your jar file, and it is used
to setup an appropriate URLClassLoader and ultimately call your main() method.
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There are three launcher subclasses (JarLauncher, WarLauncher, and PropertiesLauncher).
Their purpose is to load resources (.class files and so on.) from nested jar files or war files in directories
(as opposed to those explicitly on the classpath). In the case of JarLauncher and WarLauncher, the
nested paths are fixed. JarLauncher looks in BOOT-INF/lib/, and WarLauncher looks in WEB-
INF/lib/ and WEB-INF/lib-provided/. You can add extra jars in those locations if you want more.
The PropertiesLauncher looks in BOOT-INF/lib/ in your application archive by default, but you
can add additional locations by setting an environment variable called LOADER_PATH or loader.path
in loader.properties (which is a comma-separated list of directories, archives, or directories within
archives).
Launcher Manifest
You need to specify an appropriate Launcher as the Main-Class attribute of META-INF/
MANIFEST.MF. The actual class that you want to launch (that is, the class that contains a main method)
should be specified in the Start-Class attribute.
The following example shows a typical MANIFEST.MF for an executable jar file:
Main-Class: org.springframework.boot.loader.JarLauncher
Start-Class: com.mycompany.project.MyApplication
For a war file, it would be as follows:
Main-Class: org.springframework.boot.loader.WarLauncher
Start-Class: com.mycompany.project.MyApplication
Note
You need not specify Class-Path entries in your manifest file. The classpath is deduced from
the nested jars.
Exploded Archives
Certain PaaS implementations may choose to unpack archives before they run. For example, Cloud
Foundry operates this way. You can run an unpacked archive by starting the appropriate launcher, as
follows:
$ unzip -q myapp.jar
$ java org.springframework.boot.loader.JarLauncher
E.4 PropertiesLauncher Features
PropertiesLauncher has a few special features that can be enabled with external properties (System
properties, environment variables, manifest entries, or loader.properties). The following table
describes these properties:
Key Purpose
loader.path Comma-separated Classpath, such as lib,
${HOME}/app/lib. Earlier entries take
precedence, like a regular -classpath on the
javac command line.
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Key Purpose
loader.home Used to resolve relative paths in loader.path.
For example, given loader.path=lib,
then ${loader.home}/lib is a classpath
location (along with all jar files in that directory).
This property is also used to locate a
loader.properties file, as in the following
example /opt/app It defaults to ${user.dir}.
loader.args Default arguments for the main method (space
separated).
loader.main Name of main class to launch (for example,
com.app.Application).
loader.config.name Name of properties file (for example, launcher)
It defaults to loader.
loader.config.location Path to properties file (for example,
classpath:loader.properties). It defaults
to loader.properties.
loader.system Boolean flag to indicate that all properties should
be added to System properties It defaults to
false.
When specified as environment variables or manifest entries, the following names should be used:
Key Manifest entry Environment variable
loader.path Loader-Path LOADER_PATH
loader.home Loader-Home LOADER_HOME
loader.args Loader-Args LOADER_ARGS
loader.main Start-Class LOADER_MAIN
loader.config.location Loader-Config-Location LOADER_CONFIG_LOCATION
loader.system Loader-System LOADER_SYSTEM
Tip
Build plugins automatically move the Main-Class attribute to Start-Class when the fat jar is
built. If you use that, specify the name of the class to launch by using the Main-Class attribute
and leaving out Start-Class.
The following rules apply to working with PropertiesLauncher:
•loader.properties is searched for in loader.home, then in the root of the classpath, and then
in classpath:/BOOT-INF/classes. The first location where a file with that name exists is used.
•loader.home is the directory location of an additional properties file (overriding the default) only
when loader.config.location is not specified.
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•loader.path can contain directories (which are scanned recursively for jar and zip files), archive
paths, a directory within an archive that is scanned for jar files (for example, dependencies.jar!/
lib), or wildcard patterns (for the default JVM behavior). Archive paths can be relative to
loader.home or anywhere in the file system with a jar:file: prefix.
•loader.path (if empty) defaults to BOOT-INF/lib (meaning a local directory or a nested
one if running from an archive). Because of this, PropertiesLauncher behaves the same as
JarLauncher when no additional configuration is provided.
•loader.path can not be used to configure the location of loader.properties (the classpath
used to search for the latter is the JVM classpath when PropertiesLauncher is launched).
• Placeholder replacement is done from System and environment variables plus the properties file itself
on all values before use.
• The search order for properties (where it makes sense to look in more than one place) is environment
variables, system properties, loader.properties, the exploded archive manifest, and the archive
manifest.
E.5 Executable Jar Restrictions
You need to consider the following restrictions when working with a Spring Boot Loader packaged
application:
• Zip entry compression: The ZipEntry for a nested jar must be saved by using the
ZipEntry.STORED method. This is required so that we can seek directly to individual content within
the nested jar. The content of the nested jar file itself can still be compressed, as can any other entries
in the outer jar.
• System classLoader: Launched applications should use Thread.getContextClassLoader()
when loading classes (most libraries and frameworks do so by default). Trying to load nested jar
classes with ClassLoader.getSystemClassLoader() fails. java.util.Logging always uses
the system classloader. For this reason, you should consider a different logging implementation.
E.6 Alternative Single Jar Solutions
If the preceding restrictions mean that you cannot use Spring Boot Loader, consider the following
alternatives:
•Maven Shade Plugin
•JarClassLoader
•OneJar
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Appendix F. Dependency versions
The following table provides details of all of the dependency versions that are provided by Spring Boot
in its CLI (Command Line Interface), Maven dependency management, and Gradle plugin. When you
declare a dependency on one of these artifacts without declaring a version, the version listed in the
table is used.
Group ID Artifact ID Version
antlr antlr 2.7.7
ch.qos.logback logback-access 1.2.3
ch.qos.logback logback-classic 1.2.3
ch.qos.logback logback-core 1.2.3
com.atomikos transactions-jdbc 4.0.6
com.atomikos transactions-jms 4.0.6
com.atomikos transactions-jta 4.0.6
com.couchbase.client couchbase-spring-cache 2.1.0
com.couchbase.client java-client 2.5.9
com.datastax.cassandra cassandra-driver-core 3.4.0
com.datastax.cassandra cassandra-driver-
mapping
3.4.0
com.fasterxml classmate 1.3.4
com.fasterxml.jackson.corejackson-annotations 2.9.0
com.fasterxml.jackson.corejackson-core 2.9.6
com.fasterxml.jackson.corejackson-databind 2.9.6
com.fasterxml.jackson.dataformatjackson-dataformat-avro 2.9.6
com.fasterxml.jackson.dataformatjackson-dataformat-cbor 2.9.6
com.fasterxml.jackson.dataformatjackson-dataformat-csv 2.9.6
com.fasterxml.jackson.dataformatjackson-dataformat-ion 2.9.6
com.fasterxml.jackson.dataformatjackson-dataformat-
properties
2.9.6
com.fasterxml.jackson.dataformatjackson-dataformat-
protobuf
2.9.6
com.fasterxml.jackson.dataformatjackson-dataformat-
smile
2.9.6
com.fasterxml.jackson.dataformatjackson-dataformat-xml 2.9.6
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Group ID Artifact ID Version
com.fasterxml.jackson.dataformatjackson-dataformat-yaml 2.9.6
com.fasterxml.jackson.datatypejackson-datatype-guava 2.9.6
com.fasterxml.jackson.datatypejackson-datatype-
hibernate3
2.9.6
com.fasterxml.jackson.datatypejackson-datatype-
hibernate4
2.9.6
com.fasterxml.jackson.datatypejackson-datatype-
hibernate5
2.9.6
com.fasterxml.jackson.datatypejackson-datatype-hppc 2.9.6
com.fasterxml.jackson.datatypejackson-datatype-jaxrs 2.9.6
com.fasterxml.jackson.datatypejackson-datatype-jdk8 2.9.6
com.fasterxml.jackson.datatypejackson-datatype-joda 2.9.6
com.fasterxml.jackson.datatypejackson-datatype-json-
org
2.9.6
com.fasterxml.jackson.datatypejackson-datatype-jsr310 2.9.6
com.fasterxml.jackson.datatypejackson-datatype-jsr353 2.9.6
com.fasterxml.jackson.datatypejackson-datatype-
pcollections
2.9.6
com.fasterxml.jackson.jaxrsjackson-jaxrs-base 2.9.6
com.fasterxml.jackson.jaxrsjackson-jaxrs-cbor-
provider
2.9.6
com.fasterxml.jackson.jaxrsjackson-jaxrs-json-
provider
2.9.6
com.fasterxml.jackson.jaxrsjackson-jaxrs-smile-
provider
2.9.6
com.fasterxml.jackson.jaxrsjackson-jaxrs-xml-
provider
2.9.6
com.fasterxml.jackson.jaxrsjackson-jaxrs-yaml-
provider
2.9.6
com.fasterxml.jackson.jr jackson-jr-all 2.9.6
com.fasterxml.jackson.jr jackson-jr-objects 2.9.6
com.fasterxml.jackson.jr jackson-jr-retrofit2 2.9.6
com.fasterxml.jackson.jr jackson-jr-stree 2.9.6
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Group ID Artifact ID Version
com.fasterxml.jackson.modulejackson-module-
afterburner
2.9.6
com.fasterxml.jackson.modulejackson-module-guice 2.9.6
com.fasterxml.jackson.modulejackson-module-jaxb-
annotations
2.9.6
com.fasterxml.jackson.modulejackson-module-
jsonSchema
2.9.6
com.fasterxml.jackson.modulejackson-module-kotlin 2.9.6
com.fasterxml.jackson.modulejackson-module-mrbean 2.9.6
com.fasterxml.jackson.modulejackson-module-osgi 2.9.6
com.fasterxml.jackson.modulejackson-module-
parameter-names
2.9.6
com.fasterxml.jackson.modulejackson-module-
paranamer
2.9.6
com.fasterxml.jackson.modulejackson-module-
scala_2.10
2.9.6
com.fasterxml.jackson.modulejackson-module-
scala_2.11
2.9.6
com.fasterxml.jackson.modulejackson-module-
scala_2.12
2.9.6
com.github.ben-
manes.caffeine
caffeine 2.6.2
com.github.mxab.thymeleaf.extrasthymeleaf-extras-data-
attribute
2.0.1
com.google.appengine appengine-api-1.0-sdk 1.9.64
com.google.code.gson gson 2.8.5
com.googlecode.json-
simple
json-simple 1.1.1
com.h2database h2 1.4.197
com.hazelcast hazelcast 3.9.4
com.hazelcast hazelcast-client 3.9.4
com.hazelcast hazelcast-hibernate52 1.2.3
com.hazelcast hazelcast-spring 3.9.4
com.jayway.jsonpath json-path 2.4.0
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Group ID Artifact ID Version
com.jayway.jsonpath json-path-assert 2.4.0
com.microsoft.sqlserver mssql-jdbc 6.2.2.jre8
com.querydsl querydsl-apt 4.1.4
com.querydsl querydsl-collections 4.1.4
com.querydsl querydsl-core 4.1.4
com.querydsl querydsl-jpa 4.1.4
com.querydsl querydsl-mongodb 4.1.4
com.rabbitmq amqp-client 5.1.2
com.samskivert jmustache 1.14
com.sendgrid sendgrid-java 4.1.2
com.sun.mail javax.mail 1.6.1
com.timgroup java-statsd-client 3.1.0
com.unboundid unboundid-ldapsdk 4.0.6
com.zaxxer HikariCP 2.7.9
commons-codec commons-codec 1.11
commons-pool commons-pool 1.6
de.flapdoodle.embed de.flapdoodle.embed.mongo2.0.3
dom4j dom4j 1.6.1
io.dropwizard.metrics metrics-annotation 3.2.6
io.dropwizard.metrics metrics-core 3.2.6
io.dropwizard.metrics metrics-ehcache 3.2.6
io.dropwizard.metrics metrics-ganglia 3.2.6
io.dropwizard.metrics metrics-graphite 3.2.6
io.dropwizard.metrics metrics-healthchecks 3.2.6
io.dropwizard.metrics metrics-httpasyncclient 3.2.6
io.dropwizard.metrics metrics-jdbi 3.2.6
io.dropwizard.metrics metrics-jersey 3.2.6
io.dropwizard.metrics metrics-jersey2 3.2.6
io.dropwizard.metrics metrics-jetty8 3.2.6
io.dropwizard.metrics metrics-jetty9 3.2.6
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 378
Group ID Artifact ID Version
io.dropwizard.metrics metrics-jetty9-legacy 3.2.6
io.dropwizard.metrics metrics-json 3.2.6
io.dropwizard.metrics metrics-jvm 3.2.6
io.dropwizard.metrics metrics-log4j 3.2.6
io.dropwizard.metrics metrics-log4j2 3.2.6
io.dropwizard.metrics metrics-logback 3.2.6
io.dropwizard.metrics metrics-servlet 3.2.6
io.dropwizard.metrics metrics-servlets 3.2.6
io.lettuce lettuce-core 5.0.4.RELEASE
io.micrometer micrometer-core 1.0.6
io.micrometer micrometer-registry-
atlas
1.0.6
io.micrometer micrometer-registry-
datadog
1.0.6
io.micrometer micrometer-registry-
ganglia
1.0.6
io.micrometer micrometer-registry-
graphite
1.0.6
io.micrometer micrometer-registry-
influx
1.0.6
io.micrometer micrometer-registry-jmx 1.0.6
io.micrometer micrometer-registry-
new-relic
1.0.6
io.micrometer micrometer-registry-
prometheus
1.0.6
io.micrometer micrometer-registry-
signalfx
1.0.6
io.micrometer micrometer-registry-
statsd
1.0.6
io.micrometer micrometer-registry-
wavefront
1.0.6
io.netty netty-all 4.1.27.Final
io.netty netty-buffer 4.1.27.Final
io.netty netty-codec 4.1.27.Final
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 379
Group ID Artifact ID Version
io.netty netty-codec-dns 4.1.27.Final
io.netty netty-codec-haproxy 4.1.27.Final
io.netty netty-codec-http 4.1.27.Final
io.netty netty-codec-http2 4.1.27.Final
io.netty netty-codec-memcache 4.1.27.Final
io.netty netty-codec-mqtt 4.1.27.Final
io.netty netty-codec-redis 4.1.27.Final
io.netty netty-codec-smtp 4.1.27.Final
io.netty netty-codec-socks 4.1.27.Final
io.netty netty-codec-stomp 4.1.27.Final
io.netty netty-codec-xml 4.1.27.Final
io.netty netty-common 4.1.27.Final
io.netty netty-dev-tools 4.1.27.Final
io.netty netty-example 4.1.27.Final
io.netty netty-handler 4.1.27.Final
io.netty netty-handler-proxy 4.1.27.Final
io.netty netty-resolver 4.1.27.Final
io.netty netty-resolver-dns 4.1.27.Final
io.netty netty-transport 4.1.27.Final
io.netty netty-transport-native-
epoll
4.1.27.Final
io.netty netty-transport-native-
kqueue
4.1.27.Final
io.netty netty-transport-native-
unix-common
4.1.27.Final
io.netty netty-transport-rxtx 4.1.27.Final
io.netty netty-transport-sctp 4.1.27.Final
io.netty netty-transport-udt 4.1.27.Final
io.projectreactor reactor-core 3.1.8.RELEASE
io.projectreactor reactor-test 3.1.8.RELEASE
io.projectreactor.addons reactor-adapter 3.1.6.RELEASE
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 380
Group ID Artifact ID Version
io.projectreactor.addons reactor-extra 3.1.6.RELEASE
io.projectreactor.addons reactor-logback 3.1.6.RELEASE
io.projectreactor.ipc reactor-netty 0.7.8.RELEASE
io.projectreactor.kafka reactor-kafka 1.0.0.RELEASE
io.reactivex rxjava 1.3.8
io.reactivex rxjava-reactive-streams 1.2.1
io.reactivex.rxjava2 rxjava 2.1.16
io.rest-assured json-path 3.0.7
io.rest-assured json-schema-validator 3.0.7
io.rest-assured rest-assured 3.0.7
io.rest-assured scala-support 3.0.7
io.rest-assured spring-mock-mvc 3.0.7
io.rest-assured xml-path 3.0.7
io.searchbox jest 5.3.3
io.undertow undertow-core 1.4.25.Final
io.undertow undertow-servlet 1.4.25.Final
io.undertow undertow-websockets-jsr 1.4.25.Final
javax.annotation javax.annotation-api 1.3.2
javax.cache cache-api 1.1.0
javax.jms javax.jms-api 2.0.1
javax.json javax.json-api 1.1.2
javax.json.bind javax.json.bind-api 1.0
javax.mail javax.mail-api 1.6.1
javax.money money-api 1.0.3
javax.servlet javax.servlet-api 3.1.0
javax.servlet jstl 1.2
javax.transaction javax.transaction-api 1.2
javax.validation validation-api 2.0.1.Final
javax.xml.bind jaxb-api 2.3.0
jaxen jaxen 1.1.6
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 381
Group ID Artifact ID Version
joda-time joda-time 2.9.9
junit junit 4.12
mysql mysql-connector-java 5.1.46
net.bytebuddy byte-buddy 1.7.11
net.bytebuddy byte-buddy-agent 1.7.11
net.java.dev.jna jna 4.5.2
net.java.dev.jna jna-platform 4.5.2
net.sf.ehcache ehcache 2.10.5
net.sourceforge.htmlunit htmlunit 2.29
net.sourceforge.jtds jtds 1.3.1
net.sourceforge.nekohtml nekohtml 1.9.22
nz.net.ultraq.thymeleaf thymeleaf-layout-
dialect
2.3.0
org.apache.activemq activemq-amqp 5.15.4
org.apache.activemq activemq-blueprint 5.15.4
org.apache.activemq activemq-broker 5.15.4
org.apache.activemq activemq-camel 5.15.4
org.apache.activemq activemq-client 5.15.4
org.apache.activemq activemq-console 5.15.4
org.apache.activemq activemq-http 5.15.4
org.apache.activemq activemq-jaas 5.15.4
org.apache.activemq activemq-jdbc-store 5.15.4
org.apache.activemq activemq-jms-pool 5.15.4
org.apache.activemq activemq-kahadb-store 5.15.4
org.apache.activemq activemq-karaf 5.15.4
org.apache.activemq activemq-leveldb-store 5.15.4
org.apache.activemq activemq-log4j-appender 5.15.4
org.apache.activemq activemq-mqtt 5.15.4
org.apache.activemq activemq-openwire-
generator
5.15.4
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 382
Group ID Artifact ID Version
org.apache.activemq activemq-openwire-
legacy
5.15.4
org.apache.activemq activemq-osgi 5.15.4
org.apache.activemq activemq-partition 5.15.4
org.apache.activemq activemq-pool 5.15.4
org.apache.activemq activemq-ra 5.15.4
org.apache.activemq activemq-run 5.15.4
org.apache.activemq activemq-runtime-config 5.15.4
org.apache.activemq activemq-shiro 5.15.4
org.apache.activemq activemq-spring 5.15.4
org.apache.activemq activemq-stomp 5.15.4
org.apache.activemq activemq-web 5.15.4
org.apache.activemq artemis-amqp-protocol 2.4.0
org.apache.activemq artemis-commons 2.4.0
org.apache.activemq artemis-core-client 2.4.0
org.apache.activemq artemis-jms-client 2.4.0
org.apache.activemq artemis-jms-server 2.4.0
org.apache.activemq artemis-journal 2.4.0
org.apache.activemq artemis-native 2.4.0
org.apache.activemq artemis-selector 2.4.0
org.apache.activemq artemis-server 2.4.0
org.apache.activemq artemis-service-
extensions
2.4.0
org.apache.commons commons-dbcp2 2.2.0
org.apache.commons commons-lang3 3.7
org.apache.commons commons-pool2 2.5.0
org.apache.derby derby 10.14.1.0
org.apache.httpcomponentsfluent-hc 4.5.6
org.apache.httpcomponentshttpasyncclient 4.1.3
org.apache.httpcomponentshttpclient 4.5.6
org.apache.httpcomponentshttpclient-cache 4.5.6
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 383
Group ID Artifact ID Version
org.apache.httpcomponentshttpclient-osgi 4.5.6
org.apache.httpcomponentshttpclient-win 4.5.6
org.apache.httpcomponentshttpcore 4.4.10
org.apache.httpcomponentshttpcore-nio 4.4.10
org.apache.httpcomponentshttpmime 4.5.6
org.apache.johnzon johnzon-jsonb 1.1.8
org.apache.kafka connect-api 1.0.2
org.apache.kafka connect-file 1.0.2
org.apache.kafka connect-json 1.0.2
org.apache.kafka connect-runtime 1.0.2
org.apache.kafka connect-transforms 1.0.2
org.apache.kafka kafka_2.11 1.0.2
org.apache.kafka kafka_2.12 1.0.2
org.apache.kafka kafka-clients 1.0.2
org.apache.kafka kafka-log4j-appender 1.0.2
org.apache.kafka kafka-streams 1.0.2
org.apache.kafka kafka-tools 1.0.2
org.apache.logging.log4j log4j-1.2-api 2.10.0
org.apache.logging.log4j log4j-api 2.10.0
org.apache.logging.log4j log4j-cassandra 2.10.0
org.apache.logging.log4j log4j-core 2.10.0
org.apache.logging.log4j log4j-couchdb 2.10.0
org.apache.logging.log4j log4j-flume-ng 2.10.0
org.apache.logging.log4j log4j-iostreams 2.10.0
org.apache.logging.log4j log4j-jcl 2.10.0
org.apache.logging.log4j log4j-jmx-gui 2.10.0
org.apache.logging.log4j log4j-jul 2.10.0
org.apache.logging.log4j log4j-liquibase 2.10.0
org.apache.logging.log4j log4j-mongodb 2.10.0
org.apache.logging.log4j log4j-slf4j-impl 2.10.0
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 384
Group ID Artifact ID Version
org.apache.logging.log4j log4j-taglib 2.10.0
org.apache.logging.log4j log4j-to-slf4j 2.10.0
org.apache.logging.log4j log4j-web 2.10.0
org.apache.solr solr-analysis-extras 6.6.5
org.apache.solr solr-analytics 6.6.5
org.apache.solr solr-cell 6.6.5
org.apache.solr solr-clustering 6.6.5
org.apache.solr solr-core 6.6.5
org.apache.solr solr-dataimporthandler 6.6.5
org.apache.solr solr-dataimporthandler-
extras
6.6.5
org.apache.solr solr-langid 6.6.5
org.apache.solr solr-solrj 6.6.5
org.apache.solr solr-test-framework 6.6.5
org.apache.solr solr-uima 6.6.5
org.apache.solr solr-velocity 6.6.5
org.apache.tomcat tomcat-annotations-api 8.5.32
org.apache.tomcat tomcat-catalina-jmx-
remote
8.5.32
org.apache.tomcat tomcat-jdbc 8.5.32
org.apache.tomcat tomcat-jsp-api 8.5.32
org.apache.tomcat.embed tomcat-embed-core 8.5.32
org.apache.tomcat.embed tomcat-embed-el 8.5.32
org.apache.tomcat.embed tomcat-embed-jasper 8.5.32
org.apache.tomcat.embed tomcat-embed-websocket 8.5.32
org.aspectj aspectjrt 1.8.13
org.aspectj aspectjtools 1.8.13
org.aspectj aspectjweaver 1.8.13
org.assertj assertj-core 3.9.1
org.codehaus.btm btm 2.1.4
org.codehaus.groovy groovy 2.4.15
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 385
Group ID Artifact ID Version
org.codehaus.groovy groovy-all 2.4.15
org.codehaus.groovy groovy-ant 2.4.15
org.codehaus.groovy groovy-bsf 2.4.15
org.codehaus.groovy groovy-console 2.4.15
org.codehaus.groovy groovy-docgenerator 2.4.15
org.codehaus.groovy groovy-groovydoc 2.4.15
org.codehaus.groovy groovy-groovysh 2.4.15
org.codehaus.groovy groovy-jmx 2.4.15
org.codehaus.groovy groovy-json 2.4.15
org.codehaus.groovy groovy-jsr223 2.4.15
org.codehaus.groovy groovy-nio 2.4.15
org.codehaus.groovy groovy-servlet 2.4.15
org.codehaus.groovy groovy-sql 2.4.15
org.codehaus.groovy groovy-swing 2.4.15
org.codehaus.groovy groovy-templates 2.4.15
org.codehaus.groovy groovy-test 2.4.15
org.codehaus.groovy groovy-testng 2.4.15
org.codehaus.groovy groovy-xml 2.4.15
org.codehaus.janino janino 3.0.8
org.eclipse.jetty apache-jsp 9.4.11.v20180605
org.eclipse.jetty apache-jstl 9.4.11.v20180605
org.eclipse.jetty jetty-alpn-client 9.4.11.v20180605
org.eclipse.jetty jetty-alpn-conscrypt-
client
9.4.11.v20180605
org.eclipse.jetty jetty-alpn-conscrypt-
server
9.4.11.v20180605
org.eclipse.jetty jetty-alpn-java-client 9.4.11.v20180605
org.eclipse.jetty jetty-alpn-java-server 9.4.11.v20180605
org.eclipse.jetty jetty-alpn-openjdk8-
client
9.4.11.v20180605
org.eclipse.jetty jetty-alpn-openjdk8-
server
9.4.11.v20180605
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 386
Group ID Artifact ID Version
org.eclipse.jetty jetty-alpn-server 9.4.11.v20180605
org.eclipse.jetty jetty-annotations 9.4.11.v20180605
org.eclipse.jetty jetty-ant 9.4.11.v20180605
org.eclipse.jetty jetty-client 9.4.11.v20180605
org.eclipse.jetty jetty-continuation 9.4.11.v20180605
org.eclipse.jetty jetty-deploy 9.4.11.v20180605
org.eclipse.jetty jetty-distribution 9.4.11.v20180605
org.eclipse.jetty jetty-hazelcast 9.4.11.v20180605
org.eclipse.jetty jetty-home 9.4.11.v20180605
org.eclipse.jetty jetty-http 9.4.11.v20180605
org.eclipse.jetty jetty-http-spi 9.4.11.v20180605
org.eclipse.jetty jetty-infinispan 9.4.11.v20180605
org.eclipse.jetty jetty-io 9.4.11.v20180605
org.eclipse.jetty jetty-jaas 9.4.11.v20180605
org.eclipse.jetty jetty-jaspi 9.4.11.v20180605
org.eclipse.jetty jetty-jmx 9.4.11.v20180605
org.eclipse.jetty jetty-jndi 9.4.11.v20180605
org.eclipse.jetty jetty-nosql 9.4.11.v20180605
org.eclipse.jetty jetty-plus 9.4.11.v20180605
org.eclipse.jetty jetty-proxy 9.4.11.v20180605
org.eclipse.jetty jetty-quickstart 9.4.11.v20180605
org.eclipse.jetty jetty-rewrite 9.4.11.v20180605
org.eclipse.jetty jetty-security 9.4.11.v20180605
org.eclipse.jetty jetty-server 9.4.11.v20180605
org.eclipse.jetty jetty-servlet 9.4.11.v20180605
org.eclipse.jetty jetty-servlets 9.4.11.v20180605
org.eclipse.jetty jetty-spring 9.4.11.v20180605
org.eclipse.jetty jetty-unixsocket 9.4.11.v20180605
org.eclipse.jetty jetty-util 9.4.11.v20180605
org.eclipse.jetty jetty-util-ajax 9.4.11.v20180605
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 387
Group ID Artifact ID Version
org.eclipse.jetty jetty-webapp 9.4.11.v20180605
org.eclipse.jetty jetty-xml 9.4.11.v20180605
org.eclipse.jetty.cdi cdi-core 9.4.11.v20180605
org.eclipse.jetty.cdi cdi-servlet 9.4.11.v20180605
org.eclipse.jetty.fcgi fcgi-client 9.4.11.v20180605
org.eclipse.jetty.fcgi fcgi-server 9.4.11.v20180605
org.eclipse.jetty.gcloud jetty-gcloud-session-
manager
9.4.11.v20180605
org.eclipse.jetty.http2 http2-client 9.4.11.v20180605
org.eclipse.jetty.http2 http2-common 9.4.11.v20180605
org.eclipse.jetty.http2 http2-hpack 9.4.11.v20180605
org.eclipse.jetty.http2 http2-http-client-
transport
9.4.11.v20180605
org.eclipse.jetty.http2 http2-server 9.4.11.v20180605
org.eclipse.jetty.memcachedjetty-memcached-
sessions
9.4.11.v20180605
org.eclipse.jetty.orbit javax.servlet.jsp 2.2.0.v201112011158
org.eclipse.jetty.osgi jetty-httpservice 9.4.11.v20180605
org.eclipse.jetty.osgi jetty-osgi-boot 9.4.11.v20180605
org.eclipse.jetty.osgi jetty-osgi-boot-jsp 9.4.11.v20180605
org.eclipse.jetty.osgi jetty-osgi-boot-warurl 9.4.11.v20180605
org.eclipse.jetty.websocketjavax-websocket-client-
impl
9.4.11.v20180605
org.eclipse.jetty.websocketjavax-websocket-server-
impl
9.4.11.v20180605
org.eclipse.jetty.websocketwebsocket-api 9.4.11.v20180605
org.eclipse.jetty.websocketwebsocket-client 9.4.11.v20180605
org.eclipse.jetty.websocketwebsocket-common 9.4.11.v20180605
org.eclipse.jetty.websocketwebsocket-server 9.4.11.v20180605
org.eclipse.jetty.websocketwebsocket-servlet 9.4.11.v20180605
org.ehcache ehcache 3.5.2
org.ehcache ehcache-clustered 3.5.2
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 388
Group ID Artifact ID Version
org.ehcache ehcache-transactions 3.5.2
org.elasticsearch elasticsearch 5.6.10
org.elasticsearch.client transport 5.6.10
org.elasticsearch.distribution.integ-
test-zip
elasticsearch 5.6.10
org.elasticsearch.plugin transport-netty4-client 5.6.10
org.firebirdsql.jdbc jaybird-jdk17 3.0.4
org.firebirdsql.jdbc jaybird-jdk18 3.0.4
org.flywaydb flyway-core 5.0.7
org.freemarker freemarker 2.3.28
org.glassfish javax.el 3.0.0
org.glassfish.jersey.containersjersey-container-
servlet
2.26
org.glassfish.jersey.containersjersey-container-
servlet-core
2.26
org.glassfish.jersey.corejersey-client 2.26
org.glassfish.jersey.corejersey-common 2.26
org.glassfish.jersey.corejersey-server 2.26
org.glassfish.jersey.ext jersey-bean-validation 2.26
org.glassfish.jersey.ext jersey-entity-filtering 2.26
org.glassfish.jersey.ext jersey-spring4 2.26
org.glassfish.jersey.mediajersey-media-jaxb 2.26
org.glassfish.jersey.mediajersey-media-json-
jackson
2.26
org.glassfish.jersey.mediajersey-media-multipart 2.26
org.hamcrest hamcrest-core 1.3
org.hamcrest hamcrest-library 1.3
org.hibernate hibernate-c3p0 5.2.17.Final
org.hibernate hibernate-core 5.2.17.Final
org.hibernate hibernate-ehcache 5.2.17.Final
org.hibernate hibernate-entitymanager 5.2.17.Final
org.hibernate hibernate-envers 5.2.17.Final
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 389
Group ID Artifact ID Version
org.hibernate hibernate-hikaricp 5.2.17.Final
org.hibernate hibernate-infinispan 5.2.17.Final
org.hibernate hibernate-java8 5.2.17.Final
org.hibernate hibernate-jcache 5.2.17.Final
org.hibernate hibernate-jpamodelgen 5.2.17.Final
org.hibernate hibernate-proxool 5.2.17.Final
org.hibernate hibernate-spatial 5.2.17.Final
org.hibernate hibernate-testing 5.2.17.Final
org.hibernate.javax.persistencehibernate-jpa-2.1-api 1.0.2.Final
org.hibernate.validator hibernate-validator 6.0.11.Final
org.hibernate.validator hibernate-validator-
annotation-processor
6.0.11.Final
org.hsqldb hsqldb 2.4.1
org.infinispan infinispan-cachestore-
jdbc
9.1.7.Final
org.infinispan infinispan-cachestore-
jpa
9.1.7.Final
org.infinispan infinispan-cachestore-
leveldb
9.1.7.Final
org.infinispan infinispan-cachestore-
remote
9.1.7.Final
org.infinispan infinispan-cachestore-
rest
9.1.7.Final
org.infinispan infinispan-cachestore-
rocksdb
9.1.7.Final
org.infinispan infinispan-cdi-common 9.1.7.Final
org.infinispan infinispan-cdi-embedded 9.1.7.Final
org.infinispan infinispan-cdi-remote 9.1.7.Final
org.infinispan infinispan-cli 9.1.7.Final
org.infinispan infinispan-client-
hotrod
9.1.7.Final
org.infinispan infinispan-cloud 9.1.7.Final
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 390
Group ID Artifact ID Version
org.infinispan infinispan-clustered-
counter
9.1.7.Final
org.infinispan infinispan-commons 9.1.7.Final
org.infinispan infinispan-core 9.1.7.Final
org.infinispan infinispan-directory-
provider
9.1.7.Final
org.infinispan infinispan-embedded 9.1.7.Final
org.infinispan infinispan-embedded-
query
9.1.7.Final
org.infinispan infinispan-hibernate-
cache
9.1.7.Final
org.infinispan infinispan-jcache 9.1.7.Final
org.infinispan infinispan-jcache-
commons
9.1.7.Final
org.infinispan infinispan-jcache-
remote
9.1.7.Final
org.infinispan infinispan-lucene-
directory
9.1.7.Final
org.infinispan infinispan-objectfilter 9.1.7.Final
org.infinispan infinispan-osgi 9.1.7.Final
org.infinispan infinispan-persistence-
cli
9.1.7.Final
org.infinispan infinispan-persistence-
soft-index
9.1.7.Final
org.infinispan infinispan-query 9.1.7.Final
org.infinispan infinispan-query-dsl 9.1.7.Final
org.infinispan infinispan-remote 9.1.7.Final
org.infinispan infinispan-remote-
query-client
9.1.7.Final
org.infinispan infinispan-remote-
query-server
9.1.7.Final
org.infinispan infinispan-scripting 9.1.7.Final
org.infinispan infinispan-server-core 9.1.7.Final
org.infinispan infinispan-server-
hotrod
9.1.7.Final
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 391
Group ID Artifact ID Version
org.infinispan infinispan-server-
memcached
9.1.7.Final
org.infinispan infinispan-server-
router
9.1.7.Final
org.infinispan infinispan-server-
websocket
9.1.7.Final
org.infinispan infinispan-spring4-
common
9.1.7.Final
org.infinispan infinispan-spring4-
embedded
9.1.7.Final
org.infinispan infinispan-spring4-
remote
9.1.7.Final
org.infinispan infinispan-tasks 9.1.7.Final
org.infinispan infinispan-tasks-api 9.1.7.Final
org.infinispan infinispan-tools 9.1.7.Final
org.infinispan infinispan-tree 9.1.7.Final
org.influxdb influxdb-java 2.9
org.jboss jboss-transaction-spi 7.6.0.Final
org.jboss.logging jboss-logging 3.3.2.Final
org.jboss.narayana.jta jdbc 5.8.2.Final
org.jboss.narayana.jta jms 5.8.2.Final
org.jboss.narayana.jta jta 5.8.2.Final
org.jboss.narayana.jts narayana-jts-
integration
5.8.2.Final
org.jdom jdom2 2.0.6
org.jetbrains.kotlin kotlin-reflect 1.2.51
org.jetbrains.kotlin kotlin-runtime 1.2.51
org.jetbrains.kotlin kotlin-stdlib 1.2.51
org.jetbrains.kotlin kotlin-stdlib-jdk7 1.2.51
org.jetbrains.kotlin kotlin-stdlib-jdk8 1.2.51
org.jetbrains.kotlin kotlin-stdlib-jre7 1.2.51
org.jetbrains.kotlin kotlin-stdlib-jre8 1.2.51
org.jolokia jolokia-core 1.5.0
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 392
Group ID Artifact ID Version
org.jooq jooq 3.10.8
org.jooq jooq-codegen 3.10.8
org.jooq jooq-meta 3.10.8
org.junit.jupiter junit-jupiter-api 5.1.1
org.junit.jupiter junit-jupiter-engine 5.1.1
org.junit.jupiter junit-jupiter-params 5.1.1
org.junit.vintage junit-vintage-engine 5.1.1
org.liquibase liquibase-core 3.5.5
org.mariadb.jdbc mariadb-java-client 2.2.6
org.mockito mockito-core 2.15.0
org.mockito mockito-inline 2.15.0
org.mongodb bson 3.6.4
org.mongodb mongodb-driver 3.6.4
org.mongodb mongodb-driver-async 3.6.4
org.mongodb mongodb-driver-core 3.6.4
org.mongodb mongodb-driver-
reactivestreams
1.7.1
org.mongodb mongo-java-driver 3.6.4
org.mortbay.jasper apache-el 8.5.24.2
org.neo4j neo4j-ogm-api 3.1.0
org.neo4j neo4j-ogm-bolt-driver 3.1.0
org.neo4j neo4j-ogm-core 3.1.0
org.neo4j neo4j-ogm-http-driver 3.1.0
org.postgresql postgresql 42.2.4
org.projectlombok lombok 1.16.22
org.quartz-scheduler quartz 2.3.0
org.quartz-scheduler quartz-jobs 2.3.0
org.reactivestreams reactive-streams 1.0.2
org.seleniumhq.selenium htmlunit-driver 2.29.3
org.seleniumhq.selenium selenium-api 3.9.1
org.seleniumhq.selenium selenium-chrome-driver 3.9.1
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 393
Group ID Artifact ID Version
org.seleniumhq.selenium selenium-edge-driver 3.9.1
org.seleniumhq.selenium selenium-firefox-driver 3.9.1
org.seleniumhq.selenium selenium-ie-driver 3.9.1
org.seleniumhq.selenium selenium-java 3.9.1
org.seleniumhq.selenium selenium-opera-driver 3.9.1
org.seleniumhq.selenium selenium-remote-driver 3.9.1
org.seleniumhq.selenium selenium-safari-driver 3.9.1
org.seleniumhq.selenium selenium-support 3.9.1
org.skyscreamer jsonassert 1.5.0
org.slf4j jcl-over-slf4j 1.7.25
org.slf4j jul-to-slf4j 1.7.25
org.slf4j log4j-over-slf4j 1.7.25
org.slf4j slf4j-api 1.7.25
org.slf4j slf4j-ext 1.7.25
org.slf4j slf4j-jcl 1.7.25
org.slf4j slf4j-jdk14 1.7.25
org.slf4j slf4j-log4j12 1.7.25
org.slf4j slf4j-nop 1.7.25
org.slf4j slf4j-simple 1.7.25
org.springframework spring-aop 5.0.8.RELEASE
org.springframework spring-aspects 5.0.8.RELEASE
org.springframework spring-beans 5.0.8.RELEASE
org.springframework spring-context 5.0.8.RELEASE
org.springframework spring-context-indexer 5.0.8.RELEASE
org.springframework spring-context-support 5.0.8.RELEASE
org.springframework spring-core 5.0.8.RELEASE
org.springframework spring-expression 5.0.8.RELEASE
org.springframework spring-instrument 5.0.8.RELEASE
org.springframework spring-jcl 5.0.8.RELEASE
org.springframework spring-jdbc 5.0.8.RELEASE
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 394
Group ID Artifact ID Version
org.springframework spring-jms 5.0.8.RELEASE
org.springframework spring-messaging 5.0.8.RELEASE
org.springframework spring-orm 5.0.8.RELEASE
org.springframework spring-oxm 5.0.8.RELEASE
org.springframework spring-test 5.0.8.RELEASE
org.springframework spring-tx 5.0.8.RELEASE
org.springframework spring-web 5.0.8.RELEASE
org.springframework spring-webflux 5.0.8.RELEASE
org.springframework spring-webmvc 5.0.8.RELEASE
org.springframework spring-websocket 5.0.8.RELEASE
org.springframework.amqp spring-amqp 2.0.5.RELEASE
org.springframework.amqp spring-rabbit 2.0.5.RELEASE
org.springframework.amqp spring-rabbit-junit 2.0.5.RELEASE
org.springframework.amqp spring-rabbit-test 2.0.5.RELEASE
org.springframework.batchspring-batch-core 4.0.1.RELEASE
org.springframework.batchspring-batch-
infrastructure
4.0.1.RELEASE
org.springframework.batchspring-batch-
integration
4.0.1.RELEASE
org.springframework.batchspring-batch-test 4.0.1.RELEASE
org.springframework.boot spring-boot 2.0.4.RELEASE
org.springframework.boot spring-boot-actuator 2.0.4.RELEASE
org.springframework.boot spring-boot-actuator-
autoconfigure
2.0.4.RELEASE
org.springframework.boot spring-boot-
autoconfigure
2.0.4.RELEASE
org.springframework.boot spring-boot-
autoconfigure-processor
2.0.4.RELEASE
org.springframework.boot spring-boot-
configuration-metadata
2.0.4.RELEASE
org.springframework.boot spring-boot-
configuration-processor
2.0.4.RELEASE
org.springframework.boot spring-boot-devtools 2.0.4.RELEASE
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 395
Group ID Artifact ID Version
org.springframework.boot spring-boot-loader 2.0.4.RELEASE
org.springframework.boot spring-boot-loader-
tools
2.0.4.RELEASE
org.springframework.boot spring-boot-properties-
migrator
2.0.4.RELEASE
org.springframework.boot spring-boot-starter 2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
activemq
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
actuator
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
amqp
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-aop 2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
artemis
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
batch
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
cache
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
cloud-connectors
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
data-cassandra
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
data-cassandra-reactive
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
data-couchbase
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
data-couchbase-reactive
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
data-elasticsearch
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
data-jpa
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
data-ldap
2.0.4.RELEASE
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 396
Group ID Artifact ID Version
org.springframework.boot spring-boot-starter-
data-mongodb
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
data-mongodb-reactive
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
data-neo4j
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
data-redis
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
data-redis-reactive
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
data-rest
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
data-solr
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
freemarker
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
groovy-templates
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
hateoas
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
integration
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
jdbc
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
jersey
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
jetty
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
jooq
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
json
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
jta-atomikos
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
jta-bitronix
2.0.4.RELEASE
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 397
Group ID Artifact ID Version
org.springframework.boot spring-boot-starter-
jta-narayana
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
log4j2
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
logging
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
mail
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
mustache
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
quartz
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
reactor-netty
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
security
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
test
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
thymeleaf
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
tomcat
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
undertow
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
validation
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-web 2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
webflux
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
web-services
2.0.4.RELEASE
org.springframework.boot spring-boot-starter-
websocket
2.0.4.RELEASE
org.springframework.boot spring-boot-test 2.0.4.RELEASE
org.springframework.boot spring-boot-test-
autoconfigure
2.0.4.RELEASE
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 398
Group ID Artifact ID Version
org.springframework.cloudspring-cloud-
cloudfoundry-connector
2.0.2.RELEASE
org.springframework.cloudspring-cloud-
connectors-core
2.0.2.RELEASE
org.springframework.cloudspring-cloud-heroku-
connector
2.0.2.RELEASE
org.springframework.cloudspring-cloud-
localconfig-connector
2.0.2.RELEASE
org.springframework.cloudspring-cloud-spring-
service-connector
2.0.2.RELEASE
org.springframework.data spring-data-cassandra 2.0.9.RELEASE
org.springframework.data spring-data-commons 2.0.9.RELEASE
org.springframework.data spring-data-couchbase 3.0.9.RELEASE
org.springframework.data spring-data-
elasticsearch
3.0.9.RELEASE
org.springframework.data spring-data-envers 2.0.9.RELEASE
org.springframework.data spring-data-gemfire 2.0.9.RELEASE
org.springframework.data spring-data-geode 2.0.9.RELEASE
org.springframework.data spring-data-jpa 2.0.9.RELEASE
org.springframework.data spring-data-keyvalue 2.0.9.RELEASE
org.springframework.data spring-data-ldap 2.0.9.RELEASE
org.springframework.data spring-data-mongodb 2.0.9.RELEASE
org.springframework.data spring-data-mongodb-
cross-store
2.0.9.RELEASE
org.springframework.data spring-data-neo4j 5.0.9.RELEASE
org.springframework.data spring-data-redis 2.0.9.RELEASE
org.springframework.data spring-data-rest-core 3.0.9.RELEASE
org.springframework.data spring-data-rest-hal-
browser
3.0.9.RELEASE
org.springframework.data spring-data-rest-webmvc 3.0.9.RELEASE
org.springframework.data spring-data-solr 3.0.9.RELEASE
org.springframework.hateoasspring-hateoas 0.25.0.RELEASE
org.springframework.integrationspring-integration-amqp 5.0.7.RELEASE
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 399
Group ID Artifact ID Version
org.springframework.integrationspring-integration-core 5.0.7.RELEASE
org.springframework.integrationspring-integration-
event
5.0.7.RELEASE
org.springframework.integrationspring-integration-feed 5.0.7.RELEASE
org.springframework.integrationspring-integration-file 5.0.7.RELEASE
org.springframework.integrationspring-integration-ftp 5.0.7.RELEASE
org.springframework.integrationspring-integration-
gemfire
5.0.7.RELEASE
org.springframework.integrationspring-integration-
groovy
5.0.7.RELEASE
org.springframework.integrationspring-integration-http 5.0.7.RELEASE
org.springframework.integrationspring-integration-ip 5.0.7.RELEASE
org.springframework.integrationspring-integration-jdbc 5.0.7.RELEASE
org.springframework.integrationspring-integration-jms 5.0.7.RELEASE
org.springframework.integrationspring-integration-jmx 5.0.7.RELEASE
org.springframework.integrationspring-integration-jpa 5.0.7.RELEASE
org.springframework.integrationspring-integration-mail 5.0.7.RELEASE
org.springframework.integrationspring-integration-
mongodb
5.0.7.RELEASE
org.springframework.integrationspring-integration-mqtt 5.0.7.RELEASE
org.springframework.integrationspring-integration-
redis
5.0.7.RELEASE
org.springframework.integrationspring-integration-rmi 5.0.7.RELEASE
org.springframework.integrationspring-integration-
scripting
5.0.7.RELEASE
org.springframework.integrationspring-integration-
security
5.0.7.RELEASE
org.springframework.integrationspring-integration-sftp 5.0.7.RELEASE
org.springframework.integrationspring-integration-
stomp
5.0.7.RELEASE
org.springframework.integrationspring-integration-
stream
5.0.7.RELEASE
org.springframework.integrationspring-integration-
syslog
5.0.7.RELEASE
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 400
Group ID Artifact ID Version
org.springframework.integrationspring-integration-test 5.0.7.RELEASE
org.springframework.integrationspring-integration-
test-support
5.0.7.RELEASE
org.springframework.integrationspring-integration-
twitter
5.0.7.RELEASE
org.springframework.integrationspring-integration-
webflux
5.0.7.RELEASE
org.springframework.integrationspring-integration-
websocket
5.0.7.RELEASE
org.springframework.integrationspring-integration-ws 5.0.7.RELEASE
org.springframework.integrationspring-integration-xml 5.0.7.RELEASE
org.springframework.integrationspring-integration-xmpp 5.0.7.RELEASE
org.springframework.integrationspring-integration-
zookeeper
5.0.7.RELEASE
org.springframework.kafkaspring-kafka 2.1.8.RELEASE
org.springframework.kafkaspring-kafka-test 2.1.8.RELEASE
org.springframework.ldap spring-ldap-core 2.3.2.RELEASE
org.springframework.ldap spring-ldap-core-tiger 2.3.2.RELEASE
org.springframework.ldap spring-ldap-ldif-batch 2.3.2.RELEASE
org.springframework.ldap spring-ldap-ldif-core 2.3.2.RELEASE
org.springframework.ldap spring-ldap-odm 2.3.2.RELEASE
org.springframework.ldap spring-ldap-test 2.3.2.RELEASE
org.springframework.pluginspring-plugin-core 1.2.0.RELEASE
org.springframework.pluginspring-plugin-metadata 1.2.0.RELEASE
org.springframework.restdocsspring-restdocs-
asciidoctor
2.0.2.RELEASE
org.springframework.restdocsspring-restdocs-core 2.0.2.RELEASE
org.springframework.restdocsspring-restdocs-mockmvc 2.0.2.RELEASE
org.springframework.restdocsspring-restdocs-
restassured
2.0.2.RELEASE
org.springframework.restdocsspring-restdocs-
webtestclient
2.0.2.RELEASE
org.springframework.retryspring-retry 1.2.2.RELEASE
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 401
Group ID Artifact ID Version
org.springframework.securityspring-security-acl 5.0.7.RELEASE
org.springframework.securityspring-security-aspects 5.0.7.RELEASE
org.springframework.securityspring-security-cas 5.0.7.RELEASE
org.springframework.securityspring-security-config 5.0.7.RELEASE
org.springframework.securityspring-security-core 5.0.7.RELEASE
org.springframework.securityspring-security-crypto 5.0.7.RELEASE
org.springframework.securityspring-security-data 5.0.7.RELEASE
org.springframework.securityspring-security-ldap 5.0.7.RELEASE
org.springframework.securityspring-security-
messaging
5.0.7.RELEASE
org.springframework.securityspring-security-oauth2-
client
5.0.7.RELEASE
org.springframework.securityspring-security-oauth2-
core
5.0.7.RELEASE
org.springframework.securityspring-security-oauth2-
jose
5.0.7.RELEASE
org.springframework.securityspring-security-openid 5.0.7.RELEASE
org.springframework.securityspring-security-
remoting
5.0.7.RELEASE
org.springframework.securityspring-security-taglibs 5.0.7.RELEASE
org.springframework.securityspring-security-test 5.0.7.RELEASE
org.springframework.securityspring-security-web 5.0.7.RELEASE
org.springframework.sessionspring-session-core 2.0.5.RELEASE
org.springframework.sessionspring-session-data-
gemfire
2.0.3.RELEASE
org.springframework.sessionspring-session-data-
geode
2.0.3.RELEASE
org.springframework.sessionspring-session-data-
mongodb
2.0.2.RELEASE
org.springframework.sessionspring-session-data-
redis
2.0.5.RELEASE
org.springframework.sessionspring-session-
hazelcast
2.0.5.RELEASE
org.springframework.sessionspring-session-jdbc 2.0.5.RELEASE
Spring Boot Reference Guide
2.0.4.RELEASE Spring Boot 402
Group ID Artifact ID Version
org.springframework.ws spring-ws-core 3.0.3.RELEASE
org.springframework.ws spring-ws-security 3.0.3.RELEASE
org.springframework.ws spring-ws-support 3.0.3.RELEASE
org.springframework.ws spring-ws-test 3.0.3.RELEASE
org.springframework.ws spring-xml 3.0.3.RELEASE
org.synchronoss.cloud nio-multipart-parser 1.1.0
org.thymeleaf thymeleaf 3.0.9.RELEASE
org.thymeleaf thymeleaf-spring5 3.0.9.RELEASE
org.thymeleaf.extras thymeleaf-extras-
java8time
3.0.1.RELEASE
org.thymeleaf.extras thymeleaf-extras-
springsecurity4
3.0.2.RELEASE
org.webjars hal-browser 3325375
org.webjars webjars-locator-core 0.35
org.xerial sqlite-jdbc 3.21.0.1
org.xmlunit xmlunit-core 2.5.1
org.xmlunit xmlunit-legacy 2.5.1
org.xmlunit xmlunit-matchers 2.5.1
org.yaml snakeyaml 1.19
redis.clients jedis 2.9.0
wsdl4j wsdl4j 1.6.3
xml-apis xml-apis 1.4.01

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