以下内容引用自http://wiki.jikexueyuan.com/project/spring/java-based-configuration.html：
基于Java的配置选项，可以使你在不用配置XML的情况下编写大多数的Spring配置。
@Configuration和@Bean注解
带有@Configuration的注解类表示这个类可以使用Spring IoC容器作为bean定义的来源。@Bean注解告诉Spring，一个带有@Bean的注解方法将返回一个对象，该对象应该被注册为在Spring应用程序上下文中的bean。最简单可行的@Configuration类如下所示：
@Configuration
public class HelloWorldConfig {
@Bean
public HelloWorld helloWorld(){
return new HelloWorld();
}
}
对应XML配置如下：
<beans>
<bean id="helloWorld" class="com.jsoft.testspring.testjavaconfiguration.HelloWorld" />
</beans>
在这里，带有@Bean注解的方法名称作为bean的ID，它创建并返回实际的bean。你的配置类可以声明多个@Bean。一旦定义了配置类，你就可以使用AnnotationConfigApplicationContext来加载并把他们提供给Spring容器，如下所示：
public static void main( String[] args )
{
ApplicationContext applicationContext = new AnnotationConfigApplicationContext(HelloWorldConfig.class);
HelloWorld helloWorld = applicationContext.getBean(HelloWorld.class);
helloWorld.setMessage("Hello World!");
helloWorld.getMessage();
}
当然，你可以加载各种配置类，如下所示：
public static void main(String[] args) {
AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
ctx.register(AppConfig.class, OtherConfig.class);
ctx.register(AdditionalConfig.class);
ctx.refresh();
MyService myService = ctx.getBean(MyService.class);
myService.doStuff();
}
例子：
pom.xml：
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.jsoft.testspring</groupId>
<artifactId>testjavaconfiguration</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>testjavaconfiguration</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<!-- Spring Core -->
<!-- http://mvnrepository.com/artifact/org.springframework/spring-core -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>4.1.4.RELEASE</version>
</dependency>
<!-- Spring Context -->
<!-- http://mvnrepository.com/artifact/org.springframework/spring-context -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.1.4.RELEASE</version>
</dependency>
</dependencies>
</project>
HelloWorld.java：
package com.jsoft.testspring.testjavaconfiguration;
public class HelloWorld {
private String message;
public void setMessage(String message){
this.message = message;
}
public void getMessage(){
System.out.println(this.message);
}
}
HelloWorldConfig.java：
package com.jsoft.testspring.testjavaconfiguration;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class HelloWorldConfig {
@Bean
public HelloWorld helloWorld(){
return new HelloWorld();
}
}
App.java：
package com.jsoft.testspring.testjavaconfiguration;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
/**
* Hello world!
*
*/
public class App
{
public static void main( String[] args )
{
ApplicationContext applicationContext = new AnnotationConfigApplicationContext(HelloWorldConfig.class);
HelloWorld helloWorld = applicationContext.getBean(HelloWorld.class);
helloWorld.setMessage("Hello World!");
helloWorld.getMessage();
}
}
测试结果：
测试工程：https://github.com/easonjim/5_java_example/tree/master/springtest/test13/testjavaconfiguration
Bean的依赖性注入
当Beans依赖对方时，表达这种依赖性非常简单，只要有一个bean方法调用另一个，如下所示：
@Configuration
public class HelloWorldConfig {
@Bean
public HelloWorld helloWorld(){
return new HelloWorld(message());
}
@Bean
public String message(){
return new String("Hello World");
}
}
可以看出，有依赖性时直接在类中调用新建的方法即可。
例子：
pom.xml：
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.jsoft.testspring</groupId>
<artifactId>testjavaconfiguration</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>testjavaconfiguration</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<!-- Spring Core -->
<!-- http://mvnrepository.com/artifact/org.springframework/spring-core -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>4.1.4.RELEASE</version>
</dependency>
<!-- Spring Context -->
<!-- http://mvnrepository.com/artifact/org.springframework/spring-context -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.1.4.RELEASE</version>
</dependency>
</dependencies>
</project>
HelloWorld.java：
package com.jsoft.testspring.testjavaconfiguration;
public class HelloWorld {
private String message;
public HelloWorld(String message){
this.message = message;
}
public void getMessage(){
System.out.println(this.message);
}
}
HelloWorldConfig.java：
package com.jsoft.testspring.testjavaconfiguration;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class HelloWorldConfig {
@Bean
public HelloWorld helloWorld(){
return new HelloWorld(message());
}
@Bean
public String message(){
return new String("Hello World");
}
}
App.java：
package com.jsoft.testspring.testjavaconfiguration;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
/**
* Hello world!
*
*/
public class App
{
public static void main( String[] args )
{
ApplicationContext applicationContext = new AnnotationConfigApplicationContext(HelloWorldConfig.class);
HelloWorld helloWorld = applicationContext.getBean(HelloWorld.class);
helloWorld.getMessage();
}
}
测试结果：
测试工程：https://github.com/easonjim/5_java_example/tree/master/springtest/test13/testjavaconfiguration1
@Import注释
@import注解允许从另一个配置类中加载Bean定义。如下所示：
@Configuration
public class ConfigA {
@Bean
public A a() {
return new A();
}
}
@Configuration
@Import(ConfigA.class)
public class ConfigB {
@Bean
public B b() {
return new B();
}
}
现在，当实例化上下文时，不需要同时指定ConfigA.class和ConfigB.class，只要ConfigB类需要提供，如下所示：
public static void main(String[] args) {
ApplicationContext ctx = new AnnotationConfigApplicationContext(ConfigB.class);
A a = ctx.getBean(A.class);
B b = ctx.getBean(B.class);
}
例子：
pom.xml：
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.jsoft.testspring</groupId>
<artifactId>testjavaconfiguration</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>testjavaconfiguration</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<!-- Spring Core -->
<!-- http://mvnrepository.com/artifact/org.springframework/spring-core -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>4.1.4.RELEASE</version>
</dependency>
<!-- Spring Context -->
<!-- http://mvnrepository.com/artifact/org.springframework/spring-context -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.1.4.RELEASE</version>
</dependency>
</dependencies>
</project>
HelloWorld.java：
package com.jsoft.testspring.testjavaconfiguration;
public class HelloWorld {
private String message;
public HelloWorld(String message){
this.message = message;
}
public void getMessage(){
System.out.println(this.message);
}
}
HelloWorldConfig.java：
package com.jsoft.testspring.testjavaconfiguration;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class HelloWorldConfig {
@Bean
public HelloWorld helloWorld(){
return new HelloWorld(message());
}
@Bean
public String message(){
return new String("Hello World");
}
}
HelloWorldConfigB.java：
package com.jsoft.testspring.testjavaconfiguration;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
@Configuration
@Import(HelloWorldConfig.class)
public class HelloWorldConfigB {
@Bean
public String messageB(){
return new String("Hello B");
}
}
App.java：
package com.jsoft.testspring.testjavaconfiguration;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
/**
* Hello world!
*
*/
public class App
{
public static void main( String[] args )
{
ApplicationContext applicationContext = new AnnotationConfigApplicationContext(HelloWorldConfigB.class);
HelloWorld helloWorld = applicationContext.getBean(HelloWorld.class);
helloWorld.getMessage();
}
}
可以看出不用再次引用HelloWorldConfig.java类了。
测试结果：
测试工程：https://github.com/easonjim/5_java_example/tree/master/springtest/test13/testjavaconfiguration2
生命周期回调
@Bean注解支持指定任意的初始化和销毁回调方法，这与Spring元素中的Spring XML的init-method和destroy-method属性非常相似。如下所示：
public class Foo {
public void init() {
}
public void cleanup() {
}
}
@Configuration
public class AppConfig {
@Bean(initMethod = "init", destroyMethod = "cleanup" )
public Foo foo() {
return new Foo();
}
}
例子：
pom.xml：
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.jsoft.testspring</groupId>
<artifactId>testjavaconfiguration</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>testjavaconfiguration</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<!-- Spring Core -->
<!-- http://mvnrepository.com/artifact/org.springframework/spring-core -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>4.1.4.RELEASE</version>
</dependency>
<!-- Spring Context -->
<!-- http://mvnrepository.com/artifact/org.springframework/spring-context -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.1.4.RELEASE</version>
</dependency>
</dependencies>
</project>
HelloWorld.java：
package com.jsoft.testspring.testjavaconfiguration;
public class HelloWorld {
private String message;
public HelloWorld(String message){
this.message = message;
}
public void getMessage(){
System.out.println(this.message);
}
public void init(){
System.out.println("HelloWorld init");
}
public void cleanup(){
System.out.println("HelloWorld cleanup");
}
}
HelloWorldConfig.java：
package com.jsoft.testspring.testjavaconfiguration;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class HelloWorldConfig {
@Bean(initMethod="init",destroyMethod="cleanup")
public HelloWorld helloWorld(){
return new HelloWorld(message());
}
@Bean
public String message(){
return new String("Hello World");
}
}
App.java：
package com.jsoft.testspring.testjavaconfiguration;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.support.AbstractApplicationContext;
/**
* Hello world!
*
*/
public class App
{
public static void main( String[] args )
{
AbstractApplicationContext applicationContext = new AnnotationConfigApplicationContext(HelloWorldConfig.class);
HelloWorld helloWorld = applicationContext.getBean(HelloWorld.class);
helloWorld.getMessage();
applicationContext.registerShutdownHook();
}
}
测试结果：
测试工程：https://github.com/easonjim/5_java_example/tree/master/springtest/test13/testjavaconfiguration3
指定Bean的作用域范围
默认范围是单实例，但是你可以重写带有@Scope注解的方法，如下所示：
@Configuration
public class AppConfig {
@Bean
@Scope("prototype")
public Foo foo() {
return new Foo();
}
}
例子：
pom.xml：
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.jsoft.testspring</groupId>
<artifactId>testjavaconfiguration</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>testjavaconfiguration</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<!-- Spring Core -->
<!-- http://mvnrepository.com/artifact/org.springframework/spring-core -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>4.1.4.RELEASE</version>
</dependency>
<!-- Spring Context -->
<!-- http://mvnrepository.com/artifact/org.springframework/spring-context -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.1.4.RELEASE</version>
</dependency>
</dependencies>
</project>
HelloWorld.java：
package com.jsoft.testspring.testjavaconfiguration;
public class HelloWorld {
private String message;
public void setMessage(String message){
this.message = message;
}
public void getMessage(){
System.out.println(this.message);
}
}
HelloWorldConfig.java：
package com.jsoft.testspring.testjavaconfiguration;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Scope;
@Configuration
public class HelloWorldConfig {
@Bean
@Scope("prototype")
public HelloWorld helloWorld(){
return new HelloWorld();
}
}
@Scope的值和xml中配置的保持一致。
App.java：
package com.jsoft.testspring.testjavaconfiguration;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
/**
* Hello world!
*
*/
public class App
{
public static void main( String[] args )
{
ApplicationContext applicationContext = new AnnotationConfigApplicationContext(HelloWorldConfig.class);
HelloWorld helloWorld = applicationContext.getBean(HelloWorld.class);
helloWorld.setMessage("Hello World 1!");
helloWorld.getMessage();
HelloWorld helloWorld2 = applicationContext.getBean(HelloWorld.class);
helloWorld2.getMessage();
}
}
测试结果：
测试工程：https://github.com/easonjim/5_java_example/tree/master/springtest/test13/testjavaconfiguration4