This document contains notes on Spring Boot concepts including: 1. An overview of Spring Boot starters, auto-configuration, customization rules, and the actuator module for monitoring. 2. Details on customizing auto-configuration through property overrides, excluding specific auto-configuration classes, and dependency injection with annotations. 3. An explanation of loading order for Spring beans and when to use the @Order annotation, such as for overriding security configurations in Spring Boot applications.

1. Gilwon Oh
2015.06.03 V1.01

2.  backend developer for
interested in full stack development as well
 https://medium.com/@kobi97
 kobi97@gmail.com
2

3. Spring Boot Hello World
Spring Boot Management (Actuator)
Spring Boot Starter Web (jar vs war)
Auto-Configuration Mechanism
Customizing Rules
Order of Loading Spring Beans
When do I use @Order?
Conclusion
For developers who use Spring Framework
3

4. 1.0.1
 Add Spring Bean’s life and @Primary
4

5. jar/war
How many services do you use?
What is Spring Boot?
Why use it? 5

6. mvn package
java –jar target/demo-0.0.1-SNAPSHOT.jar (.war)
or
mvn spring-boot:run
6

7. How do I customizing Spring Boot?
It’s very important to understand
Auto-Configuration Mechanism
I would like to introduce
My Customizing Rules to you
7

8. Wait a second!
We need to know first
Spring Boot Actuator
For monitoring & auto-configuration
8

9. http://localhost:10000/autoconfig
http://localhost:10000/beans
http://localhost:10000/configprops
http://localhost:10000/env
http://localhost:10000/mappings
http://localhost:10000/dump
http://localhost:10000/info
http://localhost:10000/health
http://localhost:10000/metrics
http://localhost:10000/trace
http://localhost:10000/shutdown
*Originated in the User Account and Authentication (UAA) Server of CloudFoundry
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10. http://docs.spring.io/spring-boot/docs/1.2.3.RELEASE/reference/htmlsingle/#common-application-properties
10

11. Wait a second!
Customizing Rule 1
Overriding of
values, properties
11

12. Customizing Rule 1
- Overriding of values, properties
PropertySource order
1. Command line arguments
2. JNDI attributes from java:comp/env
3. Java System properties (System.getProperties())
4. OS environment variables
5. A RandomValuePropertySource that only has properties in random.*.
6. application-{profile}.properties(yml) – outside jar
7. - inside jar
8. application.properties(yml) - outside jar
9. - inside jar
10. @PropertySource annotations on your @Configuration classes
11. Default properties (specified using SpringApplication.setDefaultProperties)
http://docs.spring.io/spring-boot/docs/1.2.3.RELEASE/reference/htmlsingle/#boot-features-external-config 12

13. Wait a second!
Spring Boot Starter Web
jar vs war
Just Curious
13

14. (war only)
14

15. spring-boot-starter-actuator
spring-boot-starter-remote-shell
<dependencies>
...
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.test</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging> war</packaging>
<name>demo</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.2.3.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-
8</project.build.sourceEncoding>
<start-class>demo.DemoApplication</start-class>
<java.version>1.7</java.version>
</properties>
(war only)
15

16.  servlet 3.0 support code-based Configuration of the servlet container
 no web.xml, be detected automatically by ServletContainerInitializer
 In Spring,
 in pom.xml
 mvn package
 target/demo-0.0.1-SNAPSHOT.war.original (except external lib)
 target/demo-0.0.1-SNAPSHOT.war ( include /lib, /lib-provided )
auto detect
(war only)
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
<scope>provided</scope>
</dependency>
(java –jar) 16

17. Wait a second!
Spring-boot Module
to understand pom.xml
in Spring Boot
17

18. http://u4u.pe.kr/redmine/projects/nicedream/wiki/Spring_Boothttps://speakerdeck.com/dsyer/spring-boot-introduction
18

19. Auto-Configuration
Mechanism
19

20. 1
2
3
4
5
6
0
20

21. Wait a second!
Customizing Rule 2
Exclude Auto-Configuration
Classes
21

22. Customzing Rule 2
– exclude AutoConfiguration classes
@Configuration
@EnableAutoConfiguration
(exclude={DataSourceAutoConfiguration.class})
public class MyConfiguration { }
@SpringBootApplication
(exclude={DataSourceAutoConfiguration.class})
public class DemoApplication { }
22

23. Auto-Configuration – execution step
SpringApplication.refresh()
@Component
@Configuration
@Repository
@Service
@Controller
Spring-boot-actuator-1.2.3.RELEASE.jar
|-META-INF
|-spring.factories
…
org.springframework.boot.autoconfigure.
EnableAutoConfiguration=
… AuditAutoConfiguration,
… HealthIndicatorAutoConfiguration,
… TraceRepositoryAutoConfiguration,
… TraceWebFilterAutoConfiguration
Loading Auto-Configuration Class
(Using )
SpringApplication.run()
DemoApplication.main()
Loading bean
(Using )
http://tadtech.blogspot.kr/2013/10/how-spring-boot-enables-actuator-by.html
Execute Auto-configuration
2
1
3
23

24. Auto-Configuration
– ex) TraceRepositoryAutoConfiguration
How to replace InMemoryTraceRepository
with LogFileTraceRepository?
24

25. Wait a second!
Customizing Rule 3
Dependency Injection
with Annotations
25

26. Customzing Rule 3
- Dependency Injection with Annotations
26

27.  Condition annotations
 @ConditionalOnBean @ConditionalOnClass
 @ConditionalOnExpression
 @ConditionalOnJava @ConditionalOnJndi
 @ConditionalOnProperty
 @ConditionalOnResource
 @ConditionalOnWebApplication
 @ConditionalOnMissingBean
 @ConditionalOnMissingClass
 @ConditionalOnNotWebApplication
Auto-Configuration – basic elements
 Loading Auto-Configuration
 META-INF/spring.factories
 Auto-Configuration Order
 @AutoConfigureAfter
 @AutoConfigurerBefore
Check it
27

28. A bunch of @Order in Spring Boot
especially in Spring Security
When do I use @Order?
How to form the loading order
of Spring Beans?
28

29. 29
instance creation
Injects values and bean
references into bean’s
properties
BeanNameAware’s
setBeanName()
BeanFactoryAware’s
setBeanFactory()
ApplicationContextAware’s
setApplicationContext()
BeanPostProcessor’s
postProcessBeforeInitialization()
InitalizingBean’s
afterPropertiesSet()
Call custom
init-method
BeanPostProcessor’s
postProcessAfterInitalization()
DisposableBean’s
Destory()
Call custom
destory-method
Bean is ready to use
Container is shutdown
Decleartion interface
Spring in Action 4th Edition – 1.2.2 A beans’ life

30. ______________external.ExternalConfig2$$EnhancerBySpringCGLIB$$e9f78f97
______________external.ExternalConfig1$$EnhancerBySpringCGLIB$$8796bc96
______________demo.component.scan.InternalConfig1$$EnhancerBySpringCGLIB$$c949a9d2
______________demo.component.scan.InternalConfig2$$EnhancerBySpringCGLIB$$2baa7cd3
______________demo.component.scan.InternalConfig3$$EnhancerBySpringCGLIB$$8e0b4fd4
______________demo.DemoApplication$$EnhancerBySpringCGLIB$$fbcebe37
@componentScan
1
2
3
<output>
30
loading order of Spring Beans - Test (1)

31. @componentScan
1
2
3
1
23
4
5
6 Question
1. Case of using @Lazy or @Primary on @Bean?
2. Case of adding InternalConfig3.class in @Import in
InternalConfig1?
3. Case of using @Order on @Configuration or @Bean?
4. Case of Making @Component InternalConfig4 at the same
package of InternalConfig3?
31
loading order of Spring Beans - Test (2)

32. When do I use @Order?
32

33. Understand
1. Execution order is in Auto-Configuration
2. After loading of beans by @SpringBootApplication ,
check Auto-Configuration’s conditions and load remained beans
2
1
1
33

34. @Order(2147483547) SpringBootAuthenticationConfigurerAdapter
@Order(2147483636) ManagementServerProperties.ACCESS_OVERRIDE_ORDER
@Order(2147483637) ManagementSecurityAutoConfiguration
@Order(2147483640) SecurityProperties.ACCESS_OVERRIDE_ORDER
@Order(2147483642) ApplicationWebSecurityConfigurerAdapter
http://docs.spring.io/spring-security/site/docs/3.2.x/reference/htmlsingle/#multiple-httpsecurity
Order
In spring boot’s spring security
• Application override
@Order(SecurityProperties.ACCESS_OVERRIDE_ORDER)
• Actuator(ManagementServer) override
@Order(ManagementServerProperties.ACCESS_OVERRIDE_ORDER)
34

35. When do I use @Order?
filter, auto-configuration,
WebSecurityConfigurerAdapter …
35

36. Auto-Configuration
Mechanism
Loading order of
Spring Beans
How to use
customizing
spring-boot?
Customizing Rules #1,2,3 …
Spring Boot Guides
Spring Boot Sources
googling
For Ops, Actuator/Remote Shell spring-boot-
starter-web
(jar vs war)
36

37.  http://docs.spring.io/spring-boot/docs/1.2.3.RELEASE/reference/htmlsingle/ (us-guide)
 https://github.com/spring-projects/spring-boot/
 http://u4u.pe.kr/redmine/projects/nicedream/wiki/Spring_Boot (kr-guide)
 http://tadtech.blogspot.kr/2013/10/how-spring-boot-enables-actuator-by.html
 http://docs.spring.io/spring-
security/site/docs/4.0.1.RELEASE/reference/htmlsingle/#multiple-httpsecurity
 Learning Spring Boot - Greg L. Turnquist
 Spring in Action 4th
37

38. Thank you!
38