一、概述

childe类中的是关联监听者dad的，若要再增加监听者，会很不方便，且要修改代码。好的方法是封装监听者类，用addListener()方法动态添加监听者

 

二、代码

1.Test.java

class WakenUpEvent{		private long time;	private String location;	private Child source;		public WakenUpEvent(long time, String location, Child source) {		super();		this.time = time;		this.location = location;		this.source = source;	}	public long getTime() {		return time;	}	public void setTime(long time) {		this.time = time;	}	public String getLocation() {		return location;	}	public void setLocation(String location) {		this.location = location;	}	public Child getSource() {		return source;	}	public void setSource(Child source) {		this.source = source;	}		}class Child implements Runnable {		private List
     
       wakenUpListeners = new ArrayList
      
       ();		public void addWakenUpListener(WakenUpListener wul){		wakenUpListeners.add(wul);	}	public void wakeUp(){		for(int i = 0; i < wakenUpListeners.size(); i++){			WakenUpListener l = wakenUpListeners.get(i);			l.actionToWakenUp(new WakenUpEvent(System.currentTimeMillis(), "bed", this));		}	}	@Override	public void run() {		try {			Thread.sleep(3000);		} catch (Exception e) {			e.printStackTrace();		}		wakeUp();	}}interface WakenUpListener {	public void actionToWakenUp(WakenUpEvent e);}class Dad implements WakenUpListener {	public void actionToWakenUp(WakenUpEvent e) {		System.out.println("Fedd the child");	}	}class GrandFather implements WakenUpListener {	public void actionToWakenUp(WakenUpEvent e) {		System.out.println("抱孩子");	}	}public class Test {	public static void main(String[] args) {		Child c = new Child();		c.addWakenUpListener(new Dad());		c.addWakenUpListener(new GrandFather());		new Thread(c).start();	}}
      
     

　　

三、运行结果