public interface CompactDisc {
  public abstract void play();
}

@Component("SgtPeppers")
public class SgtPeppers implements CompactDisc {
  private String title = "Sgt.Pepper's Lonely Hearts Club Band";
  private String artist = "The Beatles";

  @Override
  public void play() {
    System.out.println("playing" + title + " by " + artist);
  }
}

@Component("CDplayer")//表明该类作为组件类，没必要显示的配置Bean实例,括号内为组件名
public class CDPlayer {
  /*
  * @Autowired注解可以用在构造器上，也可以用在set方法上，也能直接放在下列代码所示地方
  * spring会满足有该注解的依赖，如果只有一个bean匹配依赖需求的话，这个bean就会被装配进来
   @Autowired 默认按类型装配
  * */
  @Autowired
  private CompactDisc cd;

  public CompactDisc getCd() {
    return cd;
  }

  public void setCd(CompactDisc cd) {
    this.cd = cd;
  }
  public void play(){
    cd.play();
  }
}

public class CDPlayerTest {
  public static void main(String[] args) {
    ApplicationContext context=new ClassPathXmlApplicationContext("applicationContext.xml");
    CDPlayer cdPlayer= (CDPlayer) context.getBean("CDplayer");
    cdPlayer.play();
  }
}

<context:component-scan base-package="com.xue.soundsystem"></context:component-scan>