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, Vedran Pavić, Jay Bryant, Madhura Bhave

2.0.1.BUILD-SNAPSHOT

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
11.2. Adding Classpath Dependencies
11.3. Writing the Code
11.3.1. The @RestController and @RequestMapping Annotations
11.3.2. The @EnableAutoConfiguration Annotation
11.3.3. The “main” Method
11.4. Running the Example
11.5. Creating an Executable Jar
12. What to Read Next
III. Using Spring Boot
13. Build Systems
13.1. Dependency Management
13.2. Maven
13.2.1. Inheriting the Starter Parent
13.2.2. Using Spring Boot without the Parent POM
13.2.3. Using the Spring Boot Maven Plugin
13.3. Gradle
13.4. Ant
13.5. Starters
14. Structuring Your Code
14.1. Using the “default” Package
14.2. Locating the Main Application Class
15. Configuration Classes
15.1. Importing Additional Configuration Classes
15.2. Importing XML Configuration
16. Auto-configuration
16.1. Gradually Replacing Auto-configuration
16.2. Disabling Specific Auto-configuration Classes
17. Spring Beans and Dependency Injection
18. Using the @SpringBootApplication Annotation
19. Running Your Application
19.1. Running from an IDE
19.2. Running as a Packaged Application
19.3. Using the Maven Plugin
19.4. Using the Gradle Plugin
19.5. Hot Swapping
20. Developer Tools
20.1. Property Defaults
20.2. Automatic Restart
20.2.1. Logging changes in condition evaluation
20.2.2. Excluding Resources
20.2.3. Watching Additional Paths
20.2.4. Disabling Restart
20.2.5. Using a Trigger File
20.2.6. Customizing the Restart Classloader
20.2.7. Known Limitations
20.3. LiveReload
20.4. Global Settings
20.5. Remote Applications
20.5.1. Running the Remote Client Application
20.5.2. Remote Update
21. Packaging Your Application for Production
22. What to Read Next
IV. Spring Boot features
23. SpringApplication
23.1. Startup Failure
23.2. Customizing the Banner
23.3. Customizing SpringApplication
23.4. Fluent Builder API
23.5. Application Events and Listeners
23.6. Web Environment
23.7. Accessing Application Arguments
23.8. Using the ApplicationRunner or CommandLineRunner
23.9. Application Exit
23.10. Admin Features
24. Externalized Configuration
24.1. Configuring Random Values
24.2. Accessing Command Line Properties
24.3. Application Property Files
24.4. Profile-specific Properties
24.5. Placeholders in Properties
24.6. Using YAML Instead of Properties
24.6.1. Loading YAML
24.6.2. Exposing YAML as Properties in the Spring Environment
24.6.3. Multi-profile YAML Documents
24.6.4. YAML Shortcomings
24.6.5. Merging YAML Lists
24.7. Type-safe Configuration Properties
24.7.1. Third-party Configuration
24.7.2. Relaxed Binding
24.7.3. Properties Conversion
Converting durations
24.7.4. @ConfigurationProperties Validation
24.7.5. @ConfigurationProperties vs. @Value
25. Profiles
25.1. Adding Active Profiles
25.2. Programmatically Setting Profiles
25.3. Profile-specific Configuration Files
26. Logging
26.1. Log Format
26.2. Console Output
26.2.1. Color-coded Output
26.3. File Output
26.4. Log Levels
26.5. Custom Log Configuration
26.6. Logback Extensions
26.6.1. Profile-specific Configuration
26.6.2. Environment Properties
27. Developing Web Applications
27.1. The “Spring Web MVC Framework”
27.1.1. Spring MVC Auto-configuration
27.1.2. HttpMessageConverters
27.1.3. Custom JSON Serializers and Deserializers
27.1.4. MessageCodesResolver
27.1.5. Static Content
27.1.6. Welcome Page
27.1.7. Custom Favicon
27.1.8. Path Matching and Content Negotiation
27.1.9. ConfigurableWebBindingInitializer
27.1.10. Template Engines
27.1.11. Error Handling
Custom Error Pages
Mapping Error Pages outside of Spring MVC
27.1.12. Spring HATEOAS
27.1.13. CORS Support
27.2. The “Spring WebFlux Framework”
27.2.1. Spring WebFlux Auto-configuration
27.2.2. HTTP Codecs with HttpMessageReaders and HttpMessageWriters
27.2.3. Static Content
27.2.4. Template Engines
27.2.5. Error Handling
Custom Error Pages
27.2.6. Web Filters
27.3. JAX-RS and Jersey
27.4. Embedded Servlet Container Support
27.4.1. Servlets, Filters, and listeners
Registering Servlets, Filters, and Listeners as Spring Beans
27.4.2. Servlet Context Initialization
Scanning for Servlets, Filters, and listeners
27.4.3. The ServletWebServerApplicationContext
27.4.4. Customizing Embedded Servlet Containers
Programmatic Customization
Customizing ConfigurableServletWebServerFactory Directly
27.4.5. JSP Limitations
28. Security
28.1. MVC Security
28.2. WebFlux Security
28.3. OAuth2
28.3.1. Client
28.3.2. Server
28.4. Actuator Security
28.4.1. Cross Site Request Forgery Protection
29. Working with SQL Databases
29.1. Configure a DataSource
29.1.1. Embedded Database Support
29.1.2. Connection to a Production Database
29.1.3. Connection to a JNDI DataSource
29.2. Using JdbcTemplate
29.3. JPA and “Spring Data”
29.3.1. Entity Classes
29.3.2. Spring Data JPA Repositories
29.3.3. Creating and Dropping JPA Databases
29.3.4. Open EntityManager in View
29.4. Using H2’s Web Console
29.4.1. Changing the H2 Console’s Path
29.5. Using jOOQ
29.5.1. Code Generation
29.5.2. Using DSLContext
29.5.3. jOOQ SQL Dialect
29.5.4. Customizing jOOQ
30. Working with NoSQL Technologies
30.1. Redis
30.1.1. Connecting to Redis
30.2. MongoDB
30.2.1. Connecting to a MongoDB Database
30.2.2. MongoTemplate
30.2.3. Spring Data MongoDB Repositories
30.2.4. Embedded Mongo
30.3. Neo4j
30.3.1. Connecting to a Neo4j Database
30.3.2. Using the Embedded Mode
30.3.3. Neo4jSession
30.3.4. Spring Data Neo4j Repositories
30.3.5. Repository Example
30.4. Gemfire
30.5. Solr
30.5.1. Connecting to Solr
30.5.2. Spring Data Solr Repositories
30.6. Elasticsearch
30.6.1. Connecting to Elasticsearch by Using Jest
30.6.2. Connecting to Elasticsearch by Using Spring Data
30.6.3. Spring Data Elasticsearch Repositories
30.7. Cassandra
30.7.1. Connecting to Cassandra
30.7.2. Spring Data Cassandra Repositories
30.8. Couchbase
30.8.1. Connecting to Couchbase
30.8.2. Spring Data Couchbase Repositories
30.9. LDAP
30.9.1. Connecting to an LDAP Server
30.9.2. Spring Data LDAP Repositories
30.9.3. Embedded In-memory LDAP Server
30.10. InfluxDB
30.10.1. Connecting to InfluxDB
31. Caching
31.1. Supported Cache Providers
31.1.1. Generic
31.1.2. JCache (JSR-107)
31.1.3. EhCache 2.x
31.1.4. Hazelcast
31.1.5. Infinispan
31.1.6. Couchbase
31.1.7. Redis
31.1.8. Caffeine
31.1.9. Simple
31.1.10. None
32. Messaging
32.1. JMS
32.1.1. ActiveMQ Support
32.1.2. Artemis Support
32.1.3. Using a JNDI ConnectionFactory
32.1.4. Sending a Message
32.1.5. Receiving a Message
32.2. AMQP
32.2.1. RabbitMQ support
32.2.2. Sending a Message
32.2.3. Receiving a Message
32.3. Apache Kafka Support
32.3.1. Sending a Message
32.3.2. Receiving a Message
32.3.3. Additional Kafka Properties
33. Calling REST Services with RestTemplate
33.1. RestTemplate Customization
34. Calling REST Services with WebClient
34.1. WebClient Customization
35. Validation
36. Sending Email
37. Distributed Transactions with JTA
37.1. Using an Atomikos Transaction Manager
37.2. Using a Bitronix Transaction Manager
37.3. Using a Narayana Transaction Manager
37.4. Using a Java EE Managed Transaction Manager
37.5. Mixing XA and Non-XA JMS Connections
37.6. Supporting an Alternative Embedded Transaction Manager
38. Hazelcast
39. Quartz Scheduler
40. Spring Integration
41. Spring Session
42. Monitoring and Management over JMX
43. Testing
43.1. Test Scope Dependencies
43.2. Testing Spring Applications
43.3. Testing Spring Boot Applications
43.3.1. Detecting Web Application Type
43.3.2. Detecting Test Configuration
43.3.3. Excluding Test Configuration
43.3.4. Testing with a running server
43.3.5. Mocking and Spying Beans
43.3.6. Auto-configured Tests
43.3.7. Auto-configured JSON Tests
43.3.8. Auto-configured Spring MVC Tests
43.3.9. Auto-configured Spring WebFlux Tests
43.3.10. Auto-configured Data JPA Tests
43.3.11. Auto-configured JDBC Tests
43.3.12. Auto-configured jOOQ Tests
43.3.13. Auto-configured Data MongoDB Tests
43.3.14. Auto-configured Data Neo4j Tests
43.3.15. Auto-configured Data Redis Tests
43.3.16. Auto-configured Data LDAP Tests
43.3.17. Auto-configured REST Clients
43.3.18. Auto-configured Spring REST Docs Tests
Auto-configured Spring REST Docs Tests with Mock MVC
Auto-configured Spring REST Docs Tests with REST Assured
43.3.19. User Configuration and Slicing
43.3.20. Using Spock to Test Spring Boot Applications
43.4. Test Utilities
43.4.1. ConfigFileApplicationContextInitializer
43.4.2. TestPropertyValues
43.4.3. OutputCapture
43.4.4. TestRestTemplate
44. WebSockets
45. Web Services
46. Creating Your Own Auto-configuration
46.1. Understanding Auto-configured Beans
46.2. Locating Auto-configuration Candidates
46.3. Condition Annotations
46.3.1. Class Conditions
46.3.2. Bean Conditions
46.3.3. Property Conditions
46.3.4. Resource Conditions
46.3.5. Web Application Conditions
46.3.6. SpEL Expression Conditions
46.4. Testing your Auto-configuration
46.4.1. Simulating a Web Context
46.4.2. Overriding the Classpath
46.5. Creating Your Own Starter
46.5.1. Naming
46.5.2. autoconfigure Module
46.5.3. Starter Module
47. Kotlin support
47.1. Requirements
47.2. Null-safety
47.3. Kotlin API
47.3.1. runApplication
47.3.2. Extensions
47.4. Dependency management
47.5. @ConfigurationProperties
47.6. Testing
47.7. Resources
47.7.1. Further reading
47.7.2. Examples
48. What to Read Next
V. Spring Boot Actuator: Production-ready features
49. Enabling Production-ready Features
50. Endpoints
50.1. Enabling Endpoints
50.2. Exposing Endpoints
50.3. Securing HTTP Endpoints
50.4. Configuring Endpoints
50.5. Hypermedia for Actuator Web Endpoints
50.6. Actuator Web Endpoint Paths
50.7. CORS Support
50.8. Implementing Custom Endpoints
50.8.1. Receiving Input
Input type conversion
50.8.2. Custom Web Endpoints
Web Endpoint Request Predicates
Path
HTTP method
Consumes
Produces
Web Endpoint Response Status
Web Endpoint Range Requests
Web Endpoint Security
50.8.3. Servlet endpoints
50.8.4. Controller endpoints
50.9. Health Information
50.9.1. Auto-configured HealthIndicators
50.9.2. Writing Custom HealthIndicators
50.9.3. Reactive Health Indicators
50.9.4. Auto-configured ReactiveHealthIndicators
50.10. Application Information
50.10.1. Auto-configured InfoContributors
50.10.2. Custom Application Information
50.10.3. Git Commit Information
50.10.4. Build Information
50.10.5. Writing Custom InfoContributors
51. Monitoring and Management over HTTP
51.1. Customizing the Management Endpoint Paths
51.2. Customizing the Management Server Port
51.3. Configuring Management-specific SSL
51.4. Customizing the Management Server Address
51.5. Disabling HTTP Endpoints
52. Monitoring and Management over JMX
52.1. Customizing MBean Names
52.2. Disabling JMX Endpoints
52.3. Using Jolokia for JMX over HTTP
52.3.1. Customizing Jolokia
52.3.2. Disabling Jolokia
53. Loggers
53.1. Configure a Logger
54. Metrics
54.1. Getting started
54.2. Supported monitoring systems
54.2.1. Atlas
54.2.2. Datadog
54.2.3. Ganglia
54.2.4. Graphite
54.2.5. Influx
54.2.6. JMX
54.2.7. New Relic
54.2.8. Prometheus
54.2.9. SignalFx
54.2.10. Simple
54.2.11. StatsD
54.2.12. Wavefront
54.3. Supported Metrics
54.3.1. Spring MVC Metrics
54.3.2. Spring WebFlux Metrics
54.3.3. RestTemplate Metrics
54.3.4. Cache Metrics
54.3.5. DataSource Metrics
54.3.6. RabbitMQ Metrics
54.4. Registering custom metrics
54.5. Customizing individual metrics
54.5.1. Per-meter properties
54.6. Metrics endpoint
55. Auditing
56. HTTP Tracing
56.1. Custom HTTP tracing
57. Process Monitoring
57.1. Extending Configuration
57.2. Programmatically
58. Cloud Foundry Support
58.1. Disabling Extended Cloud Foundry Actuator Support
58.2. Cloud Foundry Self-signed Certificates
58.3. Custom context path
59. What to Read Next
VI. Deploying Spring Boot Applications
60. Deploying to the Cloud
60.1. Cloud Foundry
60.1.1. Binding to Services
60.2. Heroku
60.3. OpenShift
60.4. Amazon Web Services (AWS)
60.4.1. AWS Elastic Beanstalk
Using the Tomcat Platform
Using the Java SE Platform
60.4.2. Summary
60.5. Boxfuse and Amazon Web Services
60.6. Google Cloud
61. Installing Spring Boot Applications
61.1. Supported Operating Systems
61.2. Unix/Linux Services
61.2.1. Installation as an init.d Service (System V)
Securing an init.d Service
61.2.2. Installation as a systemd Service
61.2.3. Customizing the Startup Script
Customizing the Start Script when It Is Written
Customizing a Script When It Runs
61.3. Microsoft Windows Services
62. What to Read Next
VII. Spring Boot CLI
63. Installing the CLI
64. Using the CLI
64.1. Running Applications with the CLI
64.1.1. Deduced “grab” Dependencies
64.1.2. Deduced “grab” Coordinates
64.1.3. Default Import Statements
64.1.4. Automatic Main Method
64.1.5. Custom Dependency Management
64.2. Applications with Multiple Source Files
64.3. Packaging Your Application
64.4. Initialize a New Project
64.5. Using the Embedded Shell
64.6. Adding Extensions to the CLI
65. Developing Applications with the Groovy Beans DSL
66. Configuring the CLI with settings.xml
67. What to Read Next
VIII. Build tool plugins
68. Spring Boot Maven Plugin
68.1. Including the Plugin
68.2. Packaging Executable Jar and War Files
69. Spring Boot Gradle Plugin
70. Spring Boot AntLib Module
70.1. Spring Boot Ant Tasks
70.1.1. spring-boot:exejar
70.1.2. Examples
70.2. spring-boot:findmainclass
70.2.1. Examples
71. Supporting Other Build Systems
71.1. Repackaging Archives
71.2. Nested Libraries
71.3. Finding a Main Class
71.4. Example Repackage Implementation
72. What to Read Next
IX. ‘How-to’ guides
73. Spring Boot Application
73.1. Create Your Own FailureAnalyzer
73.2. Troubleshoot Auto-configuration
73.3. Customize the Environment or ApplicationContext Before It Starts
73.4. Build an ApplicationContext Hierarchy (Adding a Parent or Root Context)
73.5. Create a Non-web Application
74. Properties and Configuration
74.1. Automatically Expand Properties at Build Time
74.1.1. Automatic Property Expansion Using Maven
74.1.2. Automatic Property Expansion Using Gradle
74.2. Externalize the Configuration of SpringApplication
74.3. Change the Location of External Properties of an Application
74.4. Use ‘Short’ Command Line Arguments
74.5. Use YAML for External Properties
74.6. Set the Active Spring Profiles
74.7. Change Configuration Depending on the Environment
74.8. Discover Built-in Options for External Properties
75. Embedded Web Servers
75.1. Use Another Web Server
75.2. Configure Jetty
75.3. Add a Servlet, Filter, or Listener to an Application
75.3.1. Add a Servlet, Filter, or Listener by Using a Spring Bean
Disable Registration of a Servlet or Filter
75.3.2. Add Servlets, Filters, and Listeners by Using Classpath Scanning
75.4. Change the HTTP Port
75.5. Use a Random Unassigned HTTP Port
75.6. Discover the HTTP Port at Runtime
75.7. Configure SSL
75.8. Configure HTTP/2
75.8.1. HTTP/2 with Undertow
75.8.2. HTTP/2 with Jetty
75.8.3. HTTP/2 with Tomcat
75.9. Configure Access Logging
75.10. Running Behind a Front-end Proxy Server
75.10.1. Customize Tomcat’s Proxy Configuration
75.11. Configure Tomcat
75.12. Enable Multiple Connectors with Tomcat
75.13. Use Tomcat’s LegacyCookieProcessor
75.14. Configure Undertow
75.15. Enable Multiple Listeners with Undertow
75.16. Create WebSocket Endpoints Using @ServerEndpoint
75.17. Enable HTTP Response Compression
76. Spring MVC
76.1. Write a JSON REST Service
76.2. Write an XML REST Service
76.3. Customize the Jackson ObjectMapper
76.4. Customize the @ResponseBody Rendering
76.5. Handling Multipart File Uploads
76.6. Switch Off the Spring MVC DispatcherServlet
76.7. Switch off the Default MVC Configuration
76.8. Customize ViewResolvers
77. HTTP Clients
77.1. Configure RestTemplate to Use a Proxy
78. Logging
78.1. Configure Logback for Logging
78.1.1. Configure Logback for File-only Output
78.2. Configure Log4j for Logging
78.2.1. Use YAML or JSON to Configure Log4j 2
79. Data Access
79.1. Configure a Custom DataSource
79.2. Configure Two DataSources
79.3. Use Spring Data Repositories
79.4. Separate @Entity Definitions from Spring Configuration
79.5. Configure JPA Properties
79.6. Configure Hibernate Naming Strategy
79.7. Use a Custom EntityManagerFactory
79.8. Use Two EntityManagers
79.9. Use a Traditional persistence.xml File
79.10. Use Spring Data JPA and Mongo Repositories
79.11. Expose Spring Data Repositories as REST Endpoint
79.12. Configure a Component that is Used by JPA
79.13. Configure jOOQ with Two DataSources
80. Database Initialization
80.1. Initialize a Database Using JPA
80.2. Initialize a Database Using Hibernate
80.3. Initialize a Database
80.4. Initialize a Spring Batch Database
80.5. Use a Higher-level Database Migration Tool
80.5.1. Execute Flyway Database Migrations on Startup
80.5.2. Execute Liquibase Database Migrations on Startup
81. Messaging
81.1. Disable Transacted JMS Session
82. Batch Applications
82.1. Execute Spring Batch Jobs on Startup
83. Actuator
83.1. Change the HTTP Port or Address of the Actuator Endpoints
83.2. Customize the ‘whitelabel’ Error Page
84. Security
84.1. Switch off the Spring Boot Security Configuration
84.2. Change the UserDetailsService and Add User Accounts
84.3. Enable HTTPS When Running behind a Proxy Server
85. Hot Swapping
85.1. Reload Static Content
85.2. Reload Templates without Restarting the Container
85.2.1. Thymeleaf Templates
85.2.2. FreeMarker Templates
85.2.3. Groovy Templates
85.3. Fast Application Restarts
85.4. Reload Java Classes without Restarting the Container
86. Build
86.1. Generate Build Information
86.2. Generate Git Information
86.3. Customize Dependency Versions
86.4. Create an Executable JAR with Maven
86.5. Use a Spring Boot Application as a Dependency
86.6. Extract Specific Libraries When an Executable Jar Runs
86.7. Create a Non-executable JAR with Exclusions
86.8. Remote Debug a Spring Boot Application Started with Maven
86.9. Build an Executable Archive from Ant without Using spring-boot-antlib
87. Traditional Deployment
87.1. Create a Deployable War File
87.2. Convert an Existing Application to Spring Boot
87.3. Deploying a WAR to WebLogic
87.4. Use Jedis Instead of Lettuce
X. Appendices
A. Common application properties
B. Configuration Metadata
B.1. Metadata Format
B.1.1. Group Attributes
B.1.2. Property Attributes
B.1.3. Hint Attributes
B.1.4. Repeated Metadata Items
B.2. Providing Manual Hints
B.2.1. Value Hint
B.2.2. Value Providers
Any
Class Reference
Handle As
Logger Name
Spring Bean Reference
Spring Profile Name
B.3. Generating Your Own Metadata by Using the Annotation Processor
B.3.1. Nested Properties
B.3.2. Adding Additional Metadata
C. Auto-configuration classes
C.1. From the “spring-boot-autoconfigure” module
C.2. From the “spring-boot-actuator-autoconfigure” 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
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.6. Alternative Single Jar Solutions
F. Dependency versions