Spring Boot Reference Guide

User Manual:

Open the PDF directly: View PDF PDF.
Page Count: 378 [warning: Documents this large are best viewed by clicking the View PDF Link!]

Spring Boot Reference Guide
1.5.7.RELEASE
Phillip Webb , Dave Syer , Josh Long , Stéphane Nicoll , Rob Winch , Andy
Wilkinson , Marcel Overdijk , Christian Dupuis , Sébastien Deleuze , Michael Simons
Copyright © 2012-2017
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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot ii
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
Quick start Spring CLI example ......................................................................... 15
10.3. Upgrading from an earlier version of Spring Boot ............................................... 16
11. Developing your first Spring Boot application ................................................................ 17
11.1. Creating the POM ............................................................................................ 17
11.2. Adding classpath dependencies ........................................................................ 18
11.3. Writing the code ............................................................................................... 18
The @RestController and @RequestMapping annotations .................................. 19
The @EnableAutoConfiguration annotation ........................................................ 19
The “main” method ........................................................................................... 19
11.4. Running the example ........................................................................................ 19
11.5. Creating an executable jar ................................................................................ 20
12. What to read next ....................................................................................................... 22
III. Using Spring Boot ................................................................................................................ 23
13. Build systems ............................................................................................................. 24
13.1. Dependency management ................................................................................ 24
13.2. Maven .............................................................................................................. 24
Inheriting the starter parent ............................................................................... 24
Using Spring Boot without the parent POM ........................................................ 25
Changing the Java version ................................................................................ 26
Using the Spring Boot Maven plugin .................................................................. 26
13.3. Gradle .............................................................................................................. 26
13.4. Ant ................................................................................................................... 27
13.5. Starters ............................................................................................................ 28
14. Structuring your code .................................................................................................. 33
14.1. Using the “default” package .............................................................................. 33
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot iii
14.2. Locating the main application class ................................................................... 33
15. Configuration classes .................................................................................................. 35
15.1. Importing additional configuration classes .......................................................... 35
15.2. Importing XML configuration .............................................................................. 35
16. Auto-configuration ....................................................................................................... 36
16.1. Gradually replacing auto-configuration ............................................................... 36
16.2. Disabling specific auto-configuration .................................................................. 36
17. Spring Beans and dependency injection ....................................................................... 37
18. Using the @SpringBootApplication annotation .............................................................. 38
19. Running your application ............................................................................................. 39
19.1. Running from an IDE ........................................................................................ 39
19.2. Running as a packaged application ................................................................... 39
19.3. Using the Maven plugin .................................................................................... 39
19.4. Using the Gradle plugin .................................................................................... 40
19.5. Hot swapping ................................................................................................... 40
20. Developer tools ........................................................................................................... 41
20.1. Property defaults .............................................................................................. 41
20.2. Automatic restart .............................................................................................. 42
Excluding resources .......................................................................................... 43
Watching additional paths .................................................................................. 43
Disabling restart ................................................................................................ 43
Using a trigger file ............................................................................................ 44
Customizing the restart classloader .................................................................... 44
Known limitations .............................................................................................. 44
20.3. LiveReload ....................................................................................................... 45
20.4. Global settings ................................................................................................. 45
20.5. Remote applications ......................................................................................... 45
Running the remote client application ................................................................. 46
Remote update ................................................................................................. 47
Remote debug tunnel ........................................................................................ 47
21. Packaging your application for production ..................................................................... 49
22. What to read next ....................................................................................................... 50
IV. Spring Boot features ............................................................................................................ 51
23. SpringApplication ......................................................................................................... 52
23.1. Startup failure ................................................................................................... 52
23.2. Customizing the Banner .................................................................................... 53
23.3. Customizing SpringApplication .......................................................................... 54
23.4. Fluent builder API ............................................................................................. 54
23.5. Application events and listeners ........................................................................ 55
23.6. Web environment ............................................................................................. 55
23.7. Accessing application arguments ....................................................................... 56
23.8. Using the ApplicationRunner or CommandLineRunner ........................................ 56
23.9. Application exit ................................................................................................. 57
23.10. Admin features ............................................................................................... 57
24. Externalized Configuration ........................................................................................... 59
24.1. Configuring random values ............................................................................... 60
24.2. Accessing command line properties .................................................................. 60
24.3. Application property files ................................................................................... 61
24.4. Profile-specific properties .................................................................................. 62
24.5. Placeholders in properties ................................................................................. 63
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot iv
24.6. Using YAML instead of Properties ..................................................................... 63
Loading YAML .................................................................................................. 63
Exposing YAML as properties in the Spring Environment .................................... 64
Multi-profile YAML documents ........................................................................... 64
YAML shortcomings .......................................................................................... 65
Merging YAML lists ........................................................................................... 65
24.7. Type-safe Configuration Properties .................................................................... 66
Third-party configuration .................................................................................... 69
Relaxed binding ................................................................................................ 69
Properties conversion ........................................................................................ 70
@ConfigurationProperties Validation .................................................................. 70
@ConfigurationProperties vs. @Value ............................................................... 71
25. Profiles ....................................................................................................................... 72
25.1. Adding active profiles ....................................................................................... 72
25.2. Programmatically setting profiles ....................................................................... 72
25.3. Profile-specific configuration files ....................................................................... 73
26. Logging ....................................................................................................................... 74
26.1. Log format ....................................................................................................... 74
26.2. Console output ................................................................................................. 74
Color-coded output ............................................................................................ 75
26.3. File output ........................................................................................................ 76
26.4. Log Levels ....................................................................................................... 76
26.5. Custom log configuration .................................................................................. 77
26.6. Logback extensions .......................................................................................... 78
Profile-specific configuration .............................................................................. 79
Environment properties ...................................................................................... 79
27. Developing web applications ........................................................................................ 80
27.1. The ‘Spring Web MVC framework’ .................................................................... 80
Spring MVC auto-configuration .......................................................................... 80
HttpMessageConverters .................................................................................... 81
Custom JSON Serializers and Deserializers ....................................................... 81
MessageCodesResolver .................................................................................... 82
Static Content ................................................................................................... 82
Custom Favicon ................................................................................................ 84
ConfigurableWebBindingInitializer ...................................................................... 84
Template engines .............................................................................................. 84
Error Handling .................................................................................................. 84
Custom error pages .................................................................................. 85
Mapping error pages outside of Spring MVC .............................................. 86
Error Handling on WebSphere Application Server ....................................... 86
Spring HATEOAS .............................................................................................. 87
CORS support .................................................................................................. 87
27.2. JAX-RS and Jersey .......................................................................................... 87
27.3. Embedded servlet container support .................................................................. 88
Servlets, Filters, and listeners ............................................................................ 89
Registering Servlets, Filters, and listeners as Spring beans ......................... 89
Servlet Context Initialization ............................................................................... 89
Scanning for Servlets, Filters, and listeners ................................................ 89
The EmbeddedWebApplicationContext ............................................................... 89
Customizing embedded servlet containers .......................................................... 90
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot v
Programmatic customization ...................................................................... 90
Customizing ConfigurableEmbeddedServletContainer directly ...................... 91
JSP limitations .................................................................................................. 91
28. Security ...................................................................................................................... 92
28.1. OAuth2 ............................................................................................................ 93
Authorization Server .......................................................................................... 93
Resource Server ............................................................................................... 93
28.2. Token Type in User Info ................................................................................... 94
28.3. Customizing the User Info RestTemplate ........................................................... 94
Client ................................................................................................................ 95
Single Sign On ................................................................................................. 96
28.4. Actuator Security .............................................................................................. 97
29. Working with SQL databases ....................................................................................... 98
29.1. Configure a DataSource ................................................................................... 98
Embedded Database Support ............................................................................ 98
Connection to a production database ................................................................. 99
Connection to a JNDI DataSource ................................................................... 100
29.2. Using JdbcTemplate ....................................................................................... 100
29.3. JPA and ‘Spring Data’ .................................................................................... 101
Entity Classes ................................................................................................. 101
Spring Data JPA Repositories .......................................................................... 102
Creating and dropping JPA databases ............................................................. 103
Open EntityManager in View ........................................................................... 103
29.4. Using H2’s web console ................................................................................. 103
Changing the H2 console’s path ...................................................................... 103
Securing the H2 console ................................................................................. 104
29.5. Using jOOQ ................................................................................................... 104
Code Generation ............................................................................................. 104
Using DSLContext ........................................................................................... 104
Customizing jOOQ .......................................................................................... 105
30. Working with NoSQL technologies ............................................................................. 106
30.1. Redis ............................................................................................................. 106
Connecting to Redis ........................................................................................ 106
30.2. MongoDB ....................................................................................................... 106
Connecting to a MongoDB database ................................................................ 106
MongoTemplate .............................................................................................. 107
Spring Data MongoDB repositories .................................................................. 108
Embedded Mongo ........................................................................................... 108
30.3. Neo4j ............................................................................................................. 109
Connecting to a Neo4j database ...................................................................... 109
Using the embedded mode .............................................................................. 109
Neo4jSession .................................................................................................. 109
Spring Data Neo4j repositories ........................................................................ 110
Repository example ......................................................................................... 110
30.4. Gemfire .......................................................................................................... 110
30.5. Solr ................................................................................................................ 110
Connecting to Solr .......................................................................................... 111
Spring Data Solr repositories ........................................................................... 111
30.6. Elasticsearch .................................................................................................. 111
Connecting to Elasticsearch using Jest ............................................................ 111
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot vi
Connecting to Elasticsearch using Spring Data ................................................. 112
Spring Data Elasticsearch repositories ............................................................. 112
30.7. Cassandra ...................................................................................................... 112
Connecting to Cassandra ................................................................................ 113
Spring Data Cassandra repositories ................................................................. 113
30.8. Couchbase ..................................................................................................... 113
Connecting to Couchbase ................................................................................ 113
Spring Data Couchbase repositories ................................................................ 114
30.9. LDAP ............................................................................................................. 115
Connecting to an LDAP server ........................................................................ 115
Spring Data LDAP repositories ........................................................................ 115
Embedded in-memory LDAP server ................................................................. 115
31. Caching .................................................................................................................... 117
31.1. Supported cache providers ............................................................................. 118
Generic ........................................................................................................... 119
JCache (JSR-107) ........................................................................................... 119
EhCache 2.x ................................................................................................... 120
Hazelcast ........................................................................................................ 120
Infinispan ........................................................................................................ 120
Couchbase ...................................................................................................... 120
Redis .............................................................................................................. 121
Caffeine .......................................................................................................... 121
Guava (deprecated) ......................................................................................... 122
Simple ............................................................................................................ 122
None ............................................................................................................... 122
32. Messaging ................................................................................................................ 123
32.1. JMS ............................................................................................................... 123
ActiveMQ support ............................................................................................ 123
Artemis support ............................................................................................... 124
Using a JNDI ConnectionFactory ..................................................................... 124
Sending a message ........................................................................................ 124
Receiving a message ...................................................................................... 125
32.2. AMQP ............................................................................................................ 126
RabbitMQ support ........................................................................................... 126
Sending a message ........................................................................................ 126
Receiving a message ...................................................................................... 127
32.3. Apache Kafka Support .................................................................................... 128
Sending a Message ........................................................................................ 128
Receiving a Message ...................................................................................... 129
Additional Kafka Properties .............................................................................. 129
33. Calling REST services ............................................................................................... 131
33.1. RestTemplate customization ............................................................................ 131
34. Validation .................................................................................................................. 133
35. Sending email ........................................................................................................... 134
36. Distributed Transactions with JTA .............................................................................. 135
36.1. Using an Atomikos transaction manager .......................................................... 135
36.2. Using a Bitronix transaction manager .............................................................. 135
36.3. Using a Narayana transaction manager ........................................................... 136
36.4. Using a Java EE managed transaction manager .............................................. 136
36.5. Mixing XA and non-XA JMS connections ......................................................... 136
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot vii
36.6. Supporting an alternative embedded transaction manager ................................ 137
37. Hazelcast .................................................................................................................. 138
38. Spring Integration ...................................................................................................... 139
39. Spring Session .......................................................................................................... 140
40. Monitoring and management over JMX ...................................................................... 141
41. Testing ...................................................................................................................... 142
41.1. Test scope dependencies ............................................................................... 142
41.2. Testing Spring applications ............................................................................. 142
41.3. Testing Spring Boot applications ..................................................................... 143
Detecting test configuration .............................................................................. 143
Excluding test configuration ............................................................................. 144
Working with random ports .............................................................................. 144
Mocking and spying beans .............................................................................. 145
Auto-configured tests ....................................................................................... 146
Auto-configured JSON tests ............................................................................. 146
Auto-configured Spring MVC tests ................................................................... 147
Auto-configured Data JPA tests ....................................................................... 149
Auto-configured JDBC tests ............................................................................. 150
Auto-configured Data MongoDB tests ............................................................... 150
Auto-configured REST clients .......................................................................... 151
Auto-configured Spring REST Docs tests ......................................................... 152
Using Spock to test Spring Boot applications .................................................... 153
41.4. Test utilities .................................................................................................... 153
ConfigFileApplicationContextInitializer ............................................................... 153
EnvironmentTestUtils ....................................................................................... 154
OutputCapture ................................................................................................. 154
TestRestTemplate ........................................................................................... 154
42. WebSockets .............................................................................................................. 156
43. Web Services ............................................................................................................ 157
44. Creating your own auto-configuration ......................................................................... 158
44.1. Understanding auto-configured beans .............................................................. 158
44.2. Locating auto-configuration candidates ............................................................ 158
44.3. Condition annotations ..................................................................................... 158
Class conditions .............................................................................................. 159
Bean conditions .............................................................................................. 159
Property conditions .......................................................................................... 160
Resource conditions ........................................................................................ 160
Web application conditions .............................................................................. 160
SpEL expression conditions ............................................................................. 160
44.4. Creating your own starter ................................................................................ 160
Naming ........................................................................................................... 160
Autoconfigure module ...................................................................................... 161
Starter module ................................................................................................ 161
45. What to read next ..................................................................................................... 162
V. Spring Boot Actuator: Production-ready features .................................................................. 163
46. Enabling production-ready features ............................................................................ 164
47. Endpoints .................................................................................................................. 165
47.1. Customizing endpoints .................................................................................... 166
47.2. Hypermedia for actuator MVC endpoints .......................................................... 167
47.3. CORS support ................................................................................................ 167
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot viii
47.4. Adding custom endpoints ................................................................................ 167
47.5. Health information .......................................................................................... 168
47.6. Security with HealthIndicators ......................................................................... 168
Auto-configured HealthIndicators ...................................................................... 168
Writing custom HealthIndicators ....................................................................... 169
47.7. Application information .................................................................................... 170
Auto-configured InfoContributors ...................................................................... 170
Custom application info information .................................................................. 170
Git commit information ..................................................................................... 171
Build information ............................................................................................. 171
Writing custom InfoContributors ....................................................................... 171
48. Monitoring and management over HTTP .................................................................... 173
48.1. Accessing sensitive endpoints ......................................................................... 173
48.2. Customizing the management endpoint paths .................................................. 174
48.3. Customizing the management server port ........................................................ 174
48.4. Configuring management-specific SSL ............................................................. 175
48.5. Customizing the management server address .................................................. 175
48.6. Disabling HTTP endpoints ............................................................................... 175
48.7. HTTP health endpoint format and access restrictions ........................................ 176
49. Monitoring and management over JMX ...................................................................... 178
49.1. Customizing MBean names ............................................................................. 178
49.2. Disabling JMX endpoints ................................................................................. 178
49.3. Using Jolokia for JMX over HTTP ................................................................... 178
Customizing Jolokia ......................................................................................... 178
Disabling Jolokia ............................................................................................. 178
50. Monitoring and management using a remote shell (deprecated) ................................... 180
50.1. Connecting to the remote shell ........................................................................ 180
Remote shell credentials ................................................................................. 181
50.2. Extending the remote shell .............................................................................. 181
Remote shell commands ................................................................................. 181
Remote shell plugins ....................................................................................... 182
51. Loggers ..................................................................................................................... 183
51.1. Configure a Logger ......................................................................................... 183
52. Metrics ...................................................................................................................... 184
52.1. System metrics ............................................................................................... 184
52.2. DataSource metrics ........................................................................................ 185
52.3. Cache metrics ................................................................................................ 185
52.4. Tomcat session metrics .................................................................................. 186
52.5. Recording your own metrics ............................................................................ 186
52.6. Adding your own public metrics ....................................................................... 186
52.7. Special features with Java 8 ........................................................................... 187
52.8. Metric writers, exporters and aggregation ......................................................... 187
Example: Export to Redis ................................................................................ 188
Example: Export to Open TSDB ...................................................................... 188
Example: Export to Statsd ............................................................................... 189
Example: Export to JMX .................................................................................. 189
52.9. Aggregating metrics from multiple sources ....................................................... 190
52.10. Dropwizard Metrics ....................................................................................... 190
52.11. Message channel integration ......................................................................... 191
53. Auditing ..................................................................................................................... 192
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot ix
54. Tracing ..................................................................................................................... 193
54.1. Custom tracing ............................................................................................... 193
55. Process monitoring .................................................................................................... 194
55.1. Extend configuration ....................................................................................... 194
55.2. Programmatically ............................................................................................ 194
56. Cloud Foundry support .............................................................................................. 195
56.1. Disabling extended Cloud Foundry actuator support ......................................... 195
56.2. Cloud Foundry self signed certificates ............................................................. 195
56.3. Custom security configuration ......................................................................... 195
57. What to read next ..................................................................................................... 196
VI. Deploying Spring Boot applications ..................................................................................... 197
58. Deploying to the cloud ............................................................................................... 198
58.1. Cloud Foundry ................................................................................................ 198
Binding to services .......................................................................................... 199
58.2. Heroku ........................................................................................................... 199
58.3. OpenShift ....................................................................................................... 201
58.4. Amazon Web Services (AWS) ......................................................................... 201
AWS Elastic Beanstalk .................................................................................... 202
Using the Tomcat platform ....................................................................... 202
Using the Java SE platform ..................................................................... 202
Best practices ......................................................................................... 202
Summary ........................................................................................................ 202
58.5. Boxfuse and Amazon Web Services ................................................................ 202
58.6. Google Cloud ................................................................................................. 203
59. Installing Spring Boot applications .............................................................................. 205
59.1. Supported operating systems .......................................................................... 205
59.2. Unix/Linux services ......................................................................................... 205
Installation as an init.d service (System V) ....................................................... 205
Securing an init.d service ........................................................................ 206
Installation as a systemd service ..................................................................... 207
Customizing the startup script .......................................................................... 207
Customizing script when it’s written .......................................................... 208
Customizing script when it runs ............................................................... 209
59.3. Microsoft Windows services ............................................................................ 210
60. What to read next ..................................................................................................... 211
VII. Spring Boot CLI ................................................................................................................ 212
61. Installing the CLI ....................................................................................................... 213
62. Using the CLI ............................................................................................................ 214
62.1. Running applications using the CLI ................................................................. 214
Deduced “grab” dependencies ......................................................................... 215
Deduced “grab” coordinates ............................................................................. 216
Default import statements ................................................................................ 216
Automatic main method ................................................................................... 216
Custom dependency management ................................................................... 216
62.2. Testing your code ........................................................................................... 217
62.3. Applications with multiple source files .............................................................. 217
62.4. Packaging your application ............................................................................. 217
62.5. Initialize a new project .................................................................................... 218
62.6. Using the embedded shell .............................................................................. 218
62.7. Adding extensions to the CLI .......................................................................... 219
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot x
63. Developing application with the Groovy beans DSL ..................................................... 220
64. Configuring the CLI with settings.xml .......................................................................... 221
65. What to read next ..................................................................................................... 222
VIII. Build tool plugins ............................................................................................................. 223
66. Spring Boot Maven plugin .......................................................................................... 224
66.1. Including the plugin ........................................................................................ 224
66.2. Packaging executable jar and war files ............................................................ 225
67. Spring Boot Gradle plugin .......................................................................................... 226
67.1. Including the plugin ........................................................................................ 226
67.2. Gradle dependency management .................................................................... 226
67.3. Packaging executable jar and war files ............................................................ 226
67.4. Running a project in-place .............................................................................. 227
67.5. Spring Boot plugin configuration ...................................................................... 227
67.6. Repackage configuration ................................................................................. 228
67.7. Repackage with custom Gradle configuration ................................................... 229
Configuration options ....................................................................................... 229
Available layouts ............................................................................................. 230
Using a custom layout ..................................................................................... 230
67.8. Understanding how the Gradle plugin works .................................................... 231
67.9. Publishing artifacts to a Maven repository using Gradle .................................... 231
Configuring Gradle to produce a pom that inherits dependency management ...... 231
Configuring Gradle to produce a pom that imports dependency management ...... 232
68. Spring Boot AntLib module ........................................................................................ 233
68.1. Spring Boot Ant tasks ..................................................................................... 233
spring-boot:exejar ............................................................................................ 233
Examples ........................................................................................................ 233
68.2. spring-boot:findmainclass ................................................................................ 234
Examples ........................................................................................................ 234
69. Supporting other build systems .................................................................................. 235
69.1. Repackaging archives ..................................................................................... 235
69.2. Nested libraries .............................................................................................. 235
69.3. Finding a main class ....................................................................................... 235
69.4. Example repackage implementation ................................................................ 235
70. What to read next ..................................................................................................... 236
IX. ‘How-to’ guides .................................................................................................................. 237
71. Spring Boot application .............................................................................................. 238
71.1. Create your own FailureAnalyzer ..................................................................... 238
71.2. Troubleshoot auto-configuration ....................................................................... 238
71.3. Customize the Environment or ApplicationContext before it starts ...................... 239
71.4. Build an ApplicationContext hierarchy (adding a parent or root context) .............. 240
71.5. Create a non-web application .......................................................................... 240
72. Properties & configuration .......................................................................................... 241
72.1. Automatically expand properties at build time ................................................... 241
Automatic property expansion using Maven ...................................................... 241
Automatic property expansion using Gradle ...................................................... 242
72.2. Externalize the configuration of SpringApplication ............................................. 242
72.3. Change the location of external properties of an application .............................. 243
72.4. Use ‘short’ command line arguments ............................................................... 243
72.5. Use YAML for external properties .................................................................... 244
72.6. Set the active Spring profiles .......................................................................... 244
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot xi
72.7. Change configuration depending on the environment ........................................ 244
72.8. Discover built-in options for external properties ................................................ 245
73. Embedded servlet containers ..................................................................................... 246
73.1. Add a Servlet, Filter or Listener to an application .............................................. 246
Add a Servlet, Filter or Listener using a Spring bean ......................................... 246
Disable registration of a Servlet or Filter ................................................... 246
Add Servlets, Filters, and Listeners using classpath scanning ............................ 246
73.2. Change the HTTP port ................................................................................... 247
73.3. Use a random unassigned HTTP port .............................................................. 247
73.4. Discover the HTTP port at runtime .................................................................. 247
73.5. Configure SSL ................................................................................................ 247
73.6. Configure Access Logging .............................................................................. 248
73.7. Use behind a front-end proxy server ................................................................ 248
Customize Tomcat’s proxy configuration ........................................................... 249
73.8. Configure Tomcat ........................................................................................... 249
73.9. Enable Multiple Connectors with Tomcat ......................................................... 249
73.10. Use Tomcat’s LegacyCookieProcessor .......................................................... 250
73.11. Use Jetty instead of Tomcat .......................................................................... 250
73.12. Configure Jetty ............................................................................................. 251
73.13. Use Undertow instead of Tomcat ................................................................... 251
73.14. Configure Undertow ...................................................................................... 252
73.15. Enable Multiple Listeners with Undertow ........................................................ 252
73.16. Use Tomcat 7.x or 8.0 .................................................................................. 252
Use Tomcat 7.x or 8.0 with Maven .................................................................. 252
Use Tomcat 7.x or 8.0 with Gradle .................................................................. 253
73.17. Use Jetty 9.2 ................................................................................................ 253
Use Jetty 9.2 with Maven ................................................................................ 253
Use Jetty 9.2 with Gradle ................................................................................ 253
73.18. Use Jetty 8 ................................................................................................... 253
Use Jetty 8 with Maven ................................................................................... 254
Use Jetty 8 with Gradle ................................................................................... 254
73.19. Create WebSocket endpoints using @ServerEndpoint .................................... 254
73.20. Enable HTTP response compression ............................................................. 255
74. Spring MVC .............................................................................................................. 256
74.1. Write a JSON REST service ........................................................................... 256
74.2. Write an XML REST service ........................................................................... 256
74.3. Customize the Jackson ObjectMapper ............................................................. 256
74.4. Customize the @ResponseBody rendering ...................................................... 258
74.5. Handling Multipart File Uploads ....................................................................... 258
74.6. Switch off the Spring MVC DispatcherServlet ................................................... 258
74.7. Switch off the Default MVC configuration ......................................................... 259
74.8. Customize ViewResolvers ............................................................................... 259
74.9. Use Thymeleaf 3 ............................................................................................ 260
75. HTTP clients ............................................................................................................. 261
75.1. Configure RestTemplate to use a proxy ........................................................... 261
76. Logging ..................................................................................................................... 262
76.1. Configure Logback for logging ......................................................................... 262
Configure logback for file only output ............................................................... 263
76.2. Configure Log4j for logging ............................................................................. 263
Use YAML or JSON to configure Log4j 2 ......................................................... 264
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot xii
77. Data Access ............................................................................................................. 265
77.1. Configure a custom DataSource ...................................................................... 265
77.2. Configure Two DataSources ........................................................................... 267
77.3. Use Spring Data repositories .......................................................................... 268
77.4. Separate @Entity definitions from Spring configuration ..................................... 268
77.5. Configure JPA properties ................................................................................ 268
77.6. Configure Hibernate Naming Strategy .............................................................. 269
77.7. Use a custom EntityManagerFactory ............................................................... 269
77.8. Use Two EntityManagers ................................................................................ 269
77.9. Use a traditional persistence.xml ..................................................................... 270
77.10. Use Spring Data JPA and Mongo repositories ................................................ 270
77.11. Expose Spring Data repositories as REST endpoint ........................................ 271
77.12. Configure a component that is used by JPA ................................................... 271
78. Database initialization ................................................................................................ 272
78.1. Initialize a database using JPA ....................................................................... 272
78.2. Initialize a database using Hibernate ............................................................... 272
78.3. Initialize a database using Spring JDBC .......................................................... 272
78.4. Initialize a Spring Batch database ................................................................... 273
78.5. Use a higher-level database migration tool ....................................................... 273
Execute Flyway database migrations on startup ................................................ 273
Execute Liquibase database migrations on startup ............................................ 274
79. Messaging ................................................................................................................ 275
79.1. Disable transacted JMS session ...................................................................... 275
80. Batch applications ..................................................................................................... 276
80.1. Execute Spring Batch jobs on startup .............................................................. 276
81. Actuator .................................................................................................................... 277
81.1. Change the HTTP port or address of the actuator endpoints ............................. 277
81.2. Customize the ‘whitelabel’ error page .............................................................. 277
81.3. Actuator and Jersey ........................................................................................ 277
82. Security ..................................................................................................................... 278
82.1. Switch off the Spring Boot security configuration .............................................. 278
82.2. Change the AuthenticationManager and add user accounts .............................. 278
82.3. Enable HTTPS when running behind a proxy server ......................................... 278
83. Hot swapping ............................................................................................................ 280
83.1. Reload static content ...................................................................................... 280
83.2. Reload templates without restarting the container ............................................. 280
Thymeleaf templates ....................................................................................... 280
FreeMarker templates ...................................................................................... 280
Groovy templates ............................................................................................ 280
83.3. Fast application restarts .................................................................................. 280
83.4. Reload Java classes without restarting the container ........................................ 281
Configuring Spring Loaded for use with Maven ................................................. 281
Configuring Spring Loaded for use with Gradle and IntelliJ IDEA ........................ 281
84. Build ......................................................................................................................... 283
84.1. Generate build information .............................................................................. 283
84.2. Generate git information .................................................................................. 283
84.3. Customize dependency versions ..................................................................... 284
84.4. Create an executable JAR with Maven ............................................................ 284
84.5. Use a Spring Boot application as a dependency ............................................... 285
84.6. Extract specific libraries when an executable jar runs ....................................... 285
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot xiii
84.7. Create a non-executable JAR with exclusions .................................................. 286
84.8. Remote debug a Spring Boot application started with Maven ............................. 287
84.9. Remote debug a Spring Boot application started with Gradle ............................. 287
84.10. Build an executable archive from Ant without using spring-boot-antlib ............... 288
84.11. How to use Java 6 ....................................................................................... 288
Embedded servlet container compatibility ......................................................... 289
Jackson .......................................................................................................... 289
JTA API compatibility ...................................................................................... 289
85. Traditional deployment ............................................................................................... 290
85.1. Create a deployable war file ........................................................................... 290
85.2. Create a deployable war file for older servlet containers .................................... 291
85.3. Convert an existing application to Spring Boot .................................................. 291
85.4. Deploying a WAR to WebLogic ....................................................................... 293
85.5. Deploying a WAR in an Old (Servlet 2.5) Container .......................................... 293
X. Appendices ......................................................................................................................... 295
A. Common application properties ................................................................................... 296
B. Configuration meta-data .............................................................................................. 318
B.1. Meta-data format .............................................................................................. 318
Group Attributes .............................................................................................. 319
Property Attributes ........................................................................................... 320
Hint Attributes ................................................................................................. 322
Repeated meta-data items ............................................................................... 322
B.2. Providing manual hints ..................................................................................... 323
Value hint ....................................................................................................... 323
Value provider ................................................................................................. 323
Any ......................................................................................................... 324
Class reference ....................................................................................... 325
Handle As ............................................................................................... 325
Logger name .......................................................................................... 326
Spring bean reference ............................................................................. 327
Spring profile name ................................................................................. 328
B.3. Generating your own meta-data using the annotation processor .......................... 328
Nested properties ............................................................................................ 329
Adding additional meta-data ............................................................................ 329
C. Auto-configuration classes ........................................................................................... 331
C.1. From the “spring-boot-autoconfigure” module .................................................... 331
C.2. From the “spring-boot-actuator” module ............................................................ 334
D. Test auto-configuration annotations ............................................................................. 336
E. The executable jar format ........................................................................................... 338
E.1. Nested JARs ................................................................................................... 338
The executable jar file structure ....................................................................... 338
The executable war file structure ..................................................................... 338
E.2. Spring Boot’s “JarFile” class ............................................................................. 339
Compatibility with the standard Java “JarFile” ................................................... 339
E.3. Launching executable jars ................................................................................ 339
Launcher manifest ........................................................................................... 340
Exploded archives ........................................................................................... 340
E.4. PropertiesLauncher Features ............................................................................ 340
E.5. Executable jar restrictions ................................................................................. 342
Zip entry compression ..................................................................................... 342
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot xiv
System ClassLoader ....................................................................................... 342
E.6. Alternative single jar solutions .......................................................................... 342
F. Dependency versions .................................................................................................. 343
Part I. Spring Boot Documentation
This section provides a brief overview of Spring Boot reference documentation. Think of it as map for
the rest of the document. You can read this reference guide in a linear fashion, or you can skip sections
if something doesn’t interest you.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 2
1. About the documentation
The Spring Boot reference guide is available as html, pdf and epub documents. 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 3
2. Getting help
Having trouble with Spring Boot, We’d like to help!
• Try the How-to’s — 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 just 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 just want to improve them, please get involved.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 4
3. First steps
If you’re just getting started with Spring Boot, or 'Spring' in general, this is the place to start!
•From scratch: Overview | Requirements | Installation
•Tutorial: Part 1 | Part 2
•Running your example: Part 1 | Part 2
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 5
4. Working with Spring Boot
Ready to actually start using Spring Boot? We’ve got 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
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 6
5. Learning about Spring Boot features
Need more details about Spring Boot’s core features? This 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
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 7
6. Moving to production
When you’re ready to push your Spring Boot application to production, we’ve got some tricks that you
might like!
•Management endpoints: Overview | Customization
•Connection options: HTTP | JMX | SSH
•Monitoring: Metrics | Auditing | Tracing | Process
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 8
7. Advanced topics
Lastly, we have a few topics for the more advanced user.
•Deploy Spring Boot Applications: Cloud Deployment | OS Service
•Build tool plugins: Maven | Gradle
•Appendix: Application Properties | Auto-configuration classes | Executable Jars
Part II. Getting started
If you’re just getting started with Spring Boot, or 'Spring' in general, this is the section for you! Here we
answer the basic “what?”, “how?” and “why?” questions. You’ll find a gentle introduction to Spring Boot
along with installation instructions. We’ll then build our first Spring Boot application, discussing some
core principles as we go.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 10
8. Introducing Spring Boot
Spring Boot makes it easy to create stand-alone, production-grade Spring based Applications that you
can “just run”. We take an opinionated view of the Spring platform and third-party libraries so 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 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 (e.g.
embedded servers, security, metrics, health checks, externalized configuration).
• Absolutely no code generation and no requirement for XML configuration.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 11
9. System Requirements
By default, Spring Boot 1.5.7.RELEASE requires Java 7 and Spring Framework 4.3.11.RELEASE or
above. You can use Spring Boot with Java 6 with some additional configuration. See Section 84.11,
“How to use Java 6” for more details. Explicit build support is provided for Maven (3.2+), and Gradle
2 (2.9 or later) and 3.
Tip
Although you can use Spring Boot with Java 6 or 7, we generally recommend Java 8 if at all
possible.
9.1 Servlet containers
The following embedded servlet containers are supported out of the box:
Name Servlet Version Java Version
Tomcat 8 3.1 Java 7+
Tomcat 7 3.0 Java 6+
Jetty 9.3 3.1 Java 8+
Jetty 9.2 3.1 Java 7+
Jetty 8 3.0 Java 6+
Undertow 1.3 3.1 Java 7+
You can also deploy Spring Boot applications to any Servlet 3.0+ compatible container.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 12
10. Installing Spring Boot
Spring Boot can be used with “classic” Java development tools or installed as a command line tool.
Regardless, you will need Java SDK v1.6 or higher. You should check your current Java installation
before you begin:
$ java -version
If you are new to Java development, or if you just want to experiment with Spring Boot you might want
to try the Spring Boot CLI first, otherwise, read on for “classic” installation instructions.
Tip
Although Spring Boot is compatible with Java 1.6, if possible, you should consider using the latest
version of Java.
10.1 Installation instructions for the Java developer
You can use Spring Boot in the same way as any standard Java library. Simply 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; and there is nothing special about a Spring Boot
application, so you can run and debug as you would any other Java program.
Although you could just 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 don’t already have Maven installed
you can follow the instructions at maven.apache.org.
Tip
On many operating systems Maven can be installed via a package manager. If you’re an OSX
Homebrew user try brew install maven. Ubuntu users can run sudo apt-get install
maven.
Spring Boot dependencies use the org.springframework.boot groupId. Typically your Maven
POM file will inherit from the spring-boot-starter-parent project and declare dependencies to
one or more “Starters”. Spring Boot also provides an optional Maven plugin to create executable jars.
Here is 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>
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 13
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.7.RELEASE</version>
</parent>
<!-- 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 just not like our default settings. 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 2 (2.9 or later) and Gradle 3. If you don’t already have Gradle
installed you can follow the instructions at www.gradle.org/.
Spring Boot dependencies can be declared using the org.springframework.boot group. Typically
your project will declare 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’s a small script and library that you commit alongside your code to bootstrap the build process.
See docs.gradle.org/2.14.1/userguide/gradle_wrapper.html for details.
Here is a typical build.gradle file:
plugins {
id 'org.springframework.boot' version '1.5.7.RELEASE'
id 'java'
}
jar {
baseName = 'myproject'
version = '0.0.1-SNAPSHOT'
}
repositories {
jcenter()
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 14
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 is a command line tool that can be used if you want to quickly prototype with Spring.
It allows you to run Groovy scripts, which means that you have a familiar Java-like syntax, without so
much boilerplate code.
You don’t need to use the CLI to work with Spring Boot but it’s 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-1.5.7.RELEASE-bin.zip
•spring-boot-cli-1.5.7.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, or 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 with
$ sdk install springboot
$ spring --version
Spring Boot v1.5.7.RELEASE
If you are developing features for the CLI and want easy access to the version you just built, follow
these extra instructions.
$ sdk install springboot dev /path/to/spring-boot/spring-boot-cli/target/spring-boot-cli-1.5.7.RELEASE-
bin/spring-1.5.7.RELEASE/
$ sdk default springboot dev
$ spring --version
Spring CLI v1.5.7.RELEASE
This will 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 will be up-to-date.
You can see it by doing this:
$ sdk ls springboot
================================================================================
Available Springboot Versions
================================================================================
> + dev
* 1.5.7.RELEASE
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 15
================================================================================
+ - local version
* - installed
> - currently in use
================================================================================
OSX Homebrew installation
If you are on a Mac and using Homebrew, all you need to do to install the Spring Boot CLI is:
$ brew tap pivotal/tap
$ brew install springboot
Homebrew will install spring to /usr/local/bin.
Note
If you don’t see the formula, your installation of brew might be out-of-date. Just execute brew
update and try again.
MacPorts installation
If you are on a Mac and using MacPorts, all you need to do to install the Spring Boot CLI is:
$ sudo port install spring-boot-cli
Command-line completion
Spring Boot CLI ships with scripts that provide command completion for 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. To run the script manually,
e.g. if you have installed using SDKMAN!
$ . ~/.sdkman/candidates/springboot/current/shell-completion/bash/spring
$ spring <HIT TAB HERE>
grab help jar run test version
Note
If you install Spring Boot CLI using Homebrew or MacPorts, the command-line completion scripts
are automatically registered with your shell.
Quick start Spring CLI example
Here’s a really simple web application that you can use to test your installation. Create a file called
app.groovy:
@RestController
class ThisWillActuallyRun {
@RequestMapping("/")
String home() {
"Hello World!"
}
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 16
Then simply run it from a shell:
$ spring run app.groovy
Note
It will take some time when you first run the application as dependencies are downloaded.
Subsequent runs will be much quicker.
Open localhost:8080 in your favorite web browser and 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 “release notes” hosted on the
project wiki. You’ll find upgrade instructions along with a list of “new and noteworthy” features for each
release.
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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 17
11. Developing your first Spring Boot application
Let’s develop a simple “Hello World!” web application in Java that highlights some of Spring Boot’s key
features. We’ll 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’re
looking 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. This will automatically generate a new project structure so that you
can start coding right away. Check the documentation for more details.
Before we begin, open a terminal to check that you have valid versions of Java and Maven installed.
$ java -version
java version "1.7.0_51"
Java(TM) SE Runtime Environment (build 1.7.0_51-b13)
Java HotSpot(TM) 64-Bit Server VM (build 24.51-b03, mixed mode)
$ mvn -v
Apache Maven 3.2.3 (33f8c3e1027c3ddde99d3cdebad2656a31e8fdf4; 2014-08-11T13:58:10-07:00)
Maven home: /Users/user/tools/apache-maven-3.1.1
Java version: 1.7.0_51, 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 will be 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>1.5.7.RELEASE</version>
</parent>
<!-- Additional lines to be added here... -->
</project>
This should give you a working build, you can test it out by running mvn package (you can ignore the
“jar will be empty - no content was marked for inclusion!” warning for now).
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 18
Note
At this point you could import the project into an IDE (most modern Java IDE’s include built-in
support for Maven). For simplicity, we will continue to use a plain text editor for this example.
11.2 Adding classpath dependencies
Spring Boot provides a number of “Starters” that make easy to 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” simply provide dependencies that you are likely to need when developing a specific
type of application. Since we are developing a web application, we will add a spring-boot-starter-
web dependency — but before that, let’s look at what we currently have.
$ 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. Let’s edit our
pom.xml and add the spring-boot-starter-web dependency just 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 will 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. Maven will compile sources from src/
main/java by default so you need to create that folder structure, then add a file named src/main/
java/Example.java:
import org.springframework.boot.*;
import org.springframework.boot.autoconfigure.*;
import org.springframework.stereotype.*;
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);
}
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 19
Although there isn’t much code here, quite a lot is going on. Let’s step through the important parts.
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 will consider it when handling incoming
web requests.
The @RequestMapping annotation provides “routing” information. It is telling 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 will 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
will assume that you are developing a web application and setup 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 and Spring Boot will
still do 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 will bootstrap our application,
starting Spring which will in turn start 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 our application should work. Since we have used the spring-boot-starter-parent
POM we have a useful run goal that we can use to start the application. Type mvn spring-boot:run
from the root project directory to start the application:
$ mvn spring-boot:run
. ____ _ __ _ _
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 20
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v1.5.7.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 hit ctrl-c.
11.5 Creating an executable jar
Let’s 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 any standard way to load nested jar files (i.e. 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 simply packages all classes,
from all jars, into a single archive. The problem with this approach is that it becomes hard to see
which libraries you are actually using 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 allows you to actually nest jars directly.
To create an executable jar we need to add the spring-boot-maven-plugin to our pom.xml. 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 are not using the parent POM you will need to declare this configuration
yourself. See the plugin documentation for details.
Save your pom.xml and run mvn package from the command line:
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 21
$ 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:1.5.7.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:
$ 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:
$ java -jar target/myproject-0.0.1-SNAPSHOT.jar
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v1.5.7.RELEASE)
....... . . .
....... . . . (log output here)
....... . . .
........ Started Example in 2.536 seconds (JVM running for 2.864)
As before, to gracefully exit the application hit ctrl-c.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 22
12. What to read next
Hopefully this section has provided you with some of the Spring Boot basics, and got you on your way
to writing your own applications. If you’re 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 has also a bunch of samples you can run. The samples are independent of
the rest of the code (that is you don’t 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’re 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, will make your development
process just a little easier.
If you’re just starting out with Spring Boot, you should probably read the Getting Started guide before
diving into this section.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 24
13. Build systems
It is strongly recommended that you choose a build system that supports dependency management,
and one 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 will not be particularly well supported.
13.1 Dependency management
Each release of Spring Boot provides a curated list of dependencies it supports. In practice, you do not
need to provide a version for any of these dependencies in your build configuration as Spring Boot is
managing that for you. When you upgrade Spring Boot itself, these dependencies will be upgraded as
well in a consistent way.
Note
You can still specify a version and override Spring Boot’s recommendations if you feel that’s
necessary.
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) and additional dedicated support for Maven and Gradle are available as well.
Warning
Each release of Spring Boot is associated with a base version of the Spring Framework so we
highly recommend you to not specify its version on your own.
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 1.6 as the default compiler level.
• UTF-8 source encoding.
• A Dependency Management section, allowing you to omit <version> tags for common
dependencies, inherited from the spring-boot-dependencies POM.
• Sensible resource filtering.
• Sensible plugin configuration (exec plugin, surefire, Git commit ID, shade).
• Sensible resource filtering for application.properties and application.yml including
profile-specific files (e.g. application-foo.properties and application-foo.yml)
On the last point: since the default config files accept Spring style placeholders (${…}) the Maven
filtering is changed to use @..@ placeholders (you can override that with a Maven property
resource.delimiter).
Inheriting the starter parent
To configure your project to inherit from the spring-boot-starter-parent simply set the parent:
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 25
<!-- Inherit defaults from Spring Boot -->
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.7.RELEASE</version>
</parent>
Note
You should only need to specify 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’d 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 just prefer to explicitly declare all your
Maven configuration.
If you don’t 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:
<dependencyManagement>
<dependencies>
<dependency>
<!-- Import dependency management from Spring Boot -->
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<version>1.5.7.RELEASE</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
That setup does not allow you to override individual dependencies using a property as explained above.
To achieve the same result, you’d 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’d add the following to your pom.xml.
<dependencyManagement>
<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>
<scope>import</scope>
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 26
<type>pom</type>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<version>1.5.7.RELEASE</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
Note
In the example above, we specify a BOM but any dependency type can be overridden that way.
Changing the Java version
The spring-boot-starter-parent chooses fairly conservative Java compatibility. If you want to
follow our recommendation and use a later Java version you can add a java.version property:
<properties>
<java.version>1.8</java.version>
</properties>
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:
<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 only need to add the plugin, there is no need
for to configure it unless you want to change the settings defined in the parent.
13.3 Gradle
Gradle users can directly import ‘starters’ in their dependencies section. Unlike Maven, there is no
“super parent” to import to share some configuration.
repositories {
jcenter()
}
dependencies {
compile("org.springframework.boot:spring-boot-starter-web:1.5.7.RELEASE")
}
The spring-boot-gradle-plugin is also available and provides tasks to create executable jars
and run projects from source. It also provides dependency management that, among other capabilities,
allows you to omit the version number for any dependencies that are managed by Spring Boot:
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 27
plugins {
id 'org.springframework.boot' version '1.5.7.RELEASE'
id 'java'
}
repositories {
jcenter()
}
dependencies {
compile("org.springframework.boot:spring-boot-starter-web")
testCompile("org.springframework.boot:spring-boot-starter-test")
}
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 will look something like this:
<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 will look like this:
<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="1.3.0.BUILD-SNAPSHOT" />
<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>
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 28
</target>
</project>
Tip
See the Section 84.10, “Build an executable archive from Ant without using spring-boot-antlib”
“How-to” if you don’t want to use the spring-boot-antlib module.
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 technology 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, just include the spring-boot-starter-data-
jpa dependency in your project, and you are good to go.
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.
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 allow you to search dependencies by name. For
example, with the appropriate Eclipse or STS plugin installed, you can simply hit 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. A third-party starter for acme will
be typically named acme-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 Reference Guide
1.5.7.RELEASE Spring Boot 29
Name Description 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
spring-boot-starter-
data-couchbase
Starter for using Couchbase
document-oriented database
and Spring Data Couchbase
Pom
spring-boot-starter-
data-elasticsearch
Starter for using Elasticsearch
search and analytics engine
and Spring Data Elasticsearch
Pom
spring-boot-starter-
data-gemfire
Starter for using GemFire
distributed data store and
Spring Data GemFire
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-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 Jedis client
Pom
spring-boot-starter-
data-rest
Starter for exposing Spring
Data repositories over REST
using Spring Data REST
Pom
spring-boot-starter-
data-solr
Starter for using the Apache
Solr search platform with Spring
Data Solr
Pom
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 30
Name Description 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
Tomcat JDBC 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-
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
Spring Boot Narayana JTA
Starter
Pom
spring-boot-starter-
mail
Starter for using Java Mail
and Spring Framework’s email
sending support
Pom
spring-boot-starter-
mobile
Starter for building web
applications using Spring
Mobile
Pom
spring-boot-starter-
mustache
Starter for building MVC web
applications using Mustache
views
Pom
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 31
Name Description Pom
spring-boot-starter-
security
Starter for using Spring Security Pom
spring-boot-starter-
social-facebook
Starter for using Spring Social
Facebook
Pom
spring-boot-starter-
social-linkedin
Stater for using Spring Social
LinkedIn
Pom
spring-boot-starter-
social-twitter
Starter for using Spring Social
Twitter
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-
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
spring-boot-starter-
remote-shell
Starter for using the CRaSH
remote shell to monitor and
Pom
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 32
Name Description Pom
manage your application over
SSH. Deprecated since 1.5
Finally, Spring Boot also includes some 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-
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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 33
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 doesn’t 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 @ComponentScan, @EntityScan or
@SpringBootApplication annotations, since every class from every jar, will be 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 @EnableAutoConfiguration 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 @EnableAutoConfiguration annotated class will be used to search
for @Entity items.
Using a root package also allows the @ComponentScan annotation to be used without needing to
specify a basePackage attribute. You can also use the @SpringBootApplication annotation if your
main class is in the root package.
Here is a typical layout:
com
+- example
+- myproject
+- Application.java
|
+- domain
| +- Customer.java
| +- CustomerRepository.java
|
+- service
| +- CustomerService.java
|
+- web
+- CustomerController.java
The Application.java file would declare the main method, along with the basic @Configuration.
package com.example.myproject;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
@Configuration
@EnableAutoConfiguration
@ComponentScan
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 34
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 35
15. Configuration classes
Spring Boot favors Java-based configuration. Although it is possible to call
SpringApplication.run() with an XML source, we generally recommend that your primary source
is a @Configuration class. Usually the class that defines the main method is also a good candidate
as the primary @Configuration.
Tip
Many Spring configuration examples have been published on the Internet that use XML
configuration. Always try to use the equivalent Java-based configuration if possible. Searching for
Enable* annotations can be a good starting point.
15.1 Importing additional configuration classes
You don’t need to 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 additional @ImportResource annotation to load XML
configuration files.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 36
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 we will auto-configure 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 @EnableAutoConfiguration annotation. We generally
recommend that you add it to your primary @Configuration class.
16.1 Gradually replacing auto-configuration
Auto-configuration is noninvasive, 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 will back away.
If you need to find out what auto-configuration is currently being applied, and why, start your application
with the --debug switch. This will enable debug logs for a selection of core loggers and log an auto-
configuration report to the console.
16.2 Disabling specific auto-configuration
If you find that specific auto-configure classes are being applied that you don’t want, you can use the
exclude attribute of @EnableAutoConfiguration to disable them.
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 via the spring.autoconfigure.exclude property.
Tip
You can define exclusions both at the annotation level and using the property.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 37
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, in
combination with @Autowired 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.) will be automatically registered as Spring Beans.
Here is an example @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;
}
// ...
}
And if a bean has one constructor, you can omit the @Autowired.
@Service
public class DatabaseAccountService implements AccountService {
private final RiskAssessor riskAssessor;
public DatabaseAccountService(RiskAssessor riskAssessor) {
this.riskAssessor = riskAssessor;
}
// ...
}
Tip
Notice how using constructor injection allows the riskAssessor field to be marked as final,
indicating that it cannot be subsequently changed.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 38
18. Using the @SpringBootApplication annotation
Many Spring Boot developers always have their main class annotated with @Configuration,
@EnableAutoConfiguration and @ComponentScan. Since these annotations are so frequently
used together (especially if you follow the best practices above), Spring Boot provides a convenient
@SpringBootApplication alternative.
The @SpringBootApplication annotation is equivalent to using @Configuration,
@EnableAutoConfiguration and @ComponentScan with their default attributes:
package com.example.myproject;
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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 39
19. Running your application
One of the biggest advantages of packaging your application as 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 don’t 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, first you
will need to import your project. Import steps will 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 can’t directly import your project into your IDE, you may be able to generate IDE metadata 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 will see a “Port already in use” error. STS users
can use the Relaunch button rather than Run 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. For example:
$ java -jar target/myproject-0.0.1-SNAPSHOT.jar
It is also possible to run a packaged application with remote debugging support enabled. This allows
you to attach a debugger to your packaged application:
$ java -Xdebug -Xrunjdwp:server=y,transport=dt_socket,address=8000,suspend=n \
-jar target/myproject-0.0.1-SNAPSHOT.jar
19.3 Using the Maven plugin
The Spring Boot Maven plugin includes a run goal which can be used to quickly compile and run your
application. Applications run in an exploded form just like in your IDE.
$ mvn spring-boot:run
You might also want to use the useful operating system environment variable:
$ export MAVEN_OPTS=-Xmx1024m -XX:MaxPermSize=128M
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 40
19.4 Using the Gradle plugin
The Spring Boot Gradle plugin also includes a bootRun task which can be used to run your application
in an exploded form. The bootRun task is added whenever you import the spring-boot-gradle-
plugin:
$ gradle bootRun
You might also want to use this useful operating system environment variable:
$ export JAVA_OPTS=-Xmx1024m -XX:MaxPermSize=128M
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 or the Spring Loaded project can be used. The spring-boot-devtools module also
includes support for quick application restarts.
See the Chapter 20, Developer tools section below and the Hot swapping “How-to” for details.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 41
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, simply add the module dependency
to your build:
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 using java -jar or if it’s started using a special classloader, then it
is considered a “production application”. Flagging the dependency as optional is a best practice
that prevents devtools from being transitively applied to other modules using your project. Gradle
does not support optional dependencies out-of-the-box so you may want to have a look to the
propdeps-plugin in the meantime.
Tip
repackaged archives do not contain devtools by default. If you want to use certain remote devtools
feature, you’ll 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 will cache compiled templates to avoid repeatedly parsing template files. Also, Spring
MVC can add HTTP caching headers to responses when serving static resources.
Whilst 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 will disable those 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 will automatically apply sensible
development-time configuration.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 42
Tip
For a complete list of the properties that are applied see DevToolsPropertyDefaultsPostProcessor.
20.2 Automatic restart
Applications that use spring-boot-devtools will 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 will be 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 will cause the classpath to be updated and trigger a
restart. In IntelliJ IDEA, building the project (Build -> Make Project) will have the same effect.
Note
You can also start your application via the supported build plugins (i.e. Maven and Gradle) as long
as forking is enabled since DevTools need an isolated application classloader to operate properly.
Gradle and Maven do that by default when they detect DevTools on the classpath.
Tip
Automatic restart works very well when used with LiveReload. See below for details. If you use
JRebel automatic restarts will be 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 will 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 43
Restart vs Reload
The restart technology provided by Spring Boot works by using two classloaders. Classes that don’t
change (for example, those from third-party jars) are loaded into a base classloader. Classes that
you’re 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 aren’t 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. Spring
Loaded provides another option, however it doesn’t support as many frameworks and it isn’t
commercially supported.
Excluding resources
Certain resources don’t necessarily need to trigger a restart when they are changed. For example,
Thymeleaf templates can just be edited in-place. By default changing resources in /META-INF/
maven, /META-INF/resources, /resources, /static, /public or /templates will not trigger
a restart but will 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:
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 above to control whether changes
beneath the additional paths will trigger a full restart or just a live reload.
Disabling restart
If you don’t want to use the restart feature you can disable it using the
spring.devtools.restart.enabled property. In most cases you can set this in your
application.properties (this will still initialize the restart classloader but it won’t watch for file
changes).
If you need to completely disable restart support, for example, because it doesn’t work with a specific
library, you need to set a System property before calling SpringApplication.run(…). For example:
public static void main(String[] args) {
System.setProperty("spring.devtools.restart.enabled", "false");
SpringApplication.run(MyApp.class, args);
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 44
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 this 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 will only occur if Devtools has detected it has to do something. The trigger file could be updated
manually, or via an IDE plugin.
To use a trigger file use the spring.devtools.restart.trigger-file property.
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 in the Restart vs Reload section above, restart functionality is implemented by using
two classloaders. For most applications this approach works well, however, sometimes it can cause
classloading issues.
By default, any open project in your IDE will be loaded using the “restart” classloader, and any regular
.jar file will be loaded using the “base” classloader. If you work on a multi-module project, and not
each module is imported into your IDE, you may need to customize things. To do this you can create
a META-INF/spring-devtools.properties file.
The spring-devtools.properties file can contain restart.exclude. and
restart.include. prefixed properties. 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 will be applied to the classpath.
For 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 will be considered.
Tip
All META-INF/spring-devtools.properties from the classpath will be loaded. You can
package files inside your project, or in the libraries that the project consumes.
Known limitations
Restart functionality does not work well with objects that are deserialized
using a standard ObjectInputStream. If you need to deserialize data, you
may need to use Spring’s ConfigurableObjectInputStream in combination with
Thread.currentThread().getContextClassLoader().
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 45
Unfortunately, several third-party libraries deserialize without considering the context classloader. If you
find such a problem, you will 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 don’t 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 will have 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 will 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:
~/.spring-boot-devtools.properties.
spring.devtools.reload.trigger-file=.reloadtrigger
20.5 Remote applications
The Spring Boot developer tools are not just 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:
<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, for example:
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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 46
Remote devtools support is provided in two parts; there is 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 using the same
classpath as the remote project that you’re connecting to. The non-option argument passed to the
application should be the remote URL that you are connecting to.
For example, if you are using Eclipse or STS, and you have a project named my-app that you’ve
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 will look like this:
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ ___ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | | _ \___ _ __ ___| |_ ___ \ \ \ \
\\/ ___)| |_)| | | | | || (_| []::::::[] / -_) ' \/ _ \ _/ -_) ) ) ) )
' |____| .__|_| |_|_| |_\__, | |_|_\___|_|_|_\___/\__\___|/ / / /
=========|_|==============|___/===================================/_/_/_/
:: Spring Boot Remote :: 1.5.7.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)
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’s always advisable to use https:// as the connection protocol so that traffic is encrypted and
passwords cannot be intercepted.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 47
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 will monitor your application classpath for changes in the same way as the local restart.
Any updated resource will be pushed to the remote application and (if required) trigger a restart. This
can be quite helpful if you are iterating on a feature that uses a cloud service that you don’t 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 won’t be pushed to the remote server.
Remote debug tunnel
Java remote debugging is useful when diagnosing issues on a remote application. Unfortunately, it’s
not always possible to enable remote debugging when your application is deployed outside of your data
center. Remote debugging can also be tricky to setup if you are using a container based technology
such as Docker.
To help work around these limitations, devtools supports tunneling of remote debug traffic over HTTP.
The remote client provides a local server on port 8000 that you can attach a remote debugger to. Once
a connection is established, debug traffic is sent over HTTP to the remote application. You can use the
spring.devtools.remote.debug.local-port property if you want to use a different port.
You’ll need to ensure that your remote application is started with remote debugging enabled. Often
this can be achieved by configuring JAVA_OPTS. For example, with Cloud Foundry you can add the
following to your manifest.yml:
---
env:
JAVA_OPTS: "-Xdebug -Xrunjdwp:server=y,transport=dt_socket,suspend=n"
Tip
Notice that you don’t need to pass an address=NNNN option to -Xrunjdwp. If omitted Java will
simply pick a random free port.
Note
Debugging a remote service over the Internet can be slow and you might need to increase timeouts
in your IDE. For example, in Eclipse you can select Java → Debug from Preferences… and
change the Debugger timeout (ms) to a more suitable value (60000 works well in most
situations).
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 48
Warning
When using the remote debug tunnel with IntelliJ IDEA, all breakpoints must be configured to
suspend the thread rather than the VM. By default, breakpoints in IntelliJ IDEA suspend the entire
VM rather than only suspending the thread that hit the breakpoint. This has the unwanted side-
effect of suspending the thread that manages the remote debug tunnel, causing your debugging
session to freeze. When using the remote debug tunnel with IntelliJ IDEA, all breakpoints should
be configured to suspend the thread rather than the VM. Please see IDEA-165769 for further
details.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 49
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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 50
22. What to read next
You should now have good understanding of how you can use Spring Boot along with 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 will
want to use and customize. If you haven’t already, 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 52
23. SpringApplication
The SpringApplication class provides a convenient way to bootstrap a Spring application that
will be started from a main() method. In many situations you can just delegate to the static
SpringApplication.run method:
public static void main(String[] args) {
SpringApplication.run(MySpringConfiguration.class, args);
}
When your application starts you should see something similar to the following:
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: v1.5.7.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] ationConfigEmbeddedWebApplicationContext :
Refreshing
org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@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.TomcatEmbeddedServletContainerFactory :
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 will be shown, including some relevant startup details such as the
user that launched the application.
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:
***************************
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
very easily.
If no failure analyzers are able to handle the exception, you can still display
the full auto-configuration report to better understand what went wrong. To do
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 53
so you need to enable the debug property or enable DEBUG logging for
org.springframework.boot.autoconfigure.logging.AutoConfigurationReportLoggingInitializer.
For instance, if you are running your application 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 banner.location to the location of such a file. If the file has an unusual encoding you
can set banner.charset (default is UTF-8). 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 a banner.image.location
property. Images will be 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 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 1.5.7.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
(v1.5.7.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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 54
You can also use the spring.main.banner-mode property to determine if the banner has to be
printed on System.out (console), using the configured logger (log) or not at all (off).
The printed banner will be registered as a singleton bean under the name springBootBanner.
Note
YAML maps off to false so make sure to add quotes if you want to disable the banner in your
application.
spring:
main:
banner-mode: "off"
23.3 Customizing SpringApplication
If the SpringApplication defaults aren’t to your taste you can instead create a local instance and
customize it. For example, to turn off the banner you would 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 will be 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 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 just prefer using a ‘fluent’ builder API, you can use the
SpringApplicationBuilder.
The SpringApplicationBuilder allows you to chain together multiple method calls, and includes
parent and child methods that allow you to create a hierarchy.
For example:
new SpringApplicationBuilder()
.sources(Parent.class)
.child(Application.class)
.bannerMode(Banner.Mode.OFF)
.run(args);
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 55
Note
There are some restrictions when creating an ApplicationContext hierarchy, e.g. Web
components must be contained within the child context, and the same Environment will be
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 via the SpringApplication.addListeners(…) or
SpringApplicationBuilder.listeners(…) methods.
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) using the org.springframework.context.ApplicationListener key.
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
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 ApplicationReadyEvent is sent after the refresh and any related callbacks have been
processed to indicate the application is ready to service requests.
5. An ApplicationFailedEvent is sent if there is an exception on startup.
Tip
You often won’t need to use application events, but it can be handy to know that they exist.
Internally, Spring Boot uses events to handle a variety of tasks.
23.6 Web environment
A SpringApplication will attempt to create the right type of ApplicationContext
on your behalf. By default, an AnnotationConfigApplicationContext or
AnnotationConfigEmbeddedWebApplicationContext will be used, depending on whether you
are developing a web application or not.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 56
The algorithm used to determine a ‘web environment’ is fairly simplistic (based on the presence of a few
classes). You can use setWebEnvironment(boolean webEnvironment) if you need to override
the default.
It is also possible to take complete control of the ApplicationContext type that will be used by
calling setApplicationContextClass(…).
Tip
It is often desirable to call setWebEnvironment(false) 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:
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 will also register a CommandLinePropertySource with the Spring Environment.
This allows you to also inject single application arguments using the @Value annotation.
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 will be 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
above.
import org.springframework.boot.*
import org.springframework.stereotype.*
@Component
public class MyBean implements CommandLineRunner {
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 57
public void run(String... args) {
// Do something...
}
}
You can additionally implement the org.springframework.core.Ordered interface or use the
org.springframework.core.annotation.Order annotation if several CommandLineRunner or
ApplicationRunner beans are defined that must be called in a specific order.
23.9 Application exit
Each SpringApplication will register a shutdown hook with the JVM to ensure that the
ApplicationContext is closed 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.
@SpringBootApplication
public class ExitCodeApplication {
@Bean
public ExitCodeGenerator exitCodeGenerator() {
return new ExitCodeGenerator() {
@Override
public int getExitCode() {
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 will return the exit code provided by the implemented getExitCode()
method.
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 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 key
local.server.port.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 58
Note
Take care when enabling this feature as the MBean exposes a method to shutdown the
application.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 59
24. Externalized Configuration
Spring Boot allows you to externalize your configuration so 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 using the @Value annotation, accessed via Spring’s Environment abstraction or bound to
structured objects via @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 only has properties 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 using SpringApplication.setDefaultProperties).
To provide a concrete example, suppose you develop a @Component that uses a name property:
import org.springframework.stereotype.*
import org.springframework.beans.factory.annotation.*
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 60
@Component
public class MyBean {
@Value("${name}")
private String name;
// ...
}
On your application classpath (e.g. inside your jar) you can have an application.properties
that provides a sensible default property value for name. When running in a new environment, an
application.properties can be provided outside of your jar that overrides the name; and for
one-off testing, you can launch with a specific command line switch (e.g. 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 in a UN*X shell:
$ SPRING_APPLICATION_JSON='{"foo":{"bar":"spam"}}' java -jar myapp.jar
In this example you will end up with foo.bar=spam in the Spring Environment. You can also
supply the JSON as spring.application.json in a System variable:
$ java -Dspring.application.json='{"foo":"bar"}' -jar myapp.jar
or command line argument:
$ java -jar myapp.jar --spring.application.json='{"foo":"bar"}'
or as a JNDI variable java:comp/env/spring.application.json.
24.1 Configuring random values
The RandomValuePropertySource is useful for injecting random values (e.g. into secrets or test
cases). It can produce integers, longs, uuids or strings, e.g.
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 (exclusive).
24.2 Accessing command line properties
By default SpringApplication will convert any command line option arguments (starting with ‘--’,
e.g. --server.port=9000) to a property and add it to the Spring Environment. As mentioned
above, command line properties always take precedence over other property sources.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 61
If you don’t want command line properties to be added to the Environment you can disable them using
SpringApplication.setAddCommandLineProperties(false).
24.3 Application property files
SpringApplication will load properties from application.properties files in the following
locations and add 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 don’t like application.properties as the configuration file name you can switch to
another by specifying a spring.config.name environment property. You can also refer to an
explicit location using the spring.config.location environment property (comma-separated list
of directory locations, or file paths).
$ java -jar myproject.jar --spring.config.name=myproject
or
$ 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 have to be defined as an environment property (typically
OS env, system property or command line argument).
If spring.config.location contains directories (as opposed to files) they should end in / (and will
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 will be 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:
1. file:./config/
2. file:./
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 62
3. classpath:/config/
4. classpath:/
When custom config locations are configured, they are used in addition to the default locations. Custom
locations are searched before the default locations. For example, if custom locations classpath:/
custom-config/,file:./custom-config/ are configured, the search order becomes:
1. file:./custom-config/
2. classpath:custom-config/
3. file:./config/
4. file:./
5. classpath:/config/
6. classpath:/
This search ordering allows you to specify default values in one configuration file and then
selectively override those values in another. You can provide default values for you 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 overriden 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 (e.g. SPRING_CONFIG_NAME
instead of spring.config.name).
Note
If you are running 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 using
the naming convention application-{profile}.properties. The Environment has a set of
default profiles (by default [default]) which are used if no active profiles are set (i.e. if no profiles are
explicitly activated then properties from application-default.properties are loaded).
Profile-specific properties are loaded from the same locations as standard
application.properties, with profile-specific files always overriding the non-specific ones
irrespective of whether 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 via the SpringApplication
API and therefore take precedence.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 63
Note
If you have specified any files in spring.config.location, profile-specific variants of those
files will not be considered. Use directories in spring.config.location if you also 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 (e.g. 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 72.4, “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 very convenient format for specifying hierarchical
configuration data. The SpringApplication class will automatically support YAML as an alternative
to properties whenever you have the SnakeYAML library on your classpath.
Note
If you use ‘Starters’ SnakeYAML will be automatically provided via spring-boot-starter.
Loading YAML
Spring Framework provides two convenient classes that can be used to load YAML documents. The
YamlPropertiesFactoryBean will load YAML as Properties and the YamlMapFactoryBean will
load YAML as a Map.
For example, the following YAML document:
environments:
dev:
url: http://dev.bar.com
name: Developer Setup
prod:
url: http://foo.bar.com
name: My Cool App
Would be transformed into these properties:
environments.dev.url=http://dev.bar.com
environments.dev.name=Developer Setup
environments.prod.url=http://foo.bar.com
environments.prod.name=My Cool App
YAML lists are represented as property keys with [index] dereferencers, for example this YAML:
my:
servers:
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 64
- dev.bar.com
- foo.bar.com
Would be transformed into these properties:
my.servers[0]=dev.bar.com
my.servers[1]=foo.bar.com
To bind to properties like that using the Spring DataBinder 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,
e.g. this will bind to the properties above
@ConfigurationProperties(prefix="my")
public class Config {
private List<String> servers = new ArrayList<String>();
public List<String> getServers() {
return this.servers;
}
}
Note
Extra care is required when configuring lists that way as overriding will not work as you would
expect. In the example above, when my.servers is redefined in several places, the individual
elements are targeted for override, not the list. To make sure that a PropertySource with higher
precedence can override the list, you need to define it as a single property:
my:
servers: dev.bar.com,foo.bar.com
Exposing YAML as properties in the Spring Environment
The YamlPropertySourceLoader class can be used to expose YAML as a PropertySource in the
Spring Environment. This allows you to use the familiar @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. For 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 example above, the server.address property will be 127.0.0.1 if the development profile
is active. If the development and production profiles are not enabled, then the value for the property
will be 192.168.1.100.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 65
The default profiles are activated if none are explicitly active when the application context starts. So in
this YAML we set a value for security.user.password that is only available in the "default" profile:
server:
port: 8000
---
spring:
profiles: default
security:
user:
password: weak
whereas in this example, the password is always set because it isn’t attached to any profile, and it would
have to be explicitly reset in all other profiles as necessary:
server:
port: 8000
security:
user:
password: weak
Spring profiles designated using the "spring.profiles" element may optionally be negated 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 can’t be loaded via the @PropertySource annotation. So in the case that you need to load
values that way, you need to use a properties file.
Merging YAML lists
As we have seen above, any YAML content is ultimately transformed to properties. That process may
be counter intuitive when overriding “list” properties via a profile.
For example, assume a MyPojo object with name and description attributes that are null by default.
Let’s expose a list of MyPojo from FooProperties:
@ConfigurationProperties("foo")
public class FooProperties {
private final List<MyPojo> list = new ArrayList<>();
public List<MyPojo> getList() {
return this.list;
}
}
Consider the following configuration:
foo:
list:
- name: my name
description: my description
---
spring:
profiles: dev
foo:
list:
- name: my another name
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 66
If the dev profile isn’t active, FooProperties.list will contain one MyPojo entry as defined above.
If the dev profile is enabled however, the list will still only contain one entry (with name “my another
name” and description null). This configuration will not add a second MyPojo instance to the list, and
it won’t merge the items.
When a collection is specified in multiple profiles, the one with highest priority is used (and only that one):
foo:
list:
- name: my name
description: my description
- name: another name
description: another description
---
spring:
profiles: dev
foo:
list:
- name: my another name
In the example above, considering that the dev profile is active, FooProperties.list will contain
one MyPojo entry (with name “my another name” and description null).
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 allows strongly typed beans
to govern and validate the configuration of your application.
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("foo")
public class FooProperties {
private boolean enabled;
private InetAddress remoteAddress;
private final Security security = new Security();
public boolean isEnabled() { ... }
public void setEnabled(boolean enabled) { ... }
public InetAddress getRemoteAddress() { ... }
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"));
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 67
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 POJO above defines the following properties:
•foo.enabled, false by default
•foo.remote-address, with a type that can be coerced from String
•foo.security.username, with a nested "security" 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
•foo.security.password
•foo.security.roles, with a collection of String
Note
Getters and setters are usually mandatory, since binding is via standard Java Beans property
descriptors, just like in Spring MVC. There are cases where a setter may be omitted:
• 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 either accessed via an index (typically with YAML) or 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 example above)
• If nested POJO properties are initialized (like the Security field in the example above), a
setter is not required. If you want the binder to create the instance on-the-fly using its default
constructor, you will need a setter.
Some people use Project Lombok to add getters and setters automatically. Make sure that Lombok
doesn’t generate any particular constructor for such type as it will be used automatically by the
container to instantiate the object.
Tip
See also the differences between @Value and @ConfigurationProperties.
You also need to list the properties classes to register in the @EnableConfigurationProperties
annotation:
@Configuration
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 68
@EnableConfigurationProperties(FooProperties.class)
public class MyConfiguration {
}
Note
When @ConfigurationProperties bean is registered that way, the bean will have a
conventional name: <prefix>-<fqn>, where <prefix> is the environment key prefix specified
in the @ConfigurationProperties annotation and <fqn> 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 will be foo-com.example.FooProperties.
Even if the configuration above will create a regular bean for FooProperties, 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 will be configured from the Environment. You could shortcut
MyConfiguration above by making sure FooProperties is a already a bean:
@Component
@ConfigurationProperties(prefix="foo")
public class FooProperties {
// ... see above
}
This style of configuration works particularly well with the SpringApplication external YAML
configuration:
# application.yml
foo:
remote-address: 192.168.1.1
security:
username: foo
roles:
- USER
- ADMIN
# additional configuration as required
To work with @ConfigurationProperties beans you can just inject them in the same way as any
other bean.
@Service
public class MyService {
private final FooProperties properties;
@Autowired
public MyService(FooProperties properties) {
this.properties = properties;
}
//...
@PostConstruct
public void openConnection() {
Server server = new Server(this.properties.getRemoteAddress());
// ...
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 69
}
}
Tip
Using @ConfigurationProperties also allows you to generate meta-data files that can be
used by IDEs to offer auto-completion for your own keys, see the Appendix B, Configuration meta-
data appendix for details.
Third-party configuration
As well as using @ConfigurationProperties to annotate a class, you can also use it on public
@Bean methods. This 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:
@ConfigurationProperties(prefix = "bar")
@Bean
public BarComponent barComponent() {
...
}
Any property defined with the bar prefix will be mapped onto that BarComponent bean in a similar
manner as the FooProperties example above.
Relaxed binding
Spring Boot uses some relaxed rules for binding Environment properties to
@ConfigurationProperties beans, so there doesn’t need to be an exact match between the
Environment property name and the bean property name. Common examples where this is useful
include dashed separated (e.g. context-path binds to contextPath), and capitalized (e.g. PORT
binds to port) environment properties.
For example, given the following @ConfigurationProperties class:
@ConfigurationProperties(prefix="person")
public class OwnerProperties {
private String firstName;
public String getFirstName() {
return this.firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
}
The following properties names can all be used:
Table 24.1. relaxed binding
Property Note
person.firstNameStandard camel case syntax.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 70
Property Note
person.first-
name
Dashed notation, recommended for use in .properties and .yml files.
person.first_nameUnderscore notation, alternative format for use in .properties and .yml
files.
PERSON_FIRST_NAMEUpper case format. Recommended when using a system environment
variables.
Properties conversion
Spring will attempt 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 bean id conversionService) or custom property editors (via
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
require may not be fully initialized at creation time. You may want to rename your custom
ConversionService if it’s not required for configuration keys coercion and only rely on custom
converters qualified with @ConfigurationPropertiesBinding.
@ConfigurationProperties Validation
Spring Boot will attempt 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. Simply ensure that a compliant JSR-303
implementation is on your classpath, then add constraint annotations to your fields:
@ConfigurationProperties(prefix="foo")
@Validated
public class FooProperties {
@NotNull
private InetAddress remoteAddress;
// ... getters and setters
}
In order to validate values of nested properties, you must annotate the associated field as @Valid to
trigger its validation. For example, building upon the above FooProperties example:
@ConfigurationProperties(prefix="connection")
@Validated
public class FooProperties {
@NotNull
private InetAddress remoteAddress;
@Valid
private final Security security = new Security();
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 71
// ... getters and setters
public static class Security {
@NotEmpty
public String username;
// ... getters and setters
}
}
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 allows the bean to be created without having to instantiate the
@Configuration class. This avoids any problems that may be caused by early instantiation. There is
a property validation sample so you can see how to set things up.
Tip
The spring-boot-actuator module includes an endpoint that exposes all
@ConfigurationProperties beans. Simply point your web browser to /configprops or use
the equivalent JMX endpoint. See the Production ready features. section for details.
@ConfigurationProperties vs. @Value
@Value is a core container feature and it does not provide the same features as type-
safe Configuration Properties. The table below 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 to group them in a
POJO annotated with @ConfigurationProperties. Please also be aware that since @Value does
not support relaxed binding, it isn’t a great candidate if you need to provide the value using environment
variables.
Finally, while you can write a SpEL expression in @Value, such expressions are not processed from
Application property files.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 72
25. Profiles
Spring Profiles provide a way to segregate parts of your application configuration and make it
only available in certain environments. Any @Component or @Configuration can be marked with
@Profile to limit when it is loaded:
@Configuration
@Profile("production")
public class ProductionConfiguration {
// ...
}
In the normal Spring way, you can use a spring.profiles.active Environment property to
specify which profiles are active. You can specify the property in any of the usual ways, for example
you could include it in your application.properties:
spring.profiles.active=dev,hsqldb
or specify on the command line using the 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 will win. This means that you can specify active profiles in
application.properties then replace them 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 (i.e. on top of
those activated by the spring.profiles.active property): see the setAdditionalProfiles()
method.
For example, when an application with following properties is run using the switch --
spring.profiles.active=prod the proddb and prodmq profiles will also be 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 72.7,
“Change configuration depending on the environment” for more details.
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 using Spring’s ConfigurableEnvironment interface.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 73
25.3 Profile-specific configuration files
Profile-specific variants of both application.properties (or application.yml) and files
referenced via @ConfigurationProperties are considered as files are loaded. See Section 24.4,
“Profile-specific properties” for details.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 74
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 will be used for logging. Appropriate Logback routing is
also included to ensure that dependent libraries that use Java Util Logging, Commons Logging, Log4J
or SLF4J will all work correctly.
Tip
There are a lot of logging frameworks available for Java. Don’t worry if the above list seems
confusing. Generally you won’t need to change your logging dependencies and the Spring Boot
defaults will work just fine.
26.1 Log format
The default log output from Spring Boot looks like this:
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 will echo messages to the console as they are written. By default ERROR,
WARN and INFO level messages are logged. You can also enable a “debug” mode by starting your
application with a --debug flag.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 75
$ 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). This will enable 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 will be used to aid readability. You can set
spring.output.ansi.enabled to a supported value to override the auto detection.
Color coding is configured using the %clr conversion word. In its simplest form the converter will color
the output according to the log level, for example:
%clr(%5p)
The mapping of log level to a color is as follows:
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:
%clr(%d{yyyy-MM-dd HH:mm:ss.SSS}){yellow}
The following colors and styles are supported:
•blue
•cyan
•faint
•green
•magenta
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 76
•red
•yellow
26.3 File output
By default, Spring Boot will only log to the console and will 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 will rotate when they reach 10 MB and as with console output, ERROR, WARN and INFO level
messages are logged by default.
Note
The logging system is initialized early in the application lifecycle and as such logging properties
will not be found in property files loaded via @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 (so
for example in application.properties) using ‘logging.level.*=LEVEL’ where ‘LEVEL’ is one of
TRACE, DEBUG, INFO, WARN, ERROR, FATAL, OFF. The root logger can be configured using
logging.level.root. Example application.properties:
logging.level.root=WARN
logging.level.org.springframework.web=DEBUG
logging.level.org.hibernate=ERROR
Note
By default Spring Boot remaps Thymeleaf INFO messages so that they are logged at DEBUG
level. This helps to reduce noise in the standard log output. See LevelRemappingAppender
for details of how you can apply remapping in your own configuration.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 77
26.5 Custom log configuration
The various logging systems can be activated by including the appropriate libraries on the classpath,
and further customized by providing a suitable configuration file in the root of the classpath, or in a
location specified by the Spring Environment property logging.config.
You can force Spring Boot to use a particular logging system 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 isn’t possible to control
logging from @PropertySources in Spring @Configuration files. System properties and the
conventional Spring Boot external configuration files work just fine.)
Depending on your logging system, the following files will be 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 if at all possible.
To help with the customization some other properties are transferred from the Spring Environment
to System properties:
Spring Environment System Property Comments
logging.exception-
conversion-word
LOG_EXCEPTION_CONVERSION_WORDThe conversion word that’s
used when logging exceptions.
logging.file LOG_FILE Used in default log
configuration if defined.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 78
Spring Environment System Property Comments
logging.path LOG_PATH Used in default log
configuration if defined.
logging.pattern.console CONSOLE_LOG_PATTERN The log pattern to use on
the console (stdout). (Only
supported with the default
logback setup.)
logging.pattern.file FILE_LOG_PATTERN The log pattern to use in a file
(if LOG_FILE enabled). (Only
supported with the default
logback setup.)
logging.pattern.level LOG_LEVEL_PATTERN The format to use to render
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 logging systems supported can consult System properties when parsing their configuration files.
See the default configurations in spring-boot.jar for examples.
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’re using Logback, you should use :
as the delimiter between a property name and its default value and not :-.
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 will contain an
MDC entry for "user" if it exists, e.g.
2015-09-30 12:30:04.031 user:juergen INFO 22174 --- [ nio-8080-exec-0] demo.Controller
Handling authenticated request
26.6 Logback extensions
Spring Boot includes a number of extensions to Logback which can help with advanced configuration.
You can use these extensions in your logback-spring.xml configuration file.
Note
You cannot use extensions in the standard logback.xml configuration file since it’s loaded too
early. You need to either use logback-spring.xml or define a logging.config property.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 79
Warning
The extensions cannot be used with Logback’s configuration scanning. If you attempt to do so,
making changes to the configuration file will result 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 allows you to 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 using a comma-separated list.
<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 allows you to surface properties from the Spring Environment for use
within Logback. This 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>
tag, but rather than specifying a direct value you specify the source of the property (from the
Environment). You can use the scope attribute if you need to store the property somewhere other
than in local scope. If you need a fallback value in case the property is not set in the Environment,
you can use the defaultValue attribute.
<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>
Tip
The RelaxedPropertyResolver is used to access Environment properties. If specify
the source in dashed notation (my-property-name) all the relaxed variations will be tried
(myPropertyName, MY_PROPERTY_NAME etc).
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 80
27. Developing web applications
Spring Boot is well suited for web application development. You can easily create a self-contained HTTP
server using embedded Tomcat, Jetty, or Undertow. Most web applications will use the spring-boot-
starter-web module to get up and running quickly.
If you haven’t 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 using
@RequestMapping annotations.
Here is a typical example @RestController to serve 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 available at spring.io/guides that cover Spring MVC.
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 (see below).
• Automatic registration of Converter, GenericConverter, Formatter beans.
• Support for HttpMessageConverters (see below).
• Automatic registration of MessageCodesResolver (see below).
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 81
• Static index.html support.
• Custom Favicon support (see below).
• Automatic use of a ConfigurableWebBindingInitializer bean (see below).
If you want to keep Spring Boot MVC features, and you just want to add additional MVC
configuration (interceptors, formatters, view controllers etc.) you can add your own @Configuration
class of type WebMvcConfigurerAdapter, but without @EnableWebMvc. If you wish to provide
custom instances of RequestMappingHandlerMapping, RequestMappingHandlerAdapter or
ExceptionHandlerExceptionResolver you can declare a WebMvcRegistrationsAdapter
instance providing 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 (using the Jackson library) or XML (using the Jackson XML extension if available, else using
JAXB). Strings are encoded using UTF-8 by default.
If you need to add or customize converters you can use Spring Boot’s HttpMessageConverters
class:
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 will be added to the list of converters.
You can also override default converters that way.
Custom JSON Serializers and Deserializers
If you’re using 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 via a Module, but Spring Boot provides an alternative @JsonComponent annotation which
makes it easier to directly register Spring Beans.
You can use @JsonComponent directly on JsonSerializer or JsonDeserializer
implementations. You can also use it on classes that contains serializers/deserializers as inner-classes.
For example:
import java.io.*;
import com.fasterxml.jackson.core.*;
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 82
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 will be automatically registered with
Jackson, and since @JsonComponent is meta-annotated with @Component, the usual component-
scanning rules apply.
Spring Boot also provides JsonObjectSerializer and JsonObjectDeserializer base classes
which provide useful alternatives to the standard Jackson versions when serializing Objects. See the
Javadoc for details.
MessageCodesResolver
Spring MVC has a strategy for generating error codes for rendering error messages from binding errors:
MessageCodesResolver. Spring Boot will create one for you if you set the spring.mvc.message-
codes-resolver.format property PREFIX_ERROR_CODE or POSTFIX_ERROR_CODE (see the
enumeration in DefaultMessageCodesResolver.Format).
Static Content
By default Spring Boot will serve 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 you can modify that behavior by
adding your own WebMvcConfigurerAdapter 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 will not happen (unless you modify the default MVC configuration) because Spring will
always be able to handle requests through the DispatcherServlet.
By default, resources are mapped on /** but you can tune that via spring.mvc.static-path-
pattern. 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 using spring.resources.static-
locations (replacing the default values with a list of directory locations). If you do this the default
welcome page detection will switch to your custom locations, so if there is an index.html in any of
your locations on startup, it will be the home page of the application.
In addition to the ‘standard’ static resource locations above, a special case is made for Webjars content.
Any resources with a path in /webjars/** will be served from jar files if they are packaged in the
Webjars format.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 83
Tip
Do not use the src/main/webapp directory if your application will be packaged as a jar. Although
this directory is a common standard, it will only work with war packaging and it will be silently
ignored by most build tools if you generate a jar.
Spring Boot also supports 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, simply add the webjars-locator dependency. Then
declare your Webjar, taking jQuery for example, as "/webjars/jquery/dist/jquery.min.js"
which results in "/webjars/jquery/x.y.z/dist/jquery.min.js" where x.y.z is the Webjar
version.
Note
If you are using JBoss, you’ll need to declare the webjars-locator-jboss-vfs dependency
instead of the webjars-locator; otherwise all Webjars resolve as a 404.
To use cache busting, the following configuration will configure a cache busting solution for all
static resources, effectively adding a content hash in URLs, such as <link href="/css/
spring-2a2d595e6ed9a0b24f027f2b63b134d6.css"/>:
spring.resources.chain.strategy.content.enabled=true
spring.resources.chain.strategy.content.paths=/**
Note
Links to resources are rewritten at runtime in template, thanks to a
ResourceUrlEncodingFilter, auto-configured for Thymeleaf and FreeMarker. You should
manually declare this filter when using JSPs. Other template engines aren’t automatically
supported right now, 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’s why other strategies are also supported and can be combined. A "fixed" strategy
will add a static version string in the URL, without changing the file name:
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/" will use a fixed versioning
strategy "/v12/js/lib/mymodule.js" while other resources will still use the content one <link
href="/css/spring-2a2d595e6ed9a0b24f027f2b63b134d6.css"/>.
See ResourceProperties for more of the supported options.
Tip
This feature has been thoroughly described in a dedicated blog post and in Spring Framework’s
reference documentation.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 84
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 file is present, it is automatically used as the favicon of the application.
ConfigurableWebBindingInitializer
Spring MVC uses a WebBindingInitializer to initialize a WebDataBinder for a particular
request. If you create your own ConfigurableWebBindingInitializer @Bean, Spring Boot will
automatically configure Spring MVC to use it.
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. Many
other templating engines also ship their own Spring MVC integrations.
Spring Boot includes auto-configuration support for the following templating engines:
•FreeMarker
•Groovy
•Thymeleaf
•Mustache
Tip
JSPs should be avoided if possible, there are several known limitations when using them with
embedded servlet containers.
When you’re using one of these templating engines with the default configuration, your templates will
be picked up automatically from src/main/resources/templates.
Tip
IntelliJ IDEA orders the classpath differently depending on how you run your application. Running
your application in the IDE via its main method will result in a different ordering to when you
run your application 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’re affected by 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:
classpath*:/templates/.
Error Handling
Spring Boot provides an /error mapping by default 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 will produce 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 just add a View that resolves to ‘error’). To replace the default behaviour completely you can
implement ErrorController and register a bean definition of that type, or simply add a bean of type
ErrorAttributes to use the existing mechanism but replace the contents.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 85
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 that just
extend BasicErrorController and add a public method with a @RequestMapping that has
a produces attribute, and create a bean of your new type.
You can also define a @ControllerAdvice to customize the JSON document to return for a particular
controller and/or exception type.
@ControllerAdvice(basePackageClasses = FooController.class)
public class FooControllerAdvice 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 example above, if YourException is thrown by a controller defined in the same package as
FooController, a json representation of the CustomerErrorType POJO will be 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 add a file to an /error
folder. Error pages can either be static HTML (i.e. added under any of the static resource folders) or
built 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 look like this:
src/
+- main/
+- java/
| + <source code>
+- resources/
+- public/
+- error/
| +- 404.html
+- <other public assets>
To map all 5xx errors using a FreeMarker template, you’d have a structure like this:
src/
+- main/
+- java/
| + <source code>
+- resources/
+- templates/
+- error/
| +- 5xx.ftl
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 86
+- <other templates>
For more complex mappings you can also add beans that implement the ErrorViewResolver
interface.
public class MyErrorViewResolver implements ErrorViewResolver {
@Override
public ModelAndView resolveErrorView(HttpServletRequest request,
HttpStatus status, Map<String, Object> model) {
// Use the request or status to optionally return a ModelAndView
return ...
}
}
You can also use regular Spring MVC features like @ExceptionHandler methods and
@ControllerAdvice. The ErrorController will then pick up any unhandled exceptions.
Mapping error pages outside of Spring MVC
For applications that aren’t using Spring MVC, you can use the ErrorPageRegistrar interface to
directly register ErrorPages. This abstraction works directly with the underlying embedded servlet
container and will work even if you don’t 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"));
}
}
N.B. if you register an ErrorPage with a path that will end up being handled by a Filter (e.g. 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, e.g.
@Bean
public FilterRegistrationBean myFilter() {
FilterRegistrationBean registration = new FilterRegistrationBean();
registration.setFilter(new MyFilter());
...
registration.setDispatcherTypes(EnumSet.allOf(DispatcherType.class));
return registration;
}
(the default FilterRegistrationBean does not include the ERROR dispatcher type).
Error Handling on WebSphere Application Server
When deployed to a servlet container, a 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 behaviour by setting com.ibm.ws.webcontainer.invokeFlushAfterService to false
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 87
Spring HATEOAS
If you’re developing 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 hypermedia-based applications including a LinkDiscoverers (for client side support)
and an ObjectMapper configured to correctly marshal responses into the desired representation.
The ObjectMapper will be customized based on the spring.jackson.* properties or a
Jackson2ObjectMapperBuilder bean if one exists.
You can take control of Spring HATEOAS’s configuration by using @EnableHypermediaSupport.
Note that this will disable the ObjectMapper customization described above.
CORS support
Cross-origin resource sharing (CORS) is a W3C specification implemented by most browsers that allows
you to specify in a flexible way what kind of cross domain requests are authorized, instead of using
some less secure and less powerful approaches like IFRAME or JSONP.
As of version 4.2, Spring MVC supports CORS out of the box. 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:
@Configuration
public class MyConfiguration {
@Bean
public WebMvcConfigurer corsConfigurer() {
return new WebMvcConfigurerAdapter() {
@Override
public void addCorsMappings(CorsRegistry registry) {
registry.addMapping("/api/**");
}
};
}
}
27.2 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 just 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 just 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:
@Component
public class JerseyConfig extends ResourceConfig {
public JerseyConfig() {
register(Endpoint.class);
}
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 88
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 using the register method as shown above.
You can also register an arbitrary number of beans implementing ResourceConfigCustomizer for
more advanced customizations.
All the registered endpoints should be @Components with HTTP resource annotations (@GET etc.), e.g.
@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
@Autowired dependencies and inject external configuration with @Value. The Jersey servlet will be
registered and mapped to /* by default. You can change the mapping by adding @ApplicationPath
to your ResourceConfig.
By default Jersey will be set up as a Servlet in a @Bean of type ServletRegistrationBean
named jerseyServletRegistration. By default, the servlet will be initialized lazily but you
can customize it with 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 servlet has an @Order which you can set with
spring.jersey.filter.order. Both the Servlet and the Filter registrations can be given init
parameters using spring.jersey.init.* to specify a map of properties.
There is a Jersey sample so you can see how to set things up. There is also a Jersey 1.x sample.
Note that in the Jersey 1.x sample that the spring-boot maven plugin has been configured to unpack
some Jersey jars so they can be scanned by the JAX-RS implementation (because the sample asks
for them to be scanned in its Filter registration). You may need to do the same if any of your JAX-
RS resources are packaged as nested jars.
27.3 Embedded servlet container support
Spring Boot includes support for embedded Tomcat, Jetty, and Undertow servers. Most developers will
simply use the appropriate ‘Starter’ to obtain a fully configured instance. By default the embedded server
will listen 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 etc. This directory may be deleted by tmpwatch
while your application is running leading to failures. To avoid this, you may want to customize
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 89
your tmpwatch configuration so that tomcat.* directories are not deleted, or configure
server.tomcat.basedir so 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 from
the Servlet spec (e.g. HttpSessionListener) 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 will be 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 will be mapped to /. In the case of multiple
Servlet beans the bean name will be used as a path prefix. Filters will map to /*.
If convention-based mapping is not flexible enough you can use the ServletRegistrationBean,
FilterRegistrationBean and ServletListenerRegistrationBean classes for complete
control.
Servlet Context Initialization
Embedded servlet containers will 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 3rd party libraries designed to run inside a war will 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.context.embedded.ServletContextInitializer interface.
The single onStartup method provides access to the ServletContext, and can easily be used as
an adapter to an existing WebApplicationInitializer if necessary.
Scanning for Servlets, Filters, and listeners
When using an embedded container, automatic registration of @WebServlet, @WebFilter, and
@WebListener annotated classes can be enabled using @ServletComponentScan.
Tip
@ServletComponentScan will have no effect in a standalone container, where the container’s
built-in discovery mechanisms will be used instead.
The EmbeddedWebApplicationContext
Under the hood Spring Boot uses a new type of ApplicationContext for embedded servlet container
support. The EmbeddedWebApplicationContext is a special type of WebApplicationContext
that bootstraps itself by searching for a single EmbeddedServletContainerFactory bean. Usually a
TomcatEmbeddedServletContainerFactory, JettyEmbeddedServletContainerFactory,
or UndertowEmbeddedServletContainerFactory will have been auto-configured.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 90
Note
You usually won’t need to be aware of these implementation classes. Most
applications will be auto-configured and the appropriate ApplicationContext and
EmbeddedServletContainerFactory will be created on your behalf.
Customizing embedded servlet containers
Common servlet container settings can be configured 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, etc.
• Session settings: whether the session is persistent (server.session.persistence), session
timeout (server.session.timeout), location of session data (server.session.store-dir)
and session-cookie configuration (server.session.cookie.*).
• Error management: location of the error page (server.error.path), etc.
•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 configure your embedded servlet container programmatically you can
register a Spring bean that implements the EmbeddedServletContainerCustomizer
interface. EmbeddedServletContainerCustomizer provides access to the
ConfigurableEmbeddedServletContainer which includes numerous customization setter
methods.
import org.springframework.boot.context.embedded.*;
import org.springframework.stereotype.Component;
@Component
public class CustomizationBean implements EmbeddedServletContainerCustomizer {
@Override
public void customize(ConfigurableEmbeddedServletContainer container) {
container.setPort(9000);
}
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 91
Customizing ConfigurableEmbeddedServletContainer directly
If the above customization techniques are too limited, you can register the
TomcatEmbeddedServletContainerFactory, JettyEmbeddedServletContainerFactory
or UndertowEmbeddedServletContainerFactory bean yourself.
@Bean
public EmbeddedServletContainerFactory servletContainer() {
TomcatEmbeddedServletContainerFactory factory = new TomcatEmbeddedServletContainerFactory();
factory.setPort(9000);
factory.setSessionTimeout(10, TimeUnit.MINUTES);
factory.addErrorPages(new ErrorPage(HttpStatus.NOT_FOUND, "/notfound.html"));
return factory;
}
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 Tomcat it should work if you use war packaging, i.e. an executable war will work, and will also
be deployable to a standard container (not limited to, but including Tomcat). An executable jar will not
work because of a hard coded file pattern in Tomcat.
• With Jetty it should work if you use war packaging, i.e. an executable war will work, and will also be
deployable to any standard container.
• Undertow does not support JSPs.
• Creating a custom error.jsp page won’t override the default view for error handling, custom error
pages should be used instead.
There is a JSP sample so you can see how to set things up.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 92
28. Security
If Spring Security is on the classpath then web applications will be secure by default with ‘basic’
authentication on all HTTP endpoints. 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.
The default AuthenticationManager has a single user (‘user’ username and random password,
printed at INFO level when the application starts up)
Using default 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
messages, otherwise the default password will not be printed.
You can change the password by providing a security.user.password. This and other useful
properties are externalized via SecurityProperties (properties prefix "security").
The default security configuration is implemented in SecurityAutoConfiguration and in the
classes imported from there (SpringBootWebSecurityConfiguration for web security and
AuthenticationManagerConfiguration for authentication configuration which is also relevant
in non-web applications). To switch off the default web application security configuration completely
you can add a bean with @EnableWebSecurity (this does not disable the authentication manager
configuration or Actuator’s security). To customize it you normally use external properties and beans of
type WebSecurityConfigurerAdapter (e.g. to add form-based login).
Note
If you add @EnableWebSecurity and also disable Actuator security, you will get
the default form-based login for the entire application unless you add a custom
WebSecurityConfigurerAdapter.
To also switch off the authentication manager configuration you can add a bean of type
AuthenticationManager, or else configure the global AuthenticationManager by autowiring an
AuthenticationManagerBuilder into a method in one of your @Configuration classes. There
are several secure applications in the Spring Boot samples to get you started with common use cases.
The basic features you get out of the box in a web application are:
• An AuthenticationManager bean with in-memory store and a single user (see
SecurityProperties.User for the properties of the user).
• Ignored (insecure) paths for common static resource locations (/css/**, /js/**, /images/**, /
webjars/** and **/favicon.ico).
• HTTP Basic security for all other endpoints.
• Security events published to Spring’s ApplicationEventPublisher (successful and
unsuccessful authentication and access denied).
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 93
• Common low-level features (HSTS, XSS, CSRF, caching) provided by Spring Security are on by
default.
All of the above can be switched on and off or modified using external
properties (security.*). To override the access rules without changing any other
auto-configured features add a @Bean of type WebSecurityConfigurerAdapter with
@Order(SecurityProperties.ACCESS_OVERRIDE_ORDER) and configure it to meet your needs.
Note
By default, a WebSecurityConfigurerAdapter will match any path. If you don’t want to
completely override Spring Boot’s auto-configured access rules, your adapter must explicitly
configure the paths that you do want to override.
28.1 OAuth2
If you have spring-security-oauth2 on your classpath you can take advantage of some auto-
configuration to make it easy to set up Authorization or Resource Server. For full details, see the Spring
Security OAuth 2 Developers Guide.
Authorization Server
To create an Authorization Server and grant access tokens you need to use
@EnableAuthorizationServer and provide security.oauth2.client.client-id and
security.oauth2.client.client-secret] properties. The client will be registered for you in an
in-memory repository.
Having done that you will be able to use the client credentials to create an access token, for example:
$ curl client:secret@localhost:8080/oauth/token -d grant_type=password -d username=user -d password=pwd
The basic auth credentials for the /token endpoint are the client-id and client-secret. The
user credentials are the normal Spring Security user details (which default in Spring Boot to “user” and
a random password).
To switch off the auto-configuration and configure the Authorization Server features yourself just add a
@Bean of type AuthorizationServerConfigurer.
Resource Server
To use the access token you need a Resource Server (which can be the same as the Authorization
Server). Creating a Resource Server is easy, just add @EnableResourceServer and provide some
configuration to allow the server to decode access tokens. If your application is also an Authorization
Server it already knows how to decode tokens, so there is nothing else to do. If your app is a standalone
service then you need to give it some more configuration, one of the following options:
•security.oauth2.resource.user-info-uri to use the /me resource (e.g. https://
uaa.run.pivotal.io/userinfo on Pivotal Web Services (PWS))
•security.oauth2.resource.token-info-uri to use the token decoding endpoint (e.g.
https://uaa.run.pivotal.io/check_token on PWS).
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 94
If you specify both the user-info-uri and the token-info-uri then you can set a flag to say that
one is preferred over the other (prefer-token-info=true is the default).
Alternatively (instead of user-info-uri or token-info-uri) if the tokens are JWTs you can
configure a security.oauth2.resource.jwt.key-value to decode them locally (where the key
is a verification key). The verification key value is either a symmetric secret or PEM-encoded RSA public
key. If you don’t have the key and it’s public you can provide a URI where it can be downloaded (as a
JSON object with a “value” field) with security.oauth2.resource.jwt.key-uri. E.g. on PWS:
$ curl https://uaa.run.pivotal.io/token_key
{"alg":"SHA256withRSA","value":"-----BEGIN PUBLIC KEY-----\nMIIBI...\n-----END PUBLIC KEY-----\n"}
Additionally, if your authorization server has an endpoint that returns a set of JSON Web Keys(JWKs),
you can configure security.oauth2.resource.jwk.key-set-uri. E.g. on PWS:
$ curl https://uaa.run.pivotal.io/token_keys
{"keys":[{"kid":"key-1","alg":"RS256","value":"-----BEGIN PUBLIC KEY-----\nMIIBI...\n-----END PUBLIC
KEY-----\n"]}
Note
Configuring both JWT and JWK properties will cause an
error. Only one of security.oauth2.resource.jwt.key-uri (or
security.oauth2.resource.jwt.key-value) and
security.oauth2.resource.jwk.key-set-uri should be configured.
Warning
If you use the security.oauth2.resource.jwt.key-uri or
`security.oauth2.resource.jwk.key-set-uri, ` the authorization server needs to be running when
your application starts up. It will log a warning if it can’t find the key, and tell you what to do to fix it.
OAuth2 resources are protected by a filter chain with order security.oauth2.resource.filter-
order and the default is after the filter protecting the actuator endpoints by default (so actuator
endpoints will stay on HTTP Basic unless you change the order).
28.2 Token Type in User Info
Google, and certain other 3rd party identity providers, are more strict about the token type name that
is sent in the headers to the user info endpoint. The default is “Bearer” which suits most providers and
matches the spec, but if you need to change it you can set security.oauth2.resource.token-
type.
28.3 Customizing the User Info RestTemplate
If you have a user-info-uri, the resource server features use an OAuth2RestTemplate
internally to fetch user details for authentication. This is provided as a @Bean of type
UserInfoRestTemplateFactory. The default should be fine for most providers, but occasionally
you might need to add additional interceptors, or change the request authenticator (which is
how the token gets attached to outgoing requests). To add a customization just create a bean
of type UserInfoRestTemplateCustomizer - it has a single method that will be called after
the bean is created but before it is initialized. The rest template that is being customized
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 95
here is only used internally to carry out authentication. Alternatively, you could define your own
UserInfoRestTemplateFactory @Bean to take full control.
Tip
To set an RSA key value in YAML use the “pipe” continuation marker to split it over multiple lines
(“|”) and remember to indent the key value (it’s a standard YAML language feature). Example:
security:
oauth2:
resource:
jwt:
keyValue: |
-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKC...
-----END PUBLIC KEY-----
Client
To make your web-app into an OAuth2 client you can simply add @EnableOAuth2Client and
Spring Boot will create a OAuth2ClientContext and OAuth2ProtectedResourceDetails that
are necessary to create an OAuth2RestOperations. Spring Boot does not automatically create such
bean but you can easily create your own:
@Bean
public OAuth2RestTemplate oauth2RestTemplate(OAuth2ClientContext oauth2ClientContext,
OAuth2ProtectedResourceDetails details) {
return new OAuth2RestTemplate(details, oauth2ClientContext);
}
Note
You may want to add a qualifier and review your configuration as more than one RestTemplate
may be defined in your application.
This configuration uses security.oauth2.client.* as credentials (the same as you might be using
in the Authorization Server), but in addition it will need to know the authorization and token URIs in the
Authorization Server. For example:
application.yml.
security:
oauth2:
client:
clientId: bd1c0a783ccdd1c9b9e4
clientSecret: 1a9030fbca47a5b2c28e92f19050bb77824b5ad1
accessTokenUri: https://github.com/login/oauth/access_token
userAuthorizationUri: https://github.com/login/oauth/authorize
clientAuthenticationScheme: form
An application with this configuration will redirect to Github for authorization when you attempt to use
the OAuth2RestTemplate. If you are already signed into Github you won’t even notice that it has
authenticated. These specific credentials will only work if your application is running on port 8080
(register your own client app in Github or other provider for more flexibility).
To limit the scope that the client asks for when it obtains an access token you can set
security.oauth2.client.scope (comma separated or an array in YAML). By default the scope
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 96
is empty and it is up to Authorization Server to decide what the defaults should be, usually depending
on the settings in the client registration that it holds.
Note
There is also a setting for security.oauth2.client.client-authentication-scheme
which defaults to “header” (but you might need to set it to “form” if, like Github for instance, your
OAuth2 provider doesn’t like header authentication). In fact, the security.oauth2.client.*
properties are bound to an instance of AuthorizationCodeResourceDetails so all its
properties can be specified.
Tip
In a non-web application you can still create an OAuth2RestOperations and it is still wired
into the security.oauth2.client.* configuration. In this case it is a “client credentials token
grant” you will be asking for if you use it (and there is no need to use @EnableOAuth2Client
or @EnableOAuth2Sso). To prevent that infrastructure to be defined, just remove the
security.oauth2.client.client-id from your configuration (or make it the empty string).
Single Sign On
An OAuth2 Client can be used to fetch user details from the provider (if such features are available)
and then convert them into an Authentication token for Spring Security. The Resource Server
above support this via the user-info-uri property This is the basis for a Single Sign On (SSO)
protocol based on OAuth2, and Spring Boot makes it easy to participate by providing an annotation
@EnableOAuth2Sso. The Github client above can protect all its resources and authenticate using the
Github /user/ endpoint, by adding that annotation and declaring where to find the endpoint (in addition
to the security.oauth2.client.* configuration already listed above):
application.yml.
security:
oauth2:
...
resource:
userInfoUri: https://api.github.com/user
preferTokenInfo: false
Since all paths are secure by default, there is no “home” page that you can show to
unauthenticated users and invite them to login (by visiting the /login path, or the path specified by
security.oauth2.sso.login-path).
To customize the access rules or paths to protect, so you can add a “home” page for instance,
@EnableOAuth2Sso can be added to a WebSecurityConfigurerAdapter and the annotation will
cause it to be decorated and enhanced with the necessary pieces to get the /login path working. For
example, here we simply allow unauthenticated access to the home page at "/" and keep the default
for everything else:
@Configuration
static class WebSecurityConfiguration extends WebSecurityConfigurerAdapter {
@Override
public void init(WebSecurity web) {
web.ignoring().antMatchers("/");
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 97
@Override
protected void configure(HttpSecurity http) throws Exception {
http.antMatcher("/**").authorizeRequests().anyRequest().authenticated();
}
}
28.4 Actuator Security
If the Actuator is also in use, you will find:
• The management endpoints are secure even if the application endpoints are insecure.
• Security events are transformed into AuditEvent instances and published to the
AuditEventRepository.
• The default user will have the ACTUATOR role as well as the USER role.
The Actuator security features can be modified using external properties (management.security.*).
To override the application access rules add a @Bean of type WebSecurityConfigurerAdapter and
use @Order(SecurityProperties.ACCESS_OVERRIDE_ORDER) if you don’t want to override the
actuator access rules, or @Order(ManagementServerProperties.ACCESS_OVERRIDE_ORDER)
if you do want to override the actuator access rules.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 98
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
Check also the ‘How-to’ section for more advanced examples, typically to take full control over
the configuration of the DataSource.
Embedded Database Support
It’s often convenient to develop applications using an in-memory embedded database. Obviously, in-
memory databases do not provide persistent storage; you will 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 don’t need to provide
any connection URLs, simply 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, typical POM dependencies would be:
<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>
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 99
Note
You need a dependency on spring-jdbc for an embedded database to be auto-configured. In
this example it’s pulled in transitively via spring-boot-starter-data-jpa.
Tip
If, for whatever reason, you do configure the connection URL for an embedded database, care
should be taken to ensure that the database’s automatic shutdown is disabled. If you’re using
H2 you should use DB_CLOSE_ON_EXIT=FALSE to do so. If you’re using HSQLDB, you should
ensure that shutdown=true is not used. Disabling the database’s automatic shutdown allows
Spring Boot to 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 using a pooling DataSource. Here’s the
algorithm for choosing a specific implementation:
• We prefer the Tomcat pooling DataSource for its performance and concurrency, so if that is available
we always choose it.
• Otherwise, if HikariCP is available we will use it.
• If neither the Tomcat pooling datasource nor HikariCP are available and if Commons DBCP is
available we will use it, but we don’t recommend it in production and its support is deprecated.
• Lastly, if Commons DBCP2 is available we will use it.
If you use the spring-boot-starter-jdbc or spring-boot-starter-data-jpa ‘starters’ you
will automatically get a dependency to tomcat-jdbc.
Note
You can bypass that algorithm completely and specify the connection pool to use via the
spring.datasource.type property. This is especially important if you are running 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 will 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 using the spring.datasource.url property or Spring Boot
will attempt to auto-configure an embedded database.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 100
Tip
You often won’t 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. I.e. 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 using their respective prefix (spring.datasource.tomcat.*,
spring.datasource.hikari.*, and spring.datasource.dbcp2.*). Refer to the
documentation of the connection pool implementation you are using for more details.
For instance, if you are using the Tomcat connection pool you could customize many additional settings:
# 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 are deploying your Spring Boot application to an Application Server you might want to configure
and manage your DataSource using your Application Servers built-in features and access it 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:
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;
@Autowired
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 101
public MyBean(JdbcTemplate jdbcTemplate) {
this.jdbcTemplate = jdbcTemplate;
}
// ...
}
29.3 JPA and ‘Spring Data’
The Java Persistence API is a standard technology that allows you to ‘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 won’t 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.
Note
By default, Spring Boot uses Hibernate 5.0.x. However it’s also possible to use 4.3.x or 5.2.x if
you wish. Please refer to the Hibernate 4 and Hibernate 5.2 samples to see how to do so.
Entity Classes
Traditionally, JPA ‘Entity’ classes are specified in a persistence.xml file. With Spring Boot
this file is not necessary and instead ‘Entity Scanning’ is used. By default all packages
below your main configuration class (the one annotated with @EnableAutoConfiguration or
@SpringBootApplication) will be searched.
Any classes annotated with @Entity, @Embeddable or @MappedSuperclass will be considered. A
typical entity class would look something like this:
package com.example.myapp.domain;
import java.io.Serializable;
import javax.persistence.*;
@Entity
public class City implements Serializable {
@Id
@GeneratedValue
private Long id;
@Column(nullable = false)
private String name;
@Column(nullable = false)
private String state;
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 102
// ... 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 using the @EntityScan annotation. See the
Section 77.4, “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 cities in a given state.
For more complex queries you can annotate your method using Spring Data’s Query annotation.
Spring Data repositories usually extend from the Repository or CrudRepository interfaces.
If you are using auto-configuration, repositories will be searched from the package containing
your main configuration class (the one annotated with @EnableAutoConfiguration or
@SpringBootApplication) down.
Here is a typical Spring Data repository:
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);
}
Tip
We have barely scratched the surface of Spring Data JPA. For complete details check their
reference documentation.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 103
Creating and dropping JPA databases
By default, JPA databases will be automatically created only if you use an embedded database
(H2, HSQL or Derby). You can explicitly configure JPA settings using spring.jpa.* properties. For
example, to create and drop tables you can add the following 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, using
spring.jpa.properties.* (the prefix is stripped before adding them to the entity manager).
Example:
spring.jpa.properties.hibernate.globally_quoted_identifiers=true
passes hibernate.globally_quoted_identifiers 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 autoconfig is active
because the ddl-auto settings are more fine-grained.
Open EntityManager in View
If you are running a web application, Spring Boot will by default register
OpenEntityManagerInViewInterceptor to apply the "Open EntityManager in View" pattern, i.e. to
allow for lazy loading in web views. If you don’t 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 will be auto-configured when the following conditions are met:
• You are developing a 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,
then you can do so by configuring the spring.h2.console.enabled property with a value of
true. The H2 console is only intended for use during development so care should be taken to
ensure that spring.h2.console.enabled is not set to true in production.
Changing the H2 console’s path
By default the console will be available at /h2-console. You can customize the console’s path using
the spring.h2.console.path property.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 104
Securing the H2 console
When Spring Security is on the classpath and basic auth is enabled, the H2 console will be automatically
secured using basic auth. The following properties can be used to customize the security configuration:
•security.user.role
•security.basic.authorize-mode
•security.basic.enabled
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 are using 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 (e.g. h2.version)
to declare the plugin’s database dependency. Here’s 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 via the org.jooq.DSLContext interface. Spring Boot will
auto-configure a DSLContext as a Spring Bean and connect it to your application DataSource. To
use the DSLContext you can just @Autowire it:
@Component
public class JooqExample implements CommandLineRunner {
private final DSLContext create;
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 105
@Autowired
public JooqExample(DSLContext dslContext) {
this.create = dslContext;
}
}
Tip
The jOOQ manual tends to use a variable named create to hold the DSLContext, we’ve done
the same for this example.
You can then use the DSLContext to construct your queries:
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);
}
Customizing jOOQ
You can customize the SQL dialect used by jOOQ by setting spring.jooq.sql-dialect in your
application.properties. For example, to specify Postgres you would add:
spring.jooq.sql-dialect=Postgres
More advanced customizations can be achieved by defining your own @Bean definitions which will be
used when the jOOQ Configuration is created. You can define beans for the following jOOQ Types:
•ConnectionProvider
•TransactionProvider
•RecordMapperProvider
•RecordListenerProvider
•ExecuteListenerProvider
•VisitListenerProvider
You can also create your own org.jooq.Configuration @Bean if you want to take complete control
of the jOOQ configuration.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 106
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 will need to 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 Jedis client library and abstractions on top of it provided by Spring Data Redis. There
is a spring-boot-starter-data-redis ‘Starter’ for collecting the dependencies in a convenient
way.
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 will attempt to
connect to a Redis server using localhost:6379:
@Component
public class MyBean {
private StringRedisTemplate template;
@Autowired
public MyBean(StringRedisTemplate template) {
this.template = template;
}
// ...
}
If you add a @Bean of your own of any of the auto-configured types it will replace the default (except in
the case of RedisTemplate the exclusion is based on the bean name ‘redisTemplate’ not its type). If
commons-pool2 is on the classpath you will get a pooled connection factory by default.
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 ‘Starter’.
Connecting to a MongoDB database
You can inject an auto-configured org.springframework.data.mongodb.MongoDbFactory to
access Mongo databases. By default the instance will attempt to connect to a MongoDB server using
the URL mongodb://localhost/test:
import org.springframework.data.mongodb.MongoDbFactory;
import com.mongodb.DB;
@Component
public class MyBean {
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 107
private final MongoDbFactory mongo;
@Autowired
public MyBean(MongoDbFactory mongo) {
this.mongo = mongo;
}
// ...
public void example() {
DB db = mongo.getDb();
// ...
}
}
You can set spring.data.mongodb.uri property to change the URL and configure additional
settings such as the replica set:
spring.data.mongodb.uri=mongodb://user:secret@mongo1.example.com:12345,mongo2.example.com:23456/test
Alternatively, as long as you’re using Mongo 2.x, specify a host/port. For example, you might declare
the following in your application.properties:
spring.data.mongodb.host=mongoserver
spring.data.mongodb.port=27017
Note
spring.data.mongodb.host and spring.data.mongodb.port are not supported if you’re
using the Mongo 3.0 Java driver. 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 simply
delete this line from the sample above.
Tip
If you aren’t using Spring Data Mongo you can inject com.mongodb.Mongo beans instead of
using MongoDbFactory.
You can also declare your own MongoDbFactory or Mongo bean if you want to take complete control
of establishing the MongoDB connection.
MongoTemplate
Spring Data Mongo 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 simply inject:
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.stereotype.Component;
@Component
public class MyBean {
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 108
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 for you automatically based on method names.
In fact, both Spring Data JPA and Spring Data MongoDB share the same common infrastructure; so
you could take the JPA example from earlier and, assuming that City is now a Mongo data class rather
than a JPA @Entity, it will work in the same way.
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);
}
Tip
For complete details of Spring Data MongoDB, including its rich object mapping technologies,
refer to their 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 will listen on can be configured using the spring.data.mongodb.port
property. To use a randomly allocated free port use a value of zero. The MongoClient created by
MongoAutoConfiguration will be automatically configured to use the randomly allocated port.
Note
If you do not configure a custom port, the embedded support will use a random port by default
(rather than 27017).
If you have SLF4J on the classpath, output produced by Mongo will be 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 109
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 will attempt to connect to a Neo4j server using
localhost:7474:
@Component
public class MyBean {
private final Neo4jTemplate neo4jTemplate;
@Autowired
public MyBean(Neo4jTemplate neo4jTemplate) {
this.neo4jTemplate = neo4jTemplate;
}
// ...
}
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 via the spring.data.neo4j.* properties:
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 will automatically configure an in-process embedded instance of Neo4j that will
not persist any data when your application shuts down. You can explicitly disable that mode
using spring.data.neo4j.embedded.enabled=false. You can also enable persistence for the
embedded mode:
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 (i.e. the "Open Session in View" pattern). If you don’t want this behavior add
the following to your application.properties:
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 110
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; so you
could take the JPA example from earlier and, assuming that City is now a Neo4j OGM @NodeEntity
rather than a JPA @Entity, it will work in the same way.
Tip
You can customize entity scanning locations 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
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 their 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 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 111
Connecting to Solr
You can inject an auto-configured SolrClient instance as you would any other Spring bean. By default
the instance will attempt to connect to a server using localhost:8983/solr:
@Component
public class MyBean {
private SolrClient solr;
@Autowired
public MyBean(SolrClient solr) {
this.solr = solr;
}
// ...
}
If you add a @Bean of your own of type SolrClient it will replace 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 constructed for you automatically based on method names.
In fact, both Spring Data JPA and Spring Data Solr share the same common infrastructure; so you could
take the JPA example from earlier and, assuming that City is now a @SolrDocument class rather
than a JPA @Entity, it will work in the same way.
Tip
For complete details of Spring Data Solr, refer to their reference documentation.
30.6 Elasticsearch
Elasticsearch is an open source, distributed, real-time search and analytics engine. Spring Boot offers
basic auto-configuration for the Elasticsearch and 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 using Jest
If you have Jest on the classpath, you can inject an auto-configured JestClient targeting
localhost:9200 by default. You can further tune how the client is configured:
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 implementing
HttpClientConfigBuilderCustomizer for more advanced customizations. The example below
tunes additional HTTP settings:
static class HttpSettingsCustomizer implements HttpClientConfigBuilderCustomizer {
@Override
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 112
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 using Spring Data
You can inject an auto-configured ElasticsearchTemplate or Elasticsearch Client instance as
you would any other Spring Bean. By default the instance will embed a local in-memory server (a Node
in Elasticsearch terms) and use the current working directory as the home directory for the server. In
this setup, the first thing to do is to tell Elasticsearch where to store its files:
spring.data.elasticsearch.properties.path.home=/foo/bar
Alternatively, you can switch to a remote server (i.e. a TransportClient) by setting
spring.data.elasticsearch.cluster-nodes to a comma-separated ‘host:port’ list.
spring.data.elasticsearch.cluster-nodes=localhost:9300
@Component
public class MyBean {
private ElasticsearchTemplate template;
@Autowired
public MyBean(ElasticsearchTemplate template) {
this.template = template;
}
// ...
}
If you add a @Bean of your own of type ElasticsearchTemplate it will replace 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;
so you could take the JPA example from earlier and, assuming that City is now an Elasticsearch
@Document class rather than a JPA @Entity, it will work in the same way.
Tip
For complete details of Spring Data Elasticsearch, refer to their 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 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 113
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 will provide keyspace-name and contact-points
properties:
spring.data.cassandra.keyspace-name=mykeyspace
spring.data.cassandra.contact-points=cassandrahost1,cassandrahost2
@Component
public class MyBean {
private CassandraTemplate template;
@Autowired
public MyBean(CassandraTemplate template) {
this.template = template;
}
// ...
}
If you add a @Bean of your own of type CassandraTemplate it will replace 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 will need to annotate finder methods with @Query.
Tip
For complete details of Spring Data Cassandra, refer to their 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
abstractions on top of it provided by Spring Data Couchbase. There is a spring-boot-starter-
data-couchbase ‘Starter’ for collecting the dependencies in a convenient way.
Connecting to Couchbase
You can very easily 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 will
provide the bootstrap hosts, bucket name and password:
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 the empty String. Alternatively, you can define your
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 114
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 their reference documentation.
You can inject an auto-configured CouchbaseTemplate instance as you would with any other Spring
Bean as long as a default CouchbaseConfigurer is available (that happens when you enable the
couchbase support as explained above).
@Component
public class MyBean {
private final CouchbaseTemplate template;
@Autowired
public MyBean(CouchbaseTemplate template) {
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 name couchbaseTemplate
• An IndexManager @Bean with name couchbaseIndexManager
• A CustomConversions @Bean with name 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(...);
}
// ...
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 115
Tip
If you want to fully bypass the auto-configuration for Spring Data Couchbase, provide your own
org.springframework.data.couchbase.config.AbstractCouchbaseDataConfiguration
implementation.
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 then declare the URLs of your server in your
application.properties:
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.
Spring Data LDAP repositories
Spring Data includes repository support for LDAP. For complete details of Spring Data LDAP, refer to
their reference documentation.
You can also inject an auto-configured LdapTemplate instance as you would with any other Spring
Bean.
@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:
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 116
spring.ldap.embedded.base-dn=dc=spring,dc=io
By default the server will start on a random port and they trigger 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 will be used to initialize the server. You can also
use the spring.ldap.embedded.ldif property if you want to load the initialization script from a
different resource.
By default, a standard schema will be used to validate LDIF files, you can turn off validation altogether
using 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 117
31. Caching
The Spring Framework provides support for transparently adding caching to an application. At its core,
the abstraction applies caching to methods, reducing thus 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 the 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:
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 will look for an entry in the piDecimals cache matching 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.
Note
You can also use the standard JSR-107 (JCache) annotations (e.g. @CacheResult)
transparently. We strongly advise you however to not mix and match them.
If you do not add any specific cache library, Spring Boot will auto-configure a Simple provider that uses
concurrent maps in memory. When a cache is required (i.e. piDecimals in the example above), this
provider will create it on-the-fly for you. The simple provider is not really recommended for production
usage, but it’s 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. Practically 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 update or evict data from the cache transparently.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 118
Note
If you are using the cache infrastructure with beans that are not interface-based, make sure to
enable the proxyTargetClass attribute of @EnableCaching.
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 haven’t defined a bean of type CacheManager or a CacheResolver named cacheResolver
(see CachingConfigurer), Spring Boot tries to detect the following providers (in this order):
•Generic
•JCache (JSR-107) (EhCache 3, Hazelcast, Infinispan, etc)
•EhCache 2.x
•Hazelcast
•Infinispan
•Couchbase
•Redis
•Caffeine
•Guava (deprecated)
•Simple
Tip
It is also possible to force the cache provider to use via the spring.cache.type property. Use
this property if you need to disable caching altogether in certain environment (e.g. tests).
Tip
Use the spring-boot-starter-cache ‘Starter’ to quickly add basic caching dependencies.
The starter brings in spring-context-support: if you are adding 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 implementing the CacheManagerCustomizer interface. The
following 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
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 119
public void customize(ConcurrentMapCacheManager cacheManager) {
cacheManager.setAllowNullValues(false);
}
};
}
Note
In the example above, 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-
configured), the customizer won’t be invoked at all. You can have as many customizers as you
want and you can also order them as usual 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 via the presence of a javax.cache.spi.CachingProvider on the
classpath (i.e. a JSR-107 compliant caching library) and the JCacheCacheManager provided by the
spring-boot-starter-cache ‘Starter’. There are various compliant libraries out there 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 with implementation details.
# Only necessary if more than one provider is present
spring.cache.jcache.provider=com.acme.MyCachingProvider
spring.cache.jcache.config=classpath:acme.xml
Note
Since a cache library may offer both a native implementation and JSR-107 support Spring Boot
will prefer the JSR-107 support so that the same features are available if you switch to a different
JSR-107 implementation.
Tip
Spring Boot has a 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 several ways to customize the underlying javax.cache.cacheManager:
• Caches can be created on startup via 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 120
Tip
If a standard javax.cache.CacheManager bean is defined, it is wrapped automatically in a
org.springframework.cache.CacheManager implementation that the abstraction expects.
No further customization is applied on it.
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, the EhCacheCacheManager provided by the spring-boot-starter-cache ‘Starter’ and such
file is present it is used to bootstrap the cache manager. An alternate configuration file can be provided
as well using:
spring.cache.ehcache.config=classpath:config/another-config.xml
Hazelcast
Spring Boot has a 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 (or the default
bootstrap is used).
spring.cache.infinispan.config=infinispan.xml
Caches can be created on startup via the spring.cache.cache-names property. If a custom
ConfigurationBuilder bean is defined, it is used to customize them.
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, check
the documentation for more details.
Couchbase
If the Couchbase java client and the couchbase-spring-cache implementation are available and
Couchbase is configured, a CouchbaseCacheManager will be auto-configured. It is also possible
to create additional caches on startup using the spring.cache.cache-names property. These will
operate on the Bucket that was auto-configured. You can also create additional caches on another
Bucket using the customizer: assume you need two caches on the "main" Bucket (foo and bar) and
one biz cache with a custom time to live of 2sec on the another Bucket. First, you can create the
two first caches simply via configuration:
spring.cache.cache-names=foo,bar
Then define this extra @Configuration to configure the extra Bucket and the biz cache:
@Configuration
public class CouchbaseCacheConfiguration {
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 121
private final Cluster cluster;
public CouchbaseCacheConfiguration(Cluster cluster) {
this.cluster = cluster;
}
@Bean
public Bucket anotherBucket() {
return this.cluster.openBucket("another", "secret");
}
@Bean
public CacheManagerCustomizer<CouchbaseCacheManager> cacheManagerCustomizer() {
return c -> {
c.prepareCache("biz", CacheBuilder.newInstance(anotherBucket())
.withExpiration(2));
};
}
}
This sample configuration reuses the Cluster that was created via auto-configuration.
Redis
If Redis is available and configured, the RedisCacheManager is auto-configured. It is also possible to
create additional caches on startup using the spring.cache.cache-names property.
Note
By default, a key prefix is added to prevent that if two separate caches use the same key, Redis
would have overlapping keys and be likely to return invalid values. We strongly recommend to
keep this setting enabled if you create your own RedisCacheManager.
Caffeine
Caffeine is a Java 8 rewrite of Guava’s cache and will supersede the Guava support in Spring Boot 2.0.
If Caffeine is present, a CaffeineCacheManager (provided by the spring-boot-starter-cache
‘Starter’) is auto-configured. Caches can be created on startup using the spring.cache.cache-
names property and customized by one of the following (in this 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 a foo and bar caches with a maximum size of 500
and a time to live of 10 minutes
spring.cache.cache-names=foo,bar
spring.cache.caffeine.spec=maximumSize=500,expireAfterAccess=600s
Besides, 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 to all caches managed by the cache manager, it must be defined as
CacheLoader<Object, Object>. Any other generic type will be ignored by the auto-configuration.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 122
Guava (deprecated)
If Guava is present, a GuavaCacheManager is auto-configured. Caches can be created on startup
using the spring.cache.cache-names property and customized by one of the following (in this
order):
1. A cache spec defined by spring.cache.guava.spec
2. A com.google.common.cache.CacheBuilderSpec bean is defined
3. A com.google.common.cache.CacheBuilder bean is defined
For instance, the following configuration creates a foo and bar caches with a maximum size of 500
and a time to live of 10 minutes
spring.cache.cache-names=foo,bar
spring.cache.guava.spec=maximumSize=500,expireAfterAccess=600s
Besides, if a com.google.common.cache.CacheLoader bean is defined, it is automatically
associated to the GuavaCacheManager. Since the CacheLoader is going to be associated to all
caches managed by the cache manager, it must be defined as CacheLoader<Object, Object>.
Any other generic type will be ignored by the auto-configuration.
Simple
If none of the other providers can be found, a simple implementation using a ConcurrentHashMap as
cache store is configured. This is the default if no caching library is present in your application. Caches
are created on-the-fly by default but you can restrict the list of available caches using the cache-names
property. For instance, if you want only foo and bar caches:
spring.cache.cache-names=foo,bar
If you do this and your application uses a cache not listed then it will fail 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:
spring.cache.type=none
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 123
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’ and Spring Boot also provides auto-configuration options for RabbitTemplate and
RabbitMQ. There is also support for STOMP messaging natively in Spring WebSocket 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 won’t need to use it directly yourself and you 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
Spring Boot can also configure a ConnectionFactory when it detects that ActiveMQ is available on
the classpath. If the broker is present, an embedded broker is started and configured automatically (as
long as no broker URL is specified through configuration).
Note
If you are using spring-boot-starter-activemq the necessary dependencies to connect
or embed an ActiveMQ instance are provided, as well as 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 configure the PooledConnectionFactory accordingly:
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 implementing ActiveMQConnectionFactoryCustomizer for more
advanced customizations.
By default, ActiveMQ creates a destination if it does not exist yet, so destinations are resolved against
their provided names.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 124
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 started and configured automatically
(unless the mode property has been explicitly set). The supported modes are: embedded (to make
explicit that an embedded broker is required and should lead to an error if the broker is not available in
the classpath), and native to connect to a broker using the netty transport protocol. When the latter
is configured, Spring Boot configures a ConnectionFactory connecting to a broker running on the
local machine with the default settings.
Note
If you are using 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 allows you
to use the 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
the list of 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 of the supported options.
No JNDI lookup is involved at all and destinations are resolved against their names, either using 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 will attempt to locate
a JMS ConnectionFactory using JNDI. By default the locations java:/JmsXA and java:/
XAConnectionFactory will be checked. You can use the spring.jms.jndi-name property if you
need to specify an alternative location:
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:
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jms.core.JmsTemplate;
import org.springframework.stereotype.Component;
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 125
@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
MessageConverter beans are defined, they are 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 MessageConverter beans are defined,
they are associated automatically to the default factory.
The default factory is transactional by default. If you are running in an infrastructure where a
JtaTransactionManager is present, it will be associated to the listener container by default. If not,
the sessionTransacted flag will be 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 will make sure 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
Check 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 exposes another factory that uses a specific MessageConverter:
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 126
@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 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 via 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 using 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
See RabbitProperties for more of the supported options.
Tip
Check 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:
import org.springframework.amqp.core.AmqpAdmin;
import org.springframework.amqp.core.AmqpTemplate;
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 127
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.
Any org.springframework.amqp.core.Queue that is defined as a bean will be automatically used
to declare a corresponding queue on the RabbitMQ instance if necessary.
You can enable retries on the AmqpTemplate to retry operations, for example in the event 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 one is
configured automatically. If a MessageConverter or MessageRecoverer beans are defined, they
are associated automatically to the default factory.
The following component creates a listener endpoint on the someQueue queue:
@Component
public class MyBean {
@RabbitListener(queues = "someQueue")
public void processMessage(String content) {
// ...
}
}
Tip
Check 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 that
you can use to initialize a SimpleRabbitListenerContainerFactory with the same settings as
the one that is auto-configured.
For instance, the following exposes another factory that uses a specific MessageConverter:
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 128
@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 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 will be rejected and either dropped or routed to a dead-letter
exchange if the broker is configured so. Retries are disabled by default.
Important
If retries are not enabled and the listener throws an exception, by default the
delivery will be retried indefinitely. You can modify this behavior in two ways; set the
defaultRequeueRejected property to false and zero re-deliveries will be attempted; or,
throw an AmqpRejectAndDontRequeueException to signal the message should be rejected.
This is the mechanism used when retries are enabled and the maximum delivery attempts are
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:
spring.kafka.bootstrap-servers=localhost:9092
spring.kafka.consumer.group-id=myGroup
See KafkaProperties for more of the supported options.
Sending a Message
Spring’s KafkaTemplate is auto-configured and you can autowire them directly in your own beans:
@Component
public class MyBean {
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 129
private final KafkaTemplate kafkaTemplate;
@Autowired
public MyBean(KafkaTemplate kafkaTemplate) {
this.kafkaTemplate = 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 configured automatically with keys defined in spring.kafka.listener.*.
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 these properties (hyphenated or camelCase) map directly to the Apache Kafka
dotted properties for the most part, refer to the Apache Kafka documentation for details.
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: HIGH, MEDIUM and LOW. Spring Boot auto configuration supports all
HIGH importance properties, some selected MEDIUM and LOW, and any that do not have a default
value.
Only a subset of the properties supported by Kafka are available via the KafkaProperties class. If
you wish to configure the producer or consumer with additional properties that are not directly supported,
use the following:
spring.kafka.properties.foo.bar=baz
This sets the common foo.bar Kafka property to baz.
These properties will be shared by both the consumer and producer factory beans. If you wish to
customize these components with different properties, such as to use a different metrics reader for each,
you can override the bean definitions, as follows:
@Configuration
public static class CustomKafkaBeans {
/**
* Customized ProducerFactory bean.
* @param properties the kafka properties.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 130
* @return the bean.
*/
@Bean
public ProducerFactory<?, ?> kafkaProducerFactory(KafkaProperties properties) {
Map<String, Object> producerProperties = properties.buildProducerProperties();
producerProperties.put(CommonClientConfigs.METRIC_REPORTER_CLASSES_CONFIG,
MyProducerMetricsReporter.class);
return new DefaultKafkaProducerFactory<Object, Object>(producerProperties);
}
/**
* Customized ConsumerFactory bean.
* @param properties the kafka properties.
* @return the bean.
*/
@Bean
public ConsumerFactory<?, ?> kafkaConsumerFactory(KafkaProperties properties) {
Map<String, Object> consumerProperties = properties.buildConsumerProperties();
consumerProperties.put(CommonClientConfigs.METRIC_REPORTER_CLASSES_CONFIG,
MyConsumerMetricsReporter.class);
return new DefaultKafkaConsumerFactory<Object, Object>(consumerProperties);
}
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 131
33. Calling REST services
If you need to call remote REST services from your application, you can use 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 will ensure that sensible
HttpMessageConverters are applied to RestTemplate instances.
Here’s a typical example:
@Service
public class MyBean {
private final RestTemplate restTemplate;
public MyBean(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 will only affect this use of the builder.
To make an application-wide, additive customization a RestTemplateCustomizer bean can be used.
All such beans are automatically registered with the auto-configured RestTemplateBuilder and will
be applied to any templates that are built with it.
Here’s an example of 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,
HttpRequest request, HttpContext context)
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 132
throws HttpException {
if (target.getHostName().equals("192.168.0.5")) {
return null;
}
return super.determineProxy(target, request, context);
}
}).build();
restTemplate.setRequestFactory(
new HttpComponentsClientHttpRequestFactory(httpClient));
}
}
Lastly, the most extreme (and rarely used) option is to create your own RestTemplateBuilder
bean. This will switch off the auto-configuration of a RestTemplateBuilder and will prevent any
RestTemplateCustomizer beans from being used.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 133
34. Validation
The method validation feature supported by Bean Validation 1.1 is automatically enabled as long as
a JSR-303 implementation (e.g. Hibernate validator) is on the classpath. This allows bean methods to
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) {
...
}
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 134
35. Sending email
The Spring Framework provides an easy abstraction for sending email using the JavaMailSender
interface and Spring Boot provides auto-configuration for it as well as a starter module.
Tip
Check 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 the 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:
spring.mail.properties.mail.smtp.connectiontimeout=5000
spring.mail.properties.mail.smtp.timeout=3000
spring.mail.properties.mail.smtp.writetimeout=5000
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 135
36. Distributed Transactions with JTA
Spring Boot supports distributed JTA transactions across multiple XA resources 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 will be used to manage
transactions. Auto-configured JMS, DataSource and JPA beans will be 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.
36.1 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 will auto-configure Atomikos and ensure that appropriate
depends-on settings are applied to your Spring beans for correct startup and shutdown ordering.
By default Atomikos transaction logs will be written to a transaction-logs directory in your
application home directory (the directory in which your application jar file resides). You can customize
this directory by setting a spring.jta.log-dir property in your application.properties
file. Properties starting 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.
36.2 Using a Bitronix transaction manager
Bitronix is 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 will automatically configure Bitronix and post-process your beans to
ensure that startup and shutdown ordering is correct.
By default Bitronix transaction log files (part1.btm and part2.btm) will be written
to a transaction-logs directory in your application home directory. You can
customize this directory by using the spring.jta.log-dir property. Properties starting
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
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 136
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.
36.3 Using a Narayana transaction manager
Narayana is 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 will automatically configure
Narayana and post-process your beans to ensure that startup and shutdown ordering is correct.
By default Narayana transaction logs will be written to a transaction-logs directory in your
application home directory (the directory in which your application jar file resides). You can customize
this directory by setting a spring.jta.log-dir property in your application.properties
file. Properties starting 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.
36.4 Using a Java EE managed transaction manager
If you are packaging your Spring Boot application as a war or ear file and deploying it to a Java
EE application server, you can use your application servers built-in transaction manager. Spring
Boot will attempt to auto-configure a transaction manager by looking at common JNDI locations
(java:comp/UserTransaction, java:comp/TransactionManager etc). If you are using a
transaction service provided by your application server, you will generally also want to ensure
that all resources are managed by the server and exposed over JNDI. Spring Boot will attempt
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.
36.5 Mixing XA and non-XA JMS connections
When using JTA, the primary JMS ConnectionFactory bean will be XA aware and participate in
distributed transactions. In some situations you might want to process certain JMS messages 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 using the bean alias xaJmsConnectionFactory.
For example:
// Inject the primary (XA aware) ConnectionFactory
@Autowired
private ConnectionFactory defaultConnectionFactory;
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 137
// 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;
36.6 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 will transparently enroll in the distributed
transaction. DataSource and JMS auto-configuration will use JTA variants as long as 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 138
37. Hazelcast
If Hazelcast is on the classpath, Spring Boot will auto-configure a HazelcastInstance that you can
inject in your application. The HazelcastInstance is only created if a configuration is found.
You can define a com.hazelcast.config.Config bean and we’ll use that. If your configuration
defines an instance name, we’ll try to locate an existing instance rather than creating a new one.
You could also specify the hazelcast.xml configuration file to use via configuration:
spring.hazelcast.config=classpath:config/my-hazelcast.xml
Otherwise, Spring Boot tries to find the Hazelcast configuration from the default locations, that is
hazelcast.xml in the working directory or at the root of the classpath. We also check if the
hazelcast.config system property is set. Check the Hazelcast documentation for more details.
Note
Spring Boot also has an explicit caching support for Hazelcast. The HazelcastInstance is
automatically wrapped in a CacheManager implementation if caching is enabled.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 139
38. 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 etc. If Spring Integration is available on your classpath
it will be initialized through the @EnableIntegration annotation. Message processing statistics
will be published over JMX if 'spring-integration-jmx' is also on the classpath. See the
IntegrationAutoConfiguration class for more details.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 140
39. Spring Session
Spring Boot provides Spring Session auto-configuration for a wide range of stores:
• JDBC
• MongoDB
• Redis
• Hazelcast
• HashMap
If Spring Session is available, you must choose the StoreType that you wish to use to store the
sessions. For instance to use JDBC as backend store, you’d 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:
spring.session.jdbc.table-name=SESSIONS
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 141
40. Monitoring and management over JMX
Java Management Extensions (JMX) provide a standard mechanism to monitor and manage
applications. By default Spring Boot will create an MBeanServer with bean id ‘mbeanServer’ and
expose any of your beans that are annotated with Spring JMX annotations (@ManagedResource,
@ManagedAttribute, @ManagedOperation).
See the JmxAutoConfiguration class for more details.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 142
41. 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 will just use the spring-boot-starter-test ‘Starter’ which imports both Spring
Boot test modules as well has JUnit, AssertJ, Hamcrest and a number of other useful libraries.
41.1 Test scope dependencies
If you use the spring-boot-starter-test ‘Starter’ (in the test scope), you will find 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.
Note
By default, Spring Boot uses Mockito 1.x. However it’s also possible to use 2.x if you wish.
These are common libraries that we generally find useful when writing tests. You are free to add
additional test dependencies of your own if these don’t suit your needs.
41.2 Testing Spring applications
One of the major advantages of dependency injection is that it should make your code easier to unit
test. You can simply instantiate objects 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 actually involved in the process). It’s 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 just 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 143
41.3 Testing Spring Boot applications
A Spring Boot application is just 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. One thing to watch out
for though is that the external properties, logging and other features of Spring Boot are only installed in
the context by default 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 via
SpringApplication.
You can use the webEnvironment attribute of @SpringBootTest to further refine how your tests
will run:
•MOCK — Loads a WebApplicationContext and provides a mock servlet environment. Embedded
servlet containers are not started when using this annotation. If servlet APIs are not on your classpath
this mode will transparently fallback to creating a regular non-web ApplicationContext. Can be
used in conjunction with @AutoConfigureMockMvc for MockMvc-based testing of your application.
•RANDOM_PORT — Loads an EmbeddedWebApplicationContext and provides a real servlet
environment. Embedded servlet containers are started and listening on a random port.
•DEFINED_PORT — Loads an EmbeddedWebApplicationContext and provides a real servlet
environment. Embedded servlet containers are started and listening on a defined port (i.e from your
application.properties or on the default port 8080).
•NONE — Loads an ApplicationContext using SpringApplication but does not provide any
servlet environment (mock or otherwise).
Note
If your test is @Transactional, it will rollback 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, HTTP client and server will run in separate threads,
thus separate transactions. Any transaction initiated on the server won’t rollback in this case.
Note
In addition to @SpringBootTest a number of other annotations are also provided for testing
more specific slices of an application. See below for details.
Tip
Don’t forget to also add @RunWith(SpringRunner.class) to your test, otherwise the
annotations will be ignored.
Detecting test configuration
If you’re 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 144
When testing Spring Boot applications this is often not required. Spring Boot’s @*Test annotations will
search for your primary configuration automatically whenever you don’t explicitly define one.
The search algorithm works up from the package that contains the test until it finds a
@SpringBootApplication or @SpringBootConfiguration annotated class. As long as you’ve
structured your code in a sensible way your main configuration is usually found.
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 a your application’s primary
configuration, a nested @TestConfiguration class will be used in addition to your application’s
primary configuration.
Note
Spring’s test framework will cache application contexts between tests. Therefore, as long as your
tests share the same configuration (no matter how it’s discovered), the potentially time consuming
process of loading the context will only happen 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 created only for specific tests
accidentally get picked up everywhere.
As we have seen above, @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:
@RunWith(SpringRunner.class)
@SpringBootTest
@Import(MyTestsConfiguration.class)
public class MyTests {
@Test
public void exampleTest() {
...
}
}
Note
If you directly use @ComponentScan (i.e. not via @SpringBootApplication) you will need to
register the TypeExcludeFilter with it. See the Javadoc for details.
Working with random ports
If you need to start a full running server for tests, we recommend that you use random ports. If you use
@SpringBootTest(webEnvironment=WebEnvironment.RANDOM_PORT) an available port will be
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
TestRestTemplate which will resolve relative links to the running server.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 145
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 RandomPortExampleTests {
@Autowired
private TestRestTemplate restTemplate;
@Test
public void exampleTest() {
String body = this.restTemplate.getForObject("/", String.class);
assertThat(body).isEqualTo("Hello World");
}
}
Mocking and spying beans
It’s sometimes necessary to mock certain components within your application context when running
tests. For example, you may have a facade over some remote service that’s 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 will
also be injected. Mock beans are automatically reset after each test method.
Note
This feature is automatically enabled as long as your test uses one of Spring Boot’s test
annotations (i.e. @SpringBootTest). To use this feature with a different arrangement, a listener
will need to be added explicitly:
@TestExecutionListeners(MockitoTestExecutionListener.class)
Here’s a typical example where we replace 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.*;
import static org.assertj.core.api.Assertions.*;
import static org.mockito.BDDMockito.*;
@RunWith(SpringRunner.class)
@SpringBootTest
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 146
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 also use @SpyBean to wrap any existing bean with a Mockito spy. See the Javadoc
for full details.
Auto-configured tests
Spring Boot’s auto-configuration system works well for applications, but can sometimes be a little too
much for tests. It’s often helpful 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 don’t want to involve database calls in those tests; or you might be wanting to
test JPA entities, and you’re not interested in 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’s also possible to use the @AutoConfigure… annotations with the standard
@SpringBootTest annotation. You can use this combination if you’re not interested in ‘slicing’
your application but you want some of the auto-configured test beans.
Auto-configured JSON tests
To test that Object JSON serialization and deserialization is working as expected you can
use the @JsonTest annotation. @JsonTest will auto-configure Jackson ObjectMapper, any
@JsonComponent beans and any Jackson Modules. It also configures Gson if you happen to be using
that instead of, or as well as, Jackson. 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 is as expected. The JacksonTester, GsonTester and BasicJsonTester classes
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 147
can be used for Jackson, Gson and Strings respectively. Any helper fields on the test class can be
@Autowired when using @JsonTest.
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. Simply call the initFields
method of the helper in your @Before method if you aren’t using @JsonTest.
A list of the auto-configuration that is enabled by @JsonTest can be found in the appendix.
Auto-configured Spring MVC tests
To test Spring MVC controllers are working as expected you can use the @WebMvcTest
annotation. @WebMvcTest will auto-configure the Spring MVC infrastructure and limit scanned beans
to @Controller, @ControllerAdvice, @JsonComponent, Filter, WebMvcConfigurer and
HandlerMethodArgumentResolver. Regular @Component beans will not be scanned when using
this annotation.
Often @WebMvcTest will be limited to a single controller and 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 148
Tip
You can also auto-configure MockMvc in a non-@WebMvcTest (e.g. SpringBootTest) by
annotating it with @AutoConfigureMockMvc.
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"));
}
}
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 will also provide a WebClient bean and/or a
WebDriver bean. Here is an example that 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
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 149
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 will put WebDriver beans in a special “scope” to ensure that the driver is
quit after each test, and that a new instance is injected. If you don’t want this behavior you can
add @Scope("singleton") to your WebDriver @Bean definition.
A list of the auto-configuration that is enabled by @WebMvcTest can be found in the appendix.
Auto-configured Data JPA tests
@DataJpaTest can be used if you want to test JPA applications. By default it will configure an in-
memory embedded database, scan for @Entity classes and configure Spring Data JPA repositories.
Regular @Component beans will not be loaded into the ApplicationContext.
Data JPA tests are transactional and rollback at the end of each test by default, see the relevant section
in the Spring Reference Documentation for more details. If that’s 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 specifically designed for tests. If you want to use TestEntityManager
outside of @DataJpaTests you can also use the @AutoConfigureTestEntityManager
annotation. A JdbcTemplate is also available if you need that.
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;
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 150
@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");
}
}
In-memory embedded databases generally work well for tests since they are fast and don’t require
any developer installation. If, however, you prefer to run tests against a real database you can use the
@AutoConfigureTestDatabase annotation:
@RunWith(SpringRunner.class)
@DataJpaTest
@AutoConfigureTestDatabase(replace=Replace.NONE)
public class ExampleRepositoryTests {
// ...
}
A list of the auto-configuration that is enabled by @DataJpaTest can be found in the appendix.
Auto-configured JDBC tests
@JdbcTest is similar to @DataJpaTest but for pure jdbc-related tests. By default it will also configure
an in-memory embedded database and a JdbcTemplate. Regular @Component beans will not be
loaded into the ApplicationContext.
JDBC tests are transactional and rollback at the end of each test by default, see the relevant section
in the Spring Reference Documentation for more details. If that’s 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 the same way as for DataJpaTest.
A list of the auto-configuration that is enabled by @JdbcTest can be found in the appendix.
Auto-configured Data MongoDB tests
@DataMongoTest can be used if you want to test MongoDB applications. By default, it will configure
an in-memory embedded MongoDB (if available), configure a MongoTemplate, scan for @Document
classes and configure Spring Data MongoDB repositories. Regular @Component beans will not be
loaded into the ApplicationContext:
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 151
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 doesn’t require any
developer installation. If, however, you prefer to run tests against a real MongoDB server you should
exclude the embedded MongoDB auto-configuration:
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 that is enabled by @DataMongoTest can be found in the appendix.
Auto-configured REST clients
The @RestClientTest annotation can be used if you want to test REST clients. By default it will
auto-configure Jackson and GSON support, configure a RestTemplateBuilder and add support for
MockRestServiceServer. The specific beans that you want to test should be specified using value
or components attribute of @RestClientTest:
@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 that is enabled by @RestClientTest can be found in the appendix.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 152
Auto-configured Spring REST Docs tests
The @AutoConfigureRestDocs annotation can be used if you want to use Spring REST Docs in your
tests. It will automatically configure MockMvc to use Spring REST Docs and remove the need for Spring
REST Docs' JUnit rule.
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("target/generated-snippets")
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())
.andDo(document("list-users"));
}
}
In addition to configuring the output directory, @AutoConfigureRestDocs can also configure the host,
scheme, and port that will appear in any documented URIs. If you require more control over Spring
REST Docs' configuration a RestDocsMockMvcConfigurationCustomizer bean can be used:
@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 will call alwaysDo with
this result handler, thereby causing each MockMvc call to automatically generate the default snippets:
@TestConfiguration
static class ResultHandlerConfiguration {
@Bean
public RestDocumentationResultHandler restDocumentation() {
return MockMvcRestDocumentation.document("{method-name}");
}
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 153
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. Exactly how you can use Spock to test a Spring Boot application depends on the version
of Spock that you are using.
Note
Spring Boot provides dependency management for Spock 1.0. If you wish to use Spock 1.1 you
should override the spock.version property in your build.gradle or pom.xml file.
When using Spock 1.1, the annotations described above can only be used and you can annotate your
Specification with @SpringBootTest to suit the needs of your tests.
When using Spock 1.0, @SpringBootTest will not work for a web project. You need
to use @SpringApplicationConfiguration and @WebIntegrationTest(randomPort =
true). Being unable to use @SpringBootTest means that you also lose the auto-configured
TestRestTemplate bean. You can create an equivalent bean yourself using the following
configuration:
@Configuration
static class TestRestTemplateConfiguration {
@Bean
public TestRestTemplate testRestTemplate(
ObjectProvider<RestTemplateBuilder> builderProvider,
Environment environment) {
RestTemplateBuilder builder = builderProvider.getIfAvailable();
TestRestTemplate template = builder == null ? new TestRestTemplate()
: new TestRestTemplate(builder.build());
template.setUriTemplateHandler(new LocalHostUriTemplateHandler(environment));
return template;
}
}
41.4 Test utilities
A few test utility classes are packaged as part of spring-boot that are generally useful when testing
your application.
ConfigFileApplicationContextInitializer
ConfigFileApplicationContextInitializer is an ApplicationContextInitializer that
can apply to your tests to load Spring Boot application.properties files. You can use this when
you don’t need the full features provided by @SpringBootTest.
@ContextConfiguration(classes = Config.class,
initializers = ConfigFileApplicationContextInitializer.class)
Note
Using ConfigFileApplicationContextInitializer alone won’t 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
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 154
a PropertySourcesPlaceholderConfigurer or use @SpringBootTest where one will be
auto-configured for you.
EnvironmentTestUtils
EnvironmentTestUtils allows you to quickly add properties to a ConfigurableEnvironment or
ConfigurableApplicationContext. Simply call it with key=value strings:
EnvironmentTestUtils.addEnvironment(env, "org=Spring", "name=Boot");
OutputCapture
OutputCapture is a JUnit Rule that you can use to capture System.out and System.err output.
Simply declare the capture as a @Rule then use toString() for assertions:
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
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 will behave in a test-friendly way by not throwing
exceptions on server-side errors. It is recommended, but not mandatory, to use Apache HTTP Client
(version 4.3.2 or better), and if you have that on your classpath the TestRestTemplate will respond
by configuring the client appropriately. If you do use Apache’s HTTP client some additional test-friendly
features will be enabled:
• Redirects will not be followed (so you can assert the response location)
• Cookies will be ignored (so the template is stateless)
TestRestTemplate can be instantiated directly in your integration tests:
public class MyTest {
private TestRestTemplate template = new TestRestTemplate();
@Test
public void testRequest() throws Exception {
HttpHeaders headers = template.getForEntity("http://myhost.com/example",
String.class).getHeaders();
assertThat(headers.getLocation().toString(), containsString("myotherhost"));
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 155
}
Alternatively, if you are using the @SpringBootTest annotation with
WebEnvironment.RANDOM_PORT or WebEnvironment.DEFINED_PORT, you can just inject a fully
configured TestRestTemplate and start using it. If necessary, additional customizations can be
applied via the RestTemplateBuilder bean. Any URLs that do not specify a host and port will
automatically connect to the embedded server:
@RunWith(SpringRunner.class)
@SpringBootTest
public class MyTest {
@Autowired
private TestRestTemplate template;
@Test
public void testRequest() throws Exception {
HttpHeaders headers = template.getForEntity("/example", String.class).getHeaders();
assertThat(headers.getLocation().toString(), containsString("myotherhost"));
}
@TestConfiguration
static class Config {
@Bean
public RestTemplateBuilder restTemplateBuilder() {
return new RestTemplateBuilder()
.additionalMessageConverters(...)
.customizers(...);
}
}
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 156
42. WebSockets
Spring Boot provides WebSockets auto-configuration for embedded Tomcat (8 and 7), Jetty 9 and
Undertow. If you’re deploying a war file to a standalone container, Spring Boot assumes that the
container will be responsible for the configuration of its WebSocket support.
Spring Framework provides rich WebSocket support that can be easily accessed via the spring-
boot-starter-websocket module.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 157
43. Web Services
Spring Boot provides Web Services auto-configuration so that all is required is defining your
Endpoints.
The Spring Web Services features can be easily accessed via the spring-boot-starter-
webservices module.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 158
44. 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 will first cover what you need to know to build your
own auto-configuration and we will 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.
44.1 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 only applies 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 we provide (see the META-INF/spring.factories file).
44.2 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.
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 shouldn’t 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 have to be loaded that way only. Make sure that they are defined in a specific
package space and that they are never the target of component scan in particular.
44.3 Condition annotations
You almost always want to include one or more @Conditional annotations on your auto-configuration
class. The @ConditionalOnMissingBean is one common example that is used to allow developers
to ‘override’ auto-configuration if they are not happy with your defaults.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 159
Spring Boot includes a number of @Conditional annotations that you can reuse in your own code by
annotating @Configuration classes or individual @Bean methods.
Class conditions
The @ConditionalOnClass and @ConditionalOnMissingClass annotations allows
configuration to be included based on the presence or absence of specific classes. Due to the fact that
annotation metadata is parsed using ASM you can actually 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 using a String value.
Tip
If you are using @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 allow a bean to 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 allows you to 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, for instance:
@Configuration
public class MyAutoConfiguration {
@Bean
@ConditionalOnMissingBean
public MyService myService() { ... }
}
In the example above, 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 that bean definitions are added as these conditions
are evaluated based on what has been processed so far. For this reason, we recommend
only using @ConditionalOnBean and @ConditionalOnMissingBean annotations on auto-
configuration classes (since these are guaranteed to load after any user-defined beans definitions
have been added).
Note
@ConditionalOnBean and @ConditionalOnMissingBean do not prevent
@Configuration classes from being created. Using these conditions at the class level is
equivalent to marking each contained @Bean method with the annotation.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 160
Property conditions
The @ConditionalOnProperty annotation allows configuration to 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 will be matched. You can also
create more advanced checks using the havingValue and matchIfMissing attributes.
Resource conditions
The @ConditionalOnResource annotation allows configuration to be included only when a specific
resource is present. Resources can be specified using the usual Spring conventions, for example,
file:/home/user/test.dat.
Web application conditions
The @ConditionalOnWebApplication and @ConditionalOnNotWebApplication annotations
allow configuration to be included depending on whether the application is a 'web application'. A web
application is any application that is using a Spring WebApplicationContext, defines a session
scope or has a StandardServletEnvironment.
SpEL expression conditions
The @ConditionalOnExpression annotation allows configuration to be included based on the result
of a SpEL expression.
44.4 Creating your own starter
A full Spring Boot starter for a library may contain the following components:
• 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 be
enough to start using that library.
Tip
You may combine the auto-configuration code and the dependency management in a single
module if you don’t need to separate those two concerns.
Naming
Please make sure to provide a proper namespace for your starter. Do not start your module names with
spring-boot, even if you are using a different Maven groupId. We may offer an official support for
the thing you’re auto-configuring in the future.
Here is a rule of thumb. Let’s assume that you are creating a starter for "acme", name the auto-configure
module acme-spring-boot-autoconfigure and the starter acme-spring-boot-starter. If
you only have one module combining the two, use acme-spring-boot-starter.
Besides, if your starter provides configuration keys, use a proper namespace for them. In particular, do
not include your keys in the namespaces that Spring Boot uses (e.g. server, management, spring,
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 161
etc). These are "ours" and we may improve/modify them in the future in such a way it could break your
things.
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 keys definition (@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 won’t be
provided and Spring Boot will back off by default.
Starter module
The starter is an empty jar, really. Its only purpose is to provide the necessary dependencies to work
with the library; see 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 bringing
unnecessary dependencies for a typical usage of the library.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 162
45. 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 carry 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 it’s pushed to production. You can choose to manage and monitor your application using HTTP
endpoints, with JMX or even by remote shell (SSH or Telnet). Auditing, health and metrics gathering
can be automatically applied to your application.
Actuator HTTP endpoints are only available with a Spring MVC-based application. In particular, it will
not work with Jersey unless you enable Spring MVC as well.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 164
46. 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, referring 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 declaration:
dependencies {
compile("org.springframework.boot:spring-boot-starter-actuator")
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 165
47. Endpoints
Actuator endpoints allow you to monitor and interact with your application. Spring Boot includes a
number of built-in endpoints and you can also add your own. For example the health endpoint provides
basic application health information.
The way that endpoints are exposed will depend on the type of technology that you choose. Most
applications choose HTTP monitoring, where the ID of the endpoint is mapped to a URL. For example,
by default, the health endpoint will be mapped to /health.
The following technology agnostic endpoints are available:
ID Description Sensitive
Default
actuator Provides a hypermedia-based “discovery page” for the
other endpoints. Requires Spring HATEOAS to be on the
classpath.
true
auditevents Exposes audit events information for the current application. true
autoconfig Displays an auto-configuration report showing all auto-
configuration candidates and the reason why they ‘were’ or
‘were not’ applied.
true
beans Displays a complete list of all the Spring beans in your
application.
true
configprops Displays a collated list of all @ConfigurationProperties. true
dump Performs a thread dump. true
env Exposes properties from Spring’s
ConfigurableEnvironment.
true
flyway Shows any Flyway database migrations that have been
applied.
true
health Shows application health information (when the application
is secure, a simple ‘status’ when accessed over an
unauthenticated connection or full message details when
authenticated).
false
info Displays arbitrary application info. false
loggers Shows and modifies the configuration of loggers in the
application.
true
liquibase Shows any Liquibase database migrations that have been
applied.
true
metrics Shows ‘metrics’ information for the current application. true
mappings Displays a collated list of all @RequestMapping paths. true
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 166
ID Description Sensitive
Default
shutdown Allows the application to be gracefully shutdown (not enabled
by default).
true
trace Displays trace information (by default the last 100 HTTP
requests).
true
If you are using Spring MVC, the following additional endpoints can also be used:
ID Description Sensitive
Default
docs Displays documentation, including example requests and
responses, for the Actuator’s endpoints. Requires spring-
boot-actuator-docs to be on the classpath.
false
heapdump Returns a GZip compressed hprof heap dump file. true
jolokia Exposes JMX beans over HTTP (when Jolokia is on the
classpath).
true
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.
true
Note
Depending on how an endpoint is exposed, the sensitive property may be used as a security
hint. For example, sensitive endpoints will require a username/password when they are accessed
over HTTP (or simply disabled if web security is not enabled).
47.1 Customizing endpoints
Endpoints can be customized using Spring properties. You can change if an endpoint is enabled, if it
is considered sensitive and even its id.
For example, here is an application.properties that changes the sensitivity and id of the beans
endpoint and also enables shutdown.
endpoints.beans.id=springbeans
endpoints.beans.sensitive=false
endpoints.shutdown.enabled=true
Note
The prefix #endpoints + . + name” is used to uniquely identify the endpoint that is being
configured.
By default, all endpoints except for shutdown are enabled. If you prefer to specifically “opt-in” endpoint
enablement you can use the endpoints.enabled property. For example, the following will disable
all endpoints except for info:
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 167
endpoints.enabled=false
endpoints.info.enabled=true
Likewise, you can also choose to globally set the “sensitive” flag of all endpoints. By default, the sensitive
flag depends on the type of endpoint (see the table above). For example, to mark all endpoints as
sensitive except info:
endpoints.sensitive=true
endpoints.info.sensitive=false
47.2 Hypermedia for actuator MVC endpoints
If endpoints.hypermedia.enabled is set to true and Spring HATEOAS is on the classpath (e.g.
through the spring-boot-starter-hateoas or if you are using Spring Data REST) then the HTTP
endpoints from the Actuator are enhanced with hypermedia links, and a “discovery page” is added with
links to all the endpoints. The “discovery page” is available on /actuator by default. It is implemented
as an endpoint, allowing properties to be used to configure its path (endpoints.actuator.path)
and whether or not it is enabled (endpoints.actuator.enabled).
When a custom management context path is configured, the “discovery page” will automatically move
from /actuator to the root of the management context. For example, if the management context path
is /management then the discovery page will be available from /management.
If the HAL Browser is on the classpath via its webjar (org.webjars:hal-browser), or via the
spring-data-rest-hal-browser then an HTML “discovery page”, in the form of the HAL Browser,
is also provided.
47.3 CORS support
Cross-origin resource sharing (CORS) is a W3C specification that allows you to specify in a flexible
way what kind of cross domain requests are authorized. Actuator’s MVC endpoints can be configured
to support such scenarios.
CORS support is disabled by default and is only enabled once the endpoints.cors.allowed-
origins property has been set. The configuration below permits GET and POST calls from the
example.com domain:
endpoints.cors.allowed-origins=http://example.com
endpoints.cors.allowed-methods=GET,POST
Tip
Check EndpointCorsProperties for a complete list of options.
47.4 Adding custom endpoints
If you add a @Bean of type Endpoint then it will automatically be exposed over JMX and HTTP (if
there is an server available). An HTTP endpoints can be customized further by creating a bean of type
MvcEndpoint. Your MvcEndpoint is not a @Controller but it can use @RequestMapping (and
@Managed*) to expose resources.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 168
Tip
If you are doing this as a library feature consider adding a configuration class annotated with
@ManagementContextConfiguration to /META-INF/spring.factories under the key
org.springframework.boot.actuate.autoconfigure.ManagementContextConfiguration.
If you do that then the endpoint will move to a child context with all the other MVC endpoints if your
users ask for a separate management port or address. A configuration declared this way can be
a WebConfigurerAdapter if it wants to add static resources (for instance) to the management
endpoints.
47.5 Health information
Health information can be used to check the status of your running application. It is often used by
monitoring software to alert someone if a production system goes down. The default information exposed
by the health endpoint depends on how it is accessed. For an unauthenticated connection in a secure
application a simple ‘status’ message is returned, and for an authenticated connection additional details
are also displayed (see Section 48.7, “HTTP health endpoint format and access restrictions” for HTTP
details).
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.
47.6 Security with HealthIndicators
Information returned by HealthIndicators is often somewhat sensitive in nature. For example, you
probably don’t want to publish details of your database server to the world. For this reason, by default,
only the health status is exposed over an unauthenticated HTTP connection. If you are happy for
complete health information to always be exposed you can set endpoints.health.sensitive to
false.
Health responses are also cached to prevent “denial of service” attacks. Use the
endpoints.health.time-to-live property if you want to change the default cache period of 1000
milliseconds.
Auto-configured HealthIndicators
The following HealthIndicators are auto-configured by Spring Boot when appropriate:
Name Description
CassandraHealthIndicatorChecks that a Cassandra database is up.
DiskSpaceHealthIndicatorChecks for low disk space.
DataSourceHealthIndicatorChecks that a connection to DataSource can be obtained.
ElasticsearchHealthIndicatorChecks that an Elasticsearch cluster is up.
JmsHealthIndicatorChecks that a JMS broker is up.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 169
Name Description
MailHealthIndicatorChecks that a mail server is up.
MongoHealthIndicatorChecks that a Mongo database is up.
RabbitHealthIndicatorChecks that a Rabbit server is up.
RedisHealthIndicatorChecks that a Redis server is up.
SolrHealthIndicatorChecks that a Solr server is up.
Tip
It is possible to disable them all using 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.
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 example above, the health information will be available
in an entry named my.
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 using the management.health.status.order configuration property.
For example, assuming a new Status with code FATAL is being used in one of your
HealthIndicator implementations. To configure the severity order add the following to your
application properties:
management.health.status.order=FATAL, DOWN, OUT_OF_SERVICE, UNKNOWN, UP
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 170
The HTTP status code in the response reflects the overall health status (e.g. UP maps to 200,
OUT_OF_SERVICE or DOWN to 503). You might also want to register custom status mappings with the
HealthMvcEndpoint if you access the health endpoint over HTTP. For example, the following maps
FATAL to HttpStatus.SERVICE_UNAVAILABLE:
endpoints.health.mapping.FATAL=503
The default status mappings for the built-in statuses are:
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
47.7 Application information
Application information exposes various information collected from all InfoContributor beans
defined in your ApplicationContext. Spring Boot includes a number of auto-configured
InfoContributors and you can also write your own.
Auto-configured InfoContributors
The following InfoContributors are auto-configured by Spring Boot when appropriate:
Name Description
EnvironmentInfoContributorExpose any key from the Environment under the info key.
GitInfoContributorExpose git information if a git.properties file is available.
BuildInfoContributorExpose build information if a META-INF/build-info.properties file is
available.
Tip
It is possible to disable them all using the management.info.defaults.enabled property.
Custom application info information
You can customize the data exposed by the info endpoint by setting info.* Spring properties. All
Environment properties under the info key will be automatically exposed. For example, you could add
the following to your application.properties:
info.app.encoding=UTF-8
info.app.java.source=1.8
info.app.java.target=1.8
Tip
Rather than hardcoding those values you could also expand info properties at build time.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 171
Assuming you are using Maven, you could rewrite the example above 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 will be 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 (i.e. the full content of git.properties), use the
management.info.git.mode property:
management.info.git.mode=full
Build information
The info endpoint can also publish information about your build if a BuildProperties bean is
available. 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 example below 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"));
}
}
If you hit the info endpoint you should see a response that contains the following additional entry:
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 172
{
"example": {
"key" : "value"
}
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 173
48. Monitoring and management over HTTP
If you are developing a Spring MVC application, Spring Boot Actuator will auto-configure all enabled
endpoints to be exposed over HTTP. The default convention is to use the id of the endpoint as the URL
path. For example, health is exposed as /health.
48.1 Accessing sensitive endpoints
By default all sensitive HTTP endpoints are secured such that only users that have an ACTUATOR role
may access them. Security is enforced using the standard HttpServletRequest.isUserInRole
method.
Tip
Use the management.security.roles property if you want something different to ACTUATOR.
If you are deploying applications behind a firewall, you may prefer that all your actuator
endpoints can be accessed without requiring authentication. You can do this by changing the
management.security.enabled property:
application.properties.
management.security.enabled=false
Note
By default, actuator endpoints are exposed on the same port that serves regular HTTP
traffic. Take care not to accidentally expose sensitive information if you change the
management.security.enabled property.
If you’re deploying applications publicly, you may want to add ‘Spring Security’ to handle user
authentication. When ‘Spring Security’ is added, by default ‘basic’ authentication will be used with the
username user and a generated password (which is printed on the console when the application starts).
Tip
Generated passwords are logged as the application starts. Search for ‘Using default security
password’.
You can use Spring properties to change the username and password and to change the
security role(s) required to access the endpoints. For example, you might set the following in your
application.properties:
security.user.name=admin
security.user.password=secret
management.security.roles=SUPERUSER
If your application has custom security configuration and you want all your actuator endpoints to be
accessible without authentication, you need to explicitly configure that in your security configuration.
Along with that, you need to change the management.security.enabled property to false.
If your custom security configuration secures your actuator endpoints, you also need to ensure that the
authenticated user has the roles specified under management.security.roles.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 174
Tip
If you don’t have a use case for exposing basic health information to unauthenticated
users, and you have secured the actuator endpoints with custom security, you can set
management.security.enabled to false. This will inform Spring Boot to skip the additional
role check.
48.2 Customizing the management endpoint paths
Sometimes it is useful to group all management endpoints under a single path. For example, your
application might already use /info for another purpose. You can use the management.context-
path property to set a prefix for your management endpoint:
management.context-path=/manage
The application.properties example above will change the endpoint from /{id} to /manage/
{id} (e.g. /manage/info).
Note
Unless the management port has been configured to expose endpoints using a different HTTP
port, management.context-path is relative to server.context-path.
You can also change the “id” of an endpoint (using endpoints.{name}.id) which then changes the
default resource path for the MVC endpoint. Legal endpoint ids are composed only of alphanumeric
characters (because they can be exposed in a number of places, including JMX object names,
where special characters are forbidden). The MVC path can be changed separately by configuring
endpoints.{name}.path, and there is no validation on those values (so you can use anything that
is legal in a URL path). For example, to change the location of the /health endpoint to /ping/me you
can set endpoints.health.path=/ping/me.
Note
Even if an endpoint path is configured separately, it is still relative to the management.context-
path.
Tip
If you provide a custom MvcEndpoint remember to include a settable path property, and default
it to /{id} if you want your code to behave like the standard MVC endpoints. (Take a look at the
HealthMvcEndpoint to see how you might do that.) If your custom endpoint is an Endpoint
(not an MvcEndpoint) then Spring Boot will take care of the path for you.
48.3 Customizing the management server port
Exposing management endpoints 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 using a different HTTP port.
The management.port property can be used to change the HTTP port.
management.port=8081
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 175
Since your management port is often protected by a firewall, and not exposed to the public you might
not need security on the management endpoints, even if your main application is secure. In that case
you will have Spring Security on the classpath, and you can disable management security like this:
management.security.enabled=false
(If you don’t have Spring Security on the classpath then there is no need to explicitly disable the
management security in this way, and it might even break the application.)
48.4 Configuring management-specific SSL
When configured to use a custom port, the management server can also be configured with its own SSL
using the various management.ssl.* properties. For example, this allows a management server to
be available via HTTP while the main application uses HTTPS:
server.port=8443
server.ssl.enabled=true
server.ssl.key-store=classpath:store.jks
server.ssl.key-password=secret
management.port=8080
management.ssl.enabled=false
Alternatively, both the main server and the management server can use SSL but with different key stores:
server.port=8443
server.ssl.enabled=true
server.ssl.key-store=classpath:main.jks
server.ssl.key-password=secret
management.port=8080
management.ssl.enabled=true
management.ssl.key-store=classpath:management.jks
management.ssl.key-password=secret
48.5 Customizing the management server address
You can customize the address that the management endpoints are available on by setting the
management.address property. This can be useful if you want to listen only on an internal or ops-
facing network, or to only listen for connections from localhost.
Note
You can only listen on a different address if the port is different to the main server port.
Here is an example application.properties that will not allow remote management connections:
management.port=8081
management.address=127.0.0.1
48.6 Disabling HTTP endpoints
If you don’t want to expose endpoints over HTTP you can set the management port to -1:
management.port=-1
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 176
48.7 HTTP health endpoint format and access restrictions
The information exposed by the health endpoint varies depending on whether or not it’s accessed
anonymously, and whether or not the enclosing application is secure. By default, when accessed
anonymously in a secure application, any details about the server’s health are hidden and the endpoint
will simply indicate whether or not the server is up or down. Furthermore the response is cached
for a configurable period to prevent the endpoint being used in a denial of service attack. The
endpoints.health.time-to-live property is used to configure the caching period in milliseconds.
It defaults to 1000, i.e. one second.
Sample summarized HTTP response (default for anonymous request):
$ curl -i localhost:8080/health
HTTP/1.1 200
X-Application-Context: application
Content-Type: application/vnd.spring-boot.actuator.v1+json;charset=UTF-8
Content-Length: 15
{"status":"UP"}
Sample summarized HTTP response for status "DOWN" (notice the 503 status code):
$ curl -i localhost:8080/health
HTTP/1.1 503
X-Application-Context: application
Content-Type: application/vnd.spring-boot.actuator.v1+json;charset=UTF-8
Content-Length: 17
{"status":"DOWN"}
Sample detailed HTTP response:
$ curl -i localhost:8080/health
HTTP/1.1 200 OK
X-Application-Context: application
Content-Type: application/vnd.spring-boot.actuator.v1+json;charset=UTF-8
Content-Length: 221
{
"status" : "UP",
"diskSpace" : {
"status" : "UP",
"total" : 63251804160,
"free" : 31316164608,
"threshold" : 10485760
},
"db" : {
"status" : "UP",
"database" : "H2",
"hello" : 1
}
}
The above-described restrictions can be enhanced, thereby allowing only authenticated users full
access to the health endpoint in a secure application. To do so, set endpoints.health.sensitive
to true. Here’s a summary of behavior (with default sensitive flag value “false” indicated in bold):
management.security.enabledendpoints.health.sensitiveUnauthenticated Authenticated (with
right role)
false * Full content Full content
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 177
management.security.enabledendpoints.health.sensitiveUnauthenticated Authenticated (with
right role)
true false Status only Full content
true true No content Full content
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 178
49. Monitoring and management over JMX
Java Management Extensions (JMX) provide a standard mechanism to monitor and manage
applications. By default Spring Boot will expose management endpoints as JMX MBeans under the
org.springframework.boot domain.
49.1 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/Endpoint/healthEndpoint.
If your application contains more than one Spring ApplicationContext you may find that names
clash. To solve this problem you can set the 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. Here is an example
application.properties:
endpoints.jmx.domain=myapp
endpoints.jmx.unique-names=true
49.2 Disabling JMX endpoints
If you don’t want to expose endpoints over JMX you can set the endpoints.jmx.enabled property
to false:
endpoints.jmx.enabled=false
49.3 Using Jolokia for JMX over HTTP
Jolokia is a JMX-HTTP bridge giving an alternative method of accessing JMX beans. To use Jolokia,
simply include a dependency to org.jolokia:jolokia-core. For example, using Maven you would
add the following:
<dependency>
<groupId>org.jolokia</groupId>
<artifactId>jolokia-core</artifactId>
</dependency>
Jolokia can then be accessed using /jolokia on your management HTTP server.
Customizing Jolokia
Jolokia has a number of settings that you would traditionally configure using servlet parameters.
With Spring Boot you can use your application.properties, simply prefix the parameter with
jolokia.config.:
jolokia.config.debug=true
Disabling Jolokia
If you are using Jolokia but you don’t want Spring Boot to configure it, simply set the
endpoints.jolokia.enabled property to false:
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 179
endpoints.jolokia.enabled=false
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 180
50. Monitoring and management using a remote
shell (deprecated)
Spring Boot supports an integrated Java shell called ‘CRaSH’. You can use CRaSH to ssh or telnet
into your running application. To enable remote shell support, add the following dependency to your
project:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-remote-shell</artifactId>
</dependency>
Note
The remote shell is deprecated and will be removed in Spring Boot 2.0.
Tip
If you want to also enable telnet access you will additionally need a dependency on
org.crsh:crsh.shell.telnet.
Note
CRaSH requires to run with a JDK as it compiles commands on the fly. If a basic help command
fails, you are probably running with a JRE.
50.1 Connecting to the remote shell
By default the remote shell will listen for connections on port 2000. The default user is user and the
default password will be randomly generated and displayed in the log output. If your application is using
Spring Security, the shell will use the same configuration by default. If not, a simple authentication will
be applied and you should see a message like this:
Using default password for shell access: ec03e16c-4cf4-49ee-b745-7c8255c1dd7e
Linux and OSX users can use ssh to connect to the remote shell, Windows users can download and
install PuTTY.
$ ssh -p 2000 user@localhost
user@localhost's password:
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v1.5.7.RELEASE) on myhost
Type help for a list of commands. Spring Boot provides metrics, beans, autoconfig and endpoint
commands.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 181
Remote shell credentials
You can use the management.shell.auth.simple.user.name and
management.shell.auth.simple.user.password properties to configure custom connection
credentials. It is also possible to use a ‘Spring Security’ AuthenticationManager to handle login
duties. See the CrshAutoConfiguration and ShellProperties Javadoc for full details.
50.2 Extending the remote shell
The remote shell can be extended in a number of interesting ways.
Remote shell commands
You can write additional shell commands using Groovy (see the CRaSH documentation for details).
Due to limitations in CRaSH’s Java compiler, commands written in Java are not supported. By default
Spring Boot will search for commands in the following locations:
•classpath*:/commands/**
•classpath*:/crash/commands/**
Tip
You can change the search path by settings a shell.command-path-patterns property.
Note
If you are using an executable archive, any classes that a shell command depends upon must be
packaged in a nested jar rather than directly in the executable jar or war.
Here is a simple ‘hello’ command that could be loaded from src/main/resources/commands/
hello.groovy
package commands
import org.crsh.cli.Command
import org.crsh.cli.Usage
import org.crsh.command.InvocationContext
class hello {
@Usage("Say Hello")
@Command
def main(InvocationContext context) {
return "Hello"
}
}
Spring Boot adds some additional attributes to InvocationContext that you can access from your
command:
Attribute Name Description
spring.boot.version The version of Spring Boot
spring.version The version of the core Spring Framework
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 182
Attribute Name Description
spring.beanfactory Access to the Spring BeanFactory
spring.environment Access to the Spring Environment
Remote shell plugins
In addition to new commands, it is also possible to extend other CRaSH shell features. All Spring Beans
that extend org.crsh.plugin.CRaSHPlugin will be automatically registered with the shell.
For more information please refer to the CRaSH reference documentation.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 183
51. 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:
•TRACE
•DEBUG
•INFO
•WARN
•ERROR
•FATAL
•OFF
•null
with null indicating that there is no explicit configuration.
51.1 Configure a Logger
In order to configure a given logger, you POST a partial entity to the resource’s URI:
{
"configuredLevel": "DEBUG"
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 184
52. Metrics
Spring Boot Actuator includes a metrics service with ‘gauge’ and ‘counter’ support. A ‘gauge’ records
a single value; and a ‘counter’ records a delta (an increment or decrement). Spring Boot Actuator also
provides a PublicMetrics interface that you can implement to expose metrics that you cannot record
via one of those two mechanisms. Look at SystemPublicMetrics for an example.
Metrics for all HTTP requests are automatically recorded, so if you hit the metrics endpoint you should
see a response similar to this:
{
"counter.status.200.root": 20,
"counter.status.200.metrics": 3,
"counter.status.200.star-star": 5,
"counter.status.401.root": 4,
"gauge.response.star-star": 6,
"gauge.response.root": 2,
"gauge.response.metrics": 3,
"classes": 5808,
"classes.loaded": 5808,
"classes.unloaded": 0,
"heap": 3728384,
"heap.committed": 986624,
"heap.init": 262144,
"heap.used": 52765,
"nonheap": 0,
"nonheap.committed": 77568,
"nonheap.init": 2496,
"nonheap.used": 75826,
"mem": 986624,
"mem.free": 933858,
"processors": 8,
"threads": 15,
"threads.daemon": 11,
"threads.peak": 15,
"threads.totalStarted": 42,
"uptime": 494836,
"instance.uptime": 489782,
"datasource.primary.active": 5,
"datasource.primary.usage": 0.25
}
Here we can see basic memory, heap, class loading, processor and thread pool information
along with some HTTP metrics. In this instance the root (‘/’) and /metrics URLs have returned HTTP
200 responses 20 and 3 times respectively. It also appears that the root URL returned HTTP 401
(unauthorized) 4 times. The double asterisks (star-star) comes from a request matched by Spring
MVC as /** (normally a static resource).
The gauge shows the last response time for a request. So the last request to root took 2ms to respond
and the last to /metrics took 3ms.
Note
In this example we are actually accessing the endpoint over HTTP using the /metrics URL, this
explains why metrics appears in the response.
52.1 System metrics
The following system metrics are exposed by Spring Boot:
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 185
• The total system memory in KB (mem)
• The amount of free memory in KB (mem.free)
• The number of processors (processors)
• The system uptime in milliseconds (uptime)
• The application context uptime in milliseconds (instance.uptime)
• The average system load (systemload.average)
• Heap information in KB (heap, heap.committed, heap.init, heap.used)
• Thread information (threads, thread.peak, thread.daemon)
• Class load information (classes, classes.loaded, classes.unloaded)
• Garbage collection information (gc.xxx.count, gc.xxx.time)
52.2 DataSource metrics
The following metrics are exposed for each supported DataSource defined in your application:
• The number of active connections (datasource.xxx.active)
• The current usage of the connection pool (datasource.xxx.usage).
All data source metrics share the datasource. prefix. The prefix is further qualified for each data
source:
• If the data source is the primary data source (that is either the only available data source or the one
flagged @Primary amongst the existing ones), the prefix is datasource.primary.
• If the data source bean name ends with DataSource, the prefix is the name of the bean without
DataSource (i.e. datasource.batch for batchDataSource).
• In all other cases, the name of the bean is used.
It is possible to override part or all of those defaults by registering a bean with a customized version
of DataSourcePublicMetrics. 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.
52.3 Cache metrics
The following metrics are exposed for each supported cache defined in your application:
• The current size of the cache (cache.xxx.size)
• Hit ratio (cache.xxx.hit.ratio)
• Miss ratio (cache.xxx.miss.ratio)
Note
Cache providers do not expose the hit/miss ratio in a consistent way. While some expose an
aggregated value (i.e. the hit ratio since the last time the stats were cleared), others expose a
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 186
temporal value (i.e. the hit ratio of the last second). Check your caching provider documentation
for more details.
If two different cache managers happen to define the same cache, the name of the cache is prefixed
by the name of the CacheManager bean.
It is possible to override part or all of those defaults by registering a bean with a customized version
of CachePublicMetrics. By default, Spring Boot provides cache statistics for EhCache, Hazelcast,
Infinispan, JCache and Guava. You can add additional CacheStatisticsProvider beans if your
favorite caching library isn’t supported out of the box. See CacheStatisticsAutoConfiguration
for examples.
52.4 Tomcat session metrics
If you are using Tomcat as your embedded servlet container, session metrics will automatically be
exposed. The httpsessions.active and httpsessions.max keys provide the number of active
and maximum sessions.
52.5 Recording your own metrics
To record your own metrics inject a CounterService and/or GaugeService into your bean.
The CounterService exposes increment, decrement and reset methods; the GaugeService
provides a submit method.
Here is a simple example that counts the number of times that a method is invoked:
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.actuate.metrics.CounterService;
import org.springframework.stereotype.Service;
@Service
public class MyService {
private final CounterService counterService;
@Autowired
public MyService(CounterService counterService) {
this.counterService = counterService;
}
public void exampleMethod() {
this.counterService.increment("services.system.myservice.invoked");
}
}
Tip
You can use any string as a metric name but you should follow guidelines of your chosen store/
graphing technology. Some good guidelines for Graphite are available on Matt Aimonetti’s Blog.
52.6 Adding your own public metrics
To add additional metrics that are computed every time the metrics endpoint is invoked, simply register
additional PublicMetrics implementation bean(s). By default, all such beans are gathered by the
endpoint. You can easily change that by defining your own MetricsEndpoint.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 187
52.7 Special features with Java 8
The default implementation of GaugeService and CounterService provided by Spring Boot
depends on the version of Java that you are using. With Java 8 (or better) the implementation switches
to a high-performance version optimized for fast writes, backed by atomic in-memory buffers, rather than
by the immutable but relatively expensive Metric<?> type (counters are approximately 5 times faster
and gauges approximately twice as fast as the repository-based implementations). The Dropwizard
metrics services (see below) are also very efficient even for Java 7 (they have backports of some of the
Java 8 concurrency libraries), but they do not record timestamps for metric values. If performance of
metric gathering is a concern then it is always advisable to use one of the high-performance options, and
also to only read metrics infrequently, so that the writes are buffered locally and only read when needed.
Note
The old MetricRepository and its InMemoryMetricRepository implementation are not
used by default if you are on Java 8 or if you are using Dropwizard metrics.
52.8 Metric writers, exporters and aggregation
Spring Boot provides a couple of implementations of a marker interface called Exporter which
can be used to copy metric readings from the in-memory buffers to a place where they can
be analyzed and displayed. Indeed, if you provide a @Bean that implements the MetricWriter
interface (or GaugeWriter for simple use cases) and mark it @ExportMetricWriter, then it will
automatically be hooked up to an Exporter and fed metric updates every 5 seconds (configured via
spring.metrics.export.delay-millis). In addition, any MetricReader that you define and
mark as @ExportMetricReader will have its values exported by the default exporter.
Note
This feature is enabling scheduling in your application (@EnableScheduling) which can be a
problem if you run an integration test as your own scheduled tasks will start. You can disable this
behaviour by setting spring.metrics.export.enabled to false.
The default exporter is a MetricCopyExporter which tries to optimize itself by not copying values
that haven’t changed since it was last called (the optimization can be switched off using a flag
spring.metrics.export.send-latest). Note also that the Dropwizard MetricRegistry has
no support for timestamps, so the optimization is not available if you are using Dropwizard metrics (all
metrics will be copied on every tick).
The default values for the export trigger (delay-millis, includes, excludes and send-latest)
can be set as spring.metrics.export.*. Individual values for specific MetricWriters can be
set as spring.metrics.export.triggers.<name>.* where <name> is a bean name (or pattern
for matching bean names).
Warning
The automatic export of metrics is disabled if you switch off the default MetricRepository (e.g.
by using Dropwizard metrics). You can get back the same functionality be declaring a bean of
your own of type MetricReader and declaring it to be @ExportMetricReader.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 188
Example: Export to Redis
If you provide a @Bean of type RedisMetricRepository and mark it @ExportMetricWriter
the metrics are exported to a Redis cache for aggregation. The RedisMetricRepository has two
important parameters to configure it for this purpose: prefix and key (passed into its constructor).
It is best to use a prefix that is unique to the application instance (e.g. using a random value and
maybe the logical name of the application to make it possible to correlate with other instances of the
same application). The “key” is used to keep a global index of all metric names, so it should be unique
“globally”, whatever that means for your system (e.g. two instances of the same system could share a
Redis cache if they have distinct keys).
Example:
@Bean
@ExportMetricWriter
MetricWriter metricWriter(MetricExportProperties export) {
return new RedisMetricRepository(connectionFactory,
export.getRedis().getPrefix(), export.getRedis().getKey());
}
application.properties.
spring.metrics.export.redis.prefix: metrics.mysystem.${spring.application.name:application}.
${random.value:0000}
spring.metrics.export.redis.key: keys.metrics.mysystem
The prefix is constructed with the application name and id at the end, so it can easily be used to identify
a group of processes with the same logical name later.
Note
It’s important to set both the key and the prefix. The key is used for all repository operations, and
can be shared by multiple repositories. If multiple repositories share a key (like in the case where
you need to aggregate across them), then you normally have a read-only “master” repository that
has a short, but identifiable, prefix (like “metrics.mysystem”), and many write-only repositories
with prefixes that start with the master prefix (like metrics.mysystem.* in the example above).
It is efficient to read all the keys from a “master” repository like that, but inefficient to read a subset
with a longer prefix (e.g. using one of the writing repositories).
Tip
The example above uses MetricExportProperties to inject and extract the key and prefix.
This is provided to you as a convenience by Spring Boot, configured with sensible defaults. There
is nothing to stop you using your own values as long as they follow the recommendations.
Example: Export to Open TSDB
If you provide a @Bean of type OpenTsdbGaugeWriter and mark it @ExportMetricWriter metrics
are exported to Open TSDB for aggregation. The OpenTsdbGaugeWriter has a url property that
you need to set to the Open TSDB “/put” endpoint, e.g. localhost:4242/api/put). It also has a
namingStrategy that you can customize or configure to make the metrics match the data structure
you need on the server. By default it just passes through the metric name as an Open TSDB metric
name, and adds the tags “domain” (with value “org.springframework.metrics”) and “process” (with the
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 189
value equal to the object hash of the naming strategy). Thus, after running the application and generating
some metrics you can inspect the metrics in the TSD UI (localhost:4242 by default).
Example:
curl localhost:4242/api/query?start=1h-ago&m=max:counter.status.200.root
[
{
"metric": "counter.status.200.root",
"tags": {
"domain": "org.springframework.metrics",
"process": "b968a76"
},
"aggregateTags": [],
"dps": {
"1430492872": 2,
"1430492875": 6
}
}
]
Example: Export to Statsd
To export metrics to Statsd, make sure first that you have added com.timgroup:java-statsd-
client as a dependency of your project (Spring Boot provides a dependency management for it).
Then add a spring.metrics.export.statsd.host value to your application.properties
file. Connections will be opened to port 8125 unless a spring.metrics.export.statsd.port
override is provided. You can use spring.metrics.export.statsd.prefix if you want a custom
prefix.
Alternatively, you can provide a @Bean of type StatsdMetricWriter and mark it
@ExportMetricWriter:
@Value("${spring.application.name:application}.${random.value:0000}")
private String prefix = "metrics";
@Bean
@ExportMetricWriter
MetricWriter metricWriter() {
return new StatsdMetricWriter(prefix, "localhost", 8125);
}
Example: Export to JMX
If you provide a @Bean of type JmxMetricWriter marked @ExportMetricWriter the metrics are
exported as MBeans to the local server (the MBeanExporter is provided by Spring Boot JMX auto-
configuration as long as it is switched on). Metrics can then be inspected, graphed, alerted etc. using
any tool that understands JMX (e.g. JConsole or JVisualVM).
Example:
@Bean
@ExportMetricWriter
MetricWriter metricWriter(MBeanExporter exporter) {
return new JmxMetricWriter(exporter);
}
Each metric is exported as an individual MBean. The format for the ObjectNames is given by an
ObjectNamingStrategy which can be injected into the JmxMetricWriter (the default breaks up
the metric name and tags the first two period-separated sections in a way that should make the metrics
group nicely in JVisualVM or JConsole).
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 190
52.9 Aggregating metrics from multiple sources
There is an AggregateMetricReader that you can use to consolidate metrics from different physical
sources. Sources for the same logical metric just need to publish them with a period-separated prefix,
and the reader will aggregate (by truncating the metric names, and dropping the prefix). Counters are
summed and everything else (i.e. gauges) take their most recent value.
This is very useful if multiple application instances are feeding to a central (e.g. Redis)
repository and you want to display the results. Particularly recommended in conjunction with a
MetricReaderPublicMetrics for hooking up to the results to the “/metrics” endpoint.
Example:
@Autowired
private MetricExportProperties export;
@Bean
public PublicMetrics metricsAggregate() {
return new MetricReaderPublicMetrics(aggregatesMetricReader());
}
private MetricReader globalMetricsForAggregation() {
return new RedisMetricRepository(this.connectionFactory,
this.export.getRedis().getAggregatePrefix(), this.export.getRedis().getKey());
}
private MetricReader aggregatesMetricReader() {
AggregateMetricReader repository = new AggregateMetricReader(
globalMetricsForAggregation());
return repository;
}
Note
The example above uses MetricExportProperties to inject and extract the key and prefix.
This is provided to you as a convenience by Spring Boot, and the defaults will be sensible. They
are set up in MetricExportAutoConfiguration.
Note
The MetricReaders above are not @Beans and are not marked as @ExportMetricReader
because they are just collecting and analyzing data from other repositories, and don’t want to
export their values.
52.10 Dropwizard Metrics
A default MetricRegistry Spring bean will be created when you declare a dependency to the
io.dropwizard.metrics:metrics-core library; you can also register you own @Bean instance
if you need customizations. Users of the Dropwizard ‘Metrics’ library will find that Spring Boot
metrics are automatically published to com.codahale.metrics.MetricRegistry. Metrics from the
MetricRegistry are also automatically exposed via the /metrics endpoint
When Dropwizard metrics are in use, the default CounterService and GaugeService are replaced
with a DropwizardMetricServices, which is a wrapper around the MetricRegistry (so you can
@Autowired one of those services and use it as normal). You can also create “special” Dropwizard
metrics by prefixing your metric names with the appropriate type (i.e. timer.*, histogram.* for
gauges, and meter.* for counters).
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 191
52.11 Message channel integration
If a MessageChannel bean called metricsChannel exists, then a MetricWriter will be created
that writes metrics to that channel. Each message sent to the channel will contain a Delta or Metric
payload and have a metricName header. The writer is automatically hooked up to an exporter (as for
all writers), so all metric values will appear on the channel, and additional analysis or actions can be
taken by subscribers (it’s up to you to provide the channel and any subscribers you need).
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 192
53. Auditing
Spring Boot Actuator has a flexible audit framework that will publish events once Spring Security
is in play (‘authentication success’, ‘failure’ and ‘access denied’ exceptions by default). This can
be very useful for reporting, and also to implement 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 choose to use the audit services for your own business events. To do that you can either
inject the existing AuditEventRepository into your own components and use that directly, or you
can simply publish AuditApplicationEvent via the Spring ApplicationEventPublisher (using
ApplicationEventPublisherAware).
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 193
54. Tracing
Tracing is automatically enabled for all HTTP requests. You can view the trace endpoint and obtain
basic information about the last 100 requests:
[{
"timestamp": 1394343677415,
"info": {
"method": "GET",
"path": "/trace",
"headers": {
"request": {
"Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
"Connection": "keep-alive",
"Accept-Encoding": "gzip, deflate",
"User-Agent": "Mozilla/5.0 Gecko/Firefox",
"Accept-Language": "en-US,en;q=0.5",
"Cookie": "_ga=GA1.1.827067509.1390890128; ..."
"Authorization": "Basic ...",
"Host": "localhost:8080"
},
"response": {
"Strict-Transport-Security": "max-age=31536000 ; includeSubDomains",
"X-Application-Context": "application:8080",
"Content-Type": "application/json;charset=UTF-8",
"status": "200"
}
}
}
},{
"timestamp": 1394343684465,
...
}]
The following are included in the trace by default:
Name Description
Request Headers Headers from the request.
Response Headers Headers from the response.
Cookies Cookie from request headers and Set-Cookie from response
headers.
Errors The error attributes (if any).
Time Taken The time taken to service the request in milliseconds.
54.1 Custom tracing
If you need to trace additional events you can inject a TraceRepository into your Spring beans. The
add method accepts a single Map structure that will be converted to JSON and logged.
By default an InMemoryTraceRepository will be used that stores the last 100 events. You can define
your own instance of the InMemoryTraceRepository bean if you need to expand the capacity. You
can also create your own alternative TraceRepository implementation if needed.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 194
55. Process monitoring
In Spring Boot Actuator you can find a couple of classes to create files that are useful for process
monitoring:
•ApplicationPidFileWriter creates a file containing the application PID (by default in the
application directory with the file name application.pid).
•EmbeddedServerPortFileWriter creates a file (or files) containing the ports of the embedded
server (by default in the application directory with the file name application.port).
These writers are not activated by default, but you can enable them in one of the ways described below.
55.1 Extend configuration
In META-INF/spring.factories file you can activate the listener(s) that writes a PID file. Example:
org.springframework.context.ApplicationListener=\
org.springframework.boot.system.ApplicationPidFileWriter,\
org.springframework.boot.actuate.system.EmbeddedServerPortFileWriter
55.2 Programmatically
You can also activate a listener by invoking the SpringApplication.addListeners(…) method
and passing the appropriate Writer object. This method also allows you to customize the file name
and path via the Writer constructor.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 195
56. 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 NamedMvcEndpoint beans.
The extended support allows Cloud Foundry management UIs (such as the web application that you
can use to view deployed applications) to 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.
56.1 Disabling extended Cloud Foundry actuator support
If you want to fully disable the /cloudfoundryapplication endpoints you can add the following to
your application.properties file:
application.properties.
management.cloudfoundry.enabled=false
56.2 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 will need to set the following property:
application.properties.
management.cloudfoundry.skip-ssl-validation=true
56.3 Custom security configuration
If you define custom security configuration, and you want extended Cloud Foundry actuator support,
you’ll should ensure that /cloudfoundryapplication/** paths are open. Without a direct open
route, your Cloud Foundry application manager will not be able to obtain endpoint data.
For Spring Security, you’ll typically include something like mvcMatchers("/
cloudfoundryapplication/**").permitAll() in your configuration:
@Override
protected void configure(HttpSecurity http) throws Exception {
http
.authorizeRequests()
.mvcMatchers("/cloudfoundryapplication/**")
.permitAll()
.mvcMatchers("/mypath")
.hasAnyRole("SUPERUSER")
.anyRequest()
.authenticated().and()
.httpBasic();
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 196
57. 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 easily deploy Spring Boot applications to a variety of cloud platforms, to a container
images (such as Docker) or to virtual/real machines.
This section covers some of the more common deployment scenarios.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 198
58. 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 some 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, it might be an embedded web server, or it might be 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’ll look at what it takes to get the simple application that we developed in the “Getting
Started” section up and running in the Cloud.
58.1 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’ve built your application (using, for example, mvn clean package) and installed the cf
command line tool, simply deploy your application using the cf push command as follows, substituting
the path to your compiled .jar. Be sure to have logged in with your cf command line client before
pushing an application.
$ cf push acloudyspringtime -p target/demo-0.0.1-SNAPSHOT.jar
See the cf push documentation for more options. If there is a Cloud Foundry manifest.yml file
present in the same directory, it will be consulted.
Note
Here we are substituting acloudyspringtime for whatever value you give cf as the name of
your application.
At this point cf will start uploading your application:
Uploading acloudyspringtime... OK
Preparing to start acloudyspringtime... OK
-----> Downloaded app package (8.9M)
-----> Java Buildpack source: system
-----> Downloading Open JDK 1.7.0_51 from .../x86_64/openjdk-1.7.0_51.tar.gz (1.8s)
Expanding Open JDK to .java-buildpack/open_jdk (1.2s)
-----> Downloading Spring Auto Reconfiguration from 0.8.7 .../auto-reconfiguration-0.8.7.jar (0.1s)
-----> Uploading droplet (44M)
Checking status of app 'acloudyspringtime'...
0 of 1 instances running (1 starting)
...
0 of 1 instances running (1 down)
...
0 of 1 instances running (1 starting)
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 199
...
1 of 1 instances running (1 running)
App started
Congratulations! The application is now live!
It’s easy to then verify the status of the deployed application:
$ 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 hit
the application at the URI given, in this case 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: $VCAP_SERVICES). This architecture decision
is due to Cloud Foundry’s polyglot (any language and platform can be supported as a buildpack) nature;
process-scoped environment variables are language agnostic.
Environment variables don’t always make for the easiest API so Spring Boot automatically extracts them
and flattens the data into properties that can be accessed through Spring’s Environment abstraction:
@Component
class MyBean implements EnvironmentAware {
private String instanceId;
@Override
public void setEnvironment(Environment environment) {
this.instanceId = environment.getProperty("vcap.application.instance_id");
}
// ...
}
All Cloud Foundry properties are prefixed with vcap. You can use vcap properties to access application
information (such as the public URL of the application) and service information (such as database
credentials). See CloudFoundryVcapEnvironmentPostProcessor Javadoc for complete details.
Tip
The Spring Cloud Connectors project is a better fit for tasks such as configuring a DataSource.
Spring Boot includes auto-configuration support and a spring-boot-starter-cloud-
connectors starter.
58.2 Heroku
Heroku is another popular PaaS platform. To customize Heroku builds, you provide a Procfile,
which provides the incantation required to deploy an application. Heroku assigns a port for the Java
application to use and then ensures that routing to the external URI works.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 200
You must configure your application to listen on the correct port. Here’s the Procfile for our starter
REST application:
web: java -Dserver.port=$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 it when it starts up. The $PORT environment variable is assigned to us by
the Heroku PaaS.
Heroku by default will use Java 1.8. This is fine as long as your Maven or Gradle build is set to use the
same version (Maven users can use the java.version property). If you want to use JDK 1.7, create a
new file adjacent to your pom.xml and Procfile, called system.properties. In this file add the
following:
java.runtime.version=1.7
This should be everything you need. The most common workflow for Heroku deployments is to git
push the code to production.
$ 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: http://repo.spring.io/...
Downloaded: http://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
* [new branch] master -> master
Your application should now be up and running on Heroku.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 201
58.3 OpenShift
OpenShift is the RedHat public (and enterprise) PaaS solution. Like Heroku, it works by running scripts
triggered by git commits, so you can script the launching of a Spring Boot application in pretty much any
way you like as long as the Java runtime is available (which is a standard feature you can ask for at
OpenShift). To do this you can use the DIY Cartridge and hooks in your repository under .openshift/
action_hooks:
The basic model is to:
1. Ensure Java and your build tool are installed remotely, e.g. using a pre_build hook (Java and
Maven are installed by default, Gradle is not)
2. Use a build hook to build your jar (using Maven or Gradle), e.g.
#!/bin/bash
cd $OPENSHIFT_REPO_DIR
mvn package -s .openshift/settings.xml -DskipTests=true
3. Add a start hook that calls java -jar …
#!/bin/bash
cd $OPENSHIFT_REPO_DIR
nohup java -jar target/*.jar --server.port=${OPENSHIFT_DIY_PORT} --server.address=${OPENSHIFT_DIY_IP}
&
4. Use a stop hook (since the start is supposed to return cleanly), e.g.
#!/bin/bash
source $OPENSHIFT_CARTRIDGE_SDK_BASH
PID=$(ps -ef | grep java.*\.jar | grep -v grep | awk '{ print $2 }')
if [ -z "$PID" ]
then
client_result "Application is already stopped"
else
kill $PID
fi
5. Embed service bindings from environment variables provided by the platform in your
application.properties, e.g.
spring.datasource.url: jdbc:mysql://${OPENSHIFT_MYSQL_DB_HOST}:${OPENSHIFT_MYSQL_DB_PORT}/
${OPENSHIFT_APP_NAME}
spring.datasource.username: ${OPENSHIFT_MYSQL_DB_USERNAME}
spring.datasource.password: ${OPENSHIFT_MYSQL_DB_PASSWORD}
There’s a blog on running Gradle in OpenShift on their website that will get you started with a gradle
build to run the app.
58.4 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. Options include :
• AWS Elastic Beanstalk
• AWS Code Deploy
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 202
• AWS OPS Works
• AWS Cloud Formation
• AWS Container Registry
Each has different features and pricing model, here we will 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 producing a war file. There is no any special configuration
required, just follow the official guide.
Using the Java SE platform
This option applies to Spring Boot projects producing a jar file and running 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 to your application.properties:
server.port=5000
Best practices
Uploading binaries instead of sources
By default Elastic Beanstalk uploads sources and compiles them in AWS. To upload the binaries instead,
add 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 cost perspective,
to avoid it, set the environment type to “Single instance” as described in the Amazon documentation.
Single instance environments can be created using the CLI as well using 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, e.g.: how to integrate
Elastic Beanstalk into any CI / CD tool, using the Elastic Beanstalk maven plugin instead of the CLI, etc.
There is a blog covering these topics more in detail.
58.5 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
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 203
Boot and will use 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, etc).
Once you have created a Boxfuse account, connected it to your AWS account, and installed the latest
version of the Boxfuse Client, you can deploy your Spring Boot application to AWS as follows (ensure
the application has been built by Maven or Gradle first using, for example, mvn clean package):
$ boxfuse run myapp-1.0.jar -env=prod
See the boxfuse run documentation for more options. If there is a boxfuse.com/docs/commandline/
#configuration [boxfuse.conf] file present in the current directory, it will be consulted.
Tip
By default Boxfuse will activate a Spring profile named boxfuse on startup and if your
executable jar or war contains an boxfuse.com/docs/payloads/springboot.html#configuration
[application-boxfuse.properties] file, Boxfuse will base its configuration based on the
properties it contains.
At this point boxfuse will create an image for your application, upload it, and then configure and start
the necessary resources on AWS:
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.
There’s a blog on deploying Spring Boot apps on EC2 as well as documentation for the Boxfuse Spring
Boot integration on their website that will get you started with a Maven build to run the app.
58.6 Google Cloud
Google Cloud has several options that could 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 using 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 HTTP routes. Add a Java app to the project and leave it empty, then use the Google Cloud
SDK to push your Spring Boot app into that slot from the command line or CI build.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 204
App Engine needs you to create an app.yaml file to describe the resources your app requires. Normally
you put this in src/main/appengine, and it looks something like this:
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
You can deploy the app, for example, with a Maven plugin by simply adding the project ID to the build
configuration:
<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 will fail).
Note
Google App Engine Classic is tied to the Servlet 2.5 API, so you can’t deploy a Spring Application
there without some modifications. See the Servlet 2.5 section of this guide.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 205
59. Installing Spring Boot applications
In additional to running Spring Boot applications 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.
Warning
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 only make your jar or war fully executable 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>
With Gradle, the equivalent configuration is:
springBoot {
executable = true
}
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 will be used as your application’s working
directory.
59.1 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, will require the use of a custom embeddedLaunchScript.
59.2 Unix/Linux services
Spring Boot application can be easily started as Unix/Linux services using either init.d or systemd.
Installation as an init.d service (System V)
If you’ve configured Spring Boot’s Maven or Gradle plugin to generate a fully executable jar, and
you’re not using a custom embeddedLaunchScript, then your application can be used as an init.d
service. Simply 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 application’s PID using /var/run/<appname>/<appname>.pid
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 206
• 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 simply create a symlink:
$ 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:
$ 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 using your standard operating system tools. For
example, on Debian:
$ 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’s being run
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 will run the application as the user which 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. For
example:
$ chown bootapp:bootapp your-app.jar
In this case, the default executable script will run 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. Set the account’s shell to /usr/sbin/nologin, for
example.
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:
$ chmod 500 your-app.jar
Secondly, 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
contents. One way to protect against this is to make it immutable using chattr:
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 207
$ 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 will be 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:
$ 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 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 using the following example
and place it in /etc/systemd/system directory:
[Unit]
Description=myapp
After=syslog.target
[Service]
User=myapp
ExecStart=/var/myapp/myapp.jar
SuccessExitStatus=143
[Install]
WantedBy=multi-user.target
Tip
Remember to change the Description, User and ExecStart fields for your application.
Tip
Note that ExecStart field does not declare the script action command, which means that run
command is used by default.
Note that unlike when running as an init.d service, user that runs the application, PID file and console
log file are managed by systemd itself and therefore must be configured using appropriate fields in
‘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.
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
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 208
usually enough. If you find you can’t customize something that you need to, you can always use the
embeddedLaunchScript option to write your own file entirely.
Customizing script when it’s written
It often makes sense to customize elements of the start script as it’s written into the jar file. For example,
init.d scripts can provide a “description” and, since you know this up front (and it won’t 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.
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.
useStartStopDaemonIf 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 209
Customizing 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 will
usually be 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 just want to run
the script in the foreground.
USE_START_STOP_DAEMONIf 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 to put log files in (/var/log by default).
CONF_FOLDERThe name of the folder to read .conf files from (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,
but 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 in.
DEBUG if not empty will set 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).
Note
The PID_FOLDER, LOG_FOLDER and LOG_FILENAME variables are only valid for an init.d
service. With systemd the equivalent customizations are made using ‘service’ script. Check the
service unit configuration man page for more details.
With the exception of JARFILE and APP_NAME, the above settings can be configured using a .conf
file. The file is expected 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 will use the configuration file named
/var/myapp/myapp.conf.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 210
myapp.conf.
JAVA_OPTS=-Xmx1024M
LOG_FOLDER=/custom/log/folder
Tip
You can use a CONF_FOLDER environment variable to customize the location of the config file if
you don’t like it living next to the jar.
To learn about securing this file appropriately, please refer to the guidelines for securing an init.d service.
59.3 Microsoft Windows services
Spring Boot application can be started as Windows service using winsw.
A sample maintained separately to the core of Spring Boot describes step-by-step how you can create
a Windows service for your Spring Boot application.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 211
60. 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’re free to 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 can be used if you want to quickly develop with Spring.
It allows you to 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 213
61. Installing the CLI
The Spring Boot CLI can be installed manually; using SDKMAN! (the SDK Manager) or 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 214
62. Using the CLI
Once you have installed the CLI you can run it by typing spring. If you run spring without any
arguments, a simple help screen is displayed:
$ 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 use help to get more details about any of the supported commands. For 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.
$ spring version
Spring CLI v1.5.7.RELEASE
62.1 Running applications using the CLI
You can compile and run Groovy source code using the run command. The Spring Boot CLI is
completely self-contained so you don’t need any external Groovy installation.
Here is an example “hello world” web application written in Groovy:
hello.groovy.
@RestController
class WebApplication {
@RequestMapping("/")
String home() {
"Hello World!"
}
}
To compile and run the application type:
$ spring run hello.groovy
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 215
To pass command line arguments to the application, you need to use a -- to separate them from the
“spring” command arguments, e.g.
$ spring run hello.groovy -- --server.port=9000
To set JVM command line arguments you can use the JAVA_OPTS environment variable, e.g.
$ JAVA_OPTS=-Xmx1024m spring run hello.groovy
Deduced “grab” dependencies
Standard Groovy includes a @Grab annotation which allows you to declare dependencies on a third-
party libraries. This useful technique allows Groovy to 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 will attempt to deduce which libraries to “grab”
based on your code. For example, since the WebApplication code above uses @RestController
annotations, “Tomcat” and “Spring MVC” will be grabbed.
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.
@EnableReactor Project Reactor.
extends Specification Spock test.
@EnableBatchProcessing Spring Batch.
@MessageEndpoint
@EnableIntegrationPatterns
Spring Integration.
@EnableDeviceResolver Spring Mobile.
@Controller @RestController
@EnableWebMvc
Spring MVC + Embedded Tomcat.
@EnableWebSecurity Spring Security.
@EnableTransactionManagement Spring Transaction Management.
Tip
See subclasses of CompilerAutoConfiguration in the Spring Boot CLI source code to
understand exactly how customizations are applied.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 216
Deduced “grab” coordinates
Spring Boot extends Groovy’s standard @Grab support by allowing you to specify a dependency
without a group or version, for example @Grab('freemarker'). This will consult Spring Boot’s default
dependency metadata to deduce the artifact’s group and version. Note that the default metadata is tied
to the version of the CLI that you’re using – it will only change 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 example above refers to @Component, @RestController and @RequestMapping
without needing to use fully-qualified names or import statements.
Tip
Many Spring annotations will 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, that will override the default
dependency management, can be configured using the @DependencyManagementBom annotation.
The annotation’s value should specify the coordinates (groupId:artifactId:version) of one or
more Maven BOMs.
For example, the following declaration:
@DependencyManagementBom("com.example.custom-bom:1.0.0")
Will pick up custom-bom-1.0.0.pom in a Maven repository under com/example/custom-
versions/1.0.0/.
When multiple BOMs are specified they are applied in the order that they’re declared. For example:
@DependencyManagementBom(["com.example.custom-bom:1.0.0",
"com.example.another-bom:1.0.0"])
indicates that dependency management in another-bom will override 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 only use @DependencyManagementBom
at most once in your application. A useful source of dependency management (that is
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 217
a superset of Spring Boot’s dependency management) is the Spring IO Platform, e.g.
@DependencyManagementBom('io.spring.platform:platform-bom:1.1.2.RELEASE').
62.2 Testing your code
The test command allows you to compile and run tests for your application. Typical usage looks like
this:
$ spring test app.groovy tests.groovy
Total: 1, Success: 1, : Failures: 0
Passed? true
In this example, tests.groovy contains JUnit @Test methods or Spock Specification classes.
All the common framework annotations and static methods should be available to you without having
to import them.
Here is the tests.groovy file that we used above (with a JUnit test):
class ApplicationTests {
@Test
void homeSaysHello() {
assertEquals("Hello World!", new WebApplication().home())
}
}
Tip
If you have more than one test source files, you might prefer to organize them into a test
directory.
62.3 Applications with multiple source files
You can use “shell globbing” with all commands that accept file input. This allows you to easily use
multiple files from a single directory, e.g.
$ spring run *.groovy
This technique can also be useful if you want to segregate your “test” or “spec” code from the main
application code:
$ spring test app/*.groovy test/*.groovy
62.4 Packaging your application
You can use the jar command to package your application into a self-contained executable jar file.
For example:
$ spring jar my-app.jar *.groovy
The resulting jar will contain the classes produced by compiling the application and all of the application’s
dependencies so that it can then be run using java -jar. The jar file will also contain entries from the
application’s classpath. You can add explicit paths to the jar using --include and --exclude (both
are comma-separated, and both accept prefixes to the values “+” and “-” to signify that they should be
removed from the defaults). The default includes are
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 218
public/**, resources/**, static/**, templates/**, META-INF/**, *
and the default excludes are
.*, repository/**, build/**, target/**, **/*.jar, **/*.groovy
See the output of spring help jar for more information.
62.5 Initialize a new project
The init command allows you to create a new project using start.spring.io without leaving the shell.
For example:
$ spring init --dependencies=web,data-jpa my-project
Using service at https://start.spring.io
Project extracted to '/Users/developer/example/my-project'
This creates a my-project directory with a Maven-based project using spring-boot-starter-
web and spring-boot-starter-data-jpa. You can list the capabilities of the service using the --
list flag
$ 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, check the help output for more details. For instance, the
following command creates a gradle project using 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'
62.6 Using the embedded shell
Spring Boot includes command-line completion scripts for BASH and zsh shells. If you don’t use either
of these shells (perhaps you are a Windows user) then you can use the shell command to launch
an integrated shell.
$ spring shell
Spring Boot (v1.5.7.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:
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 219
$ version
Spring CLI v1.5.7.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. Hitting ctrl-c will exit the embedded shell.
62.7 Adding extensions to the CLI
You can add extensions to the CLI using the install command. The command takes one or more
sets of artifact coordinates in the format group:artifact:version. For 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 will also be installed.
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 group:artifact:version. For example:
$ spring uninstall com.example:spring-boot-cli-extension:1.0.0.RELEASE
It will uninstall the artifacts identified by the coordinates you supply and their dependencies.
To uninstall all additional dependencies you can use the --all option. For example:
$ spring uninstall --all
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 220
63. Developing application 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 using the same format. This is sometimes a
good way to include external features like middleware declarations. For 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
you can put the beans DSL in a separate file if you prefer.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 221
64. 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
Please refer to Maven’s settings documentation for further information.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 222
65. 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 will probably want to look at converting your
application to full Gradle or Maven built “groovy project”. The next section covers Spring Boot’s Build
tool plugins that 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 224
66. Spring Boot Maven plugin
The Spring Boot Maven Plugin provides Spring Boot support in Maven, allowing you to package
executable jar or war archives and run an application “in-place”. To use it you must be using Maven
3.2 (or better).
Note
Refer to the Spring Boot Maven Plugin Site for complete plugin documentation.
66.1 Including the plugin
To use the Spring Boot Maven Plugin simply include the appropriate XML in the plugins section of
your pom.xml
<?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>1.5.7.RELEASE</version>
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
This configuration will repackage 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 don’t include the <execution/> configuration as above, you can run the plugin on its own (but
only if the package goal is used as well). For example:
$ mvn package spring-boot:repackage
$ ls target/*.jar
target/myproject-1.0.0.jar target/myproject-1.0.0.jar.original
If you are using a milestone or snapshot release you will also need to add appropriate
pluginRepository elements:
<pluginRepositories>
<pluginRepository>
<id>spring-snapshots</id>
<url>http://repo.spring.io/snapshot</url>
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 225
</pluginRepository>
<pluginRepository>
<id>spring-milestones</id>
<url>http://repo.spring.io/milestone</url>
</pluginRepository>
</pluginRepositories>
66.2 Packaging executable jar and war files
Once spring-boot-maven-plugin has been included in your pom.xml it will automatically attempt
to rewrite archives to make them executable using the spring-boot:repackage goal. You should
configure your project to build a jar or war (as appropriate) using the usual packaging element:
<?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 will be enhanced by Spring Boot during the package phase. The main class that
you want to launch can either be specified using a configuration option, or by adding a Main-Class
attribute to the manifest in the usual way. If you don’t specify a main class the plugin will search 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”, e.g:
<?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 85.1, “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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 226
67. Spring Boot Gradle plugin
The Spring Boot Gradle Plugin provides Spring Boot support in Gradle, allowing you to package
executable jar or war archives, run Spring Boot applications and use the dependency management
provided by spring-boot-dependencies.
67.1 Including the plugin
To use the Spring Boot Gradle Plugin configure it using the plugins block:
plugins {
id 'org.springframework.boot' version '1.5.7.RELEASE'
}
67.2 Gradle dependency management
The spring-boot plugin automatically applies the Dependency Management Plugin and configures it
to import the spring-boot-starter-parent bom. This provides a similar dependency management
experience to the one that is enjoyed by Maven users. For example, it allows you to omit version numbers
when declaring dependencies that are managed in the bom. To make use of this functionality, simply
declare dependencies in the usual way, but leave the version number empty:
dependencies {
compile("org.springframework.boot:spring-boot-starter-web")
compile("org.thymeleaf:thymeleaf-spring4")
compile("nz.net.ultraq.thymeleaf:thymeleaf-layout-dialect")
}
Note
The version of the spring-boot gradle plugin that you declare determines the version of the
spring-boot-starter-parent bom that is imported (this ensures that builds are always
repeatable). You should always set the version of the spring-boot gradle plugin to the actual
Spring Boot version that you wish to use. Details of the versions that are provided can be found
in the appendix.
To learn more about the capabilities of the Dependency Management Plugin, please refer to its
documentation.
67.3 Packaging executable jar and war files
Once the spring-boot plugin has been applied to your project it will automatically attempt to rewrite
archives to make them executable using the bootRepackage task. You should configure your project
to build a jar or war (as appropriate) in the usual way.
The main class that you want to launch can either be specified using a configuration option, or by adding
a Main-Class attribute to the manifest. If you don’t specify a main class the plugin will search for a
class with a public static void main(String[] args) method.
Tip
Check Section 67.6, “Repackage configuration” for a full list of configuration options.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 227
To build and run a project artifact, you can type the following:
$ gradle build
$ java -jar build/libs/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 belonging to the war plugin’s providedRuntime configuration,
e.g.:
...
apply plugin: 'war'
war {
baseName = 'myapp'
version = '0.5.0'
}
repositories {
jcenter()
maven { url "http://repo.spring.io/libs-snapshot" }
}
dependencies {
compile("org.springframework.boot:spring-boot-starter-web")
providedRuntime("org.springframework.boot:spring-boot-starter-tomcat")
...
}
Tip
See the “Section 85.1, “Create a deployable war file”” section for more details on how to create
a deployable war file.
67.4 Running a project in-place
To run a project in place without building a jar first you can use the “bootRun” task:
$ gradle bootRun
If devtools has been added to your project it will automatically monitor your application for changes.
Alternatively, you can also run the application so that your static classpath resources (i.e. in src/main/
resources by default) are reloadable in the live application, which can be helpful at development time.
bootRun {
addResources = true
}
Making static classpath resources reloadable means that bootRun does not use the output of the
processResources task, i.e., when invoked using bootRun, your application will use the resources
in their unprocessed form.
67.5 Spring Boot plugin configuration
The gradle plugin automatically extends your build script DSL with a springBoot element for global
configuration of the Boot plugin. Set the appropriate properties as you would with any other Gradle
extension (see below for a list of configuration options):
springBoot {
backupSource = false
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 228
}
67.6 Repackage configuration
The plugin adds a bootRepackage task which you can also configure directly, e.g.:
bootRepackage {
mainClass = 'demo.Application'
}
The following configuration options are available:
Name Description
enabled Boolean flag to switch the repackager off (sometimes useful if you
want the other Boot features but not this one)
mainClass The main class that should be run. If not specified, and you have
applied the application plugin, the mainClassName project
property will be used. If the application plugin has not been
applied or no mainClassName has been specified, the archive
will be searched for a suitable class. "Suitable" means a unique
class with a well-formed main() method (if more than one is
found the build will fail). If you have applied the application plugin,
the main class can also be specified via its "run" task (main
property) and/or its "startScripts" task (mainClassName property)
as an alternative to using the "springBoot" configuration.
classifier A file name segment (before the extension) to add to the archive,
so that the original is preserved in its original location. Defaults
to null in which case the archive is repackaged in place. The
default is convenient for many purposes, but if you want to use
the original jar as a dependency in another project you must use a
classifier to define the executable archive.
withJarTask The name or value of the Jar task (defaults to all tasks of type
Jar) which is used to locate the archive to repackage.
customConfiguration The name of the custom configuration which is used to populate
the nested lib directory (without specifying this you get all compile
and runtime dependencies).
executable Boolean flag to indicate if jar files are fully executable on Unix like
operating systems. Defaults to false.
embeddedLaunchScript The embedded launch script to prepend to the front of the jar if it
is fully executable. If not specified the 'Spring Boot' default script
will be used.
embeddedLaunchScriptPropertiesAdditional properties that to be expanded in the launch script. The
default script supports a mode property which can contain the
values auto, service or run.
excludeDevtools Boolean flag to indicate if the devtools jar should be excluded
from the repackaged archives. Defaults to true.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 229
67.7 Repackage with custom Gradle configuration
Sometimes it may be more appropriate to not package default dependencies resolved from compile,
runtime and provided scopes. If the created executable jar file is intended to be run as it is, you
need to have all dependencies nested inside it; however, if the plan is to explode a jar file and run the
main class manually, you may already have some of the libraries available via CLASSPATH. This is a
situation where you can repackage your jar with a different set of dependencies.
Using a custom configuration will automatically disable dependency resolving from compile, runtime
and provided scopes. Custom configuration can be either defined globally (inside the springBoot
section) or per task.
task clientJar(type: Jar) {
appendix = 'client'
from sourceSets.main.output
exclude('**/*Something*')
}
task clientBoot(type: BootRepackage, dependsOn: clientJar) {
withJarTask = clientJar
customConfiguration = "mycustomconfiguration"
}
In above example, we created a new clientJar Jar task to package a customized file set from your
compiled sources. Then we created a new clientBoot BootRepackage task and instructed it to work
with only clientJar task and mycustomconfiguration.
configurations {
mycustomconfiguration.exclude group: 'log4j'
}
dependencies {
mycustomconfiguration configurations.runtime
}
The configuration that we are referring to in BootRepackage is a normal Gradle configuration. In
the above example we created a new configuration named mycustomconfiguration instructing it
to derive from a runtime and exclude the log4j group. If the clientBoot task is executed, the
repackaged boot jar will have all dependencies from runtime but no log4j jars.
Configuration options
The following configuration options are available:
Name Description
mainClass The main class that should be run by the executable archive.
providedConfiguration The name of the provided configuration (defaults to
providedRuntime).
backupSource If the original source archive should be backed-up before being
repackaged (defaults to true).
customConfiguration The name of the custom configuration.
layout The type of archive, corresponding to how the dependencies are
laid out inside (defaults to a guess based on the archive type).
See available layouts for more details.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 230
Name Description
layoutFactory A layout factory that can be used if a custom layout is required.
Alternative layouts can be provided by 3rd parties. Layout
factories are only used when layout is not specified.
requiresUnpack A list of dependencies (in the form “groupId:artifactId” that must
be unpacked from fat jars in order to run. Items are still packaged
into the fat jar, but they will be automatically unpacked when it
runs.
Available layouts
The layout attribute configures the format of the archive and whether the bootstrap loader should be
included or not. The following layouts are available:
Name Description Executable
JAR Regular executable JAR layout. Yes
WAR Executable WAR layout. provided dependencies are
placed in WEB-INF/lib-provided to avoid any clash
when the war is deployed in a servlet container.
Yes
ZIP (alias to DIR) Similar to JAR layout, using PropertiesLauncher. Yes
MODULE Bundle dependencies (excluding those with provided
scope) and project resources.
No
NONE Bundle all dependencies and project resources. No
Using a custom layout
If you have custom requirements for how to arrange the dependencies and loader classes inside the
repackaged jar, you can use a custom layout. Any library which defines one or more LayoutFactory
implementations can be added to the build script dependencies and then the layout factory becomes
available in the springBoot configuration. For example:
buildscript {
repositories {
mavenCentral()
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:1.5.7.RELEASE")
classpath("com.example:custom-layout:1.0.0")
}
}
springBoot {
layoutFactory = new com.example.CustomLayoutFactory()
}
Note
If there is only one custom LayoutFactory on the build classpath and it is listed in META-INF/
spring.factories then it is unnecessary to explicitly set it in the springBoot configuration.
Layout factories are only used when no explicit layout is specified.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 231
67.8 Understanding how the Gradle plugin works
When spring-boot is applied to your Gradle project a default task named bootRepackage is created
automatically. The bootRepackage task depends on Gradle assemble task, and when executed, it
tries to find all jar artifacts whose qualifier is empty (i.e. tests and sources jars are automatically skipped).
Due to the fact that bootRepackage finds 'all' created jar artifacts, the order of Gradle task execution
is important. Most projects only create a single jar file, so usually this is not an issue; however, if you
are planning to create a more complex project setup, with custom Jar and BootRepackage tasks,
there are few tweaks to consider.
If you are 'just' creating custom jar files from your project you can simply disable default jar and
bootRepackage tasks:
jar.enabled = false
bootRepackage.enabled = false
Another option is to instruct the default bootRepackage task to only work with a default jar task.
bootRepackage.withJarTask = jar
If you have a default project setup where the main jar file is created and repackaged, 'and' you still
want to create additional custom jars, you can combine your custom repackage tasks together and use
dependsOn so that the bootJars task will run after the default bootRepackage task is executed:
task bootJars
bootJars.dependsOn = [clientBoot1,clientBoot2,clientBoot3]
build.dependsOn(bootJars)
All the above tweaks are usually used to avoid situations where an already created boot jar is repackaged
again. Repackaging an existing boot jar will not break anything, but you may find that it includes
unnecessary dependencies.
67.9 Publishing artifacts to a Maven repository using Gradle
If you are declaring dependencies without versions and you want to publish artifacts to a Maven
repository you will need to configure the Maven publication with details of Spring Boot’s dependency
management. This can be achieved by configuring it to publish poms that inherit from spring-boot-
starter-parent or that import dependency management from spring-boot-dependencies. The
exact details of this configuration depend on how you’re using Gradle and how you’re trying to publish
the artifacts.
Configuring Gradle to produce a pom that inherits dependency
management
The following is an example of configuring Gradle to generate a pom that inherits from spring-boot-
starter-parent. Please refer to the Gradle User Guide for further information.
uploadArchives {
repositories {
mavenDeployer {
pom {
project {
parent {
groupId "org.springframework.boot"
artifactId "spring-boot-starter-parent"
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 232
version "1.5.7.RELEASE"
}
}
}
}
}
}
Configuring Gradle to produce a pom that imports dependency
management
The following is an example of configuring Gradle to generate a pom that imports the dependency
management provided by spring-boot-dependencies. Please refer to the Gradle User Guide for
further information.
uploadArchives {
repositories {
mavenDeployer {
pom {
project {
dependencyManagement {
dependencies {
dependency {
groupId "org.springframework.boot"
artifactId "spring-boot-dependencies"
version "1.5.7.RELEASE"
type "pom"
scope "import"
}
}
}
}
}
}
}
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 233
68. 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:
<project xmlns:ivy="antlib:org.apache.ivy.ant"
xmlns:spring-boot="antlib:org.springframework.boot.ant"
name="myapp" default="build">
...
</project>
You’ll need to remember to start Ant using the -lib option, for example:
$ ant -lib <folder containing spring-boot-antlib-1.5.7.RELEASE.jar>
Tip
The “Using Spring Boot” section includes a more complete example of using Apache Ant with
spring-boot-antlib
68.1 Spring Boot Ant tasks
Once the spring-boot-antlib namespace has been declared, the following additional tasks are
available.
spring-boot:exejar
The exejar task can be used to creates 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 (default is first class found
declaring 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.
Examples
Specify start-class.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 234
<spring-boot:exejar destfile="target/my-application.jar"
classes="target/classes" start-class="com.foo.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>
68.2 spring-boot:findmainclass
The findmainclass task is used internally by exejar to locate a class declaring a main. You can
also use this task directly in your build if needed. 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
Find and log.
<findmainclass classesroot="target/classes" />
Find and set.
<findmainclass classesroot="target/classes" property="main-class" />
Override and set.
<findmainclass mainclass="com.foo.MainClass" property="main-class" />
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 235
69. Supporting other build systems
If you want to use a build tool other than Maven, Gradle or Ant, you will 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. You are also free to use this library directly yourself if you need to.
69.1 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.
69.2 Nested libraries
When repackaging an archive you can include references to dependency files using the
org.springframework.boot.loader.tools.Libraries interface. We don’t 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.
69.3 Finding a main class
If you don’t use Repackager.setMainClass() to specify a main class, the repackager will use ASM
to read class files and attempt 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.
69.4 Example repackage implementation
Here is a typical example repackage:
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));
}
});
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 236
70. What to read next
If you’re 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…’ type of questions that often arise
when using Spring Boot. This is by no means an exhaustive list, but it does cover quite a lot.
If you are having a specific problem that we don’t 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’re also more than happy to extend this section; If you want to add a ‘how-to’ you can send us a
pull request.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 238
71. Spring Boot application
71.1 Create your own FailureAnalyzer
FailureAnalyzer is a great way to intercept an exception on startup and turn it into a human-readable
message, wrapped into a FailureAnalysis. Spring Boot provides such analyzer for application
context related exceptions, JSR-303 validations and more. It is actually very easy to 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 can’t handle the exception, return null to give another implementation a chance to handle
the exception.
FailureAnalyzer implementations are to be registered in a META-INF/spring.factories: the
following registers ProjectConstraintViolationFailureAnalyzer:
org.springframework.boot.diagnostics.FailureAnalyzer=\
com.example.ProjectConstraintViolationFailureAnalyzer
71.2 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 will see it if you enable DEBUG logging output. If you use the spring-
boot-actuator there is also an autoconfig endpoint that renders the report in JSON. Use that to
debug the application and see what features have been added (and which not) by Spring Boot at runtime.
Many more questions can be answered by looking at the source code and the Javadoc. Some rules
of thumb:
• Look for classes called *AutoConfiguration and read their sources, in particular 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 autoconfig endpoint
(‘/autoconfig’ or the JMX equivalent) for the same information.
• Look for classes that are @ConfigurationProperties (e.g. ServerProperties) and read
from there the available external configuration options. The @ConfigurationProperties has
a name attribute which acts as a prefix to external properties, thus ServerProperties has
prefix="server" and its configuration properties are server.port, server.address etc. In a
running Actuator app look at the configprops endpoint.
• Look for use of RelaxedPropertyResolver to pull configuration values explicitly out of the
Environment. It often is used with a prefix.
• Look for @Value annotations that bind directly to the Environment. This is less flexible than the
RelaxedPropertyResolver approach, but does allow some relaxed binding, specifically for OS
environment variables (so CAPITALS_AND_UNDERSCORES are synonyms for period.separated).
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 239
• Look for @ConditionalOnExpression annotations that switch features on and off in response to
SpEL expressions, normally evaluated with placeholders resolved from the Environment.
71.3 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 ones:
• Programmatically per application by calling the addListeners and addInitializers methods
on SpringApplication before you run it.
• Declaratively per application by setting context.initializer.classes or
context.listener.classes.
• 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 (even some
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
using EnvironmentPostProcessor. Each implementation should be registered in META-INF/
spring.factories:
org.springframework.boot.env.EnvironmentPostProcessor=com.example.YourEnvironmentPostProcessor
The implementation can load arbitrary files and add them to the Environment. For instance, this
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, null);
}
catch (IOException ex) {
throw new IllegalStateException(
"Failed to load yaml configuration from " + path, ex);
}
}
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 240
Tip
The Environment will already have 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.
This 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
obviously defines another order.
Note
While using @PropertySource on your @SpringBootApplication seems convenient and
easy enough to load a custom resource in the Environment, we do not recommend it as
Spring Boot prepares the Environment before the ApplicationContext is refreshed. Any key
defined via @PropertySource will be loaded too late to have any effect on auto-configuration.
71.4 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.
71.5 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, then it’s easy with 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 just leave the servlet API dependencies off the
classpath. If you can’t do that (e.g. you are running 2 applications from the same code base) then you
can explicitly call setWebEnvironment(false) 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 241
72. Properties & configuration
72.1 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 using the existing build configuration instead. This is possible in both
Maven and Gradle.
Automatic property expansion using Maven
You can automatically expand properties from the Maven project using resource filtering. If you use
the spring-boot-starter-parent you can then refer to your Maven ‘project properties’ via @..@
placeholders, e.g.
app.encoding=@project.build.sourceEncoding@
app.java.version=@java.version@
Note
Only production configuration is filtered that way (i.e. no filtering is applied on src/test/
resources).
Tip
The spring-boot:run can add src/main/resources directly to the classpath (for hot
reloading purposes) if you enable the addResources flag. This circumvents the resource filtering
and this feature. You can use the exec:java goal instead or customize the plugin’s configuration,
see the plugin usage page for more details.
If you don’t use the starter parent, in your pom.xml you need (inside the <build/> element):
<resources>
<resource>
<directory>src/main/resources</directory>
<filtering>true</filtering>
</resource>
</resources>
and (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>
Note
The useDefaultDelimiters property is important if you are using standard Spring
placeholders in your configuration (e.g. ${foo}). These may be expanded by the build if that
property is not set to false.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 242
Automatic property expansion using Gradle
You can automatically expand properties from the Gradle project by configuring the Java plugin’s
processResources task to do so:
processResources {
expand(project.properties)
}
You can then refer to your Gradle project’s properties via placeholders, e.g.
app.name=${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 the Spring property placeholders
need to be escaped like \${..}.
72.2 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. Or you can externalize the configuration using properties
in spring.main.*. E.g. in application.properties you might have.
spring.main.web-environment=false
spring.main.banner-mode=off
and then the Spring Boot banner will not be printed on startup, and the application will not be a web
application.
Note
The example above also demonstrates how flexible binding allows the use of underscores (_) as
well as dashes (-) in property names.
Properties defined in external configuration overrides the values specified via the Java API with the
notable exception of the sources used to create the ApplicationContext. Let’s consider this
application
new SpringApplicationBuilder()
.bannerMode(Banner.Mode.OFF)
.sources(demo.MyApp.class)
.run(args);
used with the following configuration:
spring.main.sources=com.acme.Config,com.acme.ExtraConfig
spring.main.banner-mode=console
The actual application will now show the banner (as overridden by configuration) and use
three sources for the ApplicationContext (in that order): demo.MyApp, com.acme.Config,
com.acme.ExtraConfig.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 243
72.3 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 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, and 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 using
the default locations (e.g. application.properties), system properties, environment variables or
the command line.
You can also provide 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) is the file to load (e.g. 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 will always load application.properties
as described above. If YAML is used then files with the ‘.yml’ extension are also added to the list by
default.
Spring Boot logs the configuration files that are loaded at DEBUG level and the candidates it has not
found at TRACE level.
See ConfigFileApplicationListener for more detail.
72.4 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 easily enable this by using placeholders in
application.properties, e.g.
server.port=${port:8080}
Tip
If you are inheriting from the spring-boot-starter-parent POM, the default filter token
of the maven-resources-plugins has been changed from ${*} to @ (i.e. @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.
Note
In this specific case the port binding will work in a PaaS environment like Heroku and Cloud
Foundry, since in those two platforms the PORT environment variable is set automatically and
Spring can bind to capitalized synonyms for Environment properties.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 244
72.5 Use YAML for external properties
YAML is a superset of JSON and as such is a very convenient syntax for storing external properties
in a hierarchical format. E.g.
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 stick it in the root of your classpath, and also 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 1-level deep and has period-separated
keys, a lot like people are used to with Properties files in Java.
The example YAML above corresponds to an 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.
72.6 Set the active Spring profiles
The Spring Environment has an API for this, but normally you would set a System property
(spring.profiles.active) or an OS environment variable (SPRING_PROFILES_ACTIVE). E.g.
launch your application with a -D argument (remember to put it before the main class or jar archive):
$ 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, e.g.
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.
72.7 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 (comma-separated list
of profiles) is fed into the Spring Environment.acceptsProfiles() and if any of those profiles is
active that document is included in the final merge (otherwise not).
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 245
Example:
server:
port: 9000
---
spring:
profiles: development
server:
port: 9001
---
spring:
profiles: production
server:
port: 0
In this example the default port is 9000, but if the Spring profile ‘development’ is active then the port is
9001, and if ‘production’ is active then it is 0.
The YAML documents are merged in the order they are encountered (so later values override earlier
ones).
To do the same thing with properties files you can use application-${profile}.properties to
specify profile-specific values.
72.8 Discover built-in options for external properties
Spring Boot binds external properties from application.properties (or .yml) (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
RelaxedPropertyResolver.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 246
73. Embedded servlet containers
73.1 Add a Servlet, Filter or Listener to an application
There are two ways to add Servlet, Filter, ServletContextListener and the other listeners
supported by the Servlet spec to your application. You can either provide Spring beans for them, or
enable scanning for Servlet components.
Add a Servlet, Filter or Listener using a Spring bean
To add a Servlet, Filter, or Servlet *Listener provide a @Bean definition for it. This can be very
useful when you want to inject configuration or dependencies. However, you must be very careful that
they don’t cause eager initialization of too many other beans because they have to be installed in the
container very early in the application lifecycle (e.g. it’s not a good idea to have them depend on your
DataSource or JPA configuration). You can work around restrictions like that by initializing them 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 ServletRegistrationBean instead of or as well as the underlying
component.
Note
If no dispatcherType is specified on a filter registration, it will match FORWARD,INCLUDE and
REQUEST. If async has been enabled, it will match ASYNC as well.
If you are migrating a filter that has no dispatcher element in web.xml you will need to specify
a dispatcherType yourself:
@Bean
public FilterRegistrationBean myFilterRegistration() {
FilterRegistrationBean registration = new FilterRegistrationBean();
registration.setDispatcherTypes(DispatcherType.REQUEST);
....
return registration;
}
Disable registration of a Servlet or Filter
As described above any Servlet or Filter beans will be 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. For example:
@Bean
public FilterRegistrationBean registration(MyFilter filter) {
FilterRegistrationBean registration = new FilterRegistrationBean(filter);
registration.setEnabled(false);
return registration;
}
Add Servlets, Filters, and Listeners using classpath scanning
@WebServlet, @WebFilter, and @WebListener annotated classes can be automatically
registered with an embedded servlet container by annotating a @Configuration class with
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 247
@ServletComponentScan and specifying the package(s) containing the components that you want
to register. By default, @ServletComponentScan will scan from the package of the annotated class.
73.2 Change the HTTP port
In a standalone application the main HTTP port defaults to 8080, but can be set with server.port (e.g.
in application.properties or as a System property). Thanks to relaxed binding of Environment
values you can also use SERVER_PORT (e.g. as an OS environment variable).
To switch off the HTTP endpoints completely, but still create a WebApplicationContext, use
server.port=-1 (this is sometimes useful for testing).
For more details look at the section called “Customizing embedded servlet containers” in the ‘Spring
Boot features’ section, or the ServerProperties source code.
73.3 Use a random unassigned HTTP port
To scan for a free port (using OS natives to prevent clashes) use server.port=0.
73.4 Discover the HTTP port at runtime
You can access the port the server is running on from log output or from
the EmbeddedWebApplicationContext via its EmbeddedServletContainer. The best
way to get that and be sure that it has initialized is to add a @Bean of
type ApplicationListener<EmbeddedServletContainerInitializedEvent> 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 using the @LocalServerPort annotation. For example:
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(webEnvironment=WebEnvironment.RANDOM_PORT)
public class MyWebIntegrationTests {
@Autowired
EmbeddedWebApplicationContext server;
@LocalServerPort
int port;
// ...
}
Note
@LocalServerPort is a meta-annotation for @Value("${local.server.port}"). Don’t try
to inject the port in a regular application. As we just saw, the value is only set once the container
has initialized; contrary to a test, application code callbacks are processed early (i.e. before the
value is actually available).
73.5 Configure SSL
SSL can be configured declaratively by setting the various server.ssl.* properties, typically in
application.properties or application.yml. For example:
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 248
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 like the example above means the application will no longer support plain HTTP
connector at port 8080. Spring Boot doesn’t support the configuration of both an HTTP connector and
an HTTPS connector via application.properties. If you want to have both then you’ll need to
configure one of them programmatically. It’s recommended to use 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.
73.6 Configure Access Logging
Access logs can be configured for Tomcat and Undertow via their respective namespaces.
For instance, the following logs 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 dir and said directory
is a temp directory by default so you may want to fix Tomcat’s base directory or use an absolute
path for the logs. In the example above, the logs will be available in my-tomcat/logs relative
to the working directory of the application.
Access logging for undertow can be configured in a similar fashion
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. This can be
customized via server.undertow.accesslog.directory.
73.7 Use 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 via a contract with the proxy, which
will add 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 do this
out of the box) the absolute links should be rendered correctly as long as server.use-forward-
headers is set to true in your application.properties.
Note
If your application is running in Cloud Foundry or Heroku the server.use-forward-headers
property will default to true if not specified. In all other instances it defaults to false.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 249
Customize Tomcat’s proxy configuration
If you are using Tomcat you can additionally configure the names of the headers used to carry
“forwarded” information:
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, e.g.
server.tomcat.internal-proxies=192\\.168\\.\\d{1,3}\\.\\d{1,3}
Note
The double backslashes are only required when you’re using a properties file for configuration.
If you are using YAML, single backslashes are sufficient and a value that’s equivalent to the one
shown above would be 192\.168\.\d{1,3}\.\d{1,3}.
Note
You can trust all proxies by setting the internal-proxies to empty (but don’t do this in
production).
You can take complete control of the configuration of Tomcat’s RemoteIpValve by switching the
automatic one off (i.e. set server.use-forward-headers=false) and adding a new valve instance
in a TomcatEmbeddedServletContainerFactory bean.
73.8 Configure Tomcat
Generally you can follow the advice from Section 72.8, “Discover built-in options for external properties”
about @ConfigurationProperties (ServerProperties is the main one here), but also look
at EmbeddedServletContainerCustomizer and various Tomcat-specific *Customizers that
you can add in one of those. The Tomcat APIs are quite rich so once you have access to the
TomcatEmbeddedServletContainerFactory you can modify it in a number of ways. Or the nuclear
option is to add your own TomcatEmbeddedServletContainerFactory.
73.9 Enable Multiple Connectors with Tomcat
Add a org.apache.catalina.connector.Connector to the
TomcatEmbeddedServletContainerFactory which can allow multiple connectors, e.g. HTTP and
HTTPS connector:
@Bean
public EmbeddedServletContainerFactory servletContainer() {
TomcatEmbeddedServletContainerFactory tomcat = new TomcatEmbeddedServletContainerFactory();
tomcat.addAdditionalTomcatConnectors(createSslConnector());
return tomcat;
}
private Connector createSslConnector() {
Connector connector = new Connector("org.apache.coyote.http11.Http11NioProtocol");
Http11NioProtocol protocol = (Http11NioProtocol) connector.getProtocolHandler();
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 250
try {
File keystore = new ClassPathResource("keystore").getFile();
File truststore = new ClassPathResource("keystore").getFile();
connector.setScheme("https");
connector.setSecure(true);
connector.setPort(8443);
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);
}
}
73.10 Use Tomcat’s LegacyCookieProcessor
The embedded Tomcat used by Spring Boot does not support "Version 0" of the Cookie format out of
the box, and 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’re unable to change the way that cookies are written, you can instead
configure Tomcat to use a LegacyCookieProcessor. To switch to the LegacyCookieProcessor
use an EmbeddedServletContainerCustomizer bean that adds a TomcatContextCustomizer:
@Bean
public EmbeddedServletContainerCustomizer cookieProcessorCustomizer() {
return new EmbeddedServletContainerCustomizer() {
@Override
public void customize(ConfigurableEmbeddedServletContainer container) {
if (container instanceof TomcatEmbeddedServletContainerFactory) {
((TomcatEmbeddedServletContainerFactory) container)
.addContextCustomizers(new TomcatContextCustomizer() {
@Override
public void customize(Context context) {
context.setCookieProcessor(new LegacyCookieProcessor());
}
});
}
}
};
}
73.11 Use Jetty instead of Tomcat
The Spring Boot starters (spring-boot-starter-web in particular) use Tomcat as an embedded
container by default. You need to exclude those dependencies and include the Jetty one instead. Spring
Boot provides Tomcat and Jetty dependencies bundled together as separate starters to help make this
process as easy as possible.
Example in Maven:
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 251
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jetty</artifactId>
</dependency>
Example in Gradle:
configurations {
compile.exclude module: "spring-boot-starter-tomcat"
}
dependencies {
compile("org.springframework.boot:spring-boot-starter-web:1.5.7.RELEASE")
compile("org.springframework.boot:spring-boot-starter-jetty:1.5.7.RELEASE")
// ...
}
73.12 Configure Jetty
Generally you can follow the advice from Section 72.8, “Discover built-in options for external properties”
about @ConfigurationProperties (ServerProperties is the main one here), but also look at
EmbeddedServletContainerCustomizer. The Jetty APIs are quite rich so once you have access
to the JettyEmbeddedServletContainerFactory you can modify it in a number of ways. Or the
nuclear option is to add your own JettyEmbeddedServletContainerFactory.
73.13 Use Undertow instead of Tomcat
Using Undertow instead of Tomcat is very similar to using Jetty instead of Tomcat. You need to exclude
the Tomcat dependencies and include the Undertow starter instead.
Example in Maven:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-undertow</artifactId>
</dependency>
Example in Gradle:
configurations {
compile.exclude module: "spring-boot-starter-tomcat"
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 252
dependencies {
compile("org.springframework.boot:spring-boot-starter-web:1.5.7.RELEASE")
compile("org.springframework.boot:spring-boot-starter-undertow:1.5.7.RELEASE")
// ...
}
73.14 Configure Undertow
Generally you can follow the advice from Section 72.8, “Discover built-in options for external properties”
about @ConfigurationProperties (ServerProperties and ServerProperties.Undertow
are the main ones here), but also look at EmbeddedServletContainerCustomizer. Once
you have access to the UndertowEmbeddedServletContainerFactory you can use an
UndertowBuilderCustomizer to modify Undertow’s configuration to meet your needs. Or the
nuclear option is to add your own UndertowEmbeddedServletContainerFactory.
73.15 Enable Multiple Listeners with Undertow
Add an UndertowBuilderCustomizer to the UndertowEmbeddedServletContainerFactory
and add a listener to the Builder:
@Bean
public UndertowEmbeddedServletContainerFactory embeddedServletContainerFactory() {
UndertowEmbeddedServletContainerFactory factory = new UndertowEmbeddedServletContainerFactory();
factory.addBuilderCustomizers(new UndertowBuilderCustomizer() {
@Override
public void customize(Builder builder) {
builder.addHttpListener(8080, "0.0.0.0");
}
});
return factory;
}
73.16 Use Tomcat 7.x or 8.0
Tomcat 7 & 8.0 work with Spring Boot, but the default is to use Tomcat 8.5. If you cannot use Tomcat
8.5 (for example, because you are using Java 1.6) you will need to change your classpath to reference
a different version.
Use Tomcat 7.x or 8.0 with Maven
If you are using the starters and parent you can change the Tomcat version property and additionally
import tomcat-juli. E.g. for a simple webapp or service:
<properties>
<tomcat.version>7.0.59</tomcat.version>
</properties>
<dependencies>
...
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.apache.tomcat</groupId>
<artifactId>tomcat-juli</artifactId>
<version>${tomcat.version}</version>
</dependency>
...
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 253
</dependencies>
Use Tomcat 7.x or 8.0 with Gradle
With Gradle, you can change the Tomcat version by setting the tomcat.version property and then
additionally include tomcat-juli:
ext['tomcat.version'] = '7.0.59'
dependencies {
compile 'org.springframework.boot:spring-boot-starter-web'
compile group:'org.apache.tomcat', name:'tomcat-juli', version:property('tomcat.version')
}
73.17 Use Jetty 9.2
Jetty 9.2 works with Spring Boot, but the default is to use Jetty 9.3. If you cannot use Jetty 9.3 (for
example, because you are using Java 7) you will need to change your classpath to reference Jetty 9.2.
Use Jetty 9.2 with Maven
If you are using the starters and parent you can just add the Jetty starter and override the
jetty.version property:
<properties>
<jetty.version>9.2.17.v20160517</jetty.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jetty</artifactId>
</dependency>
</dependencies>
Use Jetty 9.2 with Gradle
You can set the jetty.version property. For example, for a simple webapp or service:
ext['jetty.version'] = '9.2.17.v20160517'
dependencies {
compile ('org.springframework.boot:spring-boot-starter-web') {
exclude group: 'org.springframework.boot', module: 'spring-boot-starter-tomcat'
}
compile ('org.springframework.boot:spring-boot-starter-jetty')
}
73.18 Use Jetty 8
Jetty 8 works with Spring Boot, but the default is to use Jetty 9.3. If you cannot use Jetty 9.3 (for example,
because you are using Java 1.6) you will need to change your classpath to reference Jetty 8. You will
also need to exclude Jetty’s WebSocket-related dependencies.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 254
Use Jetty 8 with Maven
If you are using the starters and parent you can just add the Jetty starter with the required WebSocket
exclusion and change the version properties, e.g. for a simple webapp or service:
<properties>
<jetty.version>8.1.15.v20140411</jetty.version>
<jetty-jsp.version>2.2.0.v201112011158</jetty-jsp.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jetty</artifactId>
<exclusions>
<exclusion>
<groupId>org.eclipse.jetty.websocket</groupId>
<artifactId>*</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
Use Jetty 8 with Gradle
You can set the jetty.version property and exclude the WebSocket dependency, e.g. for a simple
webapp or service:
ext['jetty.version'] = '8.1.15.v20140411'
dependencies {
compile ('org.springframework.boot:spring-boot-starter-web') {
exclude group: 'org.springframework.boot', module: 'spring-boot-starter-tomcat'
}
compile ('org.springframework.boot:spring-boot-starter-jetty') {
exclude group: 'org.eclipse.jetty.websocket'
}
}
73.19 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:
@Bean
public ServerEndpointExporter serverEndpointExporter() {
return new ServerEndpointExporter();
}
This bean will register 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 255
73.20 Enable HTTP response compression
HTTP response compression is supported by Jetty, Tomcat, and Undertow. It can be enabled via
application.properties:
server.compression.enabled=true
By default, responses must be at least 2048 bytes in length for compression to be performed. This can
be configured using the server.compression.min-response-size property.
By default, responses will only be compressed if their content type is one of the following:
•text/html
•text/xml
•text/plain
•text/css
This can be configured using the server.compression.mime-types property.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 256
74. Spring MVC
74.1 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. For example:
@RestController
public class MyController {
@RequestMapping("/thing")
public MyThing thing() {
return new MyThing();
}
}
As long as MyThing can be serialized by Jackson2 (e.g. a normal POJO or Groovy object) then
localhost:8080/thing will serve a JSON representation of it by default. Sometimes in a browser
you might see XML responses because browsers tend to send accept headers that prefer XML.
74.2 Write an XML REST service
If you have the Jackson XML extension (jackson-dataformat-xml) on the classpath, it will be used
to render XML responses and the very same example as we used for JSON would work. To use it, 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’s faster than the default StAX implementation
provided by the JDK and also adds pretty print support and improved namespace handling:
<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) will be used, with
the additional requirement to have MyThing annotated as @XmlRootElement:
@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).
74.3 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 257
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
Spring Boot has also some features to make it easier to customize this behavior.
You can configure the ObjectMapper and XmlMapper instances 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 which map onto properties in the
environment:
Jackson enum Environment property
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 doesn’t 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 will apply to any mappers created 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 and
Boot’s own customizer has an order of 0, allowing additional customization to be applied both before
and after Boot’s customization.
Any beans of type com.fasterxml.jackson.databind.Module will be automatically registered
with the auto-configured Jackson2ObjectMapperBuilder and 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.
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
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 258
Jackson2ObjectMapperBuilder @Bean. Note that in either case this will disable all auto-
configuration of the ObjectMapper.
If you provide any @Beans of type MappingJackson2HttpMessageConverter then they will
replace the default value in the MVC configuration. Also, a convenience bean is provided of type
HttpMessageConverters (always available if you use the default MVC configuration) which has
some useful methods to access the default and user-enhanced message converters.
See also the Section 74.4, “Customize the @ResponseBody rendering” section and the
WebMvcAutoConfiguration source code for more details.
74.4 Customize the @ResponseBody rendering
Spring uses HttpMessageConverters to render @ResponseBody (or responses from
@RestController). You can contribute additional converters by simply adding beans of that type in a
Spring Boot context. If a bean you add is of a type that would have been included by default anyway (like
MappingJackson2HttpMessageConverter for JSON conversions) then it will replace the default
value. A convenience bean is provided of type HttpMessageConverters (always available if you
use the default MVC configuration) which has some useful methods to access the default and user-
enhanced message converters (useful, for example if you want to manually inject them into a custom
RestTemplate).
As in normal MVC usage, any WebMvcConfigurerAdapter beans that you provide can also
contribute converters by overriding the configureMessageConverters method, but 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, then you
can take control completely and do everything manually using getMessageConverters from
WebMvcConfigurationSupport.
See the WebMvcAutoConfiguration source code for more details.
74.5 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 file of 1MB per file and a maximum of
10MB of file data in a single request. You may override these values, as well as the location to which
intermediate data is stored (e.g., to the /tmp directory) and the threshold past which data is flushed to
disk by using the properties exposed in the MultipartProperties class. If you want to specify that
files be unlimited, for example, set the spring.http.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.
74.6 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, but of course you may lose some of the other Boot MVC
features. To add your own servlet and map it to the root resource just declare a @Bean of type Servlet
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 259
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).
74.7 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. This will leave all MVC configuration in your
hands.
74.8 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 are
adding 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 with bean id ‘defaultViewResolver’. This one locates
physical resources that can be rendered using the DefaultServlet (e.g. static resources and JSP
pages if you are using 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 (defaults are both empty, but accessible for
external configuration via spring.mvc.view.prefix and spring.mvc.view.suffix). It can
be overridden by providing a bean of the same type.
• A BeanNameViewResolver with id ‘beanNameViewResolver’. This is a useful member of the view
resolver chain and will pick up any beans with the same name as the View being resolved. It shouldn’t
be necessary to override or replace it.
• A ContentNegotiatingViewResolver with id ‘viewResolver’ is only added 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 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 will also have a ThymeleafViewResolver with id
‘thymeleafViewResolver’. It looks for resources by surrounding the view name with a prefix and
suffix (externalized to spring.thymeleaf.prefix and spring.thymeleaf.suffix, defaults
‘classpath:/templates/’ and ‘.html’ respectively). It can be overridden by providing a bean of the same
name.
• If you use FreeMarker you will also have a FreeMarkerViewResolver with id
‘freeMarkerViewResolver’. It looks for resources in a loader path (externalized to
spring.freemarker.templateLoaderPath, default ‘classpath:/templates/’) by surrounding
the view name with a prefix and suffix (externalized to spring.freemarker.prefix and
spring.freemarker.suffix, with empty and ‘.ftl’ defaults respectively). It can be overridden by
providing a bean of the same name.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 260
• If you use Groovy templates (actually if groovy-templates is on your classpath) you will
also have a GroovyMarkupViewResolver with id ‘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, defaults
‘classpath:/templates/’ and ‘.tpl’ respectively). It can be overridden by providing a bean of the same
name.
Check out WebMvcAutoConfiguration, ThymeleafAutoConfiguration,
FreeMarkerAutoConfiguration and GroovyTemplateAutoConfiguration
74.9 Use Thymeleaf 3
By default, spring-boot-starter-thymeleaf uses Thymeleaf 2.1. If you are using the spring-
boot-starter-parent, you can use Thymeleaf 3 by overriding the thymeleaf.version and
thymeleaf-layout-dialect.version properties, for example:
<properties>
<thymeleaf.version>3.0.2.RELEASE</thymeleaf.version>
<thymeleaf-layout-dialect.version>2.1.1</thymeleaf-layout-dialect.version>
</properties>
Note
if you are managing dependencies yourself, look at spring-boot-dependencies for the list
of artifacts that are related to those two versions.
To avoid a warning message about the HTML 5 template mode being deprecated and
the HTML template mode being used instead, you may also want to explicitly configure
spring.thymeleaf.mode to be HTML, for example:
spring.thymeleaf.mode: HTML
Please refer to the Thymeleaf 3 sample to see this in action.
If you are using any of the other auto-configured Thymeleaf Extras (Spring Security, Data Attribute, or
Java 8 Time) you should also override each of their versions to one that is compatible with Thymeleaf
3.0.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 261
75. HTTP clients
75.1 Configure RestTemplate to use a proxy
As described in Section 33.1, “RestTemplate customization”, a RestTemplateCustomizer can be
used 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. Here’s an example of configuring 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));
}
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 262
76. Logging
Spring Boot has no mandatory logging dependency, except for the Commons Logging API, of which
there are many implementations to choose from. To use Logback you need to include it and jcl-over-
slf4j (which implements the Commons Logging API) 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 only need spring-boot-starter-web since it depends transitively on the logging starter. For
example, using Maven:
<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 then you can do
that in application.properties using the "logging.level" prefix, e.g.
logging.level.org.springframework.web=DEBUG
logging.level.org.hibernate=ERROR
You can also set the location of a file to log to (in addition to the console) 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 (e.g. classpath:logback.xml for Logback), but
you can set the location of the config file using the "logging.config" property.
76.1 Configure Logback for logging
If you put a logback.xml in the root of your classpath it will be picked up from there (or 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 just want to set levels, e.g.
<?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 that base.xml in the spring-boot jar, you will see that it uses some useful System
properties which the LoggingSystem takes care of creating for you. These are:
•${PID} the current process ID.
•${LOG_FILE} if logging.file was set in Boot’s external configuration.
•${LOG_PATH} if logging.path was set (representing a directory for log files to live in).
•${LOG_EXCEPTION_CONVERSION_WORD} if logging.exception-conversion-word was set
in Boot’s external configuration.
Spring Boot also provides some nice ANSI colour terminal output on a console (but not in a log file)
using a custom Logback converter. See the default base.xml configuration for details.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 263
If Groovy is on the classpath you should be able to configure Logback with logback.groovy as well
(it will be given preference if present).
Configure logback for file only output
If you want to disable console logging and write output only to a file you need a custom logback-
spring.xml that imports file-appender.xml but not console-appender.xml:
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<include resource="org/springframework/boot/logging/logback/defaults.xml" />
<property name="LOG_FILE" value="${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:
logging.file=myapplication.log
76.2 Configure Log4j for logging
Spring Boot supports Log4j 2 for logging configuration if it is on the classpath. If you are using the
starters for assembling dependencies that means you have to exclude Logback and then include log4j 2
instead. If you aren’t using the starters then you need to provide jcl-over-slf4j (at least) in addition
to Log4j 2.
The simplest path is probably through the starters, even though it requires some jiggling with
excludes, .e.g. 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>
Note
The use of the Log4j starters gathers together the dependencies for common logging requirements
(e.g. including 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 264
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:
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
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 265
77. Data Access
77.1 Configure a custom DataSource
To configure your own DataSource define a @Bean of that type in your configuration. Spring Boot
will reuse your DataSource anywhere one is required, including database initialization. If you need to
externalize some settings, you can easily bind your DataSource to the environment (see the section
called “Third-party configuration”).
@Bean
@ConfigurationProperties(prefix="app.datasource")
public DataSource dataSource() {
return new FancyDataSource();
}
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 will be bound automatically before the DataSource is made available
to other components. The regular database initialization will also happen (so the relevant sub-set of
spring.datasource.* can still be used with your custom configuration).
You can apply the same principle if you are configuring a custom JNDI DataSource:
@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 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.
@Bean
@ConfigurationProperties("app.datasource")
public DataSource dataSource() {
return DataSourceBuilder.create().build();
}
To run an app with that DataSource, all that is needed really 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.
app.datasource.url=jdbc:mysql://localhost/test
app.datasource.username=dbuser
app.datasource.password=dbpass
app.datasource.pool-size=30
There is a catch however. 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
(The DataSource interface doesn’t expose any property). Also, if you happen to only have Hikari on
the classpath, this basic setup will not work because Hikari has no url parameter (but a jdbcUrl
parameter). You will have to rewrite your configuration as follows:
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 266
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 won’t be able to change the implementation at runtime but the list of options
will be explicit.
@Bean
@ConfigurationProperties("app.datasource")
public HikariDataSource dataSource() {
return (HikariDataSource) DataSourceBuilder.create()
.type(HikariDataSource.class).build();
}
You can even go further by leveraging what DataSourceProperties does for you, that is providing
a default embedded database if no url is provided with a sensible username and password for it. You
can easily initialize a DataSourceBuilder from the state of any DataSourceProperties so you
could just as well inject the one Spring Boot creates automatically. However, that would split your
configuration in 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:
@Bean
@Primary
@ConfigurationProperties("app.datasource")
public DataSourceProperties dataSourceProperties() {
return new DataSourceProperties();
}
@Bean
@ConfigurationProperties("app.datasource")
public HikariDataSource dataSource(DataSourceProperties properties) {
return (HikariDataSource) properties.initializeDataSourceBuilder()
.type(HikariDataSource.class).build();
}
This setup puts you in pair 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 like this:
app.datasource.url=jdbc:mysql://localhost/test
app.datasource.username=dbuser
app.datasource.password=dbpass
app.datasource.maximum-pool-size=30
Note
Because your custom configuration chooses to go with Hikari, app.datasource.type will have
no effect. In practice the builder will be 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 267
77.2 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 @Primary as various auto-
configurations down the road expect to be able to get one by type.
If you create your own DataSource, the auto-configuration will back off. In the example below, we
provide the exact same features set than what the auto-configuration provides on the primary data
source:
@Bean
@Primary
@ConfigurationProperties("app.datasource.foo")
public DataSourceProperties fooDataSourceProperties() {
return new DataSourceProperties();
}
@Bean
@Primary
@ConfigurationProperties("app.datasource.foo")
public DataSource fooDataSource() {
return fooDataSourceProperties().initializeDataSourceBuilder().build();
}
@Bean
@ConfigurationProperties("app.datasource.bar")
public BasicDataSource barDataSource() {
return (BasicDataSource) DataSourceBuilder.create()
.type(BasicDataSource.class).build();
}
Tip
fooDataSourceProperties has to be flagged @Primary so that the database initializer
feature uses your copy (should you use that).
Both data sources are also bound for advanced customizations. For instance you could configure them
as follows:
app.datasource.foo.type=com.zaxxer.hikari.HikariDataSource
app.datasource.foo.maximum-pool-size=30
app.datasource.bar.url=jdbc:mysql://localhost/test
app.datasource.bar.username=dbuser
app.datasource.bar.password=dbpass
app.datasource.bar.max-total=30
Of course, you can apply the same concept to the secondary DataSource as well:
@Bean
@Primary
@ConfigurationProperties("app.datasource.foo")
public DataSourceProperties fooDataSourceProperties() {
return new DataSourceProperties();
}
@Bean
@Primary
@ConfigurationProperties("app.datasource.foo")
public DataSource fooDataSource() {
return fooDataSourceProperties().initializeDataSourceBuilder().build();
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 268
@Bean
@ConfigurationProperties("app.datasource.bar")
public DataSourceProperties barDataSourceProperties() {
return new DataSourceProperties();
}
@Bean
@ConfigurationProperties("app.datasource.bar")
public DataSource barDataSource() {
return barDataSourceProperties().initializeDataSourceBuilder().build();
}
This final example configures two data sources on custom namespaces with the same logic than what
Spring Boot would do in auto-configuration.
77.3 Use Spring Data repositories
Spring Data can create implementations for you of @Repository interfaces of various flavors. Spring
Boot will handle 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 will 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), create some repository interfaces to handle your @Entity objects. Examples
are in the JPA sample or 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).
77.4 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, e.g.
@Configuration
@EnableAutoConfiguration
@EntityScan(basePackageClasses=City.class)
public class Application {
//...
}
77.5 Configure JPA properties
Spring Data JPA already provides some vendor-independent configuration options (e.g. for SQL
logging) and Spring Boot exposes those, and a few more for hibernate as external configuration
properties. Some of them are automatically detected according to the context so you shouldn’t have
to set them.
The spring.jpa.hibernate.ddl-auto is a special case in that it has different defaults
depending on whether you are using an embedded database (create-drop) or not (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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 269
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 need. In that case, you can
either set spring.jpa.database to default to let Hibernate figure things out or set the dialect
using the spring.jpa.database-platform property.
The most common options to set are:
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.
77.6 Configure Hibernate Naming Strategy
Spring Boot provides a consistent naming strategy regardless of the Hibernate generation
that you are using. If you are using Hibernate 4, you can customize it using
spring.jpa.hibernate.naming.strategy; Hibernate 5 defines a Physical and Implicit
naming strategies.
Spring Boot configures SpringPhysicalNamingStrategy by default. This implementation provides
the same table structure as Hibernate 4: all dots are replaced by underscores and camel cases are
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.
Concretely, a TelephoneNumber entity will be mapped to the telephone_number table.
If you’d rather use Hibernate 5’s default instead, set the following property:
spring.jpa.hibernate.naming.physical-
strategy=org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl
See HibernateJpaAutoConfiguration and JpaBaseConfiguration for more details.
77.7 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 based on
the presence of a bean of that type.
77.8 Use Two EntityManagers
Even if the default EntityManagerFactory works fine, you will need to define a new one because
otherwise the presence of the second bean of that type will switch off the default. To make it easy to do
that you can use the convenient EntityManagerBuilder provided by Spring Boot, or if you prefer
you can just use the LocalContainerEntityManagerFactoryBean directly from Spring ORM.
Example:
// add two data sources configured as above
@Bean
public LocalContainerEntityManagerFactoryBean customerEntityManagerFactory(
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 270
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. One of them could be picked up by the
default JpaTransactionManager in Spring Boot if you mark it as @Primary. The other would have
to be explicitly injected into a new instance. Or you might be able to use a JTA transaction manager
spanning both.
If you are using Spring Data, you need to configure @EnableJpaRepositories accordingly:
@Configuration
@EnableJpaRepositories(basePackageClasses = Customer.class,
entityManagerFactoryRef = "customerEntityManagerFactory")
public class CustomerConfiguration {
...
}
@Configuration
@EnableJpaRepositories(basePackageClasses = Order.class,
entityManagerFactoryRef = "orderEntityManagerFactory")
public class OrderConfiguration {
...
}
77.9 Use a traditional persistence.xml
Spring doesn’t require the use of XML to configure the JPA provider, and Spring Boot assumes you
want to take advantage of that feature. If you prefer to use persistence.xml then you need to define
your own @Bean of type LocalEntityManagerFactoryBean (with id ‘entityManagerFactory’, and
set the persistence unit name there.
See JpaBaseConfiguration for the default settings.
77.10 Use Spring Data JPA and Mongo repositories
Spring Data JPA and Spring Data Mongo can both create Repository implementations for you
automatically. If they are both present on the classpath, you might have to do some extra configuration
to tell Spring Boot which one (or both) you want to create repositories for you. The most explicit way
to do that is to use the standard Spring Data @Enable*Repositories and tell it the location of your
Repository interfaces (where ‘*’ is ‘Jpa’ or ‘Mongo’ or both).
There are also flags spring.data.*.repositories.enabled that you can use to switch the auto-
configured repositories on and off in external configuration. This is useful for instance in case you want
to switch off the Mongo repositories and still use the auto-configured MongoTemplate.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 271
The same obstacle and the same features exist for other auto-configured Spring Data repository types
(Elasticsearch, Solr). Just change the names of the annotations and flags respectively.
77.11 Expose Spring Data repositories as REST endpoint
Spring Data REST can expose the Repository implementations as REST endpoints for you as long
as Spring MVC has been enabled for the application.
Spring Boot exposes as 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 don’t specify any order on your custom RepositoryRestConfigurer it will run after the
one Spring Boot uses internally. If you need to specify an order, make sure it is higher than 0.
77.12 Configure a component that is used by JPA
If you want to configure a component that will be used by JPA then you need to ensure that the
component is initialized before JPA. Where the component is auto-configured Spring Boot will take care
of this for you. For example, when Flyway is auto-configured, Hibernate is configured to depend upon
Flyway so that the latter has a chance to initialize the database before Hibernate tries to use it.
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 are using Hibernate Search with Elasticsearch as
its index manager then any EntityManagerFactory beans must be configured to depend on the
elasticsearchClient bean:
/**
* {@link EntityManagerFactoryDependsOnPostProcessor} that ensures that
* {@link EntityManagerFactory} beans depend on the {@code elasticsearchClient} bean.
*/
@Configuration
static class ElasticsearchJpaDependencyConfiguration
extends EntityManagerFactoryDependsOnPostProcessor {
ElasticsearchJpaDependencyConfiguration() {
super("elasticsearchClient");
}
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 272
78. Database initialization
An SQL database can be initialized in different ways depending on what your stack is. Or of course you
can do it manually as long as the database is a separate process.
78.1 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. See below for more detail.
78.2 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, create-drop. Spring Boot chooses a default value
for you based on whether it thinks your database is embedded (default create-drop) or not (default
none). An embedded database is detected by looking at the Connection type: hsqldb, h2 and derby
are embedded, the rest are not. Be careful when switching from in-memory to a ‘real’ database that you
don’t 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 will be 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 probably not something you want to
be on the classpath in production. It is a Hibernate feature (nothing to do with Spring).
78.3 Initialize a database using Spring JDBC
Spring JDBC has a DataSource initializer feature. Spring Boot enables it by default and loads
SQL from the standard locations schema.sql and data.sql (in the root of the classpath). In
addition Spring Boot will load the schema-${platform}.sql and data-${platform}.sql files
(if present), where platform is the value of spring.datasource.platform, e.g. you might
choose to set it to the vendor name of the database (hsqldb, h2, oracle, mysql, postgresql
etc.). Spring Boot enables the fail-fast feature of the Spring JDBC initializer by default, so if the
scripts cause exceptions the application will fail to start. The script locations can be changed by
setting spring.datasource.schema and spring.datasource.data, and neither location will be
processed if spring.datasource.initialize=false.
To disable the fail-fast you can set spring.datasource.continue-on-error=true. This can be
useful once an application has matured and been deployed a few times, since the scripts can act as
‘poor man’s migrations’ — inserts that fail mean that the data is already there, so there would be no
need to prevent the application from running, for instance.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 273
If you want to use the schema.sql initialization in a JPA app (with Hibernate) then ddl-
auto=create-drop will lead to errors if Hibernate tries to create the same tables. To avoid those
errors set ddl-auto explicitly to "" (preferable) or "none". Whether or not you use ddl-auto=create-
drop you can always use data.sql to initialize new data.
78.4 Initialize a Spring Batch database
If you are using Spring Batch then it comes pre-packaged with SQL initialization scripts for most popular
database platforms. Spring Boot will detect your database type, and execute those scripts by default,
and in this case will switch the fail fast setting to false (errors are logged but do not prevent the application
from starting). This is because the scripts are known to be reliable and generally do not contain bugs, so
errors are ignorable, and ignoring them makes the scripts idempotent. You can switch off the initialization
explicitly using spring.batch.initializer.enabled=false.
78.5 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, e.g. ‘1’ or ‘2_1’). By default they live in a folder classpath:db/migration but
you can modify that using flyway.locations. You can also add a special {vendor} placeholder to
use vendor-specific scripts. Assume the following:
flyway.locations=db/migration/{vendor}
Rather than using db/migration, this configuration will set the folder to use according to the type of
the database (i.e. db/migration/mysql for MySQL). The list of supported database are available
in DatabaseDriver.
See also the Flyway class from flyway-core for details of available settings like schemas etc. In
addition Spring Boot provides a small set of properties in FlywayProperties that can be used to
disable the migrations, or switch off the location checking. Spring Boot will call Flyway.migrate()
to perform the database migration. If you would like more control, provide a @Bean that implements
FlywayMigrationStrategy.
Tip
If you want to make use of Flyway callbacks, those scripts should also live in the classpath:db/
migration folder.
By default Flyway will autowire the (@Primary) DataSource in your context and use that for
migrations. If you like to use a different DataSource you can create one and mark its @Bean as
@FlywayDataSource - if you do that remember to create another one and mark it as @Primary
if you want two data sources. Or you can use Flyway’s native DataSource by setting flyway.
[url,user,password] in external properties.
There is a Flyway sample so you can see how to set things up.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 274
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 will only be run when your application starts
for testing. If you want to be more sophisticated you can use profile-specific configuration to customize
flyway.locations so that certain migrations will only run when a particular profile is active. For
example, in application-dev.properties you could set flyway.locations to classpath:/
db/migration, classpath:/dev/db/migration and migrations in dev/db/migration will
only run 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.
The master change log is by default read from db/changelog/db.changelog-master.yaml but
can be set using liquibase.change-log. In addition to YAML, Liquibase also supports JSON, XML,
and SQL change log formats.
By default Liquibase will autowire the (@Primary) DataSource in your context and use that for
migrations. If you like to use a different DataSource you can create one and mark its @Bean as
@LiquibaseDataSource - if you do that remember to create another one and mark it as @Primary
if you want two data sources. Or you can use Liquibase’s native DataSource by setting liquibase.
[url,user,password] in external properties.
See LiquibaseProperties for details of available settings like contexts, default schema etc.
There is a Liquibase sample so you can see how to set things up.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 275
79. Messaging
79.1 Disable transacted JMS session
If your JMS broker does not support transacted session, you will have to disable the
support of transactions altogether. If you create your own JmsListenerContainerFactory
there is nothing to do since it won’t be transacted by default. If you want to use the
DefaultJmsListenerContainerFactoryConfigurer to reuse Spring Boot’s default, you can
disable transacted session 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;
}
This overrides the default factory and this should be applied to any other factory that your application
defines, if any.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 276
80. Batch applications
Note
By default, batch applications require a DataSource to store job details. If you want
to deviate from that, you’ll need to implement BatchConfigurer, see The Javadoc of
@EnableBatchProcessing for more details.
80.1 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 (comma-separated job name patterns).
If the application context includes a JobRegistry then 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 277
81. Actuator
81.1 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.port. To listen
on a completely different network address (e.g. if you have an internal network for management and
an external one for user applications) you can also set management.address to a valid IP address
that the server is able to bind to.
For more detail look at the ManagementServerProperties source code and Section 48.3,
“Customizing the management server port” in the ‘Production-ready features’ section.
81.2 Customize the ‘whitelabel’ error page
Spring Boot installs a ‘whitelabel’ error page that you will see in 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 which
will restore the default of the servlet container that you are using. Note that Spring Boot will still
attempt to resolve the error view so you’d probably add you own error page rather than disabling
it completely.
Overriding the error page with your own depends on the templating technology that you are using.
For example, if you are using Thymeleaf you would add an error.html template and if you are
using FreeMarker you would add an error.ftl template. In general what you need is a View
that resolves with a name of error, and/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 with id error would be a simple way of doing that. Look at
ErrorMvcAutoConfiguration for more options.
See also the section on Error Handling for details of how to register handlers in the servlet container.
81.3 Actuator and Jersey
Actuator HTTP endpoints are only available for Spring MVC-based applications. If you want to use
Jersey and still use the actuator you will need to enable Spring MVC (by depending on spring-
boot-starter-web, for example). By default, both Jersey and the Spring MVC dispatcher servlet
are mapped to the same path (/). You will need to change the path for one of them (by configuring
server.servlet-path for Spring MVC or spring.jersey.application-path for Jersey).
For example, if you add server.servlet-path=/system into application.properties, the
actuator HTTP endpoints will be available under /system.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 278
82. Security
82.1 Switch off the Spring Boot security configuration
If you define a @Configuration with @EnableWebSecurity anywhere in your application it will
switch off the default webapp security settings in Spring Boot (but leave the Actuator’s security enabled).
To tweak the defaults try setting properties in security.* (see SecurityProperties for details of
available settings) and SECURITY section of Common application properties.
82.2 Change the AuthenticationManager and add user
accounts
If you provide a @Bean of type AuthenticationManager the default one will not be created, so you
have the full feature set of Spring Security available (e.g. various authentication options).
Spring Security also provides a convenient AuthenticationManagerBuilder which can be used
to build an AuthenticationManager with common options. The recommended way to use this in a
webapp is to inject it into a void method in a WebSecurityConfigurerAdapter, e.g.
@Configuration
public class SecurityConfiguration extends WebSecurityConfigurerAdapter {
@Autowired
public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception {
auth.inMemoryAuthentication()
.withUser("barry").password("password").roles("USER"); // ... etc.
}
// ... other stuff for application security
}
You will get the best results if you put this in a nested class, or a standalone class (i.e. not mixed in
with a lot of other @Beans that might be allowed to influence the order of instantiation). The secure web
sample is a useful template to follow.
If you experience instantiation issues (e.g. using JDBC or JPA for the user detail
store) it might be worth extracting the AuthenticationManagerBuilder callback into a
GlobalAuthenticationConfigurerAdapter (in the init() method so it happens before the
authentication manager is needed elsewhere), e.g.
@Configuration
public class AuthenticationManagerConfiguration extends
GlobalAuthenticationConfigurerAdapter {
@Override
public void init(AuthenticationManagerBuilder auth) {
auth.inMemoryAuthentication() // ... etc.
}
}
82.3 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 are using Tomcat as a servlet container, then Spring Boot will add Tomcat’s own
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 279
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, e.g.
server.tomcat.remote-ip-header=x-forwarded-for
server.tomcat.protocol-header=x-forwarded-proto
(The presence of either of those properties will switch on the valve. Or you can add the RemoteIpValve
yourself by adding a TomcatEmbeddedServletContainerFactory bean.)
Spring Security can also be configured to require a secure channel for all (or some requests). To
switch that on in a Spring Boot application you just need to set security.require_ssl to true in
application.properties.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 280
83. Hot swapping
83.1 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 (e.g. 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, Make Project will trigger the necessary build. Due to the default restart
exclusions, changes to static resources will not trigger a restart of your application. They will, 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 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.
83.2 Reload templates without restarting the container
Most of the templating technologies supported by Spring Boot include a configuration option to disable
caching (see below for details). If you’re using the spring-boot-devtools module these properties
will be automatically configured for you at development time.
Thymeleaf templates
If you are using Thymeleaf, then set spring.thymeleaf.cache to false. See
ThymeleafAutoConfiguration for other Thymeleaf customization options.
FreeMarker templates
If you are using FreeMarker, then set spring.freemarker.cache to false. See
FreeMarkerAutoConfiguration for other FreeMarker customization options.
Groovy templates
If you are using Groovy templates, then set spring.groovy.template.cache to false. See
GroovyTemplateAutoConfiguration for other Groovy customization options.
83.3 Fast application restarts
The spring-boot-devtools module includes support for automatic application restarts. Whilst not
as fast as technologies such as JRebel or Spring Loaded it’s usually significantly faster than a “cold
start”. You should probably give it a try before investigating some of the more complex reload options
discussed below.
For more details see the Chapter 20, Developer tools section.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 281
83.4 Reload Java classes without restarting the container
Modern IDEs (Eclipse, IDEA, etc.) all support hot swapping of bytecode, so if you make a change that
doesn’t affect class or method signatures it should reload cleanly with no side effects.
Spring Loaded goes a little further in that it can reload class definitions with changes in the method
signatures. With some customization it can force an ApplicationContext to refresh itself (but there
is no general mechanism to ensure that would be safe for a running application anyway, so it would
only ever be a development time trick probably).
Configuring Spring Loaded for use with Maven
To use Spring Loaded with the Maven command line, just add it as a dependency in the Spring Boot
plugin declaration, e.g.
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>springloaded</artifactId>
<version>1.2.6.RELEASE</version>
</dependency>
</dependencies>
</plugin>
This normally works pretty well with Eclipse and IntelliJ IDEA as long as they have their build
configuration aligned with the Maven defaults (Eclipse m2e does this out of the box).
Configuring Spring Loaded for use with Gradle and IntelliJ IDEA
You need to jump through a few hoops if you want to use Spring Loaded in combination with Gradle and
IntelliJ IDEA. By default, IntelliJ IDEA will compile classes into a different location than Gradle, causing
Spring Loaded monitoring to fail.
To configure IntelliJ IDEA correctly you can use the idea Gradle plugin:
buildscript {
repositories { jcenter() }
dependencies {
classpath "org.springframework.boot:spring-boot-gradle-plugin:1.5.7.RELEASE"
classpath 'org.springframework:springloaded:1.2.6.RELEASE'
}
}
apply plugin: 'idea'
idea {
module {
inheritOutputDirs = false
outputDir = file("$buildDir/classes/main/")
}
}
// ...
Note
IntelliJ IDEA must be configured to use the same Java version as the command line Gradle task
and springloaded must be included as a buildscript dependency.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 282
You can also additionally enable ‘Make Project Automatically’ inside IntelliJ IDEA to automatically
compile your code whenever a file is saved.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 283
84. Build
84.1 Generate build information
Both the Maven and Gradle plugin allow to generate build information containing the coordinates, name
and version of the project. The plugin can also be configured to add additional properties through
configuration. When such file is present, Spring Boot auto-configures a BuildProperties bean.
To generate build information with Maven, add an execution for the build-info goal:
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>1.5.7.RELEASE</version>
<executions>
<execution>
<goals>
<goal>build-info</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
Tip
Check the Spring Boot Maven Plugin documentation for more details.
And to do the same with Gradle:
springBoot {
buildInfo()
}
Additional properties can be added using the DSL:
springBoot {
buildInfo {
additionalProperties = [
'foo': 'bar'
]
}
}
84.2 Generate git information
Both Maven and Gradle allow to generate 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. Simply add the following declaration to your POM:
<build>
<plugins>
<plugin>
<groupId>pl.project13.maven</groupId>
<artifactId>git-commit-id-plugin</artifactId>
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 284
</plugin>
</plugins>
</build>
Gradle users can achieve the same result using the gradle-git-properties plugin
plugins {
id "com.gorylenko.gradle-git-properties" version "1.4.17"
}
84.3 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:
<properties>
<slf4j.version>1.7.5<slf4j.version>
</properties>
Note
This 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 a specific set of third-party
dependencies. Overriding versions may cause compatibility issues.
To override dependency versions in Gradle, you can specify a version as shown below:
ext['slf4j.version'] = '1.7.5'
For additional information, please refer to the Gradle Dependency Management Plugin documentation.
84.4 Create an executable JAR with Maven
The spring-boot-maven-plugin can be used to create an executable ‘fat’ JAR. If you are using
the spring-boot-starter-parent POM you can simply declare the plugin and your jars will be
repackaged:
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
If you are not using the parent POM you can still use the plugin, however, you must additionally add
an <executions> section:
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 285
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>1.5.7.RELEASE</version>
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
See the plugin documentation for full usage details.
84.5 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 dependency.
To configure a classifier of exec in Maven, the following configuration can be used:
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<classifier>exec</classifier>
</configuration>
</plugin>
</plugins>
</build>
And when using Gradle, the following configuration can be used:
bootRepackage {
classifier = 'exec'
}
84.6 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 286
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 unpack 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>
And to do that same with Gradle:
springBoot {
requiresUnpack = ['org.jruby:jruby-complete']
}
84.7 Create a non-executable JAR with exclusions
Often if you have an executable and a non-executable jar as build products, the executable version
will have additional configuration files that are not needed in a library jar. E.g. the application.yml
configuration file might excluded from the non-executable JAR.
Here’s how to do that in Maven:
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<classifier>exec</classifier>
</configuration>
</plugin>
<plugin>
<artifactId>maven-jar-plugin</artifactId>
<executions>
<execution>
<id>exec</id>
<phase>package</phase>
<goals>
<goal>jar</goal>
</goals>
<configuration>
<classifier>exec</classifier>
</configuration>
</execution>
<execution>
<phase>package</phase>
<goals>
<goal>jar</goal>
</goals>
<configuration>
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 287
<!-- Need this to ensure application.yml is excluded -->
<forceCreation>true</forceCreation>
<excludes>
<exclude>application.yml</exclude>
</excludes>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
In Gradle you can create a new JAR archive with standard task DSL features, and then have the
bootRepackage task depend on that one using its withJarTask property:
jar {
baseName = 'spring-boot-sample-profile'
version = '0.0.0'
excludes = ['**/application.yml']
}
task('execJar', type:Jar, dependsOn: 'jar') {
baseName = 'spring-boot-sample-profile'
version = '0.0.0'
classifier = 'exec'
from sourceSets.main.output
}
bootRepackage {
withJarTask = tasks['execJar']
}
84.8 Remote debug a Spring Boot application started with
Maven
To attach a remote debugger to a Spring Boot application started with Maven you can use the
jvmArguments property of the maven plugin.
Check this example for more details.
84.9 Remote debug a Spring Boot application started with
Gradle
To attach a remote debugger to a Spring Boot application started with Gradle you can use the jvmArgs
property of bootRun task or --debug-jvm command line option.
build.gradle:
bootRun {
jvmArgs "-agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=5005"
}
Command line:
$ gradle bootRun --debug-jvm
Check Gradle Application Plugin for more details.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 288
84.10 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
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 the Main-Class is available).
5. Use the appropriate launcher, e.g. JarLauncher for a jar file, as a Main-Class attribute in the
manifest and specify the other properties it needs as manifest entries, principally a Start-Class.
Example:
<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 with a manual task that should work if you run it with
$ ant -lib <folder containing ivy-2.2.jar> clean manual
after which you can run the application with
$ java -jar target/*.jar
84.11 How to use Java 6
If you want to use Spring Boot with Java 6 there are a small number of configuration changes that you
will have to make. The exact changes depend on your application’s functionality.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 289
Embedded servlet container compatibility
If you are using one of Boot’s embedded Servlet containers you will have to use a Java 6-compatible
container. Both Tomcat 7 and Jetty 8 are Java 6 compatible. See Section 73.16, “Use Tomcat 7.x or
8.0” and Section 73.18, “Use Jetty 8” for details.
Jackson
Jackson 2.7 and later requires Java 7. If you want to use Jackson with Java 6 you will have to downgrade
to Jackson 2.6.
Spring Boot uses the Jackson BOM that was introduced as of Jackson 2.7 so you can’t just override
the jackson.version property. In order to use Jackson 2.6, you will have to define the individual
modules in the dependencyManagement section of your build, check this example for more details.
JTA API compatibility
While the Java Transaction API itself doesn’t require Java 7 the official API jar contains classes that
have been built to require Java 7. If you are using JTA then you will need to replace the official JTA 1.2
API jar with one that has been built to work on Java 6. To do so, exclude any transitive dependencies
on javax.transaction:javax.transaction-api and replace them with a dependency on
org.jboss.spec.javax.transaction:jboss-transaction-api_1.2_spec:1.0.0.Final
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 290
85. Traditional deployment
85.1 Create a deployable war file
The first step in producing a deployable war file is to provide a SpringBootServletInitializer
subclass and override its configure method. This makes use of Spring Framework’s Servlet 3.0
support and allows you to configure your application when it’s launched by the servlet container.
Typically, you update your application’s main class to extend SpringBootServletInitializer:
@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 so that your project produces a war file rather than a
jar file. If you’re using Maven and using 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:
<packaging>war</packaging>
If you’re using Gradle, you need to modify build.gradle to apply the war plugin to the project:
apply plugin: 'war'
The final step in the process is to ensure that the embedded servlet container doesn’t interfere with
the servlet container to which the war file will be deployed. To do so, you need to mark the embedded
servlet container dependency as provided.
If you’re using Maven:
<dependencies>
<!-- … -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
<scope>provided</scope>
</dependency>
<!-- … -->
</dependencies>
And if you’re using Gradle:
dependencies {
// …
providedRuntime 'org.springframework.boot:spring-boot-starter-tomcat'
// …
}
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 291
Note
If you are using a version of Gradle that supports compile only dependencies (2.12 or
later), you should continue to use providedRuntime. Among other limitations, compileOnly
dependencies are not on the test classpath so any web-based integration tests will fail.
If you’re using the Spring Boot build tools, marking the embedded servlet container dependency as
provided will produce 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 using java -jar on the command line.
Tip
Take a look at Spring Boot’s sample applications for a Maven-based example of the above-
described configuration.
85.2 Create a deployable war file for older servlet containers
Older Servlet containers don’t have support for the ServletContextInitializer bootstrap process
used in Servlet 3.0. You can still use Spring and Spring Boot in these containers but you are going to
need to add a web.xml to your application and configure it to load an ApplicationContext via a
DispatcherServlet.
85.3 Convert an existing application to Spring Boot
For a non-web application it should be easy (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 and/or jar. Useful reading
is in the Getting Started Guide on Converting a jar to a war.
Create a deployable war by extending SpringBootServletInitializer (e.g. in a class called
Application), and add the Spring Boot @SpringBootApplication annotation. 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 just a Spring ApplicationContext and 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 first.
Static resources can be moved to /public (or /static or /resources or /META-INF/resources)
in the classpath root. Same for messages.properties (Spring Boot detects this automatically in the
root of the classpath).
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 292
Vanilla usage of Spring DispatcherServlet and Spring Security should require no further changes. If
you have other features in your application, using other servlets or filters for instance, then you may need
to add some configuration to your Application context, 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 was a <servlet/> and <servlet-mapping/> in web.xml.
• A @Bean of type Filter or FilterRegistrationBean behaves similarly (like a <filter/> and
<filter-mapping/>.
• An ApplicationContext in an XML file can be added through an @ImportResource in your
Application. Or simple cases where annotation configuration is heavily used already can be
recreated in a few lines as @Bean definitions.
Once the war is working we make it executable by adding a main method to our Application, e.g.
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 the main method, something like:
@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.
• Applications without a context hierarchy.
All of these should be amenable to translation, but each might require slightly different tricks.
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
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 293
can be moved into a SpringBootServletInitializer. If your existing application has more than
one ApplicationContext (e.g. if it uses AbstractDispatcherServletInitializer) then you
might be able to squash all your context sources into a single SpringApplication. The main
complication you might encounter is if that doesn’t 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 will usually need 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 a Spring Boot application,
and the guidance above might help, but your mileage may vary.
85.4 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 would be something like this:
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.web.SpringBootServletInitializer;
import org.springframework.web.WebApplicationInitializer;
@SpringBootApplication
public class MyApplication extends SpringBootServletInitializer implements WebApplicationInitializer {
}
If you use logback, you will also need to tell WebLogic to prefer the packaged version rather than the
version that pre-installed with the server. You can do this 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>
85.5 Deploying a WAR in an Old (Servlet 2.5) Container
Spring Boot uses Servlet 3.0 APIs to initialize the ServletContext (register Servlets etc.) so
you can’t use the same application out of the box in a Servlet 2.5 container. It is however possible
to run a Spring Boot application on an older container with some special tools. If you include
org.springframework.boot:spring-boot-legacy as a dependency (maintained separately to
the core of Spring Boot and currently available at 1.0.2.RELEASE), all you should need to do is create
a web.xml and declare a context listener to create the application context and your filters and servlets.
The context listener is a special purpose one for Spring Boot, but the rest of it is normal for a Spring
application in Servlet 2.5. Example:
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 294
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
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/web-
app_2_5.xsd">
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>demo.Application</param-value>
</context-param>
<listener>
<listener-class>org.springframework.boot.legacy.context.web.SpringBootContextLoaderListener</
listener-class>
</listener>
<filter>
<filter-name>metricsFilter</filter-name>
<filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
</filter>
<filter-mapping>
<filter-name>metricsFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<servlet>
<servlet-name>appServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextAttribute</param-name>
<param-value>org.springframework.web.context.WebApplicationContext.ROOT</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>appServlet</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
In this example we are using a single application context (the one created by the context listener)
and attaching it to the DispatcherServlet using an init parameter. This is normal in a Spring Boot
application (you normally only have one application context).
Part X. Appendices
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 296
Appendix A. Common application
properties
Various properties can be specified inside your application.properties/application.yml file
or as command line switches. This section 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. It is also perfectly legit to define your own properties.
Warning
This sample file is meant as a guide only. Do not copy/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
# ----------------------------------------
# BANNER
banner.charset=UTF-8 # Banner file encoding.
banner.location=classpath:banner.txt # Banner file location.
banner.image.location=classpath:banner.gif # Banner image file location (jpg/png can also be used).
banner.image.width= # Width of the banner image in chars (default 76)
banner.image.height= # Height of the banner image in chars (default based on image height)
banner.image.margin= # Left hand image margin in chars (default 2)
banner.image.invert= # If images should be inverted for dark terminal themes (default false)
# 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`
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. Only supported with the default
logback setup.
logging.pattern.file= # Appender pattern for output to the file. Only supported with the default logback
setup.
logging.pattern.level= # Appender pattern for log level (default %5p). Only supported 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=false # Whether subclass-based (CGLIB) proxies are to be created (true) as
opposed to standard Java interface-based proxies (false).
# IDENTITY (ContextIdApplicationContextInitializer)
spring.application.index= # Application index.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 297
spring.application.name= # Application name.
# ADMIN (SpringApplicationAdminJmxAutoConfiguration)
spring.application.admin.enabled=false # 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.
# SPRING CORE
spring.beaninfo.ignore=true # 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. Check CaffeineSpec for more details on
the spec format.
spring.cache.couchbase.expiration=0 # Entry expiration in milliseconds. By default the entries never
expire.
spring.cache.ehcache.config= # The location of the configuration file to use to initialize EhCache.
spring.cache.guava.spec= # The spec to use to create caches. Check CacheBuilderSpec for more details on
the spec format.
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. Only needed if more than one JSR-107 implementation is
available on the classpath.
spring.cache.type= # Cache type, auto-detected according to the environment by default.
# SPRING CONFIG - using environment property only (ConfigFileApplicationListener)
spring.config.location= # Config file locations.
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 to others mail 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 # Test that the mail server is available on startup.
spring.mail.username= # Login user of the SMTP server.
# APPLICATION SETTINGS (SpringApplication)
spring.main.banner-mode=console # Mode used to display the banner when the application runs.
spring.main.sources= # Sources (class name, package name or XML resource location) to include in the
ApplicationContext.
spring.main.web-environment= # Run the application in a web environment (auto-detected by default).
# FILE ENCODING (FileEncodingApplicationListener)
spring.mandatory-file-encoding= # Expected character encoding the application must use.
# INTERNATIONALIZATION (MessageSourceAutoConfiguration)
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 298
spring.messages.always-use-message-format=false # Set whether to always apply the MessageFormat rules,
parsing even messages without arguments.
spring.messages.basename=messages # Comma-separated list of basenames, each following the ResourceBundle
convention.
spring.messages.cache-seconds=-1 # Loaded resource bundle files cache expiration, in seconds. When set
to -1, bundles are cached forever.
spring.messages.encoding=UTF-8 # Message bundles encoding.
spring.messages.fallback-to-system-locale=true # Set whether to fall back to the system Locale if no
files for a specific Locale have been found.
# OUTPUT
spring.output.ansi.enabled=detect # Configure the ANSI output.
# PID FILE (ApplicationPidFileWriter)
spring.pid.fail-on-write-error= # Fail 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 (or list if using YAML) of active profiles.
spring.profiles.include= # Unconditionally activate the specified comma separated profiles (or list of
profiles if using YAML).
# SENDGRID (SendGridAutoConfiguration)
spring.sendgrid.api-key= # SendGrid api key (alternative to username/password).
spring.sendgrid.username= # SendGrid account username.
spring.sendgrid.password= # SendGrid account password.
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 to.
server.compression.enabled=false # If 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 response size that is required for compression to be
performed.
server.connection-timeout= # Time in milliseconds that connectors will wait for another HTTP request
before closing the connection. When not set, the connector's container-specific default will be used.
Use a value of -1 to indicate no (i.e. infinite) timeout.
server.context-parameters.*= # Servlet context init parameters. For instance `server.context-
parameters.a=alpha`
server.context-path= # Context path of the application.
server.display-name=application # Display name of the application.
server.max-http-header-size=0 # Maximum size in bytes of the HTTP message header.
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 # Enable the default error page displayed in browsers in case of a
server error.
server.jetty.acceptors= # Number of acceptor threads to use.
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.jsp-servlet.class-name=org.apache.jasper.servlet.JspServlet # The class name of the JSP servlet.
server.jsp-servlet.init-parameters.*= # Init parameters used to configure the JSP servlet
server.jsp-servlet.registered=true # Whether or not the JSP servlet is registered
server.port=8080 # Server HTTP port.
server.server-header= # Value to use for the Server response header (no header is sent if empty)
server.servlet-path=/ # Path of the main dispatcher servlet.
server.use-forward-headers= # If X-Forwarded-* headers should be applied to the HttpRequest.
server.session.cookie.comment= # Comment for the session cookie.
server.session.cookie.domain= # Domain for the session cookie.
server.session.cookie.http-only= # "HttpOnly" flag for the session cookie.
server.session.cookie.max-age= # Maximum age of the session cookie in seconds.
server.session.cookie.name= # Session cookie name.
server.session.cookie.path= # Path of the session cookie.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 299
server.session.cookie.secure= # "Secure" flag for the session cookie.
server.session.persistent=false # Persist session data between restarts.
server.session.store-dir= # Directory used to store session data.
server.session.timeout= # Session timeout in seconds.
server.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= # Maximum queue length for incoming connection requests when all possible
request processing threads are in use.
server.tomcat.accesslog.buffered=true # Buffer output such that it is only flushed periodically.
server.tomcat.accesslog.directory=logs # Directory in which log files are created. Can be relative to
the tomcat base dir or absolute.
server.tomcat.accesslog.enabled=false # Enable access log.
server.tomcat.accesslog.file-date-format=.yyyy-MM-dd # Date format to place in log file name.
server.tomcat.accesslog.pattern=common # Format pattern for access logs.
server.tomcat.accesslog.prefix=access_log # Log file name prefix.
server.tomcat.accesslog.rename-on-rotate=false # Defer inclusion of the date stamp in the file name
until rotate time.
server.tomcat.accesslog.request-attributes-enabled=false # Set request attributes for IP address,
Hostname, protocol and port used for the request.
server.tomcat.accesslog.rotate=true # 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=30 # Delay in seconds between the invocation of
backgroundProcess methods.
server.tomcat.basedir= # Tomcat base directory. If not specified a temporary directory will be 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= # Maximum number of connections that the server will accept and process
at any given time.
server.tomcat.max-http-post-size=0 # Maximum size in bytes of the HTTP post content.
server.tomcat.max-threads=0 # Maximum amount of worker threads.
server.tomcat.min-spare-threads=0 # Minimum amount 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 that indicates that 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.uri-encoding=UTF-8 # Character encoding to use to decode the URI.
server.undertow.accesslog.dir= # Undertow access log directory.
server.undertow.accesslog.enabled=false # Enable 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 # Enable access log rotation.
server.undertow.accesslog.suffix=log # Log file name suffix.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 300
server.undertow.buffer-size= # Size of each buffer in bytes.
server.undertow.direct-buffers= # Allocate buffers outside the Java heap.
server.undertow.io-threads= # Number of I/O threads to create for the worker.
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 (FreeMarkerAutoConfiguration)
spring.freemarker.allow-request-override=false # Set whether HttpServletRequest attributes are allowed
to override (hide) controller generated model attributes of the same name.
spring.freemarker.allow-session-override=false # Set whether HttpSession attributes are allowed to
override (hide) controller generated model attributes of the same name.
spring.freemarker.cache=false # Enable template caching.
spring.freemarker.charset=UTF-8 # Template encoding.
spring.freemarker.check-template-location=true # Check that the templates location exists.
spring.freemarker.content-type=text/html # Content-Type value.
spring.freemarker.enabled=true # Enable MVC view resolution for this technology.
spring.freemarker.expose-request-attributes=false # Set whether all request attributes should be added
to the model prior to merging with the template.
spring.freemarker.expose-session-attributes=false # Set whether all HttpSession attributes should be
added to the model prior to merging with the template.
spring.freemarker.expose-spring-macro-helpers=true # Set whether to expose a RequestContext for use by
Spring's macro library, under the name "springMacroRequestContext".
spring.freemarker.prefer-file-system-access=true # 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.
spring.freemarker.request-context-attribute= # Name of the RequestContext attribute for all views.
spring.freemarker.settings.*= # Well-known FreeMarker keys which will be passed to FreeMarker's
Configuration.
spring.freemarker.suffix= # 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 (GroovyTemplateAutoConfiguration)
spring.groovy.template.allow-request-override=false # Set whether HttpServletRequest attributes are
allowed to override (hide) controller generated model attributes of the same name.
spring.groovy.template.allow-session-override=false # Set whether HttpSession attributes are allowed to
override (hide) controller generated model attributes of the same name.
spring.groovy.template.cache= # Enable template caching.
spring.groovy.template.charset=UTF-8 # Template encoding.
spring.groovy.template.check-template-location=true # Check that the templates location exists.
spring.groovy.template.configuration.*= # See GroovyMarkupConfigurer
spring.groovy.template.content-type=test/html # Content-Type value.
spring.groovy.template.enabled=true # Enable MVC view resolution for this technology.
spring.groovy.template.expose-request-attributes=false # Set whether all request attributes should be
added to the model prior to merging with the template.
spring.groovy.template.expose-session-attributes=false # Set whether all HttpSession attributes should
be added to the model prior to merging with the template.
spring.groovy.template.expose-spring-macro-helpers=true # Set 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 # Specify if application/hal+json responses
should be sent to requests that accept application/json.
# HTTP message conversion
spring.http.converters.preferred-json-mapper=jackson # Preferred JSON mapper to use for HTTP message
conversion. Set to "gson" to force the use of Gson when both it and Jackson are on the classpath.
# 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 # Enable http encoding support.
spring.http.encoding.force= # Force the encoding to the configured charset on HTTP requests and
responses.
spring.http.encoding.force-request= # Force the encoding to the configured charset on HTTP requests.
Defaults to true when "force" has not been specified.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 301
spring.http.encoding.force-response= # Force the encoding to the configured charset on HTTP responses.
spring.http.encoding.mapping= # Locale to Encoding mapping.
# MULTIPART (MultipartProperties)
spring.http.multipart.enabled=true # Enable support of multi-part uploads.
spring.http.multipart.file-size-threshold=0 # Threshold after which files will be written to disk.
Values can use the suffixed "MB" or "KB" to indicate a Megabyte or Kilobyte size.
spring.http.multipart.location= # Intermediate location of uploaded files.
spring.http.multipart.max-file-size=1MB # Max file size. Values can use the suffixed "MB" or "KB" to
indicate a Megabyte or Kilobyte size.
spring.http.multipart.max-request-size=10MB # Max request size. Values can use the suffixed "MB" or "KB"
to indicate a Megabyte or Kilobyte size.
spring.http.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.
spring.jackson.deserialization.*= # Jackson on/off features that affect the way Java objects are
deserialized.
spring.jackson.generator.*= # Jackson on/off features for generators.
spring.jackson.joda-date-time-format= # Joda date time format string. If not configured, "date-format"
will be 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`
# JERSEY (JerseyProperties)
spring.jersey.application-path= # Path that serves as the base URI for the application. Overrides the
value of "@ApplicationPath" if specified.
spring.jersey.filter.order=0 # Jersey filter chain order.
spring.jersey.init.*= # Init parameters to pass to Jersey via 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.urls= # LDAP URLs of the server.
spring.ldap.base= # Base suffix from which all operations should originate.
spring.ldap.username= # Login user of the server.
spring.ldap.password= # Login password of the server.
spring.ldap.base-environment.*= # LDAP specification settings.
# EMBEDDED LDAP (EmbeddedLdapProperties)
spring.ldap.embedded.base-dn= # The base DN
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= # Embedded LDAP port.
spring.ldap.embedded.validation.enabled=true # Enable LDAP schema validation.
spring.ldap.embedded.validation.schema= # Path to the custom schema.
# SPRING MOBILE DEVICE VIEWS (DeviceDelegatingViewResolverAutoConfiguration)
spring.mobile.devicedelegatingviewresolver.enable-fallback=false # Enable support for fallback
resolution.
spring.mobile.devicedelegatingviewresolver.enabled=false # Enable device view resolver.
spring.mobile.devicedelegatingviewresolver.mobile-prefix=mobile/ # Prefix that gets prepended to view
names for mobile devices.
spring.mobile.devicedelegatingviewresolver.mobile-suffix= # Suffix that gets appended to view names for
mobile devices.
spring.mobile.devicedelegatingviewresolver.normal-prefix= # Prefix that gets prepended to view names for
normal devices.
spring.mobile.devicedelegatingviewresolver.normal-suffix= # Suffix that gets appended to view names for
normal devices.
spring.mobile.devicedelegatingviewresolver.tablet-prefix=tablet/ # Prefix that gets prepended to view
names for tablet devices.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 302
spring.mobile.devicedelegatingviewresolver.tablet-suffix= # Suffix that gets appended to view names for
tablet devices.
# SPRING MOBILE SITE PREFERENCE (SitePreferenceAutoConfiguration)
spring.mobile.sitepreference.enabled=true # Enable SitePreferenceHandler.
# MUSTACHE TEMPLATES (MustacheAutoConfiguration)
spring.mustache.allow-request-override= # Set whether HttpServletRequest attributes are allowed to
override (hide) controller generated model attributes of the same name.
spring.mustache.allow-session-override= # Set whether HttpSession attributes are allowed to override
(hide) controller generated model attributes of the same name.
spring.mustache.cache= # Enable template caching.
spring.mustache.charset= # Template encoding.
spring.mustache.check-template-location= # Check that the templates location exists.
spring.mustache.content-type= # Content-Type value.
spring.mustache.enabled= # Enable MVC view resolution for this technology.
spring.mustache.expose-request-attributes= # Set whether all request attributes should be added to the
model prior to merging with the template.
spring.mustache.expose-session-attributes= # Set whether all HttpSession attributes should be added to
the model prior to merging with the template.
spring.mustache.expose-spring-macro-helpers= # Set 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=.html # 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 (in milliseconds) before asynchronous request
handling times out.
spring.mvc.date-format= # Date format to use. For instance `dd/MM/yyyy`.
spring.mvc.dispatch-trace-request=false # Dispatch TRACE requests to the FrameworkServlet doService
method.
spring.mvc.dispatch-options-request=true # Dispatch OPTIONS requests to the FrameworkServlet doService
method.
spring.mvc.favicon.enabled=true # Enable resolution of favicon.ico.
spring.mvc.formcontent.putfilter.enabled=true # Enable Spring's HttpPutFormContentFilter.
spring.mvc.ignore-default-model-on-redirect=true # If 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 # Enable warn logging of exceptions resolved by a
"HandlerExceptionResolver".
spring.mvc.media-types.*= # Maps file extensions to media types for content negotiation.
spring.mvc.message-codes-resolver-format= # Formatting strategy for message codes. For instance
`PREFIX_ERROR_CODE`.
spring.mvc.servlet.load-on-startup=-1 # Load on startup priority of the Spring Web Services servlet.
spring.mvc.static-path-pattern=/** # Path pattern used for static resources.
spring.mvc.throw-exception-if-no-handler-found=false # If 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 # Enable default resource handling.
spring.resources.cache-period= # Cache period for the resources served by the resource handler, in
seconds.
spring.resources.chain.cache=true # Enable caching in the Resource chain.
spring.resources.chain.enabled= # Enable the Spring Resource Handling chain. Disabled by default unless
at least one strategy has been enabled.
spring.resources.chain.gzipped=false # Enable resolution of already gzipped resources.
spring.resources.chain.html-application-cache=false # Enable HTML5 application cache manifest rewriting.
spring.resources.chain.strategy.content.enabled=false # Enable the content Version Strategy.
spring.resources.chain.strategy.content.paths=/** # Comma-separated list of patterns to apply to the
Version Strategy.
spring.resources.chain.strategy.fixed.enabled=false # Enable the fixed Version Strategy.
spring.resources.chain.strategy.fixed.paths=/** # Comma-separated list of patterns to apply to the
Version Strategy.
spring.resources.chain.strategy.fixed.version= # Version string to use for the Version Strategy.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 303
spring.resources.static-locations=classpath:/META-INF/resources/,classpath:/resources/,classpath:/
static/,classpath:/public/ # Locations of static resources.
# SPRING SESSION (SessionProperties)
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.initializer.enabled= # Create the required session tables on startup if necessary.
Enabled automatically if the default table name is set or a custom schema is configured.
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 database table used to store sessions.
spring.session.mongo.collection-name=sessions # Collection name used to store sessions.
spring.session.redis.flush-mode=on-save # Sessions flush mode.
spring.session.redis.namespace= # Namespace for keys used to store sessions.
spring.session.store-type= # Session store type.
# SPRING SOCIAL (SocialWebAutoConfiguration)
spring.social.auto-connection-views=false # Enable the connection status view for supported providers.
# SPRING SOCIAL FACEBOOK (FacebookAutoConfiguration)
spring.social.facebook.app-id= # your application's Facebook App ID
spring.social.facebook.app-secret= # your application's Facebook App Secret
# SPRING SOCIAL LINKEDIN (LinkedInAutoConfiguration)
spring.social.linkedin.app-id= # your application's LinkedIn App ID
spring.social.linkedin.app-secret= # your application's LinkedIn App Secret
# SPRING SOCIAL TWITTER (TwitterAutoConfiguration)
spring.social.twitter.app-id= # your application's Twitter App ID
spring.social.twitter.app-secret= # your application's Twitter App Secret
# THYMELEAF (ThymeleafAutoConfiguration)
spring.thymeleaf.cache=true # Enable template caching.
spring.thymeleaf.check-template=true # Check that the template exists before rendering it.
spring.thymeleaf.check-template-location=true # Check that the templates location exists.
spring.thymeleaf.content-type=text/html # Content-Type value.
spring.thymeleaf.enabled=true # Enable MVC Thymeleaf view resolution.
spring.thymeleaf.encoding=UTF-8 # Template encoding.
spring.thymeleaf.excluded-view-names= # Comma-separated list of view names that should be excluded from
resolution.
spring.thymeleaf.mode=HTML5 # Template mode to be applied to templates. See also
StandardTemplateModeHandlers.
spring.thymeleaf.prefix=classpath:/templates/ # Prefix that gets prepended to view names when building a
URL.
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 that can be resolved.
# SPRING WEB SERVICES (WebServicesProperties)
spring.webservices.path=/services # Path that serves as the base URI for the services.
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.
# ----------------------------------------
# SECURITY PROPERTIES
# ----------------------------------------
# SECURITY (SecurityProperties)
security.basic.authorize-mode=role # Security authorize mode to apply.
security.basic.enabled=true # Enable basic authentication.
security.basic.path=/** # Comma-separated list of paths to secure.
security.basic.realm=Spring # HTTP basic realm name.
security.enable-csrf=false # Enable Cross Site Request Forgery support.
security.filter-order=0 # Security filter chain order.
security.filter-dispatcher-types=ASYNC, FORWARD, INCLUDE, REQUEST # Security filter chain dispatcher
types.
security.headers.cache=true # Enable cache control HTTP headers.
security.headers.content-security-policy= # Value for content security policy header.
security.headers.content-security-policy-mode=default # Content security policy mode.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 304
security.headers.content-type=true # Enable "X-Content-Type-Options" header.
security.headers.frame=true # Enable "X-Frame-Options" header.
security.headers.hsts=all # HTTP Strict Transport Security (HSTS) mode (none, domain, all).
security.headers.xss=true # Enable cross site scripting (XSS) protection.
security.ignored= # Comma-separated list of paths to exclude from the default secured paths.
security.require-ssl=false # Enable secure channel for all requests.
security.sessions=stateless # Session creation policy (always, never, if_required, stateless).
security.user.name=user # Default user name.
security.user.password= # Password for the default user name. A random password is logged on startup by
default.
security.user.role=USER # Granted roles for the default user name.
# SECURITY OAUTH2 CLIENT (OAuth2ClientProperties)
security.oauth2.client.client-id= # OAuth2 client id.
security.oauth2.client.client-secret= # OAuth2 client secret. A random secret is generated by default
# SECURITY OAUTH2 RESOURCES (ResourceServerProperties)
security.oauth2.resource.filter-order= # The order of the filter chain used to authenticate tokens.
security.oauth2.resource.id= # Identifier of the resource.
security.oauth2.resource.jwt.key-uri= # The URI of the JWT token. Can be set if the value is not
available and the key is public.
security.oauth2.resource.jwt.key-value= # The verification key of the JWT token. Can either be a
symmetric secret or PEM-encoded RSA public key.
security.oauth2.resource.jwk.key-set-uri= # The URI for getting the set of keys that can be used to
validate the token.
security.oauth2.resource.prefer-token-info=true # Use the token info, can be set to false to use the
user info.
security.oauth2.resource.service-id=resource #
security.oauth2.resource.token-info-uri= # URI of the token decoding endpoint.
security.oauth2.resource.token-type= # The token type to send when using the userInfoUri.
security.oauth2.resource.user-info-uri= # URI of the user endpoint.
# SECURITY OAUTH2 SSO (OAuth2SsoProperties)
security.oauth2.sso.filter-order= # Filter order to apply if not providing an explicit
WebSecurityConfigurerAdapter
security.oauth2.sso.login-path=/login # Path to the login page, i.e. the one that triggers the redirect
to the OAuth2 Authorization Server
# ----------------------------------------
# DATA PROPERTIES
# ----------------------------------------
# FLYWAY (FlywayProperties)
flyway.baseline-description= #
flyway.baseline-version=1 # version to start migration
flyway.baseline-on-migrate= #
flyway.check-location=false # Check that migration scripts location exists.
flyway.clean-on-validation-error= #
flyway.enabled=true # Enable flyway.
flyway.encoding= #
flyway.ignore-failed-future-migration= #
flyway.init-sqls= # SQL statements to execute to initialize a connection immediately after obtaining it.
flyway.locations=classpath:db/migration # locations of migrations scripts
flyway.out-of-order= #
flyway.password= # JDBC password if you want Flyway to create its own DataSource
flyway.placeholder-prefix= #
flyway.placeholder-replacement= #
flyway.placeholder-suffix= #
flyway.placeholders.*= #
flyway.schemas= # schemas to update
flyway.sql-migration-prefix=V #
flyway.sql-migration-separator= #
flyway.sql-migration-suffix=.sql #
flyway.table= #
flyway.url= # JDBC url of the database to migrate. If not set, the primary configured data source is
used.
flyway.user= # Login user of the database to migrate.
flyway.validate-on-migrate= #
# LIQUIBASE (LiquibaseProperties)
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 305
liquibase.change-log=classpath:/db/changelog/db.changelog-master.yaml # Change log configuration path.
liquibase.check-change-log-location=true # Check the change log location exists.
liquibase.contexts= # Comma-separated list of runtime contexts to use.
liquibase.default-schema= # Default database schema.
liquibase.drop-first=false # Drop the database schema first.
liquibase.enabled=true # Enable liquibase support.
liquibase.labels= # Comma-separated list of runtime labels to use.
liquibase.parameters.*= # Change log parameters.
liquibase.password= # Login password of the database to migrate.
liquibase.rollback-file= # File to which rollback SQL will be written when an update is performed.
liquibase.url= # JDBC url of the database to migrate. If not set, the primary configured data source is
used.
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.query=1 # Number of sockets per node against the Query (N1QL) service.
spring.couchbase.env.endpoints.view=1 # Number of sockets per node against the view service.
spring.couchbase.env.ssl.enabled= # 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=5000 # Bucket connections timeout in milliseconds.
spring.couchbase.env.timeouts.key-value=2500 # Blocking operations performed on a specific key timeout
in milliseconds.
spring.couchbase.env.timeouts.query=7500 # N1QL query operations timeout in milliseconds.
spring.couchbase.env.timeouts.socket-connect=1000 # Socket connect connections timeout in milliseconds.
spring.couchbase.env.timeouts.view=7500 # Regular and geospatial view operations timeout in
milliseconds.
# DAO (PersistenceExceptionTranslationAutoConfiguration)
spring.dao.exceptiontranslation.enabled=true # 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-millis= # Socket option: connection time out.
spring.data.cassandra.consistency-level= # Queries consistency level.
spring.data.cassandra.contact-points=localhost # Comma-separated list of 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.read-timeout-millis= # Socket option: read time out.
spring.data.cassandra.reconnection-policy= # Reconnection policy class.
spring.data.cassandra.repositories.enabled= # Enable Cassandra repositories.
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.enabled=true # Enable Couchbase repositories.
# ELASTICSEARCH (ElasticsearchProperties)
spring.data.elasticsearch.cluster-name=elasticsearch # Elasticsearch cluster name.
spring.data.elasticsearch.cluster-nodes= # Comma-separated list of cluster node addresses. If not
specified, starts a client node.
spring.data.elasticsearch.properties.*= # Additional properties used to configure the client.
spring.data.elasticsearch.repositories.enabled=true # Enable Elasticsearch repositories.
# DATA LDAP
spring.data.ldap.repositories.enabled=true # Enable LDAP repositories.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 306
# MONGODB (MongoProperties)
spring.data.mongodb.authentication-database= # Authentication database name.
spring.data.mongodb.database=test # 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=localhost # 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=27017 # Mongo server port. Cannot be set with uri.
spring.data.mongodb.repositories.enabled=true # Enable Mongo repositories.
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 # Enable Redis repositories.
# NEO4J (Neo4jProperties)
spring.data.neo4j.compiler= # Compiler to use.
spring.data.neo4j.embedded.enabled=true # Enable embedded mode if the embedded driver is available.
spring.data.neo4j.open-in-view=false # 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 # 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-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= # Enable enum value translation via 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= # Return a response body after creating an entity.
spring.data.rest.return-body-on-update= # 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 # Enable Solr repositories.
spring.data.solr.zk-host= # ZooKeeper host address in the form HOST:PORT.
# DATASOURCE (DataSourceAutoConfiguration & DataSourceProperties)
spring.datasource.continue-on-error=false # Do not stop if an error occurs while initializing the
database.
spring.datasource.data= # Data (DML) script resource references.
spring.datasource.data-username= # User 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 # Generate a random datasource name.
spring.datasource.hikari.*= # Hikari specific settings
spring.datasource.initialize=true # Populate the database using 'data.sql'.
spring.datasource.jmx-enabled=false # 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=testdb # Name of the datasource.
spring.datasource.password= # Login password of the database.
spring.datasource.platform=all # Platform to use in the schema resource (schema-${platform}.sql).
spring.datasource.schema= # Schema (DDL) script resource references.
spring.datasource.schema-username= # User 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 Boot Reference Guide
1.5.7.RELEASE Spring Boot 307
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 user 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=3000 # Connection timeout in milliseconds.
spring.elasticsearch.jest.multi-threaded=true # 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=3000 # Read timeout in milliseconds.
spring.elasticsearch.jest.uris=http://localhost:9200 # Comma-separated list of the Elasticsearch
instances to use.
spring.elasticsearch.jest.username= # Login user.
# H2 Web Console (H2ConsoleProperties)
spring.h2.console.enabled=false # Enable the console.
spring.h2.console.path=/h2-console # Path at which the console will be available.
spring.h2.console.settings.trace=false # Enable trace output.
spring.h2.console.settings.web-allow-others=false # Enable remote access.
# JOOQ (JooqAutoConfiguration)
spring.jooq.sql-dialect= # SQLDialect JOOQ used when communicating with the configured datasource. For
instance `POSTGRES`
# JPA (JpaBaseConfiguration, HibernateJpaAutoConfiguration)
spring.data.jpa.repositories.enabled=true # Enable JPA repositories.
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 # Initialize the schema on startup.
spring.jpa.hibernate.ddl-auto= # DDL mode. This is actually a shortcut for the "hibernate.hbm2ddl.auto"
property. Default to "create-drop" when using an embedded database, "none" otherwise.
spring.jpa.hibernate.naming.implicit-strategy= # Hibernate 5 implicit naming strategy fully qualified
name.
spring.jpa.hibernate.naming.physical-strategy= # Hibernate 5 physical naming strategy fully qualified
name.
spring.jpa.hibernate.naming.strategy= # Hibernate 4 naming strategy fully qualified name. Not supported
with Hibernate 5.
spring.jpa.hibernate.use-new-id-generator-mappings= # Use Hibernate's newer IdentifierGenerator for
AUTO, TABLE and SEQUENCE.
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 # Enable logging of SQL statements.
# JTA (JtaAutoConfiguration)
spring.jta.enabled=true # 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 or not to ignore the
transacted flag when creating session.
spring.jta.atomikos.connectionfactory.local-transaction-mode=false # Whether or not 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 Boot Reference Guide
1.5.7.RELEASE Spring Boot 308
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.datasource.borrow-connection-timeout=30 # Timeout, in seconds, for borrowing
connections from the pool.
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.properties.checkpoint-interval=500 # Interval between checkpoints.
spring.jta.atomikos.properties.default-jta-timeout=10000 # Default timeout for JTA transactions.
spring.jta.atomikos.properties.enable-logging=true # Enable disk logging.
spring.jta.atomikos.properties.force-shutdown-on-vm-exit=false # Specify if 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=300000 # Maximum timeout (in milliseconds) that can be
allowed for transactions.
spring.jta.atomikos.properties.serial-jta-transactions=true # Specify if 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 # Use different (and concurrent) threads
for two-phase commit on the participating resources.
spring.jta.atomikos.properties.transaction-manager-unique-name= # 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 or not the transaction
manager should allow mixing XA and non-XA transactions.
spring.jta.bitronix.connectionfactory.apply-transaction-timeout=false # Whether or not the transaction
timeout should be set on the XAResource when it is enlisted.
spring.jta.bitronix.connectionfactory.automatic-enlisting-enabled=true # Whether or not resources should
be enlisted and delisted automatically.
spring.jta.bitronix.connectionfactory.cache-producers-consumers=true # Whether or not produces and
consumers should be cached.
spring.jta.bitronix.connectionfactory.defer-connection-release=true # Whether or not the provider can
run many transactions on the same connection and supports transaction interleaving.
spring.jta.bitronix.connectionfactory.ignore-recovery-failures=false # Whether or not 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 or not connections
in the ACCESSIBLE state can be shared within the context of a transaction.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 309
spring.jta.bitronix.connectionfactory.test-connections=true # Whether or not 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 or not TMJOIN should be used when
starting XAResources.
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 or not the transaction manager
should allow mixing XA and non-XA transactions.
spring.jta.bitronix.datasource.apply-transaction-timeout=false # Whether or not the transaction timeout
should be set on the XAResource when it is enlisted.
spring.jta.bitronix.datasource.automatic-enlisting-enabled=true # Whether or not resources should be
enlisted and delisted automatically.
spring.jta.bitronix.datasource.cursor-holdability= # The default cursor holdability for connections.
spring.jta.bitronix.datasource.defer-connection-release=true # Whether or not the database can run many
transactions on the same connection and supports transaction interleaving.
spring.jta.bitronix.datasource.enable-jdbc4-connection-test= # Whether or not Connection.isValid() is
called when acquiring a connection from the pool.
spring.jta.bitronix.datasource.ignore-recovery-failures=false # Whether or not 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 or not 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, 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 or not TMJOIN should be used when starting
XAResources.
spring.jta.bitronix.properties.allow-multiple-lrc=false # Allow multiple LRC resources to be enlisted
into the same transaction.
spring.jta.bitronix.properties.asynchronous2-pc=false # 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 # Recover only the current node.
spring.jta.bitronix.properties.debug-zero-resource-transaction=false # 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 # 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 # Enable filtering of logs so that only mandatory
logs are written.
spring.jta.bitronix.properties.force-batching-enabled=true # Set if disk forces are batched.
spring.jta.bitronix.properties.forced-write-enabled=true # Set if logs are forced to disk.
spring.jta.bitronix.properties.graceful-shutdown-interval=60 # Maximum amount of seconds the TM will
wait 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 Boot Reference Guide
1.5.7.RELEASE Spring Boot 310
spring.jta.bitronix.properties.journal=disk # Name of the journal. Can be 'disk', 'null' or a class
name.
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.
Default 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 # Log a warning for
transactions executed without a single enlisted resource.
# NARAYANA (NarayanaProperties)
spring.jta.narayana.default-timeout=60 # Transaction timeout in seconds.
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 # Enable one phase commit optimisation.
spring.jta.narayana.periodic-recovery-period=120 # Interval in which periodic recovery scans are
performed in seconds.
spring.jta.narayana.recovery-backoff-period=10 # Back off period between first and second phases of the
recovery scan in seconds.
spring.jta.narayana.recovery-db-pass= # Database password to be used by recovery manager.
spring.jta.narayana.recovery-db-user= # Database username to be used by recovery manager.
spring.jta.narayana.recovery-jms-pass= # JMS password to be used by recovery manager.
spring.jta.narayana.recovery-jms-user= # JMS username to be used by 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=2.6.10 # 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, will override host, port and password (user will be ignored), e.g.
redis://user:password@example.com:6379
spring.redis.host=localhost # Redis server host.
spring.redis.password= # Login password of the redis server.
spring.redis.ssl=false # Enable SSL support.
spring.redis.pool.max-active=8 # Max number of connections that can be allocated by the pool at a given
time. Use a negative value for no limit.
spring.redis.pool.max-idle=8 # Max number of "idle" connections in the pool. Use a negative value to
indicate an unlimited number of idle connections.
spring.redis.pool.max-wait=-1 # Maximum amount of time (in milliseconds) a connection allocation
should block before throwing an exception when the pool is exhausted. Use a negative value to block
indefinitely.
spring.redis.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.port=6379 # Redis server port.
spring.redis.sentinel.master= # Name of Redis server.
spring.redis.sentinel.nodes= # Comma-separated list of host:port pairs.
spring.redis.timeout=0 # Connection timeout in milliseconds.
# TRANSACTION (TransactionProperties)
spring.transaction.default-timeout= # Default transaction timeout in seconds.
spring.transaction.rollback-on-commit-failure= # Perform the rollback on commit failures.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 311
# ----------------------------------------
# INTEGRATION PROPERTIES
# ----------------------------------------
# ACTIVEMQ (ActiveMQProperties)
spring.activemq.broker-url= # URL of the ActiveMQ broker. Auto-generated by default.
spring.activemq.close-timeout=15000 # Time to wait, in milliseconds, before considering a close
complete.
spring.activemq.in-memory=true # Specify if the default broker URL should be in memory. Ignored if an
explicit broker has been specified.
spring.activemq.non-blocking-redelivery=false # Do not stop message delivery before re-delivering
messages from a rolled back transaction. This implies that message order will not be preserved when
this is enabled.
spring.activemq.password= # Login password of the broker.
spring.activemq.send-timeout=0 # Time to wait, in milliseconds, on Message sends for a response. Set it
to 0 to indicate to wait forever.
spring.activemq.user= # Login user of the broker.
spring.activemq.packages.trust-all= # 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 # 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=-1 # Blocking period, in milliseconds, before throwing an
exception if the pool is still full.
spring.activemq.pool.create-connection-on-startup=true # 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=0 # Connection expiration timeout in milliseconds.
spring.activemq.pool.idle-timeout=30000 # Connection idle timeout in milliseconds.
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 "JMXException" occurs.
spring.activemq.pool.time-between-expiration-check=-1 # Time to sleep, in milliseconds, between runs of
the idle connection eviction thread. When negative, no idle connection eviction thread runs.
spring.activemq.pool.use-anonymous-producers=true # 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 # Enable embedded mode if the Artemis server APIs are available.
spring.artemis.embedded.persistent=false # 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.initializer.enabled= # Create the required batch tables on startup if necessary. Enabled
automatically if no custom table prefix is set or if a custom schema is configured.
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.
# 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 Boot Reference Guide
1.5.7.RELEASE Spring Boot 312
spring.jms.listener.max-concurrency= # Maximum number of concurrent consumers.
spring.jms.pub-sub-domain=false # Specify if the default destination type is topic.
spring.jms.template.default-destination= # Default destination to use on send/receive operations that do
not have a destination parameter.
spring.jms.template.delivery-delay= # Delivery delay to use for send calls in milliseconds.
spring.jms.template.delivery-mode= # Delivery mode. Enable QoS when set.
spring.jms.template.priority= # Priority of a message when sending. Enable QoS when set.
spring.jms.template.qos-enabled= # Enable explicit QoS when sending a message.
spring.jms.template.receive-timeout= # Timeout to use for receive calls in milliseconds.
spring.jms.template.time-to-live= # Time-to-live of a message when sending in milliseconds. Enable QoS
when set.
# APACHE KAFKA (KafkaProperties)
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 in milliseconds that the consumer offsets are
auto-committed to Kafka if 'enable.auto.commit' true.
spring.kafka.consumer.auto-offset-reset= # What to do when there is no initial offset in Kafka or if the
current offset does not exist any more 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= # If true the consumer's offset will be periodically committed
in the background.
spring.kafka.consumer.fetch-max-wait= # Maximum amount of time in milliseconds the server will
block 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 the server should return for a fetch
request in bytes.
spring.kafka.consumer.group-id= # Unique string that identifies the consumer group this consumer belongs
to.
spring.kafka.consumer.heartbeat-interval= # Expected time in milliseconds 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.value-deserializer= # Deserializer class for values.
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 in milliseconds between offset commits when ackMode is "TIME" or
"COUNT_TIME".
spring.kafka.listener.concurrency= # Number of threads to run in the listener containers.
spring.kafka.listener.poll-timeout= # Timeout in milliseconds to use when polling the consumer.
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= # Number of records to batch before sending.
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.retries= # When greater than zero, enables retrying of failed sends.
spring.kafka.producer.value-serializer= # Serializer class for values.
spring.kafka.properties.*= # Additional properties 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.truststore-location= # Location of the trust store file.
spring.kafka.ssl.truststore-password= # Store password for the trust store file.
spring.kafka.template.default-topic= # Default topic to which messages will be sent.
# RABBIT (RabbitProperties)
spring.rabbitmq.addresses= # Comma-separated list of addresses to which the client should connect.
spring.rabbitmq.cache.channel.checkout-timeout= # Number of milliseconds 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 Boot Reference Guide
1.5.7.RELEASE Spring Boot 313
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, in milliseconds; zero for infinite.
spring.rabbitmq.dynamic=true # Create an AmqpAdmin bean.
spring.rabbitmq.host=localhost # RabbitMQ host.
spring.rabbitmq.listener.simple.acknowledge-mode= # Acknowledge mode of container.
spring.rabbitmq.listener.simple.auto-startup=true # Start the container automatically on startup.
spring.rabbitmq.listener.simple.concurrency= # Minimum number of consumers.
spring.rabbitmq.listener.simple.default-requeue-rejected= # Whether or not to requeue delivery failures;
default `true`.
spring.rabbitmq.listener.simple.idle-event-interval= # How often idle container events should be
published in milliseconds.
spring.rabbitmq.listener.simple.max-concurrency= # Maximum number of consumers.
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 or not publishing retries are enabled.
spring.rabbitmq.listener.simple.retry.initial-interval=1000 # Interval 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=10000 # Maximum interval between attempts.
spring.rabbitmq.listener.simple.retry.multiplier=1.0 # A multiplier to apply to the previous delivery
retry interval.
spring.rabbitmq.listener.simple.retry.stateless=true # Whether or not retry is stateless or stateful.
spring.rabbitmq.listener.simple.transaction-size= # Number of messages to be processed in a transaction.
For best results it should be less than or equal to the prefetch count.
spring.rabbitmq.password= # Login to authenticate against the broker.
spring.rabbitmq.port=5672 # RabbitMQ port.
spring.rabbitmq.publisher-confirms=false # Enable publisher confirms.
spring.rabbitmq.publisher-returns=false # Enable publisher returns.
spring.rabbitmq.requested-heartbeat= # Requested heartbeat timeout, in seconds; zero for none.
spring.rabbitmq.ssl.enabled=false # 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.trust-store= # Trust store that holds SSL certificates.
spring.rabbitmq.ssl.trust-store-password= # Password used to access the trust store.
spring.rabbitmq.ssl.algorithm= # SSL algorithm to use. By default configure by the rabbit client
library.
spring.rabbitmq.template.mandatory=false # Enable mandatory messages.
spring.rabbitmq.template.receive-timeout=0 # Timeout for `receive()` methods.
spring.rabbitmq.template.reply-timeout=5000 # Timeout for `sendAndReceive()` methods.
spring.rabbitmq.template.retry.enabled=false # Set to true to enable retries in the `RabbitTemplate`.
spring.rabbitmq.template.retry.initial-interval=1000 # Interval between the first and second attempt to
publish a message.
spring.rabbitmq.template.retry.max-attempts=3 # Maximum number of attempts to publish a message.
spring.rabbitmq.template.retry.max-interval=10000 # Maximum number of attempts to publish a message.
spring.rabbitmq.template.retry.multiplier=1.0 # A multiplier to apply to the previous publishing retry
interval.
spring.rabbitmq.username= # Login user to authenticate to the broker.
spring.rabbitmq.virtual-host= # Virtual host to use when connecting to the broker.
# ----------------------------------------
# ACTUATOR PROPERTIES
# ----------------------------------------
# ENDPOINTS (AbstractEndpoint subclasses)
endpoints.enabled=true # Enable endpoints.
endpoints.sensitive= # Default endpoint sensitive setting.
endpoints.actuator.enabled=true # Enable the endpoint.
endpoints.actuator.path= # Endpoint URL path.
endpoints.actuator.sensitive=false # Enable security on the endpoint.
endpoints.auditevents.enabled= # Enable the endpoint.
endpoints.auditevents.path= # Endpoint path.
endpoints.auditevents.sensitive=false # Enable security on the endpoint.
endpoints.autoconfig.enabled= # Enable the endpoint.
endpoints.autoconfig.id= # Endpoint identifier.
endpoints.autoconfig.path= # Endpoint path.
endpoints.autoconfig.sensitive= # Mark if the endpoint exposes sensitive information.
endpoints.beans.enabled= # Enable the endpoint.
endpoints.beans.id= # Endpoint identifier.
endpoints.beans.path= # Endpoint path.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 314
endpoints.beans.sensitive= # Mark if the endpoint exposes sensitive information.
endpoints.configprops.enabled= # Enable the endpoint.
endpoints.configprops.id= # Endpoint identifier.
endpoints.configprops.keys-to-sanitize=password,secret,key,token,.*credentials.*,vcap_services # Keys
that should be sanitized. Keys can be simple strings that the property ends with or regex expressions.
endpoints.configprops.path= # Endpoint path.
endpoints.configprops.sensitive= # Mark if the endpoint exposes sensitive information.
endpoints.docs.curies.enabled=false # Enable the curie generation.
endpoints.docs.enabled=true # Enable actuator docs endpoint.
endpoints.docs.path=/docs #
endpoints.docs.sensitive=false #
endpoints.dump.enabled= # Enable the endpoint.
endpoints.dump.id= # Endpoint identifier.
endpoints.dump.path= # Endpoint path.
endpoints.dump.sensitive= # Mark if the endpoint exposes sensitive information.
endpoints.env.enabled= # Enable the endpoint.
endpoints.env.id= # Endpoint identifier.
endpoints.env.keys-to-sanitize=password,secret,key,token,.*credentials.*,vcap_services # Keys that
should be sanitized. Keys can be simple strings that the property ends with or regex expressions.
endpoints.env.path= # Endpoint path.
endpoints.env.sensitive= # Mark if the endpoint exposes sensitive information.
endpoints.flyway.enabled= # Enable the endpoint.
endpoints.flyway.id= # Endpoint identifier.
endpoints.flyway.sensitive= # Mark if the endpoint exposes sensitive information.
endpoints.health.enabled= # Enable the endpoint.
endpoints.health.id= # Endpoint identifier.
endpoints.health.mapping.*= # Mapping of health statuses to HttpStatus codes. By default, registered
health statuses map to sensible defaults (i.e. UP maps to 200).
endpoints.health.path= # Endpoint path.
endpoints.health.sensitive= # Mark if the endpoint exposes sensitive information.
endpoints.health.time-to-live=1000 # Time to live for cached result, in milliseconds.
endpoints.heapdump.enabled= # Enable the endpoint.
endpoints.heapdump.path= # Endpoint path.
endpoints.heapdump.sensitive= # Mark if the endpoint exposes sensitive information.
endpoints.hypermedia.enabled=false # Enable hypermedia support for endpoints.
endpoints.info.enabled= # Enable the endpoint.
endpoints.info.id= # Endpoint identifier.
endpoints.info.path= # Endpoint path.
endpoints.info.sensitive= # Mark if the endpoint exposes sensitive information.
endpoints.jolokia.enabled=true # Enable Jolokia endpoint.
endpoints.jolokia.path=/jolokia # Endpoint URL path.
endpoints.jolokia.sensitive=true # Enable security on the endpoint.
endpoints.liquibase.enabled= # Enable the endpoint.
endpoints.liquibase.id= # Endpoint identifier.
endpoints.liquibase.sensitive= # Mark if the endpoint exposes sensitive information.
endpoints.logfile.enabled=true # Enable the endpoint.
endpoints.logfile.external-file= # External Logfile to be accessed.
endpoints.logfile.path=/logfile # Endpoint URL path.
endpoints.logfile.sensitive=true # Enable security on the endpoint.
endpoints.loggers.enabled=true # Enable the endpoint.
endpoints.loggers.id= # Endpoint identifier.
endpoints.loggers.path=/logfile # Endpoint path.
endpoints.loggers.sensitive=true # Mark if the endpoint exposes sensitive information.
endpoints.mappings.enabled= # Enable the endpoint.
endpoints.mappings.id= # Endpoint identifier.
endpoints.mappings.path= # Endpoint path.
endpoints.mappings.sensitive= # Mark if the endpoint exposes sensitive information.
endpoints.metrics.enabled= # Enable the endpoint.
endpoints.metrics.filter.enabled=true # Enable the metrics servlet filter.
endpoints.metrics.filter.gauge-submissions=merged # Http filter gauge submissions (merged, per-http-
method)
endpoints.metrics.filter.counter-submissions=merged # Http filter counter submissions (merged, per-http-
method)
endpoints.metrics.id= # Endpoint identifier.
endpoints.metrics.path= # Endpoint path.
endpoints.metrics.sensitive= # Mark if the endpoint exposes sensitive information.
endpoints.shutdown.enabled= # Enable the endpoint.
endpoints.shutdown.id= # Endpoint identifier.
endpoints.shutdown.path= # Endpoint path.
endpoints.shutdown.sensitive= # Mark if the endpoint exposes sensitive information.
endpoints.trace.enabled= # Enable the endpoint.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 315
endpoints.trace.filter.enabled=true # Enable the trace servlet filter.
endpoints.trace.id= # Endpoint identifier.
endpoints.trace.path= # Endpoint path.
endpoints.trace.sensitive= # Mark if the endpoint exposes sensitive information.
# ENDPOINTS CORS CONFIGURATION (EndpointCorsProperties)
endpoints.cors.allow-credentials= # Set whether credentials are supported. When not set, credentials are
not supported.
endpoints.cors.allowed-headers= # Comma-separated list of headers to allow in a request. '*' allows all
headers.
endpoints.cors.allowed-methods=GET # Comma-separated list of methods to allow. '*' allows all methods.
endpoints.cors.allowed-origins= # Comma-separated list of origins to allow. '*' allows all origins. When
not set, CORS support is disabled.
endpoints.cors.exposed-headers= # Comma-separated list of headers to include in a response.
endpoints.cors.max-age=1800 # How long, in seconds, the response from a pre-flight request can be cached
by clients.
# JMX ENDPOINT (EndpointMBeanExportProperties)
endpoints.jmx.domain= # JMX domain name. Initialized with the value of 'spring.jmx.default-domain' if
set.
endpoints.jmx.enabled=true # Enable JMX export of all endpoints.
endpoints.jmx.static-names= # Additional static properties to append to all ObjectNames of MBeans
representing Endpoints.
endpoints.jmx.unique-names=false # Ensure that ObjectNames are modified in case of conflict.
# JOLOKIA (JolokiaProperties)
jolokia.config.*= # See Jolokia manual
# MANAGEMENT HTTP SERVER (ManagementServerProperties)
management.add-application-context-header=true # Add the "X-Application-Context" HTTP header in each
response.
management.address= # Network address that the management endpoints should bind to.
management.context-path= # Management endpoint context-path. For instance `/actuator`
management.cloudfoundry.enabled= # Enable extended Cloud Foundry actuator endpoints
management.cloudfoundry.skip-ssl-validation= # Skip SSL verification for Cloud Foundry actuator endpoint
security calls
management.port= # Management endpoint HTTP port. Uses the same port as the application by default.
Configure a different port to use management-specific SSL.
management.security.enabled=true # Enable security.
management.security.roles=ACTUATOR # Comma-separated list of roles that can access the management
endpoint.
management.security.sessions=stateless # Session creating policy to use (always, never, if_required,
stateless).
management.ssl.ciphers= # Supported SSL ciphers. Requires a custom management.port.
management.ssl.client-auth= # Whether client authentication is wanted ("want") or needed ("need").
Requires a trust store. Requires a custom management.port.
management.ssl.enabled= # Enable SSL support. Requires a custom management.port.
management.ssl.enabled-protocols= # Enabled SSL protocols. Requires a custom management.port.
management.ssl.key-alias= # Alias that identifies the key in the key store. Requires a custom
management.port.
management.ssl.key-password= # Password used to access the key in the key store. Requires a custom
management.port.
management.ssl.key-store= # Path to the key store that holds the SSL certificate (typically a jks file).
Requires a custom management.port.
management.ssl.key-store-password= # Password used to access the key store. Requires a custom
management.port.
management.ssl.key-store-provider= # Provider for the key store. Requires a custom management.port.
management.ssl.key-store-type= # Type of the key store. Requires a custom management.port.
management.ssl.protocol=TLS # SSL protocol to use. Requires a custom management.port.
management.ssl.trust-store= # Trust store that holds SSL certificates. Requires a custom
management.port.
management.ssl.trust-store-password= # Password used to access the trust store. Requires a custom
management.port.
management.ssl.trust-store-provider= # Provider for the trust store. Requires a custom management.port.
management.ssl.trust-store-type= # Type of the trust store. Requires a custom management.port.
# HEALTH INDICATORS
management.health.db.enabled=true # Enable database health check.
management.health.cassandra.enabled=true # Enable cassandra health check.
management.health.couchbase.enabled=true # Enable couchbase health check.
management.health.defaults.enabled=true # Enable default health indicators.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 316
management.health.diskspace.enabled=true # 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 that should be available, in bytes.
management.health.elasticsearch.enabled=true # Enable elasticsearch health check.
management.health.elasticsearch.indices= # Comma-separated index names.
management.health.elasticsearch.response-timeout=100 # The time, in milliseconds, to wait for a response
from the cluster.
management.health.jms.enabled=true # Enable JMS health check.
management.health.ldap.enabled=true # Enable LDAP health check.
management.health.mail.enabled=true # Enable Mail health check.
management.health.mongo.enabled=true # Enable MongoDB health check.
management.health.rabbit.enabled=true # Enable RabbitMQ health check.
management.health.redis.enabled=true # Enable Redis health check.
management.health.solr.enabled=true # Enable Solr health check.
management.health.status.order=DOWN, OUT_OF_SERVICE, UP, UNKNOWN # Comma-separated list of health
statuses in order of severity.
# INFO CONTRIBUTORS (InfoContributorProperties)
management.info.build.enabled=true # Enable build info.
management.info.defaults.enabled=true # Enable default info contributors.
management.info.env.enabled=true # Enable environment info.
management.info.git.enabled=true # Enable git info.
management.info.git.mode=simple # Mode to use to expose git information.
# REMOTE SHELL (ShellProperties)
management.shell.auth.type=simple # Authentication type. Auto-detected according to the environment.
management.shell.auth.jaas.domain=my-domain # JAAS domain.
management.shell.auth.key.path= # Path to the authentication key. This should point to a valid ".pem"
file.
management.shell.auth.simple.user.name=user # Login user.
management.shell.auth.simple.user.password= # Login password.
management.shell.auth.spring.roles=ACTUATOR # Comma-separated list of required roles to login to the
CRaSH console.
management.shell.command-path-patterns=classpath*:/commands/**,classpath*:/crash/commands/** # Patterns
to use to look for commands.
management.shell.command-refresh-interval=-1 # Scan for changes and update the command if necessary (in
seconds).
management.shell.config-path-patterns=classpath*:/crash/* # Patterns to use to look for configurations.
management.shell.disabled-commands=jpa*,jdbc*,jndi* # Comma-separated list of commands to disable.
management.shell.disabled-plugins= # Comma-separated list of plugins to disable. Certain plugins are
disabled by default based on the environment.
management.shell.ssh.auth-timeout = # Number of milliseconds after user will be prompted to login again.
management.shell.ssh.enabled=true # Enable CRaSH SSH support.
management.shell.ssh.idle-timeout = # Number of milliseconds after which unused connections are closed.
management.shell.ssh.key-path= # Path to the SSH server key.
management.shell.ssh.port=2000 # SSH port.
management.shell.telnet.enabled=false # Enable CRaSH telnet support. Enabled by default if the
TelnetPlugin is available.
management.shell.telnet.port=5000 # Telnet port.
# TRACING (TraceProperties)
management.trace.include=request-headers,response-headers,cookies,errors # Items to be included in the
trace.
# METRICS EXPORT (MetricExportProperties)
spring.metrics.export.aggregate.key-pattern= # Pattern that tells the aggregator what to do with the
keys from the source repository.
spring.metrics.export.aggregate.prefix= # Prefix for global repository if active.
spring.metrics.export.delay-millis=5000 # Delay in milliseconds between export ticks. Metrics are
exported to external sources on a schedule with this delay.
spring.metrics.export.enabled=true # Flag to enable metric export (assuming a MetricWriter is
available).
spring.metrics.export.excludes= # List of patterns for metric names to exclude. Applied after the
includes.
spring.metrics.export.includes= # List of patterns for metric names to include.
spring.metrics.export.redis.key=keys.spring.metrics # Key for redis repository export (if active).
spring.metrics.export.redis.prefix=spring.metrics # Prefix for redis repository if active.
spring.metrics.export.send-latest= # Flag to switch off any available optimizations based on not
exporting unchanged metric values.
spring.metrics.export.statsd.host= # Host of a statsd server to receive exported metrics.
spring.metrics.export.statsd.port=8125 # Port of a statsd server to receive exported metrics.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 317
spring.metrics.export.statsd.prefix= # Prefix for statsd exported metrics.
spring.metrics.export.triggers.*= # Specific trigger properties per MetricWriter bean name.
# ----------------------------------------
# DEVTOOLS PROPERTIES
# ----------------------------------------
# DEVTOOLS (DevToolsProperties)
spring.devtools.livereload.enabled=true # 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 # Enable automatic restart.
spring.devtools.restart.exclude=META-INF/maven/**,META-INF/resources/**,resources/**,static/**,public/
**,templates/**,**/*Test.class,**/*Tests.class,git.properties # Patterns that should be excluded from
triggering a full restart.
spring.devtools.restart.poll-interval=1000 # Amount of time (in milliseconds) to wait between polling
for classpath changes.
spring.devtools.restart.quiet-period=400 # Amount of quiet time (in milliseconds) required without any
classpath changes before a restart is triggered.
spring.devtools.restart.trigger-file= # Name of a specific file that when changed will trigger the
restart check. If not specified any classpath file change will trigger the restart.
# REMOTE DEVTOOLS (RemoteDevToolsProperties)
spring.devtools.remote.context-path=/.~~spring-boot!~ # Context path used to handle the remote
connection.
spring.devtools.remote.debug.enabled=true # Enable remote debug support.
spring.devtools.remote.debug.local-port=8000 # Local remote debug server port.
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 # Enable remote restart.
spring.devtools.remote.secret= # A shared secret required to establish a connection (required to enable
remote support).
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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 318
Appendix B. Configuration meta-data
Spring Boot jars are shipped with meta-data files that provide details of all supported configuration
properties. The files are designed to allow IDE developers to offer contextual help and “code completion”
as users are working with application.properties or application.yml files.
The majority of the meta-data file is generated automatically at compile time by processing all items
annotated with @ConfigurationProperties. However, it is possible to write part of the meta-data
manually for corner cases or more advanced use cases.
B.1 Meta-data format
Configuration meta-data 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 hint categorized under "hints":
{"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."
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 319
},
{
"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 don’t 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 just exist in their own
right.
Finally, “hints” are additional information used to assist the user in configuring a given property. When
configuring the spring.jpa.hibernate.ddl-auto property, a tool can use it 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 following attributes:
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 was based on a class annotated with
@ConfigurationProperties the attribute would contain the
fully qualified name of that class. If it was based on a @Bean
method, it would be the return type of that method. The attribute
may be omitted if the type is not known.
description String A short description of the group that can be displayed to users.
May be omitted if no description is available. It is recommended
that descriptions are a 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 was based on a @Bean method annotated
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 320
Name Type Purpose
with @ConfigurationProperties this attribute would contain
the fully qualified name of the @Configuration class containing
the method. The attribute may be omitted if the source type is not
known.
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. May
be omitted if the source method is not known.
Property Attributes
The JSON object contained in the properties array can contain the following attributes:
Name Type Purpose
name String The full name of the property. Names are in lowercase dashed
form (e.g. 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>. This
attribute can be used to guide the user as to the types of values
that they can enter. For consistency, the type of a primitive is
specified using its wrapper counterpart, i.e. boolean becomes
java.lang.Boolean. Note that this class may be a complex
type that gets converted from a String as values are bound. May
be omitted if the type is not known.
description String A short description of the group that can be displayed to users.
May be omitted if no description is available. It is recommended
that descriptions are a 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 was from a class annotated with
@ConfigurationProperties this attribute would contain the
fully qualified name of that class. May be omitted if the source type
is not known.
defaultValue Object The default value which will be used if the property is not specified.
Can also be an array of value(s) if the type of the property is an
array. May be omitted if the default value is not known.
deprecation Deprecation Specify if the property is deprecated. May be omitted if the field is
not deprecated or if that information is not known. See below for
more details.
The JSON object contained in the deprecation attribute of each properties element can contain
the following attributes:
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 321
Name Type Purpose
level String The level of deprecation, can be either warning (default) or
error. When a property has a warning deprecation level it
should still be bound in the environment. When it has an error
deprecation level however, the property is no longer managed and
will not be bound.
reason String A short description of the reason why the property was
deprecated. May be omitted if no reason is available. It is
recommended that descriptions are a 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 is replacing this deprecated
property. May be omitted if there is no replacement for this
property.
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, let’s assume the app.foo.target property was confusing and was renamed to
app.foo.name
@ConfigurationProperties("app.foo")
public class FooProperties {
private String name;
public String getName() { ... }
public void setName(String name) { ... }
@DeprecatedConfigurationProperty(replacement = "app.foo.name")
@Deprecated
public String getTarget() {
return getName();
}
@Deprecated
public void setTarget(String target) {
setName(target);
}
}
Note
There is no way to set a level as warning is always assumed since code is still handling the
property.
The code above 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
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 322
API, the automatic deprecation hint in the meta-data will go away as well. If you want to keep a hint,
adding manual meta-data with an error deprecation level ensures that users are still informed about
that property and is particularly useful when a replacement is provided.
Hint Attributes
The JSON object contained in the hints array can contain the following attributes:
Name Type Purpose
name String The full name of the property that this hint refers to. Names are
in lowercase dashed form (e.g. server.servlet-path). If the
property refers to a map (e.g. system.contexts) the hint either
applies to the keys of the map (system.context.keys) or the
values (system.context.values). This attribute is mandatory.
values ValueHint[] A list of valid values as defined by the ValueHint object (see
below). Each entry defines the value and may have a description
providers ValueProvider[] A list of providers as defined by the ValueProvider object
(see below). 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 following
attributes:
Name Type Purpose
value Object A valid value for the element to which the hint refers to. Can also
be an array of value(s) if the type of the property is an array. This
attribute is mandatory.
description String A short description of the value that can be displayed to users.
May be omitted if no description is available. It is recommended
that descriptions are a 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 following
attributes:
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 to.
parameters JSON object Any additional parameter that the provider supports (check the
documentation of the provider for more details).
Repeated meta-data items
It is perfectly acceptable for “property” and “group” objects with the same name to appear multiple times
within a meta-data file. For example, you could bind two separate classes to the same prefix, with each
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 323
potentially offering overlap of property names. While this is not supposed to be a frequent scenario,
consumers of meta-data should take care to ensure that they support such scenarios.
B.2 Providing manual hints
To improve the user experience and further assist the user in configuring a given property, you can
provide additional meta-data that:
1. Describes the list of potential values for a property.
2. 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 above, we provide
5 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 be used to refer to the keys and the values
respectively.
Let’s assume a foo.contexts that maps magic String values to an integer:
@ConfigurationProperties("foo")
public class FooProperties {
private Map<String,Integer> contexts;
// getters and setters
}
The magic values are foo and bar for instance. In order to offer additional content assistance for the
keys, you could add the following to the manual meta-data of the module:
{"hints": [
{
"name": "foo.contexts.keys",
"values": [
{
"value": "foo"
},
{
"value": "bar"
}
]
}
]}
Note
Of course, you should have an Enum for those two values instead. This is by far the most effective
approach to auto-completion if your IDE supports it.
Value provider
Providers are a powerful way of attaching semantics to a property. We define in the section below the
official providers that you can use for your own hints. Bare in mind however that your favorite IDE may
implement some of these or none of them. It could eventually provide its own as well.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 324
Note
As this is a new feature, IDE vendors will have to catch up with this new feature.
The table below summarizes the list of supported providers:
Name Description
any Permit any additional value to be provided.
class-reference Auto-complete the classes available in the project. Usually
constrained by a base class that is specified via the target
parameter.
handle-as Handle the property as if it was defined by the type defined via the
mandatory target parameter.
logger-name Auto-complete valid logger names. Typically, package and class
names available in the current project can be auto-completed.
spring-bean-reference Auto-complete the available bean names in the current project.
Usually constrained by a base class that is specified via the
target parameter.
spring-profile-name Auto-complete the available Spring profile names in the project.
Tip
No more than one provider can be active for a given property but you can specify several providers
if they can all manage the property in some ways. Make sure to place the most powerful provider
first as the IDE must use the first one in the JSON section it can handle. If no provider for a given
property is supported, no special content assistance is provided either.
Any
The any provider permits any additional values to be provided. Regular value validation based on the
property type should be applied if this is supported.
This provider will be typically used if you have a list of values and any extra values are still to be
considered as valid.
The example below offers on and off as auto-completion values for system.state; any other value
is also allowed:
{"hints": [
{
"name": "system.state",
"values": [
{
"value": "on"
},
{
"value": "off"
}
],
"providers": [
{
"name": "any"
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 325
}
]
}
]}
Class reference
The class-reference provider auto-completes classes available in the project. This provider supports
these 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 if only concrete classes are to be
considered as valid candidates.
The meta-data snippet below corresponds to the standard server.jsp-servlet.class-name
property that defines the JspServlet class name to use:
{"hints": [
{
"name": "server.jsp-servlet.class-name",
"providers": [
{
"name": "class-reference",
"parameters": {
"target": "javax.servlet.http.HttpServlet"
}
}
]
}
]}
Handle As
The handle-as provider allows you to 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 don’t want your
configuration classes to rely on classes that may not be on the classpath. This provider supports these
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 that lists the possible values for the property (By all means, try to define the
property with the Enum type instead as no further hint should be required for the IDE to auto-complete
the values).
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 326
•java.nio.charset.Charset: auto-completion of charset/encoding values (e.g. UTF-8)
•java.util.Locale: auto-completion of locales (e.g. en_US)
•org.springframework.util.MimeType: auto-completion of content type values (e.g. text/
plain)
•org.springframework.core.io.Resource: auto-completion of Spring’s Resource abstraction
to refer to a file on the filesystem or on the classpath. (e.g. classpath:/foo.properties)
Note
If multiple values can be provided, use a Collection or Array type to teach the IDE about it.
The meta-data snippet below corresponds to the standard 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 as we need to keep
the original String value to pass it to the Liquibase API.
{"hints": [
{
"name": "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 could be supported as well.
Since a logger name can be any arbitrary name, really, this provider should allow any value but could
highlight valid packages and class names that are not available in the project’s classpath.
The meta-data snippet below 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"
}
]
},
{
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 327
"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 these 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 meta-data snippet below corresponds to the standard spring.jmx.server property that defines
the name of the MBeanServer bean to use:
{"hints": [
{
"name": "spring.jmx.server",
"providers": [
{
"name": "spring-bean-reference",
"parameters": {
"target": "javax.management.MBeanServer"
}
}
]
}
]}
Note
The binder is not aware of the meta-data so if you provide that hint, you will still need to transform
the bean name into an actual Bean reference using the ApplicationContext.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 328
Spring profile name
The spring-profile-name provider auto-completes the Spring profiles that are defined in the
configuration of the current project.
The meta-data snippet below 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 meta-data using the annotation
processor
You can easily generate your own configuration meta-data 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, simply include spring-boot-configuration-processor as an optional dependency,
for example with Maven you would add:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-configuration-processor</artifactId>
<optional>true</optional>
</dependency>
With Gradle, you can use the propdeps-plugin and specify:
dependencies {
optional "org.springframework.boot:spring-boot-configuration-processor"
}
compileJava.dependsOn(processResources)
Note
You need to add compileJava.dependsOn(processResources) to your build to ensure
that resources are processed before code is compiled. Without this directive any additional-
spring-configuration-metadata.json files will not be processed.
The processor will pick up both classes and methods that are annotated with
@ConfigurationProperties. The Javadoc for field values within configuration classes will be 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.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 329
Properties are discovered via the presence of standard getters and setters with special handling for
collection types (that will be 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 only
runs 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:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<proc>none</proc>
</configuration>
</plugin>
Nested properties
The annotation processor will automatically consider inner classes as nested properties. For example,
the following class:
@ConfigurationProperties(prefix="server")
public class ServerProperties {
private String name;
private Host host;
// ... getter and setters
private static class Host {
private String ip;
private int port;
// ... getter and setters
}
}
Will produce meta-data 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
meta-data property is generated for each of them.
Adding additional meta-data
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
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 330
some attributes of an existing key. To support such cases and allow you to provide custom "hints",
the annotation processor will automatically merge items from META-INF/additional-spring-
configuration-metadata.json into the main meta-data 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 brand 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 don’t have any additional properties, simply don’t add it.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 331
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 autoconfig report in your application for more details of
which features are switched on. (start the app with --debug or -Ddebug, or in an Actuator application
use the autoconfig 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
CassandraRepositoriesAutoConfiguration javadoc
CloudAutoConfiguration javadoc
ConfigurationPropertiesAutoConfiguration javadoc
CouchbaseAutoConfiguration javadoc
CouchbaseDataAutoConfiguration javadoc
CouchbaseRepositoriesAutoConfiguration javadoc
DataSourceAutoConfiguration javadoc
DataSourceTransactionManagerAutoConfiguration javadoc
DeviceDelegatingViewResolverAutoConfiguration javadoc
DeviceResolverAutoConfiguration javadoc
DispatcherServletAutoConfiguration javadoc
ElasticsearchAutoConfiguration javadoc
ElasticsearchDataAutoConfiguration javadoc
ElasticsearchRepositoriesAutoConfiguration javadoc
EmbeddedLdapAutoConfiguration javadoc
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 332
Configuration Class Links
EmbeddedMongoAutoConfiguration javadoc
EmbeddedServletContainerAutoConfiguration javadoc
ErrorMvcAutoConfiguration javadoc
FacebookAutoConfiguration javadoc
FallbackWebSecurityAutoConfiguration javadoc
FlywayAutoConfiguration javadoc
FreeMarkerAutoConfiguration javadoc
GroovyTemplateAutoConfiguration javadoc
GsonAutoConfiguration javadoc
H2ConsoleAutoConfiguration javadoc
HazelcastAutoConfiguration javadoc
HazelcastJpaDependencyAutoConfiguration javadoc
HibernateJpaAutoConfiguration javadoc
HttpEncodingAutoConfiguration javadoc
HttpMessageConvertersAutoConfiguration javadoc
HypermediaAutoConfiguration javadoc
IntegrationAutoConfiguration javadoc
JacksonAutoConfiguration javadoc
JdbcTemplateAutoConfiguration javadoc
JerseyAutoConfiguration javadoc
JestAutoConfiguration javadoc
JmsAutoConfiguration javadoc
JmxAutoConfiguration javadoc
JndiConnectionFactoryAutoConfiguration javadoc
JndiDataSourceAutoConfiguration javadoc
JooqAutoConfiguration javadoc
JpaRepositoriesAutoConfiguration javadoc
JtaAutoConfiguration javadoc
KafkaAutoConfiguration javadoc
LdapAutoConfiguration javadoc
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 333
Configuration Class Links
LdapDataAutoConfiguration javadoc
LdapRepositoriesAutoConfiguration javadoc
LinkedInAutoConfiguration javadoc
LiquibaseAutoConfiguration javadoc
MailSenderAutoConfiguration javadoc
MailSenderValidatorAutoConfiguration javadoc
MessageSourceAutoConfiguration javadoc
MongoAutoConfiguration javadoc
MongoDataAutoConfiguration javadoc
MongoRepositoriesAutoConfiguration javadoc
MultipartAutoConfiguration javadoc
MustacheAutoConfiguration javadoc
Neo4jDataAutoConfiguration javadoc
Neo4jRepositoriesAutoConfiguration javadoc
OAuth2AutoConfiguration javadoc
PersistenceExceptionTranslationAutoConfiguration javadoc
ProjectInfoAutoConfiguration javadoc
PropertyPlaceholderAutoConfiguration javadoc
RabbitAutoConfiguration javadoc
ReactorAutoConfiguration javadoc
RedisAutoConfiguration javadoc
RedisRepositoriesAutoConfiguration javadoc
RepositoryRestMvcAutoConfiguration javadoc
SecurityAutoConfiguration javadoc
SecurityFilterAutoConfiguration javadoc
SendGridAutoConfiguration javadoc
ServerPropertiesAutoConfiguration javadoc
SessionAutoConfiguration javadoc
SitePreferenceAutoConfiguration javadoc
SocialWebAutoConfiguration javadoc
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 334
Configuration Class Links
SolrAutoConfiguration javadoc
SolrRepositoriesAutoConfiguration javadoc
SpringApplicationAdminJmxAutoConfiguration javadoc
SpringDataWebAutoConfiguration javadoc
ThymeleafAutoConfiguration javadoc
TransactionAutoConfiguration javadoc
TwitterAutoConfiguration javadoc
ValidationAutoConfiguration javadoc
WebClientAutoConfiguration javadoc
WebMvcAutoConfiguration javadoc
WebServicesAutoConfiguration javadoc
WebSocketAutoConfiguration javadoc
WebSocketMessagingAutoConfiguration javadoc
XADataSourceAutoConfiguration javadoc
C.2 From the “spring-boot-actuator” module
The following auto-configuration classes are from the spring-boot-actuator module:
Configuration Class Links
AuditAutoConfiguration javadoc
CacheStatisticsAutoConfiguration javadoc
CloudFoundryActuatorAutoConfiguration javadoc
CrshAutoConfiguration javadoc
EndpointAutoConfiguration javadoc
EndpointMBeanExportAutoConfiguration javadoc
EndpointWebMvcAutoConfiguration javadoc
HealthIndicatorAutoConfiguration javadoc
InfoContributorAutoConfiguration javadoc
JolokiaAutoConfiguration javadoc
ManagementServerPropertiesAutoConfiguration javadoc
ManagementWebSecurityAutoConfiguration javadoc
MetricExportAutoConfiguration javadoc
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 335
Configuration Class Links
MetricFilterAutoConfiguration javadoc
MetricRepositoryAutoConfiguration javadoc
MetricsChannelAutoConfiguration javadoc
MetricsDropwizardAutoConfiguration javadoc
PublicMetricsAutoConfiguration javadoc
TraceRepositoryAutoConfiguration javadoc
TraceWebFilterAutoConfiguration javadoc
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 336
Appendix D. Test auto-configuration
annotations
Here is a table of 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
@DataMongoTest org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration
org.springframework.boot.autoconfigure.data.mongo.MongoDataAutoConfiguration
org.springframework.boot.autoconfigure.data.mongo.MongoRepositoriesAutoConfiguration
org.springframework.boot.autoconfigure.mongo.MongoAutoConfiguration
org.springframework.boot.autoconfigure.mongo.embedded.EmbeddedMongoAutoConfiguration
@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
org.springframework.boot.autoconfigure.transaction.TransactionAutoConfiguration
org.springframework.boot.test.autoconfigure.jdbc.TestDatabaseAutoConfiguration
@JsonTest org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration
org.springframework.boot.autoconfigure.gson.GsonAutoConfiguration
org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration
org.springframework.boot.test.autoconfigure.json.JsonTestersAutoConfiguration
@RestClientTest org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration
org.springframework.boot.autoconfigure.gson.GsonAutoConfiguration
org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration
org.springframework.boot.autoconfigure.web.HttpMessageConvertersAutoConfiguration
org.springframework.boot.autoconfigure.web.WebClientAutoConfiguration
org.springframework.boot.test.autoconfigure.web.client.MockRestServiceServerAutoConfiguration
org.springframework.boot.test.autoconfigure.web.client.WebClientRestTemplateAutoConfiguration
@WebMvcTest org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration
org.springframework.boot.autoconfigure.context.MessageSourceAutoConfiguration
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 337
Test slice Imported auto-configuration
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.jackson.JacksonAutoConfiguration
org.springframework.boot.autoconfigure.mustache.MustacheAutoConfiguration
org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration
org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration
org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration
org.springframework.boot.autoconfigure.web.HttpMessageConvertersAutoConfiguration
org.springframework.boot.autoconfigure.web.ServerPropertiesAutoConfiguration
org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration
org.springframework.boot.test.autoconfigure.web.servlet.MockMvcAutoConfiguration
org.springframework.boot.test.autoconfigure.web.servlet.MockMvcSecurityAutoConfiguration
org.springframework.boot.test.autoconfigure.web.servlet.MockMvcWebClientAutoConfiguration
org.springframework.boot.test.autoconfigure.web.servlet.MockMvcWebDriverAutoConfiguration
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 338
Appendix E. The executable jar
format
The spring-boot-loader modules allows Spring Boot to support executable jar and war files. If
you’re using the Maven or Gradle plugin, executable jars are automatically generated and you generally
won’t 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 (i.e. jar files that are themselves
contained within a jar). This can be problematic if you are looking to distribute a self-contained application
that you can just run from the command line without unpacking.
To solve this problem, many developers use “shaded” jars. A shaded jar simply 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 you are actually using 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 allows you
to 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
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 339
| +-springframework
| +-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 allows you to 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:
myapp.jar
+-------------------+-------------------------+
| /BOOT-INF/classes | /BOOT-INF/lib/mylib.jar |
|+-----------------+||+-----------+----------+|
|| A.class ||| B.class | C.class ||
|+-----------------+||+-----------+----------+|
+-------------------+-------------------------+
^ ^ ^
0063 3452 3980
The example above shows how A.class can be found in /BOOT-INF/classes in myapp.jar
position 0063. B.class from the nested jar can actually be found in myapp.jar position 3452 and
C.class is at position 3980.
Armed with this information, we can load specific nested entries by simply seeking to the appropriate
part of the outer jar. We don’t need to unpack the archive and we don’t 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 will return a URL that
opens a java.net.JarURLConnection compatible connection 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 jars main entry point. It is the actual Main-Class in your jar file and it’s used to
setup an appropriate URLClassLoader and ultimately call your main() method.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 340
There are 3 launcher subclasses (JarLauncher, WarLauncher and PropertiesLauncher). Their
purpose is to load resources (.class files etc.) from nested jar files or war files in directories (as
opposed to 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/ so you just 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 LOADER_PATH or loader.path in
loader.properties (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 (i.e. the class that you wrote that contains a
main method) should be specified in the Start-Class attribute.
For example, here is 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:
Main-Class: org.springframework.boot.loader.WarLauncher
Start-Class: com.mycompany.project.MyApplication
Note
You do not need to specify Class-Path entries in your manifest file, the classpath will be deduced
from the nested jars.
Exploded archives
Certain PaaS implementations may choose to unpack archives before they run. For example, Cloud
Foundry operates in this way. You can run an unpacked archive by simply starting the appropriate
launcher:
$ 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).
Note
PropertiesLauncher supports loading properties from loader.properties and also (for
historic reasons) application.properties. We recommend using loader.properties
exclusively, as support for application.properties is deprecated and may be removed in
the future.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 341
Key Purpose
loader.path Comma-separated Classpath, e.g. lib,
${HOME}/app/lib. Earlier entries take
precedence, just like a regular -classpath on
the javac command line.
loader.home Used to resolve relative paths in
loader.path. E.g. loader.path=lib then
${loader.home}/lib is a classpath location
(along with all jar files in that directory). Also
used to locate a loader.properties file.
Example /opt/app (defaults to ${user.dir}).
loader.args Default arguments for the main method (space
separated)
loader.main Name of main class to launch, e.g.
com.app.Application.
loader.config.name Name of properties file, e.g. launcher (defaults
to loader).
loader.config.location Path to properties file, e.g.
classpath:loader.properties (defaults to
loader.properties).
loader.system Boolean flag to indicate that all properties should
be added to System properties (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 are using that, specify the name of the class to launch using the Main-Class attribute
and leave out Start-Class.
•loader.properties are searched for in loader.home then in the root of the classpath, then in
classpath:/BOOT-INF/classes. The first location that exists is used.
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 342
•loader.home is only the directory location of an additional properties file (overriding the default) as
long as loader.config.location is not specified.
•loader.path can contain directories (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 env vars,
system properties, loader.properties, exploded archive manifest, archive manifest.
E.5 Executable jar restrictions
There are a number of restrictions that you need to consider when working with a Spring Boot Loader
packaged application.
Zip entry compression
The ZipEntry for a nested jar must be saved 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 will do this by default). Trying to load nested jar classes via
ClassLoader.getSystemClassLoader() will fail. Please be aware that 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 above restrictions mean that you cannot use Spring Boot Loader the following alternatives could
be considered:
•Maven Shade Plugin
•JarClassLoader
•OneJar
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 343
Appendix F. Dependency versions
The table below provides details of all of the dependency versions that are provided by Spring Boot in
its CLI, Maven dependency management and Gradle plugin. When you declare a dependency on one
of these artifacts without declaring a version the version that is listed in the table will be used.
Group ID Artifact ID Version
antlr antlr 2.7.7
ch.qos.logback logback-access 1.1.11
ch.qos.logback logback-classic 1.1.11
ch.qos.logback logback-core 1.1.11
com.atomikos transactions-jdbc 3.9.3
com.atomikos transactions-jms 3.9.3
com.atomikos transactions-jta 3.9.3
com.couchbase.client couchbase-spring-cache 2.1.0
com.couchbase.client java-client 2.3.7
com.datastax.cassandra cassandra-driver-core 3.1.4
com.datastax.cassandra cassandra-driver-
mapping
3.1.4
com.fasterxml classmate 1.3.4
com.fasterxml.jackson.corejackson-annotations 2.8.0
com.fasterxml.jackson.corejackson-core 2.8.10
com.fasterxml.jackson.corejackson-databind 2.8.10
com.fasterxml.jackson.dataformatjackson-dataformat-avro 2.8.10
com.fasterxml.jackson.dataformatjackson-dataformat-cbor 2.8.10
com.fasterxml.jackson.dataformatjackson-dataformat-csv 2.8.10
com.fasterxml.jackson.dataformatjackson-dataformat-ion 2.8.10
com.fasterxml.jackson.dataformatjackson-dataformat-
properties
2.8.10
com.fasterxml.jackson.dataformatjackson-dataformat-
protobuf
2.8.10
com.fasterxml.jackson.dataformatjackson-dataformat-
smile
2.8.10
com.fasterxml.jackson.dataformatjackson-dataformat-xml 2.8.10
com.fasterxml.jackson.dataformatjackson-dataformat-yaml 2.8.10
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 344
Group ID Artifact ID Version
com.fasterxml.jackson.datatypejackson-datatype-guava 2.8.10
com.fasterxml.jackson.datatypejackson-datatype-
hibernate3
2.8.10
com.fasterxml.jackson.datatypejackson-datatype-
hibernate4
2.8.10
com.fasterxml.jackson.datatypejackson-datatype-
hibernate5
2.8.10
com.fasterxml.jackson.datatypejackson-datatype-hppc 2.8.10
com.fasterxml.jackson.datatypejackson-datatype-jaxrs 2.8.10
com.fasterxml.jackson.datatypejackson-datatype-jdk8 2.8.10
com.fasterxml.jackson.datatypejackson-datatype-joda 2.8.10
com.fasterxml.jackson.datatypejackson-datatype-json-
org
2.8.10
com.fasterxml.jackson.datatypejackson-datatype-jsr310 2.8.10
com.fasterxml.jackson.datatypejackson-datatype-jsr353 2.8.10
com.fasterxml.jackson.datatypejackson-datatype-
pcollections
2.8.10
com.fasterxml.jackson.jaxrsjackson-jaxrs-base 2.8.10
com.fasterxml.jackson.jaxrsjackson-jaxrs-cbor-
provider
2.8.10
com.fasterxml.jackson.jaxrsjackson-jaxrs-json-
provider
2.8.10
com.fasterxml.jackson.jaxrsjackson-jaxrs-smile-
provider
2.8.10
com.fasterxml.jackson.jaxrsjackson-jaxrs-xml-
provider
2.8.10
com.fasterxml.jackson.jaxrsjackson-jaxrs-yaml-
provider
2.8.10
com.fasterxml.jackson.jr jackson-jr-all 2.8.10
com.fasterxml.jackson.jr jackson-jr-objects 2.8.10
com.fasterxml.jackson.jr jackson-jr-retrofit2 2.8.10
com.fasterxml.jackson.jr jackson-jr-stree 2.8.10
com.fasterxml.jackson.modulejackson-module-
afterburner
2.8.10
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 345
Group ID Artifact ID Version
com.fasterxml.jackson.modulejackson-module-guice 2.8.10
com.fasterxml.jackson.modulejackson-module-jaxb-
annotations
2.8.10
com.fasterxml.jackson.modulejackson-module-
jsonSchema
2.8.10
com.fasterxml.jackson.modulejackson-module-kotlin 2.8.10
com.fasterxml.jackson.modulejackson-module-mrbean 2.8.10
com.fasterxml.jackson.modulejackson-module-osgi 2.8.10
com.fasterxml.jackson.modulejackson-module-
parameter-names
2.8.10
com.fasterxml.jackson.modulejackson-module-
paranamer
2.8.10
com.fasterxml.jackson.modulejackson-module-
scala_2.10
2.8.10
com.fasterxml.jackson.modulejackson-module-
scala_2.11
2.8.10
com.fasterxml.jackson.modulejackson-module-
scala_2.12
2.8.10
com.gemstone.gemfire gemfire 8.2.4
com.github.ben-
manes.caffeine
caffeine 2.3.5
com.github.mxab.thymeleaf.extrasthymeleaf-extras-data-
attribute
1.3
com.google.appengine appengine-api-1.0-sdk 1.9.56
com.google.code.gson gson 2.8.1
com.googlecode.json-
simple
json-simple 1.1.1
com.h2database h2 1.4.196
com.hazelcast hazelcast 3.7.8
com.hazelcast hazelcast-client 3.7.8
com.hazelcast hazelcast-hibernate4 3.7.1
com.hazelcast hazelcast-hibernate5 1.1.3
com.hazelcast hazelcast-spring 3.7.8
com.jayway.jsonpath json-path 2.2.0
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 346
Group ID Artifact ID Version
com.jayway.jsonpath json-path-assert 2.2.0
com.microsoft.sqlserver mssql-jdbc 6.1.0.jre7
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.samskivert jmustache 1.13
com.sendgrid sendgrid-java 2.2.2
com.sun.mail javax.mail 1.5.6
com.timgroup java-statsd-client 3.1.0
com.unboundid unboundid-ldapsdk 3.2.1
com.zaxxer HikariCP 2.5.1
com.zaxxer HikariCP-java6 2.3.13
com.zaxxer HikariCP-java7 2.4.13
commons-beanutils commons-beanutils 1.9.3
commons-codec commons-codec 1.10
commons-collections commons-collections 3.2.2
commons-dbcp commons-dbcp 1.4
commons-digester commons-digester 2.1
commons-pool commons-pool 1.6
de.flapdoodle.embed de.flapdoodle.embed.mongo1.50.5
dom4j dom4j 1.6.1
io.dropwizard.metrics metrics-core 3.1.5
io.dropwizard.metrics metrics-ganglia 3.1.5
io.dropwizard.metrics metrics-graphite 3.1.5
io.dropwizard.metrics metrics-servlets 3.1.5
io.projectreactor reactor-bus 2.0.8.RELEASE
io.projectreactor reactor-core 2.0.8.RELEASE
io.projectreactor reactor-groovy 2.0.8.RELEASE
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 347
Group ID Artifact ID Version
io.projectreactor reactor-groovy-
extensions
2.0.8.RELEASE
io.projectreactor reactor-logback 2.0.8.RELEASE
io.projectreactor reactor-net 2.0.8.RELEASE
io.projectreactor reactor-stream 2.0.8.RELEASE
io.projectreactor.spring reactor-spring-context 2.0.7.RELEASE
io.projectreactor.spring reactor-spring-core 2.0.7.RELEASE
io.projectreactor.spring reactor-spring-
messaging
2.0.7.RELEASE
io.projectreactor.spring reactor-spring-webmvc 2.0.7.RELEASE
io.searchbox jest 2.0.4
io.undertow undertow-core 1.4.20.Final
io.undertow undertow-servlet 1.4.20.Final
io.undertow undertow-websockets-jsr 1.4.20.Final
javax.cache cache-api 1.0.0
javax.jms jms-api 1.1-rev-1
javax.mail javax.mail-api 1.5.6
javax.servlet javax.servlet-api 3.1.0
javax.servlet jstl 1.2
javax.transaction javax.transaction-api 1.2
javax.validation validation-api 1.1.0.Final
jaxen jaxen 1.1.6
joda-time joda-time 2.9.9
junit junit 4.12
mysql mysql-connector-java 5.1.44
net.java.dev.jna jna 4.2.2
net.sf.ehcache ehcache 2.10.4
net.sourceforge.htmlunit htmlunit 2.21
net.sourceforge.jtds jtds 1.3.1
net.sourceforge.nekohtml nekohtml 1.9.22
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 348
Group ID Artifact ID Version
nz.net.ultraq.thymeleaf thymeleaf-layout-
dialect
1.4.0
org.apache.activemq activemq-amqp 5.14.5
org.apache.activemq activemq-blueprint 5.14.5
org.apache.activemq activemq-broker 5.14.5
org.apache.activemq activemq-camel 5.14.5
org.apache.activemq activemq-client 5.14.5
org.apache.activemq activemq-console 5.14.5
org.apache.activemq activemq-http 5.14.5
org.apache.activemq activemq-jaas 5.14.5
org.apache.activemq activemq-jdbc-store 5.14.5
org.apache.activemq activemq-jms-pool 5.14.5
org.apache.activemq activemq-kahadb-store 5.14.5
org.apache.activemq activemq-karaf 5.14.5
org.apache.activemq activemq-leveldb-store 5.14.5
org.apache.activemq activemq-log4j-appender 5.14.5
org.apache.activemq activemq-mqtt 5.14.5
org.apache.activemq activemq-openwire-
generator
5.14.5
org.apache.activemq activemq-openwire-
legacy
5.14.5
org.apache.activemq activemq-osgi 5.14.5
org.apache.activemq activemq-partition 5.14.5
org.apache.activemq activemq-pool 5.14.5
org.apache.activemq activemq-ra 5.14.5
org.apache.activemq activemq-run 5.14.5
org.apache.activemq activemq-runtime-config 5.14.5
org.apache.activemq activemq-shiro 5.14.5
org.apache.activemq activemq-spring 5.14.5
org.apache.activemq activemq-stomp 5.14.5
org.apache.activemq activemq-web 5.14.5
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 349
Group ID Artifact ID Version
org.apache.activemq artemis-amqp-protocol 1.5.5
org.apache.activemq artemis-commons 1.5.5
org.apache.activemq artemis-core-client 1.5.5
org.apache.activemq artemis-jms-client 1.5.5
org.apache.activemq artemis-jms-server 1.5.5
org.apache.activemq artemis-journal 1.5.5
org.apache.activemq artemis-native 1.5.5
org.apache.activemq artemis-selector 1.5.5
org.apache.activemq artemis-server 1.5.5
org.apache.activemq artemis-service-
extensions
1.5.5
org.apache.commons commons-dbcp2 2.1.1
org.apache.commons commons-pool2 2.4.2
org.apache.derby derby 10.13.1.1
org.apache.httpcomponentshttpasyncclient 4.1.3
org.apache.httpcomponentshttpclient 4.5.3
org.apache.httpcomponentshttpcore 4.4.6
org.apache.httpcomponentshttpmime 4.5.3
org.apache.logging.log4j log4j-1.2-api 2.7
org.apache.logging.log4j log4j-api 2.7
org.apache.logging.log4j log4j-api-scala_2.10 2.7
org.apache.logging.log4j log4j-api-scala_2.11 2.7
org.apache.logging.log4j log4j-core 2.7
org.apache.logging.log4j log4j-flume-ng 2.7
org.apache.logging.log4j log4j-iostreams 2.7
org.apache.logging.log4j log4j-jcl 2.7
org.apache.logging.log4j log4j-jmx-gui 2.7
org.apache.logging.log4j log4j-jul 2.7
org.apache.logging.log4j log4j-liquibase 2.7
org.apache.logging.log4j log4j-nosql 2.7
org.apache.logging.log4j log4j-slf4j-impl 2.7
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 350
Group ID Artifact ID Version
org.apache.logging.log4j log4j-taglib 2.7
org.apache.logging.log4j log4j-web 2.7
org.apache.solr solr-solrj 5.5.4
org.apache.tomcat tomcat-jdbc 8.5.20
org.apache.tomcat tomcat-jsp-api 8.5.20
org.apache.tomcat.embed tomcat-embed-core 8.5.20
org.apache.tomcat.embed tomcat-embed-el 8.5.20
org.apache.tomcat.embed tomcat-embed-jasper 8.5.20
org.apache.tomcat.embed tomcat-embed-websocket 8.5.20
org.aspectj aspectjrt 1.8.10
org.aspectj aspectjtools 1.8.10
org.aspectj aspectjweaver 1.8.10
org.assertj assertj-core 2.6.0
org.codehaus.btm btm 2.1.4
org.codehaus.groovy groovy 2.4.12
org.codehaus.groovy groovy-all 2.4.12
org.codehaus.groovy groovy-ant 2.4.12
org.codehaus.groovy groovy-bsf 2.4.12
org.codehaus.groovy groovy-console 2.4.12
org.codehaus.groovy groovy-docgenerator 2.4.12
org.codehaus.groovy groovy-groovydoc 2.4.12
org.codehaus.groovy groovy-groovysh 2.4.12
org.codehaus.groovy groovy-jmx 2.4.12
org.codehaus.groovy groovy-json 2.4.12
org.codehaus.groovy groovy-jsr223 2.4.12
org.codehaus.groovy groovy-nio 2.4.12
org.codehaus.groovy groovy-servlet 2.4.12
org.codehaus.groovy groovy-sql 2.4.12
org.codehaus.groovy groovy-swing 2.4.12
org.codehaus.groovy groovy-templates 2.4.12
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 351
Group ID Artifact ID Version
org.codehaus.groovy groovy-test 2.4.12
org.codehaus.groovy groovy-testng 2.4.12
org.codehaus.groovy groovy-xml 2.4.12
org.codehaus.janino janino 2.7.8
org.crashub crash.cli 1.3.2
org.crashub crash.connectors.ssh 1.3.2
org.crashub crash.connectors.telnet 1.3.2
org.crashub crash.embed.spring 1.3.2
org.crashub crash.plugins.cron 1.3.2
org.crashub crash.plugins.mail 1.3.2
org.crashub crash.shell 1.3.2
org.eclipse.jetty apache-jsp 9.4.6.v20170531
org.eclipse.jetty apache-jstl 9.4.6.v20170531
org.eclipse.jetty jetty-annotations 9.4.6.v20170531
org.eclipse.jetty jetty-client 9.4.6.v20170531
org.eclipse.jetty jetty-continuation 9.4.6.v20170531
org.eclipse.jetty jetty-deploy 9.4.6.v20170531
org.eclipse.jetty jetty-http 9.4.6.v20170531
org.eclipse.jetty jetty-http-spi 9.4.6.v20170531
org.eclipse.jetty jetty-infinispan 9.4.6.v20170531
org.eclipse.jetty jetty-io 9.4.6.v20170531
org.eclipse.jetty jetty-jaas 9.4.6.v20170531
org.eclipse.jetty jetty-jaspi 9.4.6.v20170531
org.eclipse.jetty jetty-jmx 9.4.6.v20170531
org.eclipse.jetty jetty-jndi 9.4.6.v20170531
org.eclipse.jetty jetty-nosql 9.4.6.v20170531
org.eclipse.jetty jetty-plus 9.4.6.v20170531
org.eclipse.jetty jetty-proxy 9.4.6.v20170531
org.eclipse.jetty jetty-quickstart 9.4.6.v20170531
org.eclipse.jetty jetty-rewrite 9.4.6.v20170531
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 352
Group ID Artifact ID Version
org.eclipse.jetty jetty-runner 9.4.6.v20170531
org.eclipse.jetty jetty-security 9.4.6.v20170531
org.eclipse.jetty jetty-server 9.4.6.v20170531
org.eclipse.jetty jetty-servlet 9.4.6.v20170531
org.eclipse.jetty jetty-servlets 9.4.6.v20170531
org.eclipse.jetty jetty-spring 9.4.6.v20170531
org.eclipse.jetty jetty-start 9.4.6.v20170531
org.eclipse.jetty jetty-util 9.4.6.v20170531
org.eclipse.jetty jetty-util-ajax 9.4.6.v20170531
org.eclipse.jetty jetty-webapp 9.4.6.v20170531
org.eclipse.jetty jetty-xml 9.4.6.v20170531
org.eclipse.jetty.http2 http2-client 9.4.6.v20170531
org.eclipse.jetty.http2 http2-common 9.4.6.v20170531
org.eclipse.jetty.http2 http2-hpack 9.4.6.v20170531
org.eclipse.jetty.http2 http2-server 9.4.6.v20170531
org.eclipse.jetty.orbit javax.servlet.jsp 2.2.0.v201112011158
org.eclipse.jetty.websocketjavax-websocket-client-
impl
9.4.6.v20170531
org.eclipse.jetty.websocketjavax-websocket-server-
impl
9.4.6.v20170531
org.eclipse.jetty.websocketwebsocket-client 9.4.6.v20170531
org.eclipse.jetty.websocketwebsocket-server 9.4.6.v20170531
org.eclipse.jetty.websocketwebsocket-servlet 9.4.6.v20170531
org.ehcache ehcache 3.2.3
org.ehcache ehcache-clustered 3.2.3
org.ehcache ehcache-transactions 3.2.3
org.elasticsearch elasticsearch 2.4.6
org.firebirdsql.jdbc jaybird-jdk16 2.2.13
org.firebirdsql.jdbc jaybird-jdk17 2.2.13
org.firebirdsql.jdbc jaybird-jdk18 2.2.13
org.flywaydb flyway-core 3.2.1
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 353
Group ID Artifact ID Version
org.freemarker freemarker 2.3.26-incubating
org.glassfish javax.el 3.0.0
org.glassfish.jersey.bundles.repackagedjersey-guava 2.25.1
org.glassfish.jersey.containersjersey-container-
servlet
2.25.1
org.glassfish.jersey.containersjersey-container-
servlet-core
2.25.1
org.glassfish.jersey.corejersey-client 2.25.1
org.glassfish.jersey.corejersey-common 2.25.1
org.glassfish.jersey.corejersey-server 2.25.1
org.glassfish.jersey.ext jersey-bean-validation 2.25.1
org.glassfish.jersey.ext jersey-entity-filtering 2.25.1
org.glassfish.jersey.ext jersey-spring3 2.25.1
org.glassfish.jersey.mediajersey-media-jaxb 2.25.1
org.glassfish.jersey.mediajersey-media-json-
jackson
2.25.1
org.glassfish.jersey.mediajersey-media-multipart 2.25.1
org.hamcrest hamcrest-core 1.3
org.hamcrest hamcrest-library 1.3
org.hibernate hibernate-core 5.0.12.Final
org.hibernate hibernate-ehcache 5.0.12.Final
org.hibernate hibernate-entitymanager 5.0.12.Final
org.hibernate hibernate-envers 5.0.12.Final
org.hibernate hibernate-java8 5.0.12.Final
org.hibernate hibernate-jpamodelgen 5.0.12.Final
org.hibernate hibernate-validator 5.3.5.Final
org.hibernate hibernate-validator-
annotation-processor
5.3.5.Final
org.hsqldb hsqldb 2.3.5
org.infinispan infinispan-jcache 8.2.8.Final
org.infinispan infinispan-spring4-
common
8.2.8.Final
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 354
Group ID Artifact ID Version
org.infinispan infinispan-spring4-
embedded
8.2.8.Final
org.javassist javassist 3.21.0-GA
org.jboss jboss-transaction-spi 7.6.0.Final
org.jboss.logging jboss-logging 3.3.1.Final
org.jboss.narayana.jta jdbc 5.5.30.Final
org.jboss.narayana.jta jms 5.5.30.Final
org.jboss.narayana.jta jta 5.5.30.Final
org.jboss.narayana.jts narayana-jts-
integration
5.5.30.Final
org.jdom jdom2 2.0.6
org.jolokia jolokia-core 1.3.7
org.jooq jooq 3.9.5
org.jooq jooq-codegen 3.9.5
org.jooq jooq-meta 3.9.5
org.json json 20140107
org.liquibase liquibase-core 3.5.3
org.mariadb.jdbc mariadb-java-client 1.5.9
org.mockito mockito-core 1.10.19
org.mongodb mongodb-driver 3.4.3
org.mongodb mongo-java-driver 3.4.3
org.mortbay.jasper apache-el 8.0.33
org.neo4j neo4j-ogm-api 2.1.5
org.neo4j neo4j-ogm-compiler 2.1.5
org.neo4j neo4j-ogm-core 2.1.5
org.neo4j neo4j-ogm-http-driver 2.1.5
org.postgresql postgresql 9.4.1212.jre7
org.projectlombok lombok 1.16.18
org.seleniumhq.selenium htmlunit-driver 2.21
org.seleniumhq.selenium selenium-api 2.53.1
org.seleniumhq.selenium selenium-chrome-driver 2.53.1
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 355
Group ID Artifact ID Version
org.seleniumhq.selenium selenium-firefox-driver 2.53.1
org.seleniumhq.selenium selenium-ie-driver 2.53.1
org.seleniumhq.selenium selenium-java 2.53.1
org.seleniumhq.selenium selenium-remote-driver 2.53.1
org.seleniumhq.selenium selenium-safari-driver 2.53.1
org.seleniumhq.selenium selenium-support 2.53.1
org.skyscreamer jsonassert 1.4.0
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-jdk14 1.7.25
org.slf4j slf4j-log4j12 1.7.25
org.slf4j slf4j-simple 1.7.25
org.spockframework spock-core 1.0-groovy-2.4
org.spockframework spock-spring 1.0-groovy-2.4
org.springframework spring-aop 4.3.11.RELEASE
org.springframework spring-aspects 4.3.11.RELEASE
org.springframework spring-beans 4.3.11.RELEASE
org.springframework spring-context 4.3.11.RELEASE
org.springframework spring-context-support 4.3.11.RELEASE
org.springframework spring-core 4.3.11.RELEASE
org.springframework spring-expression 4.3.11.RELEASE
org.springframework spring-instrument 4.3.11.RELEASE
org.springframework spring-instrument-
tomcat
4.3.11.RELEASE
org.springframework spring-jdbc 4.3.11.RELEASE
org.springframework spring-jms 4.3.11.RELEASE
org.springframework springloaded 1.2.8.RELEASE
org.springframework spring-messaging 4.3.11.RELEASE
org.springframework spring-orm 4.3.11.RELEASE
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 356
Group ID Artifact ID Version
org.springframework spring-oxm 4.3.11.RELEASE
org.springframework spring-test 4.3.11.RELEASE
org.springframework spring-tx 4.3.11.RELEASE
org.springframework spring-web 4.3.11.RELEASE
org.springframework spring-webmvc 4.3.11.RELEASE
org.springframework spring-webmvc-portlet 4.3.11.RELEASE
org.springframework spring-websocket 4.3.11.RELEASE
org.springframework.amqp spring-amqp 1.7.4.RELEASE
org.springframework.amqp spring-rabbit 1.7.4.RELEASE
org.springframework.batchspring-batch-core 3.0.8.RELEASE
org.springframework.batchspring-batch-
infrastructure
3.0.8.RELEASE
org.springframework.batchspring-batch-
integration
3.0.8.RELEASE
org.springframework.batchspring-batch-test 3.0.8.RELEASE
org.springframework.boot spring-boot 1.5.7.RELEASE
org.springframework.boot spring-boot-actuator 1.5.7.RELEASE
org.springframework.boot spring-boot-actuator-
docs
1.5.7.RELEASE
org.springframework.boot spring-boot-
autoconfigure
1.5.7.RELEASE
org.springframework.boot spring-boot-
autoconfigure-processor
1.5.7.RELEASE
org.springframework.boot spring-boot-
configuration-metadata
1.5.7.RELEASE
org.springframework.boot spring-boot-
configuration-processor
1.5.7.RELEASE
org.springframework.boot spring-boot-devtools 1.5.7.RELEASE
org.springframework.boot spring-boot-loader 1.5.7.RELEASE
org.springframework.boot spring-boot-loader-
tools
1.5.7.RELEASE
org.springframework.boot spring-boot-starter 1.5.7.RELEASE
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 357
Group ID Artifact ID Version
org.springframework.boot spring-boot-starter-
activemq
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
actuator
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
amqp
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-aop 1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
artemis
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
batch
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
cache
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
cloud-connectors
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
data-cassandra
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
data-couchbase
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
data-elasticsearch
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
data-gemfire
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
data-jpa
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
data-ldap
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
data-mongodb
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
data-neo4j
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
data-redis
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
data-rest
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
data-solr
1.5.7.RELEASE
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 358
Group ID Artifact ID Version
org.springframework.boot spring-boot-starter-
freemarker
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
groovy-templates
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
hateoas
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
integration
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
jdbc
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
jersey
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
jetty
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
jooq
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
jta-atomikos
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
jta-bitronix
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
jta-narayana
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
log4j2
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
logging
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
mail
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
mobile
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
mustache
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
remote-shell
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
security
1.5.7.RELEASE
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 359
Group ID Artifact ID Version
org.springframework.boot spring-boot-starter-
social-facebook
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
social-linkedin
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
social-twitter
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
test
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
thymeleaf
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
tomcat
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
undertow
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
validation
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-web 1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
web-services
1.5.7.RELEASE
org.springframework.boot spring-boot-starter-
websocket
1.5.7.RELEASE
org.springframework.boot spring-boot-test 1.5.7.RELEASE
org.springframework.boot spring-boot-test-
autoconfigure
1.5.7.RELEASE
org.springframework.cloudspring-cloud-
cloudfoundry-connector
1.2.4.RELEASE
org.springframework.cloudspring-cloud-core 1.2.4.RELEASE
org.springframework.cloudspring-cloud-heroku-
connector
1.2.4.RELEASE
org.springframework.cloudspring-cloud-
localconfig-connector
1.2.4.RELEASE
org.springframework.cloudspring-cloud-spring-
service-connector
1.2.4.RELEASE
org.springframework.data spring-cql 1.5.7.RELEASE
org.springframework.data spring-data-cassandra 1.5.7.RELEASE
org.springframework.data spring-data-commons 1.13.7.RELEASE
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 360
Group ID Artifact ID Version
org.springframework.data spring-data-couchbase 2.2.7.RELEASE
org.springframework.data spring-data-
elasticsearch
2.1.7.RELEASE
org.springframework.data spring-data-envers 1.1.7.RELEASE
org.springframework.data spring-data-gemfire 1.9.7.RELEASE
org.springframework.data spring-data-jpa 1.11.7.RELEASE
org.springframework.data spring-data-keyvalue 1.2.7.RELEASE
org.springframework.data spring-data-ldap 1.0.7.RELEASE
org.springframework.data spring-data-mongodb 1.10.7.RELEASE
org.springframework.data spring-data-mongodb-
cross-store
1.10.7.RELEASE
org.springframework.data spring-data-mongodb-
log4j
1.10.7.RELEASE
org.springframework.data spring-data-neo4j 4.2.7.RELEASE
org.springframework.data spring-data-redis 1.8.7.RELEASE
org.springframework.data spring-data-rest-core 2.6.7.RELEASE
org.springframework.data spring-data-rest-hal-
browser
2.6.7.RELEASE
org.springframework.data spring-data-rest-webmvc 2.6.7.RELEASE
org.springframework.data spring-data-solr 2.1.7.RELEASE
org.springframework.hateoasspring-hateoas 0.23.0.RELEASE
org.springframework.integrationspring-integration-amqp 4.3.12.RELEASE
org.springframework.integrationspring-integration-core 4.3.12.RELEASE
org.springframework.integrationspring-integration-
event
4.3.12.RELEASE
org.springframework.integrationspring-integration-feed 4.3.12.RELEASE
org.springframework.integrationspring-integration-file 4.3.12.RELEASE
org.springframework.integrationspring-integration-ftp 4.3.12.RELEASE
org.springframework.integrationspring-integration-
gemfire
4.3.12.RELEASE
org.springframework.integrationspring-integration-
groovy
4.3.12.RELEASE
org.springframework.integrationspring-integration-http 4.3.12.RELEASE
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 361
Group ID Artifact ID Version
org.springframework.integrationspring-integration-ip 4.3.12.RELEASE
org.springframework.integrationspring-integration-
java-dsl
1.2.3.RELEASE
org.springframework.integrationspring-integration-jdbc 4.3.12.RELEASE
org.springframework.integrationspring-integration-jms 4.3.12.RELEASE
org.springframework.integrationspring-integration-jmx 4.3.12.RELEASE
org.springframework.integrationspring-integration-jpa 4.3.12.RELEASE
org.springframework.integrationspring-integration-mail 4.3.12.RELEASE
org.springframework.integrationspring-integration-
mongodb
4.3.12.RELEASE
org.springframework.integrationspring-integration-mqtt 4.3.12.RELEASE
org.springframework.integrationspring-integration-
redis
4.3.12.RELEASE
org.springframework.integrationspring-integration-rmi 4.3.12.RELEASE
org.springframework.integrationspring-integration-
scripting
4.3.12.RELEASE
org.springframework.integrationspring-integration-
security
4.3.12.RELEASE
org.springframework.integrationspring-integration-sftp 4.3.12.RELEASE
org.springframework.integrationspring-integration-
stomp
4.3.12.RELEASE
org.springframework.integrationspring-integration-
stream
4.3.12.RELEASE
org.springframework.integrationspring-integration-
syslog
4.3.12.RELEASE
org.springframework.integrationspring-integration-test 4.3.12.RELEASE
org.springframework.integrationspring-integration-
twitter
4.3.12.RELEASE
org.springframework.integrationspring-integration-
websocket
4.3.12.RELEASE
org.springframework.integrationspring-integration-ws 4.3.12.RELEASE
org.springframework.integrationspring-integration-xml 4.3.12.RELEASE
org.springframework.integrationspring-integration-xmpp 4.3.12.RELEASE
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 362
Group ID Artifact ID Version
org.springframework.integrationspring-integration-
zookeeper
4.3.12.RELEASE
org.springframework.kafkaspring-kafka 1.1.6.RELEASE
org.springframework.kafkaspring-kafka-test 1.1.6.RELEASE
org.springframework.ldap spring-ldap-core 2.3.1.RELEASE
org.springframework.ldap spring-ldap-core-tiger 2.3.1.RELEASE
org.springframework.ldap spring-ldap-ldif-batch 2.3.1.RELEASE
org.springframework.ldap spring-ldap-ldif-core 2.3.1.RELEASE
org.springframework.ldap spring-ldap-odm 2.3.1.RELEASE
org.springframework.ldap spring-ldap-test 2.3.1.RELEASE
org.springframework.mobilespring-mobile-device 1.1.5.RELEASE
org.springframework.pluginspring-plugin-core 1.2.0.RELEASE
org.springframework.pluginspring-plugin-metadata 1.2.0.RELEASE
org.springframework.restdocsspring-restdocs-core 1.1.3.RELEASE
org.springframework.restdocsspring-restdocs-mockmvc 1.1.3.RELEASE
org.springframework.restdocsspring-restdocs-
restassured
1.1.3.RELEASE
org.springframework.retryspring-retry 1.2.1.RELEASE
org.springframework.securityspring-security-acl 4.2.3.RELEASE
org.springframework.securityspring-security-aspects 4.2.3.RELEASE
org.springframework.securityspring-security-cas 4.2.3.RELEASE
org.springframework.securityspring-security-config 4.2.3.RELEASE
org.springframework.securityspring-security-core 4.2.3.RELEASE
org.springframework.securityspring-security-crypto 4.2.3.RELEASE
org.springframework.securityspring-security-data 4.2.3.RELEASE
org.springframework.securityspring-security-jwt 1.0.8.RELEASE
org.springframework.securityspring-security-ldap 4.2.3.RELEASE
org.springframework.securityspring-security-
messaging
4.2.3.RELEASE
org.springframework.securityspring-security-openid 4.2.3.RELEASE
org.springframework.securityspring-security-
remoting
4.2.3.RELEASE
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 363
Group ID Artifact ID Version
org.springframework.securityspring-security-taglibs 4.2.3.RELEASE
org.springframework.securityspring-security-test 4.2.3.RELEASE
org.springframework.securityspring-security-web 4.2.3.RELEASE
org.springframework.security.oauthspring-security-oauth 2.0.14.RELEASE
org.springframework.security.oauthspring-security-oauth2 2.0.14.RELEASE
org.springframework.sessionspring-session 1.3.1.RELEASE
org.springframework.sessionspring-session-data-
gemfire
1.3.1.RELEASE
org.springframework.sessionspring-session-data-
mongo
1.3.1.RELEASE
org.springframework.sessionspring-session-data-
redis
1.3.1.RELEASE
org.springframework.sessionspring-session-
hazelcast
1.3.1.RELEASE
org.springframework.sessionspring-session-jdbc 1.3.1.RELEASE
org.springframework.socialspring-social-config 1.1.4.RELEASE
org.springframework.socialspring-social-core 1.1.4.RELEASE
org.springframework.socialspring-social-facebook 2.0.3.RELEASE
org.springframework.socialspring-social-facebook-
web
2.0.3.RELEASE
org.springframework.socialspring-social-linkedin 1.0.2.RELEASE
org.springframework.socialspring-social-security 1.1.4.RELEASE
org.springframework.socialspring-social-twitter 1.1.2.RELEASE
org.springframework.socialspring-social-web 1.1.4.RELEASE
org.springframework.ws spring-ws-core 2.4.0.RELEASE
org.springframework.ws spring-ws-security 2.4.0.RELEASE
org.springframework.ws spring-ws-support 2.4.0.RELEASE
org.springframework.ws spring-ws-test 2.4.0.RELEASE
org.thymeleaf thymeleaf 2.1.5.RELEASE
org.thymeleaf thymeleaf-spring4 2.1.5.RELEASE
org.thymeleaf.extras thymeleaf-extras-
conditionalcomments
2.1.2.RELEASE
Spring Boot Reference Guide
1.5.7.RELEASE Spring Boot 364
Group ID Artifact ID Version
org.thymeleaf.extras thymeleaf-extras-
java8time
2.1.0.RELEASE
org.thymeleaf.extras thymeleaf-extras-
springsecurity4
2.1.3.RELEASE
org.webjars hal-browser 9f96c74
org.webjars webjars-locator 0.32-1
org.xerial sqlite-jdbc 3.15.1
org.yaml snakeyaml 1.17
redis.clients jedis 2.9.0
wsdl4j wsdl4j 1.6.3
xml-apis xml-apis 1.4.01

Navigation menu