Spring--@configuration 和 @Bean

参考：http://wiki.jikexueyuan.com/project/spring/java-based-configuration.html

@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：

 package org.wzh.di.demo1.congiration;

 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;

 @Configuration
 public class HelloWorldConfig {
     @Bean
     public HelloWorld helloWorld() {
         return new HelloWorld();
     }
 }

 package org.wzh.di.demo1.congiration;

 public class HelloWorld {

     private String message;

     public String getMessage() {
         return message;
     }

     public void setMessage(String message) {
         this.message = message;
     }

 }

 package org.wzh.di.demo1.congiration;

 import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;

 public class Test {

     public static void main(String[] args) {
         ApplicationContext ctx = new AnnotationConfigApplicationContext(HelloWorldConfig.class);
         HelloWorld helloWorld = ctx.getBean(HelloWorld.class);
         helloWorld.setMessage("Hello World!");
         String msg = helloWorld.getMessage();
         System.out.println(msg);
     }

 }

也可以加载其他配置类，这里只写用法

 package org.wzh.di.demo1.congiration;

 import org.springframework.context.annotation.AnnotationConfigApplicationContext;

 public class Test2 {

     public static void main(String[] args) {
         AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
         ctx.register(HelloWorldConfig.class);
         ctx.refresh();
         HelloWorld helloWorld = ctx.getBean(HelloWorld.class);
         helloWorld.setMessage("Hello World 2!");
         String msg = helloWorld.getMessage();
         System.out.println(msg);
     }

 }