Spring Boot Reference Guide

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Spring Boot Reference Guide
Authors
Phillip Webb, Dave Syer, Josh Long, Stéphane Nicoll, Rob Winch, Andy Wilkinson, Marcel Overdijk, Christian Dupuis, Sébastien Deleuze, Michael
Simons
1.5.9.RELEASE
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.
Table of Contents
I. Spring Boot Documentation
1. About the documentation
2. Getting help
3. First steps
4. Working with Spring Boot
5. Learning about Spring Boot features
6. Moving to production
7. Advanced topics
II. Getting started
8. Introducing Spring Boot
9. System Requirements
9.1. Servlet containers
10. Installing Spring Boot
10.1. Installation instructions for the Java developer
10.1.1. Maven installation
10.1.2. Gradle installation
10.2. Installing the Spring Boot CLI
10.2.1. Manual installation
10.2.2. Installation with SDKMAN!
10.2.3. OSX Homebrew installation
10.2.4. MacPorts installation
10.2.5. Command-line completion
10.2.6. Quick start Spring CLI example
10.3. Upgrading from an earlier version of Spring Boot
11. Developing your first Spring Boot application
11.1. Creating the POM

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2. Adding classpath dependencies
3. Writing the code
3.1. The @RestController and @RequestMapping annotations
3.2. The @EnableAutoConfiguration annotation
3.3. The “main” method
4. Running the example
5. Creating an executable jar
What to read next
III. Using Spring Boot
Build systems
1. Dependency management
2. Maven
2.1. Inheriting the starter parent
2.2. Using Spring Boot without the parent POM
2.3. Changing the Java version
2.4. Using the Spring Boot Maven plugin
3. Gradle
4. Ant
5. Starters
Structuring your code
1. Using the “default” package
2. Locating the main application class
Configuration classes
1. Importing additional configuration classes
2. Importing XML configuration
Auto-configuration
1. Gradually replacing auto-configuration
2. Disabling specific auto-configuration
Spring Beans and dependency injection
Using the @SpringBootApplication annotation
Running your application
1. Running from an IDE
2. Running as a packaged application
3. Using the Maven plugin
4. Using the Gradle plugin
5. Hot swapping
Developer tools
1. Property defaults
2. Automatic restart
2.1. Excluding resources
2.2. Watching additional paths
2.3. Disabling restart
2.4. Using a trigger file

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2.5. Customizing the restart classloader
2.6. Known limitations
3. LiveReload
4. Global settings
5. Remote applications
5.1. Running the remote client application
5.2. Remote update
5.3. Remote debug tunnel
Packaging your application for production
What to read next
IV. Spring Boot features
SpringApplication
1. Startup failure
2. Customizing the Banner
3. Customizing SpringApplication
4. Fluent builder API
5. Application events and listeners
6. Web environment
7. Accessing application arguments
8. Using the ApplicationRunner or CommandLineRunner
9. Application exit
10. Admin features
Externalized Configuration
1. Configuring random values
2. Accessing command line properties
3. Application property files
4. Profile-specific properties
5. Placeholders in properties
6. Using YAML instead of Properties
6.1. Loading YAML
6.2. Exposing YAML as properties in the Spring Environment
6.3. Multi-profile YAML documents
6.4. YAML shortcomings
6.5. Merging YAML lists
7. Type-safe Configuration Properties
7.1. Third-party configuration
7.2. Relaxed binding
7.3. Properties conversion
7.4. @ConfigurationProperties Validation
7.5. @ConfigurationProperties vs. @Value
Profiles
1. Adding active profiles
2. Programmatically setting profiles
3. Profile-specific configuration files
Logging

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1. Log format
2. Console output
2.1. Color-coded output
3. File output
4. Log Levels
5. Custom log configuration
6. Logback extensions
6.1. Profile-specific configuration
6.2. Environment properties
Developing web applications
1. The ‘Spring Web MVC framework’
1.1. Spring MVC auto-configuration
1.2. HttpMessageConverters
1.3. Custom JSON Serializers and Deserializers
1.4. MessageCodesResolver
1.5. Static Content
1.6. Custom Favicon
1.7. ConfigurableWebBindingInitializer
1.8. Template engines
1.9. Error Handling
Custom error pages
Mapping error pages outside of Spring MVC
Error Handling on WebSphere Application Server
1.10. Spring HATEOAS
1.11. CORS support
2. JAX-RS and Jersey
3. Embedded servlet container support
3.1. Servlets, Filters, and listeners
Registering Servlets, Filters, and listeners as Spring beans
3.2. Servlet Context Initialization
Scanning for Servlets, Filters, and listeners
3.3. The EmbeddedWebApplicationContext
3.4. Customizing embedded servlet containers
Programmatic customization
Customizing ConfigurableEmbeddedServletContainer directly
3.5. JSP limitations
Security
1. OAuth2
1.1. Authorization Server
1.2. Resource Server
2. Token Type in User Info
3. Customizing the User Info RestTemplate
3.1. Client
3.2. Single Sign On
4. Actuator Security
Working with SQL databases
1. Configure a DataSource
1.1. Embedded Database Support
1.2. Connection to a production database
1.3. Connection to a JNDI DataSource
2. Using JdbcTemplate
3. JPA and ‘Spring Data’
3.1. Entity Classes
3.2. Spring Data JPA Repositories
3.3. Creating and dropping JPA databases
3.4. Open EntityManager in View
4. Using H2’s web console

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4.1. Changing the H2 console’s path
4.2. Securing the H2 console
5. Using jOOQ
5.1. Code Generation
5.2. Using DSLContext
5.3. Customizing jOOQ
Working with NoSQL technologies
1. Redis
1.1. Connecting to Redis
2. MongoDB
2.1. Connecting to a MongoDB database
2.2. MongoTemplate
2.3. Spring Data MongoDB repositories
2.4. Embedded Mongo
3. Neo4j
3.1. Connecting to a Neo4j database
3.2. Using the embedded mode
3.3. Neo4jSession
3.4. Spring Data Neo4j repositories
3.5. Repository example
4. Gemfire
5. Solr
5.1. Connecting to Solr
5.2. Spring Data Solr repositories
6. Elasticsearch
6.1. Connecting to Elasticsearch using Jest
6.2. Connecting to Elasticsearch using Spring Data
6.3. Spring Data Elasticsearch repositories
7. Cassandra
7.1. Connecting to Cassandra
7.2. Spring Data Cassandra repositories
8. Couchbase
8.1. Connecting to Couchbase
8.2. Spring Data Couchbase repositories
9. LDAP
9.1. Connecting to an LDAP server
9.2. Spring Data LDAP repositories
9.3. Embedded in-memory LDAP server
Caching
1. Supported cache providers
1.1. Generic
1.2. JCache (JSR-107)
1.3. EhCache 2.x
1.4. Hazelcast
1.5. Infinispan
1.6. Couchbase
1.7. Redis
1.8. Caffeine
1.9. Guava (deprecated)
1.10. Simple
1.11. None
Messaging
1. JMS
1.1. ActiveMQ support
1.2. Artemis support
1.3. Using a JNDI ConnectionFactory
1.4. Sending a message
1.5. Receiving a message
2. AMQP
2.1. RabbitMQ support

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2.2. Sending a message
2.3. Receiving a message
3. Apache Kafka Support
3.1. Sending a Message
3.2. Receiving a Message
3.3. Additional Kafka Properties
Calling REST services
1. RestTemplate customization
Validation
Sending email
Distributed Transactions with JTA
1. Using an Atomikos transaction manager
2. Using a Bitronix transaction manager
3. Using a Narayana transaction manager
4. Using a Java EE managed transaction manager
5. Mixing XA and non-XA JMS connections
6. Supporting an alternative embedded transaction manager
Hazelcast
Spring Integration
Spring Session
Monitoring and management over JMX
Testing
1. Test scope dependencies
2. Testing Spring applications
3. Testing Spring Boot applications
3.1. Detecting test configuration
3.2. Excluding test configuration
3.3. Working with random ports
3.4. Mocking and spying beans
3.5. Auto-configured tests
3.6. Auto-configured JSON tests
3.7. Auto-configured Spring MVC tests
3.8. Auto-configured Data JPA tests
3.9. Auto-configured JDBC tests
3.10. Auto-configured Data MongoDB tests
3.11. Auto-configured REST clients
3.12. Auto-configured Spring REST Docs tests
3.13. User configuration and slicing
3.14. Using Spock to test Spring Boot applications
4. Test utilities
4.1. ConfigFileApplicationContextInitializer
4.2. EnvironmentTestUtils
4.3. OutputCapture
4.4. TestRestTemplate
WebSockets
Web Services
Creating your own auto-configuration

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1. Understanding auto-configured beans
2. Locating auto-configuration candidates
3. Condition annotations
3.1. Class conditions
3.2. Bean conditions
3.3. Property conditions
3.4. Resource conditions
3.5. Web application conditions
3.6. SpEL expression conditions
4. Creating your own starter
4.1. Naming
4.2. Autoconfigure module
4.3. Starter module
What to read next
V. Spring Boot Actuator: Production-ready features
Enabling production-ready features
Endpoints
1. Customizing endpoints
2. Hypermedia for actuator MVC endpoints
3. CORS support
4. Adding custom endpoints
5. Health information
6. Security with HealthIndicators
6.1. Auto-configured HealthIndicators
6.2. Writing custom HealthIndicators
7. Application information
7.1. Auto-configured InfoContributors
7.2. Custom application info information
7.3. Git commit information
7.4. Build information
7.5. Writing custom InfoContributors
Monitoring and management over HTTP
1. Accessing sensitive endpoints
2. Customizing the management endpoint paths
3. Customizing the management server port
4. Configuring management-specific SSL
5. Customizing the management server address
6. Disabling HTTP endpoints
7. HTTP health endpoint format and access restrictions
Monitoring and management over JMX
1. Customizing MBean names
2. Disabling JMX endpoints
3. Using Jolokia for JMX over HTTP
3.1. Customizing Jolokia
3.2. Disabling Jolokia
Monitoring and management using a remote shell (deprecated)
1. Connecting to the remote shell

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1.1. Remote shell credentials
2. Extending the remote shell
2.1. Remote shell commands
2.2. Remote shell plugins
Loggers
1. Configure a Logger
Metrics
1. System metrics
2. DataSource metrics
3. Cache metrics
4. Tomcat session metrics
5. Recording your own metrics
6. Adding your own public metrics
7. Special features with Java 8
8. Metric writers, exporters and aggregation
8.1. Example: Export to Redis
8.2. Example: Export to Open TSDB
8.3. Example: Export to Statsd
8.4. Example: Export to JMX
9. Aggregating metrics from multiple sources
10. Dropwizard Metrics
11. Message channel integration
Auditing
Tracing
1. Custom tracing
Process monitoring
1. Extend configuration
2. Programmatically
Cloud Foundry support
1. Disabling extended Cloud Foundry actuator support
2. Cloud Foundry self signed certificates
3. Custom security configuration
What to read next
VI. Deploying Spring Boot applications
Deploying to the cloud
1. Cloud Foundry
1.1. Binding to services
2. Heroku
3. OpenShift
4. Amazon Web Services (AWS)
4.1. AWS Elastic Beanstalk
Using the Tomcat platform
Using the Java SE platform

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Best practices
4.2. Summary
5. Boxfuse and Amazon Web Services
6. Google Cloud
Installing Spring Boot applications
1. Supported operating systems
2. Unix/Linux services
2.1. Installation as an init.d service (System V)
Securing an init.d service
2.2. Installation as a systemd service
2.3. Customizing the startup script
Customizing script when it’s written
Customizing script when it runs
3. Microsoft Windows services
What to read next
VII. Spring Boot CLI
Installing the CLI
Using the CLI
1. Running applications using the CLI
1.1. Deduced “grab” dependencies
1.2. Deduced “grab” coordinates
1.3. Default import statements
1.4. Automatic main method
1.5. Custom dependency management
2. Testing your code
3. Applications with multiple source files
4. Packaging your application
5. Initialize a new project
6. Using the embedded shell
7. Adding extensions to the CLI
Developing application with the Groovy beans DSL
Configuring the CLI with settings.xml
What to read next
VIII. Build tool plugins
Spring Boot Maven plugin
1. Including the plugin
2. Packaging executable jar and war files
Spring Boot Gradle plugin
1. Including the plugin
2. Gradle dependency management
3. Packaging executable jar and war files
4. Running a project in-place

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5. Spring Boot plugin configuration
6. Repackage configuration
7. Repackage with custom Gradle configuration
7.1. Configuration options
7.2. Available layouts
7.3. Using a custom layout
8. Understanding how the Gradle plugin works
9. Publishing artifacts to a Maven repository using Gradle
9.1. Configuring Gradle to produce a pom that inherits dependency management
9.2. Configuring Gradle to produce a pom that imports dependency management
Spring Boot AntLib module
1. Spring Boot Ant tasks
1.1. spring-boot:exejar
1.2. Examples
2. spring-boot:findmainclass
2.1. Examples
Supporting other build systems
1. Repackaging archives
2. Nested libraries
3. Finding a main class
4. Example repackage implementation
What to read next
IX. ‘How-to’ guides
Spring Boot application
1. Create your own FailureAnalyzer
2. Troubleshoot auto-configuration
3. Customize the Environment or ApplicationContext before it starts
4. Build an ApplicationContext hierarchy (adding a parent or root context)
5. Create a non-web application
Properties & configuration
1. Automatically expand properties at build time
1.1. Automatic property expansion using Maven
1.2. Automatic property expansion using Gradle
2. Externalize the configuration of SpringApplication
3. Change the location of external properties of an application
4. Use ‘short’ command line arguments
5. Use YAML for external properties
6. Set the active Spring profiles
7. Change configuration depending on the environment
8. Discover built-in options for external properties
Embedded servlet containers
1. Add a Servlet, Filter or Listener to an application
1.1. Add a Servlet, Filter or Listener using a Spring bean
Disable registration of a Servlet or Filter
1.2. Add Servlets, Filters, and Listeners using classpath scanning

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2. Change the HTTP port
3. Use a random unassigned HTTP port
4. Discover the HTTP port at runtime
5. Configure SSL
6. Configure Access Logging
7. Use behind a front-end proxy server
7.1. Customize Tomcat’s proxy configuration
8. Configure Tomcat
9. Enable Multiple Connectors with Tomcat
10. Use Tomcat’s LegacyCookieProcessor
11. Use Jetty instead of Tomcat
12. Configure Jetty
13. Use Undertow instead of Tomcat
14. Configure Undertow
15. Enable Multiple Listeners with Undertow
16. Use Tomcat 7.x or 8.0
16.1. Use Tomcat 7.x or 8.0 with Maven
16.2. Use Tomcat 7.x or 8.0 with Gradle
17. Use Jetty 9.2
17.1. Use Jetty 9.2 with Maven
17.2. Use Jetty 9.2 with Gradle
18. Use Jetty 8
18.1. Use Jetty 8 with Maven
18.2. Use Jetty 8 with Gradle
19. Create WebSocket endpoints using @ServerEndpoint
20. Enable HTTP response compression
Spring MVC
1. Write a JSON REST service
2. Write an XML REST service
3. Customize the Jackson ObjectMapper
4. Customize the @ResponseBody rendering
5. Handling Multipart File Uploads
6. Switch off the Spring MVC DispatcherServlet
7. Switch off the Default MVC configuration
8. Customize ViewResolvers
9. Use Thymeleaf 3
HTTP clients
1. Configure RestTemplate to use a proxy
Logging
1. Configure Logback for logging
1.1. Configure logback for file only output
2. Configure Log4j for logging
2.1. Use YAML or JSON to configure Log4j 2
Data Access
1. Configure a custom DataSource

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2. Configure Two DataSources
3. Use Spring Data repositories
4. Separate @Entity definitions from Spring configuration
5. Configure JPA properties
6. Configure Hibernate Naming Strategy
7. Use a custom EntityManagerFactory
8. Use Two EntityManagers
9. Use a traditional persistence.xml
10. Use Spring Data JPA and Mongo repositories
11. Expose Spring Data repositories as REST endpoint
12. Configure a component that is used by JPA
Database initialization
1. Initialize a database using JPA
2. Initialize a database using Hibernate
3. Initialize a database
4. Initialize a Spring Batch database
5. Use a higher-level database migration tool
5.1. Execute Flyway database migrations on startup
5.2. Execute Liquibase database migrations on startup
Messaging
1. Disable transacted JMS session
Batch applications
1. Execute Spring Batch jobs on startup
Actuator
1. Change the HTTP port or address of the actuator endpoints
2. Customize the ‘whitelabel’ error page
3. Actuator and Jersey
Security
1. Switch off the Spring Boot security configuration
2. Change the AuthenticationManager and add user accounts
3. Enable HTTPS when running behind a proxy server
Hot swapping
1. Reload static content
2. Reload templates without restarting the container
2.1. Thymeleaf templates
2.2. FreeMarker templates
2.3. Groovy templates
3. Fast application restarts
4. Reload Java classes without restarting the container
4.1. Configuring Spring Loaded for use with Maven
4.2. Configuring Spring Loaded for use with Gradle and IntelliJ IDEA
Build
1. Generate build information

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84.2. Generate git information
84.3. Customize dependency versions
84.4. Create an executable JAR with Maven
84.5. Use a Spring Boot application as a dependency
84.6. Extract specific libraries when an executable jar runs
84.7. Create a non-executable JAR with exclusions
84.8. Remote debug a Spring Boot application started with Maven
84.9. Remote debug a Spring Boot application started with Gradle
84.10. Build an executable archive from Ant without using spring-boot-antlib
84.11. How to use Java 6
84.11.1. Embedded servlet container compatibility
84.11.2. Jackson
84.11.3. JTA API compatibility
85. Traditional deployment
85.1. Create a deployable war file
85.2. Create a deployable war file for older servlet containers
85.3. Convert an existing application to Spring Boot
85.4. Deploying a WAR to WebLogic
85.5. Deploying a WAR in an Old (Servlet 2.5) Container
X. Appendices
A. Common application properties
B. Configuration meta-data
B.1. Meta-data format
B.1.1. Group Attributes
B.1.2. Property Attributes
B.1.3. Hint Attributes
B.1.4. Repeated meta-data items
B.2. Providing manual hints
B.2.1. Value hint
B.2.2. Value provider
Any
Class reference
Handle As
Logger name
Spring bean reference
Spring profile name
B.3. Generating your own meta-data using the annotation processor
B.3.1. Nested properties
B.3.2. Adding additional meta-data
C. Auto-configuration classes
C.1. From the “spring-boot-autoconfigure” module
C.2. From the “spring-boot-actuator” module
D. Test auto-configuration annotations
E. The executable jar format
E.1. Nested JARs
E.1.1. The executable jar file structure
E.1.2. The executable war file structure

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E.2. Spring Boot’s “JarFile” class
E.2.1. Compatibility with the standard Java “JarFile”
E.3. Launching executable jars
E.3.1. Launcher manifest
E.3.2. Exploded archives
E.4. PropertiesLauncher Features
E.5. Executable jar restrictions
E.5.1. Zip entry compression
E.5.2. System ClassLoader
E.6. Alternative single jar solutions
F. Dependency versions
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.
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.
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.
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.
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
4. Working with Spring Boot
Ready to actually start using Spring Boot? We’ve got you covered.
Build systems: Maven | Gradle | Ant | Starters

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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
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
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
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.
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.

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9. System Requirements

By default, Spring Boot 1.5.9.RELEASE requires Java 7 and Spring Framework 4.3.13.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.

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.

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.

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).

10.1.1 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.

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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">

<groupId>com.example</groupId>

<artifactId>myproject</artifactId>

<version>0.0.1-SNAPSHOT</version>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-parent</artifactId>

<version>1.5.9.RELEASE</version>

</parent>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-web</artifactId>

</dependency>

</dependencies>

<build>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-maven-plugin</artifactId>

</plugin>

</plugins>

</build>

</project>

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 Section 13.2.2, “Using Spring Boot

without the parent POM” for an alternative solution that uses an import scope.

10.1.2 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:

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plugins {

id 'org.springframework.boot' version '1.5.9.RELEASE'

id 'java'

}

jar {

baseName = 'myproject'

version = '0.0.1-SNAPSHOT'

}

repositories {

jcenter()

}

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.

10.2.1 Manual installation

You can download the Spring CLI distribution from the Spring software repository:

spring-boot-cli-1.5.9.RELEASE-bin.zip

spring-boot-cli-1.5.9.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).

10.2.2 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 v1.5.9.RELEASE

If you are developing features for the CLI and want easy access to the version you just built, follow these extra instructions.

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

================================================================================

$ sdk install springboot dev /path/to/spring-boot/spring-boot-cli/target/spring-boot-cli-1.5.9.RELEASE-bin/spring-1.5.9.RELEAS

$ sdk default springboot dev

$ spring --version

Spring CLI v1.5.9.RELEASE

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================================================================================

Available Springboot Versions

================================================================================

> + dev

* 1.5.9.RELEASE

================================================================================

+ - local version

* - installed

> - currently in use

================================================================================

10.2.3 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 .

If you don’t see the formula, your installation of brew might be out-of-date. Just execute brew update and try again.

10.2.4 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

10.2.5 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

If you install Spring Boot CLI using Homebrew or MacPorts, the command-line completion scripts are automatically registered with

your shell.

10.2.6 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!"

}

Then simply run it from a shell:

$ spring run app.groovy

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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.

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.

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

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">

<groupId>com.example</groupId>

<artifactId>myproject</artifactId>

<version>0.0.1-SNAPSHOT</version>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-parent</artifactId>

<version>1 5 9 RELEASE</version>

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<version>1.5.9.RELEASE</version>

</parent>

</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).

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:

<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);

}

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}

Although there isn’t much code here, quite a lot is going on. Let’s step through the important parts.

11.3.1 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.

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.

11.3.2 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.

11.3.3 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 :: (v1.5.9.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!

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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>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-maven-plugin</artifactId>

</plugin>

</plugins>

</build>

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:

$ 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:1.5.9.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

. ____ _ __ _ _

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/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \

( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \

\\/ ___)| |_)| | | | | || (_| | ) ) ) )

' |____| .__|_| |_|_| |_\__, | / / / /

=========|_|==============|___/=/_/_/_/

:: Spring Boot :: (v1.5.9.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 .

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.

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.

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.

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.

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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 ).

13.2.1 Inheriting the starter parent

To configure your project to inherit from the spring-boot-starter-parent simply set the parent :

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-parent</artifactId>

<version>1.5.9.RELEASE</version>

</parent>

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 .

<spring-data-releasetrain.version>Fowler-SR2</spring-data-releasetrain.version>

</properties>

Check the spring-boot-dependencies pom for a list of supported properties.

13.2.2 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:

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-dependencies</artifactId>

<version>1.5.9.RELEASE</version>

<scope>import</scope>

</dependency>

</dependencies>

</dependencyManagement>

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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 .

<groupId>org.springframework.data</groupId>

<artifactId>spring-data-releasetrain</artifactId>

<version>Fowler-SR2</version>

<scope>import</scope>

</dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-dependencies</artifactId>

<version>1.5.9.RELEASE</version>

<scope>import</scope>

</dependency>

</dependencies>

</dependencyManagement>

In the example above, we specify a BOM but any dependency type can be overridden that way.

13.2.3 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:

<java.version>1.8</java.version>

</properties>

13.2.4 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>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-maven-plugin</artifactId>

</plugin>

</plugins>

</build>

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()

}

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dependencies {

compile("org.springframework.boot:spring-boot-starter-web:1.5.9.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:

plugins {

id 'org.springframework.boot' version '1.5.9.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">

</configurations>

<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">

<target name="resolve" description="--> retrieve dependencies with ivy">

<ivy:retrieve pattern="lib/[conf]/[artifact]-[type]-[revision].[ext]" />

</target>

</path>

</target>

</target>

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</target>

<spring-boot:exejar destfile="build/myapp.jar" classes="build/classes">

<spring-boot:lib>

</spring-boot:lib>

</spring-boot:exejar>

</target>

</project>

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-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

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Name Description 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-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-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

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Name Description 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 manage your application over

SSH. Deprecated since 1.5

Pom

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

For a list of additional community contributed starters, see the README file in the spring-boot-starters module on GitHub.

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.

We recommend that you follow Java’s recommended package naming conventions and use a reversed domain name (for example,

com.example.project ).

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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

public class Application {

public static void main(String[] args) {

SpringApplication.run(Application.class, args);

}

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 .

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

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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.

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.

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.

You can define exclusions both at the annotation level and using the property.

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;

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@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;

}

// ...

}

Notice how using constructor injection allows the riskAssessor field to be marked as final , indicating that it cannot be

subsequently changed.

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);

}

@SpringBootApplication also provides aliases to customize the attributes of @EnableAutoConfiguration and

@ComponentScan .

19. Running your application

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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.

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.

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

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

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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.

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.

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-devtools</artifactId>

</dependency>

</dependencies>

Gradle.

dependencies {

compile("org.springframework.boot:spring-boot-devtools")

}

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.

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.

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

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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.

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.

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.

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) ).

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 .

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.

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.

20.2.1 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/**

if you want to keep those defaults and add additional exclusions, use the spring.devtools.restart.additional-exclude

property instead.

20.2.2 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.

20.2.3 Disabling restart

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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);

}

20.2.4 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.

You might want to set spring.devtools.restart.trigger-file as a global setting so that all your projects behave in the same

way.

20.2.5 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

All property keys must be unique. As long as a property starts with restart.include. or restart.exclude. it will be considered.

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.

20.2.6 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() .

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.

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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 .

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>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-maven-plugin</artifactId>

<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

Enabling spring-boot-devtools on a remote application is a security risk. You should never enable support on a production

deployment.

Remote devtools support is provided in two parts; 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.

20.5.1 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).

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A running remote client will look like this:

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.

It’s always advisable to use https:// as the connection protocol so that traffic is encrypted and passwords cannot be intercepted.

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.

20.5.2 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.

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.

20.5.3 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"

Notice that you don’t need to pass an address=NNNN option to -Xrunjdwp . If omitted Java will simply pick a random free port.

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

. ____ _ __ _ _

/\\ / ___'_ __ _ _(_)_ __ __ _ ___ _ \ \ \ \

( ( )\___ | '_ | '_| | '_ \/ _` | | _ \___ _ __ ___| |_ ___ \ \ \ \

\\/ ___)| |_)| | | | | || (_| []::::::[] / -_) ' \/ _ \ _/ -_) ) ) ) )

' |____| .__|_| |_|_| |_\__, | |_|_\___|_|_|_\___/\__\___|/ / / /

=========|_|==============|___/===================================/_/_/_/

:: Spring Boot Remote :: 1.5.9.RELEASE

2015-06-10 18:25:06.632 INFO 14938 --- [ main] o.s.b.devtools.RemoteSpringApplication : Starting RemoteSpringAppl

2015-06-10 18:25:06.671 INFO 14938 --- [ main] s.c.a.AnnotationConfigApplicationContext : Refreshing org.springfram

2015-06-10 18:25:07.043 WARN 14938 --- [ main] o.s.b.d.r.c.RemoteClientConfiguration : The connection to http://

2015-06-10 18:25:07.074 INFO 14938 --- [ main] o.s.b.d.a.OptionalLiveReloadServer : LiveReload server is runn

2015-06-10 18:25:07.130 INFO 14938 --- [ main] o.s.b.devtools.RemoteSpringApplication : Started RemoteSpringAppli

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(60000 works well in most situations).

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.

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.

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.

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:

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

. ____ _ __ _ _

/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \

( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \

\\/ ___)| |_)| | | | | || (_| | ) ) ) )

' |____| .__|_| |_|_| |_\__, | / / / /

=========|_|==============|___/=/_/_/_/

:: Spring Boot :: v1.5.9.RELEASE

2013-07-31 00:08:16.117 INFO 56603 --- [ main] o.s.b.s.app.SampleApplication : Starting SampleApplicatio

2013-07-31 00:08:16.166 INFO 56603 --- [ main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springfram

2014-03-04 13:09:54.912 INFO 41370 --- [ main] .t.TomcatEmbeddedServletContainerFactory : Server initialized with p

2014-03-04 13:09:56.501 INFO 41370 --- [ main] o.s.b.s.app.SampleApplication : Started SampleApplication

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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.

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 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 1.5.9.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 (v1.5.9.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 .

The SpringApplication.setBanner(… ) method can be used if you want to generate a banner programmatically. Use the

org.springframework.boot.Banner interface and implement your own printBanner() method.

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You can also use the spring.main.banner-mode property to determine if the banner has to be printed on System.out ( console ), using the

configured logger ( log ) or not at all ( off ).

The printed banner will be registered as a singleton bean under the name springBootBanner .

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);

}

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);

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.

Some events are actually triggered before the ApplicationContext is created so you cannot register a listener on those as a

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@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.

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.

Application events are sent using Spring Framework’s event publishing mechanism. Part of this mechanism ensures that an event published to the

listeners in a child context is also published to the listeners in any ancestors contexts. As a result of this, if your application uses a hierarchy of

SpringApplication instances, a listener may receive multiple instances of the same type of application event.

To allow your listener to distinguish between an event for its context and an event for a descendant context, it should request that its application

context is injected and then compare the injected context with context of the event. The context can be injected by implementing

ApplicationContextAware or, if the listener is a bean, using @Autowired .

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.

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(… ) .

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();

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// if run with "--debug logfile.txt" debug=true, files=["logfile.txt"]

}

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 {

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.

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23.10 Admin features

It is possible to enable admin-related features for the application by specifying the spring.application.admin.enabled property. This exposes

the SpringApplicationAdminMXBean on the platform MBeanServer . You could use this feature to administer your Spring Boot application

remotely. This could also be useful for any service wrapper implementation.

If you want to know on which HTTP port the application is running, get the property with key local.server.port .

Take care when enabling this feature as the MBean exposes a method to shutdown the application.

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.*

@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" ).

The SPRING_APPLICATION_JSON properties can be supplied on the command line with an environment variable. For example in a

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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.

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).

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

$ java -jar myproject.jar --spring.config.location=classpath:/default.properties,classpath:/override.properties

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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:./

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.

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 ).

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.

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

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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.

If you use ‘Starters’ SnakeYAML will be automatically provided via spring-boot-starter .

24.6.1 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

prod:

url: http://foo.bar.com

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:

- 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;

}

Extra care is required when configuring lists that way as overriding will not work as you would expect. In the example above, when

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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

24.6.2 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.

24.6.3 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 .

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.

24.6.4 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.

24.6.5 Merging YAML lists

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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

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;

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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"));

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

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.

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See also the differences between @Value and @ConfigurationProperties .

You also need to list the properties classes to register in the @EnableConfigurationProperties annotation:

@Configuration

@EnableConfigurationProperties(FooProperties.class)

public class MyConfiguration {

}

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 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());

// ...

}

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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.

24.7.1 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.

24.7.2 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.firstName Standard camel case syntax.

person.first-name Dashed notation, recommended for use in .properties and .yml files.

person.first_name Underscore notation, alternative format for use in .properties and .yml files.

PERSON_FIRST_NAME Upper case format. Recommended when using a system environment variables.

24.7.3 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 ).

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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 .

24.7.4 @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();

// ... 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.

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.

24.7.5 @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 :

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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.

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

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

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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.

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.

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.

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:

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.

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.

$ java -jar myapp.jar --debug

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.

2014-03-05 10:57:51.112 INFO 45469 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine:

2014-03-05 10:57:51.253 INFO 45469 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embed

2014-03-05 10:57:51.253 INFO 45469 --- [ost-startStop-1] o.s.web.context.ContextLoader : Root WebApplicationContex

2014-03-05 10:57:51.698 INFO 45469 --- [ost-startStop-1] o.s.b.c.e.ServletRegistrationBean : Mapping servlet: 'dispatc

2014-03-05 10:57:51.702 INFO 45469 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean : Mapping filter: 'hiddenHt

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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).

26.2.1 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

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.file logging.path Example 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.

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logging.file logging.path Example Description

(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.

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.

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

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.

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 .

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

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.

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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_WORD The conversion word that’s used when logging

exceptions.

logging.file LOG_FILE Used in default log configuration if defined.

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.

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

:- .

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.

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.

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 [[

ERROR in ch.qos.logback.core.joran.spi.Interpreter@4:71 - no applicable action for [springProfile], current ElementPath is [[c

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26.6.1 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>

</springProfile>

</springProfile>

26.6.2 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"/>

<remoteHost>${fluentHost}</remoteHost>

...

</appender>

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).

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)

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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.

27.1.1 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).

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 .

27.1.2 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.

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27.1.3 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.*;

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.

27.1.4 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 ).

27.1.5 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.

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.

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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.

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=/**

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.

This feature has been thoroughly described in a dedicated blog post and in Spring Framework’s reference documentation.

27.1.6 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.

27.1.7 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.

27.1.8 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

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Mustache

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 .

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/ .

27.1.9 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.

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

CustomErrorType 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:

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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

+- <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());

...

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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

27.1.10 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.

27.1.11 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() {

}

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}

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 .

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 your tmpwatch configuration so that tomcat.* directories are not deleted, or configure server.tomcat.basedir so

that embedded Tomcat uses a different location.

27.3.1 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.

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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.

27.3.2 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 .

@ServletComponentScan will have no effect in a standalone container, where the container’s built-in discovery mechanisms will be

used instead.

27.3.3 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.

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.

27.3.4 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.

See the ServerProperties class for a complete list.

Programmatic customization

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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);

}

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.

27.3.5 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.

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

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.

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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).

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).

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.

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.

28.1.1 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 .

28.1.2 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:

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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).

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"]}

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.

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 here is only used internally to carry out authentication. Alternatively, you could define your own

UserInfoRestTemplateFactory @Bean to take full control.

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-----

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28.3.1 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);

}

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 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.

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.

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).

28.3.2 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:

...

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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("/");

}

@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.

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.

Check also the ‘How-to’ section for more advanced examples, typically to take full control over the configuration of the DataSource.

29.1.1 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.

The ‘How-to’ section includes a section on how to initialize a database

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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.

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:

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-data-jpa</artifactId>

</dependency>

<groupId>org.hsqldb</groupId>

<artifactId>hsqldb</artifactId>

<scope>runtime</scope>

</dependency>

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 .

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.

29.1.2 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 .

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.

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

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You should at least specify the url using the spring.datasource.url property or Spring Boot will attempt to auto-configure an

embedded database.

You often won’t need to specify the driver-class-name since Spring boot can deduce it for most databases from the url .

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

29.1.3 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

public MyBean(JdbcTemplate jdbcTemplate) {

this.jdbcTemplate = jdbcTemplate;

}

// ...

}

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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.

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.

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.

29.3.1 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;

// ... 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

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}

You can customize entity scanning locations using the @EntityScan annotation. See the Section 77.4, “Separate @Entity definitions

from Spring configuration” how-to.

29.3.2 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);

}

We have barely scratched the surface of Spring Data JPA. For complete details check their reference documentation.

29.3.3 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

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.

29.3.4 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 .

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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

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.

29.4.1 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.

29.4.2 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.

29.5.1 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:

<artifactId>jooq-codegen-maven</artifactId>

...

</executions>

<groupId>com.h2database</groupId>

<version>${h2.version}</version>

</dependency>

</dependencies>

<jdbc>

<driver>org.h2.Driver</driver>

<url>jdbc:h2:~/yourdatabase</url>

</jdbc>

...

</generator>

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</configuration>

</plugin>

29.5.2 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;

@Autowired

public JooqExample(DSLContext dslContext) {

this.create = dslContext;

}

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);

}

29.5.3 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.

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

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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.

30.1.1 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’.

30.2.1 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 {

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 :

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spring.data.mongodb.host=mongoserver

spring.data.mongodb.port=27017

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.

If spring.data.mongodb.port is not specified the default of 27017 is used. You could simply delete this line from the sample

above.

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.

30.2.2 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 {

private final MongoTemplate mongoTemplate;

@Autowired

public MyBean(MongoTemplate mongoTemplate) {

this.mongoTemplate = mongoTemplate;

}

// ...

}

See the MongoOperations Javadoc for complete details.

30.2.3 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);

}

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You can customize document scanning locations using the @EntityScan annotation.

For complete details of Spring Data MongoDB, including its rich object mapping technologies, refer to their reference documentation.

30.2.4 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.

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.

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’.

30.3.1 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

30.3.2 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:

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spring.data.neo4j.uri=file://var/tmp/graph.db

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.

30.3.3 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.data.neo4j.open-in-view=false

30.3.4 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.

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

30.3.5 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);

}

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.

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30.5.1 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.

30.5.2 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.

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.

30.6.1 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

public void customize(HttpClientConfig.Builder builder) {

builder.maxTotalConnection(100).defaultMaxTotalConnectionPerRoute(5);

}

To take full control over the registration, define a JestClient bean.

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30.6.2 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.

30.6.3 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.

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.

30.7.1 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

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public MyBean(CassandraTemplate template) {

this.template = template;

}

// ...

}

If you add a @Bean of your own of type CassandraTemplate it will replace the default.

30.7.2 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 .

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.

30.8.1 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

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 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.

30.8.2 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) {

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this.template = template;

}

// ...

}

There are a few beans that you can define in your own configuration to override those provided by the auto-configuration:

A CouchbaseTemplate @Bean with 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(...);

}

// ...

}

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.

30.9.1 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.

30.9.2 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;

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@Autowired

public MyBean(LdapTemplate template) {

this.template = template;

}

// ...

}

30.9.3 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.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.

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.

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.

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

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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.

It is also possible to update or evict data from the cache transparently.

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

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).

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

public void customize(ConcurrentMapCacheManager cacheManager) {

cacheManager.setAllowNullValues(false);

}

};

}

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 .

31.1.1 Generic

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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.

31.1.2 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

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.

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.

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.

31.1.3 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

31.1.4 Hazelcast

Spring Boot has a general support for Hazelcast. If a HazelcastInstance has been auto-configured, it is automatically wrapped in a

CacheManager .

31.1.5 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.

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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.

31.1.6 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 {

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.

31.1.7 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.

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 .

31.1.8 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

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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.

31.1.9 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.

31.1.10 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.

31.1.11 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

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.

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32.1.1 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).

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

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.

32.1.2 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.

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.

32.1.3 Using a JNDI ConnectionFactory

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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

32.1.4 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;

@Component

public class MyBean {

private final JmsTemplate jmsTemplate;

@Autowired

public MyBean(JmsTemplate jmsTemplate) {

this.jmsTemplate = jmsTemplate;

}

// ...

}

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 .

32.1.5 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) {

// ...

}

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.

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For instance, the following exposes another factory that uses a specific MessageConverter :

@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’.

32.2.1 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.

Check Understanding AMQP, the protocol used by RabbitMQ for more details.

32.2.2 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;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Component;

@Component

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public class MyBean {

private final AmqpAdmin amqpAdmin;

private final AmqpTemplate amqpTemplate;

@Autowired

public MyBean(AmqpAdmin amqpAdmin, AmqpTemplate amqpTemplate) {

this.amqpAdmin = amqpAdmin;

this.amqpTemplate = amqpTemplate;

}

// ...

}

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.

32.2.3 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) {

// ...

}

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 :

@Configuration

static class RabbitConfiguration {

@Bean

public SimpleRabbitListenerContainerFactory myFactory(

SimpleRabbitListenerContainerFactoryConfigurer configurer) {

SimpleRabbitListenerContainerFactory factory =

new SimpleRabbitListenerContainerFactory();

configurer.configure(factory, connectionFactory);

factory.setMessageConverter(myMessageConverter());

return factory;

}

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}

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.

32.3.1 Sending a Message

Spring’s KafkaTemplate is auto-configured and you can autowire them directly in your own beans:

@Component

public class MyBean {

private final KafkaTemplate kafkaTemplate;

@Autowired

public MyBean(KafkaTemplate kafkaTemplate) {

this.kafkaTemplate = kafkaTemplate;

}

// ...

}

32.3.2 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:

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@Component

public class MyBean {

@KafkaListener(topics = "someTopic")

public void processMessage(String content) {

// ...

}

32.3.3 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.

* @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);

}

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,

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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);

}

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)

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.

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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) {

...

}

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.

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

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.

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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.

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 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.

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:

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// Inject the primary (XA aware) ConnectionFactory

@Autowired

private ConnectionFactory defaultConnectionFactory;

// 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.

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.

Spring Boot also has an explicit caching support for Hazelcast. The HazelcastInstance is automatically wrapped in a

CacheManager implementation if caching is enabled.

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.

39. Spring Session

Spring Boot provides Spring Session auto-configuration for a wide range of stores:

JDBC

MongoDB

Redis

Hazelcast

HashMap

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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

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

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.

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.

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.

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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).

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.

In addition to @SpringBootTest a number of other annotations are also provided for testing more specific slices of an application.

See below for details.

Don’t forget to also add @RunWith(SpringRunner.class) to your test, otherwise the annotations will be ignored.

41.3.1 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.

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 use a test annotation to test a more specific slice of your application with such setup, you should avoid adding configuration that

are specific to a particular area on the main’s application class.

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.

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.

41.3.2 Excluding test configuration

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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() {

...

}

If you directly use @ComponentScan (i.e. not via @SpringBootApplication ) you will need to register the TypeExcludeFilter with

it. See the Javadoc for details.

41.3.3 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.

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");

}

41.3.4 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.

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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.

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

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.

41.3.5 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.

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 .

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.

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41.3.6 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 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");

}

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.

41.3.7 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.

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@WebMvcTest also auto-configures MockMvc . Mock MVC offers a powerful way to quickly test MVC controllers without needing to start a full HTTP

server.

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"));

}

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

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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");

}

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.

41.3.8 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;

@Test

public void testExample() throws Exception {

this.entityManager.persist(new User("sboot", "1234"));

User user = this.repository.findByUsername("sboot");

assertThat(user.getUsername()).isEqualTo("sboot");

assertThat(user.getVin()).isEqualTo("1234");

}

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In-memory embedded databases generally work well for tests since they are fast and 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.

41.3.9 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.

41.3.10 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 :

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:

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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.

41.3.11 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.

41.3.12 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

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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}");

}

41.3.13 User configuration and slicing

If you’ve structured your code in a sensible way, your @SpringBootApplication class is used by default as the configuration of your tests.

It then becomes important not to litter the application’s main class with configuration that are are specific to a particular area of its functionality.

Let’s assume that you are using Spring Batch and you’re relying on the auto-configuration for it. Your could define your @SpringBootApplication

as follows:

@SpringBootApplication

@EnableBatchProcessing

public class SampleApplication { ... }

Because this class is the source configuration for the test, any slice test will actually attempt to start Spring Batch, which is definitely not what you

want to do. A recommended approach is to move that area-specific configuration to a separate @Configuration class at the same level as your

application.

@Configuration

@EnableBatchProcessing

public class BatchConfiguration { ... }

Depending on the surface area of your application, you may either have a single ApplicationConfiguration class for your

customizations or one class per domain area when it makes sense. The latter approach allows you to enable it in one of your test if

necessary via @Import .

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Another source of confusion is classpath scanning. Let’s assume that, while you’ve structured your code in a sensible way, you need to scan an

additional package. Your application may look like this:

@SpringBootApplication

@ComponentScan({ "com.example.app", "org.acme.another" })

public class SampleApplication { ... }

This effectively overrides the default component scan directive with the side effect of scanning those two packages regardless of the slice that

you’ve chosen. For instance a @DataJpaTest will all of a sudden scan components and user configurations of your application. Again, moving the

custom directive to a separate class is a good way to fix this issue.

If this is not an option for you, you can create a @SpringBootConfiguration somewhere in the hierarchy of your test so that it is

used instead. Or you can specify a source for your test which will disable the behaviour of finding a default one.

41.3.14 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.

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.

41.4.1 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)

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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 a PropertySourcesPlaceholderConfigurer or use @SpringBootTest where one will be auto-configured

for you.

41.4.2 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");

41.4.3 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"));

}

41.4.4 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"));

}

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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(...);

}

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.

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.

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.

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

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@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.

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 includes a number of @Conditional annotations that you can reuse in your own code by annotating @Configuration classes or

individual @Bean methods.

44.3.1 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.

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.

44.3.2 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() { ... }

}

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In the example above, the myService bean is going to be created if no bean of type MyService is already contained in the

ApplicationContext .

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).

@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.

44.3.3 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.

44.3.4 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 .

44.3.5 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 .

44.3.6 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.

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.

44.4.1 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 , etc). These are "ours" and we may improve/modify them in the future in such a way it

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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.

44.4.2 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.

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.

44.4.3 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.

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.

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:

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-actuator</artifactId>

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</dependency>

</dependencies>

For Gradle, use the declaration:

dependencies {

compile("org.springframework.boot:spring-boot-starter-actuator")

}

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

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:

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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

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

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 :

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

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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

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.

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.

47.6.1 Auto-configured HealthIndicators

The following HealthIndicators are auto-configured by Spring Boot when appropriate:

Name Description

CassandraHealthIndicator Checks that a Cassandra database is up.

DiskSpaceHealthIndicator Checks for low disk space.

DataSourceHealthIndicator Checks that a connection to DataSource can be obtained.

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Name Description

ElasticsearchHealthIndicator Checks that an Elasticsearch cluster is up.

JmsHealthIndicator Checks that a JMS broker is up.

MailHealthIndicator Checks that a mail server is up.

MongoHealthIndicator Checks that a Mongo database is up.

RabbitHealthIndicator Checks that a Rabbit server is up.

RedisHealthIndicator Checks that a Redis server is up.

SolrHealthIndicator Checks that a Solr server is up.

It is possible to disable them all using the management.health.defaults.enabled property.

47.6.2 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();

}

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

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 503 (service unavailable):

endpoints.health.mapping.FATAL=503

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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.

47.7.1 Auto-configured InfoContributors

The following InfoContributors are auto-configured by Spring Boot when appropriate:

Name Description

EnvironmentInfoContributor Expose any key from the Environment under the info key.

GitInfoContributor Expose git information if a git.properties file is available.

BuildInfoContributor Expose build information if a META-INF/build-info.properties file is available.

It is possible to disable them all using the management.info.defaults.enabled property.

47.7.2 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

Rather than hardcoding those values you could also expand info properties at build time.

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@

47.7.3 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.

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.

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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

47.7.4 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.

The Maven and Gradle plugins can both generate that file, see Generate build information for more details.

47.7.5 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:

{

"example": {

"key" : "value"

}

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.

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.

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management.security.enabled=false

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).

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 .

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 ).

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 .

Even if an endpoint path is configured separately, it is still relative to the management.context-path .

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.

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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

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 .

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

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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.enabled endpoints.health.sensitive Unauthenticated Authenticated (with right role)

false * Full content Full content

true false Status only Full content

true true No content Full content

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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:

<groupId>org.jolokia</groupId>

<artifactId>jolokia-core</artifactId>

</dependency>

Jolokia can then be accessed using /jolokia on your management HTTP server.

49.3.1 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

49.3.2 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 :

endpoints.jolokia.enabled=false

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:

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-remote-shell</artifactId>

</dependency>

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The remote shell is deprecated and will be removed in Spring Boot 2.0.

If you want to also enable telnet access you will additionally need a dependency on org.crsh:crsh.shell.telnet .

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 :: (v1.5.9.RELEASE) on myhost

Type help for a list of commands. Spring Boot provides metrics , beans , autoconfig and endpoint commands.

50.1.1 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.

50.2.1 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/**

You can change the search path by settings a shell.command-path-patterns property.

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

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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.beanfactory Access to the Spring BeanFactory

spring.environment Access to the Spring Environment

50.2.2 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.

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"

}

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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 .

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:

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 )

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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 )

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 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;

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@Autowired

public MyService(CounterService counterService) {

this.counterService = counterService;

}

public void exampleMethod() {

this.counterService.increment("services.system.myservice.invoked");

}

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 .

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.

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.

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).

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 .

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52.8.1 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.

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).

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.

52.8.2 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 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

}

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}

]

52.8.3 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);

}

52.8.4 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).

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() {

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private MetricReader aggregatesMetricReader() {

AggregateMetricReader repository = new AggregateMetricReader(

globalMetricsForAggregation());

return repository;

}

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 .

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).

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).

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 ).

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; ..."

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"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.

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

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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.

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.

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();

}

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.

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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.

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.

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)

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0 of 1 instances running (1 starting)

...

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 ...

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/ .

58.1.1 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.

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.

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

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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.

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

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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

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

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.

58.4.1 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:

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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

58.4.2 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 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.

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.

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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.

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:

<groupId>com.google.cloud.tools</groupId>

<artifactId>appengine-maven-plugin</artifactId>

<project>myproject</project>

</configuration>

</plugin>

Then deploy with mvn appengine:deploy (if you need to authenticate first the build will fail).

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.

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.

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:

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<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-maven-plugin</artifactId>

</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 .

59.2.1 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

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

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

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.

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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.

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 :

$ 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

59.2.2 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

Remember to change the Description , User and ExecStart fields for your application.

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

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Refer to man systemctl for more details.

59.2.3 Customizing the startup script

The default embedded startup script written by the Maven or Gradle plugin can be customized in a number of ways. For most people, using the

default script along with a few customizations is usually enough. If you find you 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 .

initInfoProvides The Provides section of “INIT INFO”. Defaults to spring-boot-application for Gradle and to

${project.artifactId} for Maven.

initInfoRequiredStart The Required-Start section of “INIT INFO”. Defaults to $remote_fs $syslog $network .

initInfoRequiredStop The Required-Stop section of “INIT INFO”. Defaults to $remote_fs $syslog $network .

initInfoDefaultStart The Default-Start section of “INIT INFO”. Defaults to 2 3 4 5 .

initInfoDefaultStop The Default-Stop section of “INIT INFO”. Defaults to 0 1 6 .

initInfoShortDescription The Short-Description section of “INIT INFO”. Defaults to Spring Boot Application for Gradle and to

${project.name} for Maven.

initInfoDescription The Description section of “INIT INFO”. Defaults to Spring Boot Application for Gradle and to

${project.description} (falling back to ${project.name} ) for Maven.

initInfoChkconfig The 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.

logFilename The 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.

pidFilename The default value for the name of the pid file in PID_FOLDER . Only valid for an init.d service.

useStartStopDaemon If the start-stop-daemon command, when it’s available, should be used to control the process. Defaults to

true .

stopWaitTime The default value for STOP_WAIT_TIME . Only valid for an init.d service. Defaults to 60 seconds.

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.

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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_DAEMON If 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_FOLDER The name of the folder to read .conf files from (same folder as jar-file by default).

LOG_FILENAME The 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_TIME The time in seconds to wait when stopping the application before forcing a shutdown ( 60 by default).

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 .

myapp.conf.

JAVA_OPTS=-Xmx1024M

LOG_FOLDER=/custom/log/folder

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

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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.

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.

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.

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

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The version command provides a quick way to check which version of Spring Boot you are using.

$ spring version

Spring CLI v1.5.9.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

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

When setting JAVA_OPTS on Microsoft Windows, make sure to quote the entire instruction such as

set "JAVA_OPTS=-Xms256m -Xmx2048m" . This will ensure the values are passed properly to the process.

62.1.1 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.

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Items Grabs

@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.

See subclasses of CompilerAutoConfiguration in the Spring Boot CLI source code to understand exactly how customizations are

applied.

62.1.2 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.

62.1.3 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.

Many Spring annotations will work without using import statements. Try running your application to see what fails before adding

imports.

62.1.4 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 .

62.1.5 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/ .

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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 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())

}

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

public/**, resources/**, static/**, templates/**, META-INF/**, *

and the default excludes are

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.*, 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 (v1.5.9.RELEASE)

Hit TAB to complete. Type \'help' and hit RETURN for help, and \'exit' to quit.

From inside the embedded shell you can run other commands directly:

$ version

Spring CLI v1.5.9.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

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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

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.

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.

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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.

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).

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">

<build>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-maven-plugin</artifactId>

<version>1.5.9.RELEASE</version>

<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:

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$ 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:

<id>spring-snapshots</id>

<url>http://repo.spring.io/snapshot</url>

</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">

</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">

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-web</artifactId>

</dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-tomcat</artifactId>

<scope>provided</scope>

</dependency>

</dependencies>

</project>

See the “Section 85.1, “Create a deployable war file”” section for more details on how to create a deployable war file.

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Advanced configuration options and examples are available in the plugin info page.

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 '1.5.9.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")

}

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.

Check Section 67.6, “Repackage configuration” for a full list of configuration options.

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'

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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")

...

}

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

}

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)

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Name Description

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.

embeddedLaunchScriptProperties Additional 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 .

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'

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}

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.

67.7.1 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.

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.

67.7.2 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

67.7.3 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:

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buildscript {

repositories {

mavenCentral()

}

dependencies {

classpath("org.springframework.boot:spring-boot-gradle-plugin:1.5.9.RELEASE")

classpath("com.example:custom-layout:1.0.0")

}

springBoot {

layoutFactory = new com.example.CustomLayoutFactory()

}

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.

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.

67.9.1 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.

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uploadArchives {

repositories {

mavenDeployer {

pom {

project {

parent {

groupId "org.springframework.boot"

artifactId "spring-boot-starter-parent"

version "1.5.9.RELEASE"

}

67.9.2 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 "1.5.9.RELEASE"

type "pom"

scope "import"

}

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-1.5.9.RELEASE.jar>

The “Using Spring Boot” section includes a more complete example of using Apache Ant with spring-boot-antlib

68.1 Spring Boot Ant tasks

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Once the spring-boot-antlib namespace has been declared, the following additional tasks are available.

68.1.1 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.

68.1.2 Examples

Specify start-class.

<spring-boot:exejar destfile="target/my-application.jar"

classes="target/classes" start-class="com.foo.MyApplication">

</resources>

<lib>

</lib>

</spring-boot:exejar>

Detect start-class.

<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)

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68.2.1 Examples

Find and log.

Find and set.

Override and set.

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));

}

});

70. What to read next

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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.

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 ).

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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);

}

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.

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.

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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.

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.

72.1.1 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@

Only production configuration is filtered that way (i.e. no filtering is applied on src/test/resources ).

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):

<directory>src/main/resources</directory>

</resource>

</resources>

and (inside <plugins/> ):

<groupId>org.apache.maven.plugins</groupId>

<artifactId>maven-resources-plugin</artifactId>

</delimiters>

<useDefaultDelimiters>false</useDefaultDelimiters>

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</configuration>

</plugin>

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 .

72.1.2 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}

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.

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 .

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).

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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}

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.

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.

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:

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.

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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).

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 .

73. Embedded servlet containers

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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.

73.1.1 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.

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;

}

73.1.2 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 @ServletComponentScan and specifying the package(s) containing the components that you want to

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 Section 27.3.4, “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 .

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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;

// ...

}

@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:

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)

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

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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 .

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 .

73.7.1 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}

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} .

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());

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tomcat.addAdditionalTomcatConnectors(createSslConnector());

return tomcat;

}

private Connector createSslConnector() {

Connector connector = new Connector("org.apache.coyote.http11.Http11NioProtocol");

Http11NioProtocol protocol = (Http11NioProtocol) connector.getProtocolHandler();

try {

File keystore = new ClassPathResource("keystore").getFile();

File truststore = new ClassPathResource("keystore").getFile();

connector.setScheme("https");

connector.setSecure(true);

connector.setPort(8443);

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.

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Example in Maven:

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-web</artifactId>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-tomcat</artifactId>

</exclusion>

</exclusions>

</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:1.5.9.RELEASE")

compile("org.springframework.boot:spring-boot-starter-jetty:1.5.9.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:

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-web</artifactId>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-tomcat</artifactId>

</exclusion>

</exclusions>

</dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-undertow</artifactId>

</dependency>

Example in Gradle:

configurations {

compile.exclude module: "spring-boot-starter-tomcat"

}

dependencies {

compile("org springframework boot:spring boot starter web:1 5 9 RELEASE")

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compile("org.springframework.boot:spring-boot-starter-web:1.5.9.RELEASE")

compile("org.springframework.boot:spring-boot-starter-undertow:1.5.9.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.

73.16.1 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:

<tomcat.version>7.0.59</tomcat.version>

</properties>

...

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-web</artifactId>

</dependency>

<groupId>org.apache.tomcat</groupId>

<artifactId>tomcat-juli</artifactId>

<version>${tomcat.version}</version>

</dependency>

...

</dependencies>

73.16.2 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'

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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.

73.17.1 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:

<jetty.version>9.2.17.v20160517</jetty.version>

</properties>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-web</artifactId>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-tomcat</artifactId>

</exclusion>

</exclusions>

</dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-jetty</artifactId>

</dependency>

</dependencies>

73.17.2 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.

73.18.1 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:

<jetty.version>8.1.15.v20140411</jetty.version>

<jetty-jsp.version>2.2.0.v201112011158</jetty-jsp.version>

</properties>

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<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-web</artifactId>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-tomcat</artifactId>

</exclusion>

</exclusions>

</dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-jetty</artifactId>

<groupId>org.eclipse.jetty.websocket</groupId>

</exclusion>

</exclusions>

</dependency>

</dependencies>

73.18.2 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.

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

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This can be configured using the server.compression.mime-types property.

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:

<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:

<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.

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

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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.DeserializationFeature spring.jackson.deserialization.<feature_name>=true|false

com.fasterxml.jackson.core.JsonGenerator.Feature spring.jackson.generator.<feature_name>=true|false

com.fasterxml.jackson.databind.MapperFeature spring.jackson.mapper.<feature_name>=true|false

com.fasterxml.jackson.core.JsonParser.Feature spring.jackson.parser.<feature_name>=true|false

com.fasterxml.jackson.databind.SerializationFeature spring.jackson.serialization.<feature_name>=true|false

com.fasterxml.jackson.annotation.JsonInclude.Include spring.jackson.default-property-inclusion=always|non_null|non_ab

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 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.

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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 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.

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.

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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:

<thymeleaf.version>3.0.2.RELEASE</thymeleaf.version>

<thymeleaf-layout-dialect.version>2.1.1</thymeleaf-layout-dialect.version>

</properties>

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.

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));

}

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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:

<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>

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.

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).

76.1.1 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"?>

<appender-ref ref="FILE" />

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</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:

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-web</artifactId>

</dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter</artifactId>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-logging</artifactId>

</exclusion>

</exclusions>

</dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-log4j2</artifactId>

</dependency>

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.

76.2.1 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

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

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Section 24.7.1, “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:

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

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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

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.

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();

}

fooDataSourceProperties has to be flagged @Primary so that the database initializer feature uses your copy (should you use

that).

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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();

}

@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 {

//...

}

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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.

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(

EntityManagerFactoryBuilder builder) {

return builder

.dataSource(customerDataSource())

.packages(Customer.class)

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.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 .

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 a set of useful properties from the spring.data.rest namespace that customize the RepositoryRestConfiguration . If

you need to provide additional customization, you should use a RepositoryRestConfigurer bean.

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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");

}

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.

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).

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78.3 Initialize a database

Spring Boot can automatically create the schema (DDL scripts) of your DataSource and initialize it (DML scripts): it loads SQL from the standard

root classpath locations schema.sql and data.sql , respectively. In addition Spring Boot will process the schema-${platform}.sql and

data-${platform}.sql files (if present), where platform is the value of spring.datasource.platform . This allows you to switch to

database specific scripts if necessary, 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.

You can tune that using spring.datasource.continue-on-error .

In a JPA-based app, you can choose to let Hibernate create the schema or use schema.sql but not both. Make sure to disable

spring.jpa.hibernate.ddl-auto if you chose the later.

You can also disable initialization by setting spring.datasource.initialize to false .

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.

78.5.1 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 .

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.

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

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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.

78.5.2 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.

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.

80. Batch applications

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.

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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).

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 .

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

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@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 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 .

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.

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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.

83.2.1 Thymeleaf templates

If you are using Thymeleaf, then set spring.thymeleaf.cache to false . See ThymeleafAutoConfiguration for other Thymeleaf

customization options.

83.2.2 FreeMarker templates

If you are using FreeMarker, then set spring.freemarker.cache to false . See FreeMarkerAutoConfiguration for other FreeMarker

customization options.

83.2.3 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.

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).

83.4.1 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.

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-maven-plugin</artifactId>

<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).

83.4.2 Configuring Spring Loaded for use with Gradle and IntelliJ IDEA

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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:1.5.9.RELEASE"

classpath 'org.springframework:springloaded:1.2.6.RELEASE'

}

apply plugin: 'idea'

idea {

module {

inheritOutputDirs = false

outputDir = file("$buildDir/classes/main/")

}

// ...

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.

You can also additionally enable ‘Make Project Automatically’ inside IntelliJ IDEA to automatically compile your code whenever a file is saved.

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>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-maven-plugin</artifactId>

<version>1.5.9.RELEASE</version>

<goals>

<goal>build-info</goal>

</goals>

</execution>

</executions>

</plugin>

</plugins>

</build>

Check the Spring Boot Maven Plugin documentation for more details.

And to do the same with Gradle:

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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>

<groupId>pl.project13.maven</groupId>

<artifactId>git-commit-id-plugin</artifactId>

</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"

}

The commit time in git.properties is expected to match the format yyyy-MM-dd’T’HH:mm:ssZ . This is the default format for both

plugins listed above. Using this format allows the time to be parsed into a Date and its format when serialized to JSON to be

controlled by Jackson’s date serialization configuration settings.

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:

<slf4j.version>1.7.5<slf4j.version>

</properties>

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.

Each Spring Boot release is designed and tested against a specific set of third-party dependencies. Overriding versions may cause

compatibility issues.

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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>

<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:

<build>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-maven-plugin</artifactId>

<version>1.5.9.RELEASE</version>

<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>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-maven-plugin</artifactId>

</configuration>

</plugin>

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</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.

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>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-maven-plugin</artifactId>

<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>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-maven-plugin</artifactId>

</configuration>

</plugin>

<artifactId>maven-jar-plugin</artifactId>

<phase>package</phase>

<goals>

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</goals>

</configuration>

</execution>

<phase>package</phase>

<goals>

</goals>

<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

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Check Gradle Application Plugin for more details.

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:

</mappedresources>

</mappedresources>

</mappedresources>

</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.

84.11.1 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.

84.11.2 Jackson

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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.

84.11.3 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

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:

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:

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-tomcat</artifactId>

<scope>provided</scope>

</dependency>

</dependencies>

And if you’re using Gradle:

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dependencies {

// …

providedRuntime 'org.springframework.boot:spring-boot-starter-tomcat'

// …

}

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.

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).

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/> .

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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);

}

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 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 {

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}

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:

<?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-class>org.springframework.boot.legacy.context.web.SpringBootContextLoaderListener</listener-class>

</listener>

<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-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>

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</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

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.

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.

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= # Whether subclass-based (CGLIB) proxies are to be created (true) as opposed to standard Java i

# IDENTITY (ContextIdApplicationContextInitializer)

spring.application.index= # Application index.

spring.application.name= # Application name.

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# 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 adm

# 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 comp

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.messages.always-use-message-format=false # Set whether to always apply the MessageFormat rules, parsing even messages w

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 cach

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 Loca

# 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).

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# 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

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 connec

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.

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 threa

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 a

server.tomcat.accesslog.enabled=false # Enable access log.

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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

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 sc

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 S

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.

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) cont

spring.freemarker.allow-session-override=false # Set whether HttpSession attributes are allowed to override (hide) controller

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 m

spring.freemarker.expose-session-attributes=false # Set whether all HttpSession attributes should be added to the model prior

spring.freemarker.expose-spring-macro-helpers=true # Set whether to expose a RequestContext for use by Spring's macro library,

spring.freemarker.prefer-file-system-access=true # Prefer file system access for template loading. File system access enables

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=.ftl # Suffix that gets appended to view names when building a URL.

spring.freemarker.template-loader-path=classpath:/templates/ # Comma-separated list of template paths.

spring.freemarker.view-names= # White list of view names that can be resolved.

# GROOVY TEMPLATES (GroovyTemplateAutoConfiguration)

spring.groovy.template.allow-request-override=false # Set whether HttpServletRequest attributes are allowed to override (hide)

spring.groovy.template.allow-session-override=false # Set whether HttpSession attributes are allowed to override (hide) contro

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

spring.groovy.template.expose-session-attributes=false # Set whether all HttpSession attributes should be added to the model p

spring.groovy.template.expose-spring-macro-helpers=true # Set whether to expose a RequestContext for use by Spring's macro lib

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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

# HTTP message conversion

spring.http.converters.preferred-json-mapper=jackson # Preferred JSON mapper to use for HTTP message conversion. Set to "gson"

# HTTP encoding (HttpEncodingProperties)

spring.http.encoding.charset=UTF-8 # Charset of HTTP requests and responses. Added to the "Content-Type" header if not set exp

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 "fo

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

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 Ki

spring.http.multipart.max-request-size=10MB # Max request size. Values can use the suffixed "MB" or "KB" to indicate a Megabyt

spring.http.multipart.resolve-lazily=false # Whether to resolve the multipart request lazily at the time of file or parameter

# JACKSON (JacksonProperties)

spring.jackson.date-format= # Date format string or a fully-qualified date format class name. For instance `yyyy-MM-dd HH:mm:s

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 fallb

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-quali

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 "@ApplicationPa

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.

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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.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

spring.mustache.allow-session-override= # Set whether HttpSession attributes are allowed to override (hide) controller generat

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

spring.mustache.expose-session-attributes= # Set whether all HttpSession attributes should be added to the model prior to merg

spring.mustache.expose-spring-macro-helpers= # Set whether to expose a RequestContext for use by Spring's macro library, under

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 sce

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

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

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.resources.static-locations=classpath:/META-INF/resources/,classpath:/resources/,classpath:/static/,classpath:/public/ #

# 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 i

spring.session.jdbc.schema=classpath:org/springframework/session/jdbc/schema-@@platform@@.sql # Path to the SQL file to use to

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.

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# 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.

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 publ

security.oauth2.resource.jwt.key-value= # The verification key of the JWT token. Can either be a symmetric secret or PEM-encod

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 #

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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 Authoriz

# ----------------------------------------

# 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)

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 oth

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)

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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 n

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.

# 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=true # Register OpenSessionInViewInterceptor. Binds a Neo4j Session to the thread for the entir

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.

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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 DDL or DML scripts (e.g. schema-${platform}.sql or data-${platform}.sq

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.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 f

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 "databasePl

spring.jpa.database-platform= # Name of the target database to operate on, auto-detected by default. Can be alternatively set

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 "

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 en

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.

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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 p

spring.jta.atomikos.connectionfactory.ignore-session-transacted-flag=true # Whether or not to ignore the transacted flag when

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 t

spring.jta.atomikos.connectionfactory.max-idle-time=60 # The time, in seconds, after which connections are cleaned up from the

spring.jta.atomikos.connectionfactory.max-lifetime=0 # The time, in seconds, that a connection can be pooled for before being

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 li

spring.jta.atomikos.connectionfactory.unique-resource-name=jmsConnectionFactory # The unique name used to identify the resourc

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 destroy

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 th

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 o

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

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 mixi

spring.jta.bitronix.connectionfactory.apply-transaction-timeout=false # Whether or not the transaction timeout should be set o

spring.jta.bitronix.connectionfactory.automatic-enlisting-enabled=true # Whether or not resources should be enlisted and delis

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

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

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 stat

spring.jta.bitronix.connectionfactory.test-connections=true # Whether or not connections should be tested when acquired from t

spring.jta.bitronix.connectionfactory.two-pc-ordering-position=1 # The position that this resource should take during two-phas

spring.jta.bitronix.connectionfactory.unique-name=jmsConnectionFactory # The unique name used to identify the resource during

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

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 a

spring.jta.bitronix.datasource.apply-transaction-timeout=false # Whether or not the transaction timeout should be set on the X

spring.jta.bitronix.datasource.automatic-enlisting-enabled=true # Whether or not resources should be enlisted and delisted aut

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 sa

spring.jta.bitronix.datasource.enable-jdbc4-connection-test= # Whether or not Connection.isValid() is called when acquiring a

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.

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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 t

spring.jta.bitronix.datasource.share-transaction-connections=false # Whether or not connections in the ACCESSIBLE state can b

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 commi

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 transactio

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 proc

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

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

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

spring.jta.bitronix.properties.jndi-transaction-synchronization-registry-name= # JNDI name of the TransactionSynchronizationRe

spring.jta.bitronix.properties.jndi-user-transaction-name= # JNDI name of the UserTransaction.

spring.jta.bitronix.properties.journal=disk # Name of the journal. Can be 'disk', 'null' or a class name.

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

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 s

# 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-sep

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 secon

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@e

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 v

spring.redis.pool.max-idle=8 # Max number of "idle" connections in the pool. Use a negative value to indicate an unlimited num

spring.redis.pool.max-wait=-1 # Maximum amount of time (in milliseconds) a connection allocation should block before throwing

spring.redis.pool.min-idle=0 # Target for the minimum number of idle connections to maintain in the pool. This setting only ha

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.

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# TRANSACTION (TransactionProperties)

spring.transaction.default-timeout= # Default transaction timeout in seconds.

spring.transaction.rollback-on-commit-failure= # Perform the rollback on commit failures.

# ----------------------------------------

# 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

spring.activemq.non-blocking-redelivery=false # Do not stop message delivery before re-delivering messages from a rolled back

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 wa

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

spring.activemq.pool.block-if-full-timeout=-1 # Blocking period, in milliseconds, before throwing an exception if the pool is

spring.activemq.pool.create-connection-on-startup=true # Create a connection on startup. Can be used to warm-up the pool on st

spring.activemq.pool.enabled=false # Whether a PooledConnectionFactory should be created instead of a regular ConnectionFactor

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 ev

spring.activemq.pool.use-anonymous-producers=true # Use only one anonymous "MessageProducer" instance. Set it to false to crea

# 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 cust

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

spring.batch.schema=classpath:org/springframework/batch/core/schema-@@platform@@.sql # Path to the SQL file to use to initiali

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-configurati

spring.jms.listener.acknowledge-mode= # Acknowledge mode of the container. By default, the listener is transacted with automat

spring.jms.listener.auto-startup=true # Start the container automatically on startup.

spring.jms.listener.concurrency= # Minimum number of concurrent consumers.

spring.jms.listener.max-concurrency= # Maximum number of concurrent consumers.

spring.jms.pub-sub-domain=false # 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 destinatio

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)

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spring.kafka.bootstrap-servers= # Comma-delimited list of host:port pairs to use for establishing the initial connection to th

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

spring.kafka.consumer.auto-offset-reset= # What to do when there is no initial offset in Kafka or if the current offset does n

spring.kafka.consumer.bootstrap-servers= # Comma-delimited list of host:port pairs to use for establishing the initial connect

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 fetc

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

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 connect

spring.kafka.producer.buffer-memory= # Total bytes of memory the producer can use to buffer records waiting to be sent to the

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 bee

spring.rabbitmq.cache.channel.size= # Number of channels to retain in the cache.

spring.rabbitmq.cache.connection.mode=channel # Connection factory cache mode.

spring.rabbitmq.cache.connection.size= # Number of connections to cache.

spring.rabbitmq.connection-timeout= # Connection timeout, 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

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 messa

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 s

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.

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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.

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

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 c

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 HTTP status codes. By default, registered health statuses map to s

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.

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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.

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

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

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. Req

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 man

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.

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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.

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 severit

# 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 com

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

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 repo

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

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 va

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.metrics.export.statsd.prefix= # Prefix for statsd exported metrics.

spring.metrics.export.triggers.*= # Specific trigger properties per MetricWriter bean name.

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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"

# ----------------------------------------

# 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

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 befor

spring.devtools.restart.trigger-file= # Name of a specific file that when changed will trigger the restart check. If not speci

# 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.

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"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."

{

"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.

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.

B.1.1 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.

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Name Type Purpose

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 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.

B.1.2 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:

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.

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Name Type Purpose

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.

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);

}

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 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.

B.1.3 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

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Name Type Purpose

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).

B.1.4 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 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.

B.2.1 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

}

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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"

}

]

}

]}

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.

B.2.2 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.

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.

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.

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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"

}

]

}

]}

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:

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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).

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 )

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"

}

]

{

"name": "logging.level.values",

"values": [

{

"value": "trace"

{

"value": "debug"

{

"value": "info"

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{

"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"

}

]

}

]}

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 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": [

{

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"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:

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-configuration-processor</artifactId>

</dependency>

With Gradle, you can use the propdeps-plugin and specify:

dependencies {

optional "org.springframework.boot:spring-boot-configuration-processor"

}

compileJava.dependsOn(processResources)

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.

You should only use simple text with @ConfigurationProperties field Javadoc since they are not processed before being added to

the JSON.

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.

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:

<groupId>org.apache.maven.plugins</groupId>

<artifactId>maven-compiler-plugin</artifactId>

</configuration>

</plugin>

B.3.1 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;

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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.

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.

B.3.2 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 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.

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

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Configuration Class Links
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
EmbeddedMongoAutoConfiguration javadoc
EmbeddedServletContainerAutoConfiguration javadoc
ErrorMvcAutoConfiguration javadoc
FacebookAutoConfiguration javadoc
FallbackWebSecurityAutoConfiguration javadoc
FlywayAutoConfiguration javadoc
FreeMarkerAutoConfiguration javadoc
GroovyTemplateAutoConfiguration javadoc
GsonAutoConfiguration javadoc
H2ConsoleAutoConfiguration javadoc
HazelcastAutoConfiguration javadoc

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Configuration Class Links
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
LdapDataAutoConfiguration javadoc
LdapRepositoriesAutoConfiguration javadoc
LinkedInAutoConfiguration javadoc
LiquibaseAutoConfiguration javadoc
MailSenderAutoConfiguration javadoc
MailSenderValidatorAutoConfiguration javadoc
MessageSourceAutoConfiguration javadoc
MongoAutoConfiguration javadoc

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Configuration Class Links
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
SolrAutoConfiguration javadoc
SolrRepositoriesAutoConfiguration javadoc
SpringApplicationAdminJmxAutoConfiguration javadoc
SpringDataWebAutoConfiguration javadoc
ThymeleafAutoConfiguration javadoc

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Configuration Class Links
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
MetricFilterAutoConfiguration javadoc
MetricRepositoryAutoConfiguration javadoc

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Configuration Class Links

MetricsChannelAutoConfiguration javadoc

MetricsDropwizardAutoConfiguration javadoc

PublicMetricsAutoConfiguration javadoc

TraceRepositoryAutoConfiguration javadoc

TraceWebFilterAutoConfiguration javadoc

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

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Test slice Imported auto-configuration

@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

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

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.

E.1.1 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>

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+-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.

E.1.2 The executable war file structure

Spring Boot Loader compatible war files should be structured in the following way:

example.war

+-META-INF

| +-MANIFEST.MF

+-org

| +-springframework

| +-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.

E.2.1 Compatibility with the standard Java “JarFile”

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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.

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).

E.3.1 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

You do not need to specify Class-Path entries in your manifest file, the classpath will be deduced from the nested jars.

E.3.2 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 ).

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.

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.

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Key Purpose

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

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.

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.

E.5.1 Zip entry compression

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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.

E.5.2 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

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.core jackson-annotations 2.8.0

com.fasterxml.jackson.core jackson-core 2.8.10

com.fasterxml.jackson.core jackson-databind 2.8.10

com.fasterxml.jackson.dataformat jackson-dataformat-avro 2.8.10

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Group ID Artifact ID Version

com.fasterxml.jackson.dataformat jackson-dataformat-cbor 2.8.10

com.fasterxml.jackson.dataformat jackson-dataformat-csv 2.8.10

com.fasterxml.jackson.dataformat jackson-dataformat-ion 2.8.10

com.fasterxml.jackson.dataformat jackson-dataformat-properties 2.8.10

com.fasterxml.jackson.dataformat jackson-dataformat-protobuf 2.8.10

com.fasterxml.jackson.dataformat jackson-dataformat-smile 2.8.10

com.fasterxml.jackson.dataformat jackson-dataformat-xml 2.8.10

com.fasterxml.jackson.dataformat jackson-dataformat-yaml 2.8.10

com.fasterxml.jackson.datatype jackson-datatype-guava 2.8.10

com.fasterxml.jackson.datatype jackson-datatype-hibernate3 2.8.10

com.fasterxml.jackson.datatype jackson-datatype-hibernate4 2.8.10

com.fasterxml.jackson.datatype jackson-datatype-hibernate5 2.8.10

com.fasterxml.jackson.datatype jackson-datatype-hppc 2.8.10

com.fasterxml.jackson.datatype jackson-datatype-jaxrs 2.8.10

com.fasterxml.jackson.datatype jackson-datatype-jdk8 2.8.10

com.fasterxml.jackson.datatype jackson-datatype-joda 2.8.10

com.fasterxml.jackson.datatype jackson-datatype-json-org 2.8.10

com.fasterxml.jackson.datatype jackson-datatype-jsr310 2.8.10

com.fasterxml.jackson.datatype jackson-datatype-jsr353 2.8.10

com.fasterxml.jackson.datatype jackson-datatype-pcollections 2.8.10

com.fasterxml.jackson.jaxrs jackson-jaxrs-base 2.8.10

com.fasterxml.jackson.jaxrs jackson-jaxrs-cbor-provider 2.8.10

com.fasterxml.jackson.jaxrs jackson-jaxrs-json-provider 2.8.10

com.fasterxml.jackson.jaxrs jackson-jaxrs-smile-provider 2.8.10

com.fasterxml.jackson.jaxrs jackson-jaxrs-xml-provider 2.8.10

com.fasterxml.jackson.jaxrs jackson-jaxrs-yaml-provider 2.8.10

com.fasterxml.jackson.jr jackson-jr-all 2.8.10

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Group ID Artifact ID Version

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.module jackson-module-afterburner 2.8.10

com.fasterxml.jackson.module jackson-module-guice 2.8.10

com.fasterxml.jackson.module jackson-module-jaxb-annotations 2.8.10

com.fasterxml.jackson.module jackson-module-jsonSchema 2.8.10

com.fasterxml.jackson.module jackson-module-kotlin 2.8.10

com.fasterxml.jackson.module jackson-module-mrbean 2.8.10

com.fasterxml.jackson.module jackson-module-osgi 2.8.10

com.fasterxml.jackson.module jackson-module-parameter-names 2.8.10

com.fasterxml.jackson.module jackson-module-paranamer 2.8.10

com.fasterxml.jackson.module jackson-module-scala_2.10 2.8.10

com.fasterxml.jackson.module jackson-module-scala_2.11 2.8.10

com.fasterxml.jackson.module jackson-module-scala_2.12 2.8.10

com.gemstone.gemfire gemfire 8.2.7

com.github.ben-manes.caffeine caffeine 2.3.5

com.github.mxab.thymeleaf.extras thymeleaf-extras-data-attribute 1.3

com.google.appengine appengine-api-1.0-sdk 1.9.59

com.google.code.gson gson 2.8.2

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

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Group ID Artifact ID Version

com.jayway.jsonpath json-path 2.2.0

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.mongo 1.50.5

dom4j dom4j 1.6.1

io.dropwizard.metrics metrics-annotation 3.1.5

io.dropwizard.metrics metrics-core 3.1.5

io.dropwizard.metrics metrics-ehcache 3.1.5

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Group ID Artifact ID Version

io.dropwizard.metrics metrics-ganglia 3.1.5

io.dropwizard.metrics metrics-graphite 3.1.5

io.dropwizard.metrics metrics-healthchecks 3.1.5

io.dropwizard.metrics metrics-httpasyncclient 3.1.5

io.dropwizard.metrics metrics-jdbi 3.1.5

io.dropwizard.metrics metrics-jersey 3.1.5

io.dropwizard.metrics metrics-jersey2 3.1.5

io.dropwizard.metrics metrics-jetty8 3.1.5

io.dropwizard.metrics metrics-jetty9 3.1.5

io.dropwizard.metrics metrics-jetty9-legacy 3.1.5

io.dropwizard.metrics metrics-json 3.1.5

io.dropwizard.metrics metrics-jvm 3.1.5

io.dropwizard.metrics metrics-log4j 3.1.5

io.dropwizard.metrics metrics-log4j2 3.1.5

io.dropwizard.metrics metrics-logback 3.1.5

io.dropwizard.metrics metrics-servlet 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

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

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Group ID Artifact ID Version

io.projectreactor.spring reactor-spring-webmvc 2.0.7.RELEASE

io.searchbox jest 2.0.4

io.undertow undertow-core 1.4.21.Final

io.undertow undertow-servlet 1.4.21.Final

io.undertow undertow-websockets-jsr 1.4.21.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.java.dev.jna jna-platform 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

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

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Group ID Artifact ID Version

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

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

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Group ID Artifact ID Version

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 2.4.3

org.apache.derby derby 10.13.1.1

org.apache.httpcomponents httpasyncclient 4.1.3

org.apache.httpcomponents httpclient 4.5.3

org.apache.httpcomponents httpcore 4.4.8

org.apache.httpcomponents httpmime 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

org.apache.logging.log4j log4j-taglib 2.7

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Group ID Artifact ID Version

org.apache.logging.log4j log4j-web 2.7

org.apache.solr solr-analysis-extras 5.5.5

org.apache.solr solr-analytics 5.5.5

org.apache.solr solr-cell 5.5.5

org.apache.solr solr-clustering 5.5.5

org.apache.solr solr-core 5.5.5

org.apache.solr solr-dataimporthandler 5.5.5

org.apache.solr solr-dataimporthandler-extras 5.5.5

org.apache.solr solr-langid 5.5.5

org.apache.solr solr-map-reduce 5.5.5

org.apache.solr solr-morphlines-cell 5.5.5

org.apache.solr solr-morphlines-core 5.5.5

org.apache.solr solr-solrj 5.5.5

org.apache.solr solr-test-framework 5.5.5

org.apache.solr solr-uima 5.5.5

org.apache.solr solr-velocity 5.5.5

org.apache.tomcat tomcat-annotations-api 8.5.23

org.apache.tomcat tomcat-jdbc 8.5.23

org.apache.tomcat tomcat-jsp-api 8.5.23

org.apache.tomcat.embed tomcat-embed-core 8.5.23

org.apache.tomcat.embed tomcat-embed-el 8.5.23

org.apache.tomcat.embed tomcat-embed-jasper 8.5.23

org.apache.tomcat.embed tomcat-embed-websocket 8.5.23

org.aspectj aspectjrt 1.8.13

org.aspectj aspectjtools 1.8.13

org.aspectj aspectjweaver 1.8.13

org.assertj assertj-core 2.6.0

1/17/2018 Spring Boot Reference Guide

https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-documentation-about 252/266

Group ID Artifact ID Version

org.codehaus.btm btm 2.1.4

org.codehaus.groovy groovy 2.4.13

org.codehaus.groovy groovy-all 2.4.13

org.codehaus.groovy groovy-ant 2.4.13

org.codehaus.groovy groovy-bsf 2.4.13

org.codehaus.groovy groovy-console 2.4.13

org.codehaus.groovy groovy-docgenerator 2.4.13

org.codehaus.groovy groovy-groovydoc 2.4.13

org.codehaus.groovy groovy-groovysh 2.4.13

org.codehaus.groovy groovy-jmx 2.4.13

org.codehaus.groovy groovy-json 2.4.13

org.codehaus.groovy groovy-jsr223 2.4.13

org.codehaus.groovy groovy-nio 2.4.13

org.codehaus.groovy groovy-servlet 2.4.13

org.codehaus.groovy groovy-sql 2.4.13

org.codehaus.groovy groovy-swing 2.4.13

org.codehaus.groovy groovy-templates 2.4.13

org.codehaus.groovy groovy-test 2.4.13

org.codehaus.groovy groovy-testng 2.4.13

org.codehaus.groovy groovy-xml 2.4.13

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

1/17/2018 Spring Boot Reference Guide

https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-documentation-about 253/266

Group ID Artifact ID Version

org.crashub crash.shell 1.3.2

org.eclipse.jetty apache-jsp 9.4.7.v20170914

org.eclipse.jetty apache-jstl 9.4.7.v20170914

org.eclipse.jetty jetty-alpn-client 9.4.7.v20170914

org.eclipse.jetty jetty-alpn-java-client 9.4.7.v20170914

org.eclipse.jetty jetty-alpn-java-server 9.4.7.v20170914

org.eclipse.jetty jetty-alpn-server 9.4.7.v20170914

org.eclipse.jetty jetty-annotations 9.4.7.v20170914

org.eclipse.jetty jetty-ant 9.4.7.v20170914

org.eclipse.jetty jetty-client 9.4.7.v20170914

org.eclipse.jetty jetty-continuation 9.4.7.v20170914

org.eclipse.jetty jetty-deploy 9.4.7.v20170914

org.eclipse.jetty jetty-hazelcast 9.4.7.v20170914

org.eclipse.jetty jetty-http 9.4.7.v20170914

org.eclipse.jetty jetty-http-spi 9.4.7.v20170914

org.eclipse.jetty jetty-infinispan 9.4.7.v20170914

org.eclipse.jetty jetty-io 9.4.7.v20170914

org.eclipse.jetty jetty-jaas 9.4.7.v20170914

org.eclipse.jetty jetty-jaspi 9.4.7.v20170914

org.eclipse.jetty jetty-jmx 9.4.7.v20170914

org.eclipse.jetty jetty-jndi 9.4.7.v20170914

org.eclipse.jetty jetty-nosql 9.4.7.v20170914

org.eclipse.jetty jetty-plus 9.4.7.v20170914

org.eclipse.jetty jetty-proxy 9.4.7.v20170914

org.eclipse.jetty jetty-quickstart 9.4.7.v20170914

org.eclipse.jetty jetty-rewrite 9.4.7.v20170914

org.eclipse.jetty jetty-runner 9.4.7.v20170914

1/17/2018 Spring Boot Reference Guide

https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-documentation-about 254/266

Group ID Artifact ID Version

org.eclipse.jetty jetty-security 9.4.7.v20170914

org.eclipse.jetty jetty-server 9.4.7.v20170914

org.eclipse.jetty jetty-servlet 9.4.7.v20170914

org.eclipse.jetty jetty-servlets 9.4.7.v20170914

org.eclipse.jetty jetty-spring 9.4.7.v20170914

org.eclipse.jetty jetty-start 9.4.7.v20170914

org.eclipse.jetty jetty-unixsocket 9.4.7.v20170914

org.eclipse.jetty jetty-util 9.4.7.v20170914

org.eclipse.jetty jetty-util-ajax 9.4.7.v20170914

org.eclipse.jetty jetty-webapp 9.4.7.v20170914

org.eclipse.jetty jetty-xml 9.4.7.v20170914

org.eclipse.jetty.cdi cdi-core 9.4.7.v20170914

org.eclipse.jetty.cdi cdi-servlet 9.4.7.v20170914

org.eclipse.jetty.fcgi fcgi-client 9.4.7.v20170914

org.eclipse.jetty.fcgi fcgi-server 9.4.7.v20170914

org.eclipse.jetty.gcloud jetty-gcloud-session-manager 9.4.7.v20170914

org.eclipse.jetty.http2 http2-client 9.4.7.v20170914

org.eclipse.jetty.http2 http2-common 9.4.7.v20170914

org.eclipse.jetty.http2 http2-hpack 9.4.7.v20170914

org.eclipse.jetty.http2 http2-http-client-transport 9.4.7.v20170914

org.eclipse.jetty.http2 http2-server 9.4.7.v20170914

org.eclipse.jetty.memcached jetty-memcached-sessions 9.4.7.v20170914

org.eclipse.jetty.orbit javax.servlet.jsp 2.2.0.v201112011158

org.eclipse.jetty.osgi jetty-httpservice 9.4.7.v20170914

org.eclipse.jetty.osgi jetty-osgi-boot 9.4.7.v20170914

org.eclipse.jetty.osgi jetty-osgi-boot-jsp 9.4.7.v20170914

org.eclipse.jetty.osgi jetty-osgi-boot-warurl 9.4.7.v20170914

1/17/2018 Spring Boot Reference Guide

https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-documentation-about 255/266

Group ID Artifact ID Version

org.eclipse.jetty.websocket javax-websocket-client-impl 9.4.7.v20170914

org.eclipse.jetty.websocket javax-websocket-server-impl 9.4.7.v20170914

org.eclipse.jetty.websocket websocket-api 9.4.7.v20170914

org.eclipse.jetty.websocket websocket-client 9.4.7.v20170914

org.eclipse.jetty.websocket websocket-common 9.4.7.v20170914

org.eclipse.jetty.websocket websocket-server 9.4.7.v20170914

org.eclipse.jetty.websocket websocket-servlet 9.4.7.v20170914

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

org.freemarker freemarker 2.3.27-incubating

org.glassfish javax.el 3.0.0

org.glassfish.jersey.bundles.repackaged jersey-guava 2.25.1

org.glassfish.jersey.containers jersey-container-servlet 2.25.1

org.glassfish.jersey.containers jersey-container-servlet-core 2.25.1

org.glassfish.jersey.core jersey-client 2.25.1

org.glassfish.jersey.core jersey-common 2.25.1

org.glassfish.jersey.core jersey-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.media jersey-media-jaxb 2.25.1

1/17/2018 Spring Boot Reference Guide

https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-documentation-about 256/266

Group ID Artifact ID Version

org.glassfish.jersey.media jersey-media-json-jackson 2.25.1

org.glassfish.jersey.media jersey-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 5.3.6.Final

org.hibernate hibernate-validator-annotation-processor 5.3.6.Final

org.hsqldb hsqldb 2.3.5

org.infinispan infinispan-jcache 8.2.8.Final

org.infinispan infinispan-spring4-common 8.2.8.Final

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 3.9.6

org.jooq jooq-codegen 3.9.6

1/17/2018 Spring Boot Reference Guide

https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-documentation-about 257/266

Group ID Artifact ID Version

org.jooq jooq-meta 3.9.6

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

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

1/17/2018 Spring Boot Reference Guide

https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-documentation-about 258/266

Group ID Artifact ID Version

org.slf4j slf4j-api 1.7.25

org.slf4j slf4j-ext 1.7.25

org.slf4j slf4j-jcl 1.7.25

org.slf4j slf4j-jdk14 1.7.25

org.slf4j slf4j-log4j12 1.7.25

org.slf4j slf4j-nop 1.7.25

org.slf4j slf4j-simple 1.7.25

org.spockframework spock-core 1.0-groovy-2.4

org.spockframework spock-spring 1.0-groovy-2.4

org.springframework spring-aop 4.3.13.RELEASE

org.springframework spring-aspects 4.3.13.RELEASE

org.springframework spring-beans 4.3.13.RELEASE

org.springframework spring-context 4.3.13.RELEASE

org.springframework spring-context-support 4.3.13.RELEASE

org.springframework spring-core 4.3.13.RELEASE

org.springframework spring-expression 4.3.13.RELEASE

org.springframework spring-instrument 4.3.13.RELEASE

org.springframework spring-instrument-tomcat 4.3.13.RELEASE

org.springframework spring-jdbc 4.3.13.RELEASE

org.springframework spring-jms 4.3.13.RELEASE

org.springframework springloaded 1.2.8.RELEASE

org.springframework spring-messaging 4.3.13.RELEASE

org.springframework spring-orm 4.3.13.RELEASE

org.springframework spring-oxm 4.3.13.RELEASE

org.springframework spring-test 4.3.13.RELEASE

org.springframework spring-tx 4.3.13.RELEASE

org.springframework spring-web 4.3.13.RELEASE

1/17/2018 Spring Boot Reference Guide

https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-documentation-about 259/266

Group ID Artifact ID Version

org.springframework spring-webmvc 4.3.13.RELEASE

org.springframework spring-webmvc-portlet 4.3.13.RELEASE

org.springframework spring-websocket 4.3.13.RELEASE

org.springframework.amqp spring-amqp 1.7.4.RELEASE

org.springframework.amqp spring-rabbit 1.7.4.RELEASE

org.springframework.batch spring-batch-core 3.0.8.RELEASE

org.springframework.batch spring-batch-infrastructure 3.0.8.RELEASE

org.springframework.batch spring-batch-integration 3.0.8.RELEASE

org.springframework.batch spring-batch-test 3.0.8.RELEASE

org.springframework.boot spring-boot 1.5.9.RELEASE

org.springframework.boot spring-boot-actuator 1.5.9.RELEASE

org.springframework.boot spring-boot-actuator-docs 1.5.9.RELEASE

org.springframework.boot spring-boot-autoconfigure 1.5.9.RELEASE

org.springframework.boot spring-boot-autoconfigure-processor 1.5.9.RELEASE

org.springframework.boot spring-boot-configuration-metadata 1.5.9.RELEASE

org.springframework.boot spring-boot-configuration-processor 1.5.9.RELEASE

org.springframework.boot spring-boot-devtools 1.5.9.RELEASE

org.springframework.boot spring-boot-loader 1.5.9.RELEASE

org.springframework.boot spring-boot-loader-tools 1.5.9.RELEASE

org.springframework.boot spring-boot-starter 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-activemq 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-actuator 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-amqp 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-aop 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-artemis 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-batch 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-cache 1.5.9.RELEASE

1/17/2018 Spring Boot Reference Guide

https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-documentation-about 260/266

Group ID Artifact ID Version

org.springframework.boot spring-boot-starter-cloud-connectors 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-data-cassandra 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-data-couchbase 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-data-elasticsearch 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-data-gemfire 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-data-jpa 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-data-ldap 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-data-mongodb 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-data-neo4j 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-data-redis 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-data-rest 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-data-solr 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-freemarker 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-groovy-templates 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-hateoas 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-integration 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-jdbc 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-jersey 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-jetty 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-jooq 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-jta-atomikos 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-jta-bitronix 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-jta-narayana 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-log4j2 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-logging 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-mail 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-mobile 1.5.9.RELEASE

1/17/2018 Spring Boot Reference Guide

https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-documentation-about 261/266

Group ID Artifact ID Version

org.springframework.boot spring-boot-starter-mustache 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-remote-shell 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-security 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-social-facebook 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-social-linkedin 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-social-twitter 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-test 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-thymeleaf 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-tomcat 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-undertow 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-validation 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-web 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-web-services 1.5.9.RELEASE

org.springframework.boot spring-boot-starter-websocket 1.5.9.RELEASE

org.springframework.boot spring-boot-test 1.5.9.RELEASE

org.springframework.boot spring-boot-test-autoconfigure 1.5.9.RELEASE

org.springframework.cloud spring-cloud-cloudfoundry-connector 1.2.5.RELEASE

org.springframework.cloud spring-cloud-core 1.2.5.RELEASE

org.springframework.cloud spring-cloud-heroku-connector 1.2.5.RELEASE

org.springframework.cloud spring-cloud-localconfig-connector 1.2.5.RELEASE

org.springframework.cloud spring-cloud-spring-service-connector 1.2.5.RELEASE

org.springframework.data spring-cql 1.5.9.RELEASE

org.springframework.data spring-data-cassandra 1.5.9.RELEASE

org.springframework.data spring-data-commons 1.13.9.RELEASE

org.springframework.data spring-data-couchbase 2.2.9.RELEASE

org.springframework.data spring-data-elasticsearch 2.1.9.RELEASE

org.springframework.data spring-data-envers 1.1.9.RELEASE

1/17/2018 Spring Boot Reference Guide

https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-documentation-about 262/266

Group ID Artifact ID Version

org.springframework.data spring-data-gemfire 1.9.9.RELEASE

org.springframework.data spring-data-jpa 1.11.9.RELEASE

org.springframework.data spring-data-keyvalue 1.2.9.RELEASE

org.springframework.data spring-data-ldap 1.0.9.RELEASE

org.springframework.data spring-data-mongodb 1.10.9.RELEASE

org.springframework.data spring-data-mongodb-cross-store 1.10.9.RELEASE

org.springframework.data spring-data-mongodb-log4j 1.10.9.RELEASE

org.springframework.data spring-data-neo4j 4.2.9.RELEASE

org.springframework.data spring-data-redis 1.8.9.RELEASE

org.springframework.data spring-data-rest-core 2.6.9.RELEASE

org.springframework.data spring-data-rest-hal-browser 2.6.9.RELEASE

org.springframework.data spring-data-rest-webmvc 2.6.9.RELEASE

org.springframework.data spring-data-solr 2.1.9.RELEASE

org.springframework.hateoas spring-hateoas 0.23.0.RELEASE

org.springframework.integration spring-integration-amqp 4.3.12.RELEASE

org.springframework.integration spring-integration-core 4.3.12.RELEASE

org.springframework.integration spring-integration-event 4.3.12.RELEASE

org.springframework.integration spring-integration-feed 4.3.12.RELEASE

org.springframework.integration spring-integration-file 4.3.12.RELEASE

org.springframework.integration spring-integration-ftp 4.3.12.RELEASE

org.springframework.integration spring-integration-gemfire 4.3.12.RELEASE

org.springframework.integration spring-integration-groovy 4.3.12.RELEASE

org.springframework.integration spring-integration-http 4.3.12.RELEASE

org.springframework.integration spring-integration-ip 4.3.12.RELEASE

org.springframework.integration spring-integration-java-dsl 1.2.3.RELEASE

org.springframework.integration spring-integration-jdbc 4.3.12.RELEASE

org.springframework.integration spring-integration-jms 4.3.12.RELEASE

1/17/2018 Spring Boot Reference Guide

https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-documentation-about 263/266

Group ID Artifact ID Version

org.springframework.integration spring-integration-jmx 4.3.12.RELEASE

org.springframework.integration spring-integration-jpa 4.3.12.RELEASE

org.springframework.integration spring-integration-mail 4.3.12.RELEASE

org.springframework.integration spring-integration-mongodb 4.3.12.RELEASE

org.springframework.integration spring-integration-mqtt 4.3.12.RELEASE

org.springframework.integration spring-integration-redis 4.3.12.RELEASE

org.springframework.integration spring-integration-rmi 4.3.12.RELEASE

org.springframework.integration spring-integration-scripting 4.3.12.RELEASE

org.springframework.integration spring-integration-security 4.3.12.RELEASE

org.springframework.integration spring-integration-sftp 4.3.12.RELEASE

org.springframework.integration spring-integration-stomp 4.3.12.RELEASE

org.springframework.integration spring-integration-stream 4.3.12.RELEASE

org.springframework.integration spring-integration-syslog 4.3.12.RELEASE

org.springframework.integration spring-integration-test 4.3.12.RELEASE

org.springframework.integration spring-integration-twitter 4.3.12.RELEASE

org.springframework.integration spring-integration-websocket 4.3.12.RELEASE

org.springframework.integration spring-integration-ws 4.3.12.RELEASE

org.springframework.integration spring-integration-xml 4.3.12.RELEASE

org.springframework.integration spring-integration-xmpp 4.3.12.RELEASE

org.springframework.integration spring-integration-zookeeper 4.3.12.RELEASE

org.springframework.kafka spring-kafka 1.1.7.RELEASE

org.springframework.kafka spring-kafka-test 1.1.7.RELEASE

org.springframework.ldap spring-ldap-core 2.3.2.RELEASE

org.springframework.ldap spring-ldap-core-tiger 2.3.2.RELEASE

org.springframework.ldap spring-ldap-ldif-batch 2.3.2.RELEASE

org.springframework.ldap spring-ldap-ldif-core 2.3.2.RELEASE

org.springframework.ldap spring-ldap-odm 2.3.2.RELEASE

1/17/2018 Spring Boot Reference Guide

https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-documentation-about 264/266

Group ID Artifact ID Version

org.springframework.ldap spring-ldap-test 2.3.2.RELEASE

org.springframework.mobile spring-mobile-device 1.1.5.RELEASE

org.springframework.plugin spring-plugin-core 1.2.0.RELEASE

org.springframework.plugin spring-plugin-metadata 1.2.0.RELEASE

org.springframework.restdocs spring-restdocs-core 1.1.3.RELEASE

org.springframework.restdocs spring-restdocs-mockmvc 1.1.3.RELEASE

org.springframework.restdocs spring-restdocs-restassured 1.1.3.RELEASE

org.springframework.retry spring-retry 1.2.1.RELEASE

org.springframework.security spring-security-acl 4.2.3.RELEASE

org.springframework.security spring-security-aspects 4.2.3.RELEASE

org.springframework.security spring-security-cas 4.2.3.RELEASE

org.springframework.security spring-security-config 4.2.3.RELEASE

org.springframework.security spring-security-core 4.2.3.RELEASE

org.springframework.security spring-security-crypto 4.2.3.RELEASE

org.springframework.security spring-security-data 4.2.3.RELEASE

org.springframework.security spring-security-jwt 1.0.8.RELEASE

org.springframework.security spring-security-ldap 4.2.3.RELEASE

org.springframework.security spring-security-messaging 4.2.3.RELEASE

org.springframework.security spring-security-openid 4.2.3.RELEASE

org.springframework.security spring-security-remoting 4.2.3.RELEASE

org.springframework.security spring-security-taglibs 4.2.3.RELEASE

org.springframework.security spring-security-test 4.2.3.RELEASE

org.springframework.security spring-security-web 4.2.3.RELEASE

org.springframework.security.oauth spring-security-oauth 2.0.14.RELEASE

org.springframework.security.oauth spring-security-oauth2 2.0.14.RELEASE

org.springframework.session spring-session 1.3.1.RELEASE

org.springframework.session spring-session-data-gemfire 1.3.1.RELEASE

1/17/2018 Spring Boot Reference Guide

https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-documentation-about 265/266

Group ID Artifact ID Version

org.springframework.session spring-session-data-mongo 1.3.1.RELEASE

org.springframework.session spring-session-data-redis 1.3.1.RELEASE

org.springframework.session spring-session-hazelcast 1.3.1.RELEASE

org.springframework.session spring-session-jdbc 1.3.1.RELEASE

org.springframework.social spring-social-config 1.1.4.RELEASE

org.springframework.social spring-social-core 1.1.4.RELEASE

org.springframework.social spring-social-facebook 2.0.3.RELEASE

org.springframework.social spring-social-facebook-web 2.0.3.RELEASE

org.springframework.social spring-social-linkedin 1.0.2.RELEASE

org.springframework.social spring-social-security 1.1.4.RELEASE

org.springframework.social spring-social-twitter 1.1.2.RELEASE

org.springframework.social spring-social-web 1.1.4.RELEASE

org.springframework.ws spring-ws-core 2.4.2.RELEASE

org.springframework.ws spring-ws-security 2.4.2.RELEASE

org.springframework.ws spring-ws-support 2.4.2.RELEASE

org.springframework.ws spring-ws-test 2.4.2.RELEASE

org.thymeleaf thymeleaf 2.1.6.RELEASE

org.thymeleaf thymeleaf-spring4 2.1.6.RELEASE

org.thymeleaf.extras thymeleaf-extras-conditionalcomments 2.1.2.RELEASE

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

1/17/2018 Spring Boot Reference Guide

https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-documentation-about 266/266

Group ID Artifact ID Version

xml-apis xml-apis 1.4.01

Spring Boot Reference Guide

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