方式三：更具备通用性，添加监听事件（让多个人同时监听小孩醒来这个事件并作出相应动作，dad和mom就是观察者）
class Dad implements WakeUpActionListener{
@Override
public void wakeUpAction(WakeUpEvent wakeUpEvent)
{
System.out.println("爸爸给小孩喂奶。。。");
}
}
class Mom implements WakeUpActionListener{
@Override
public void wakeUpAction(WakeUpEvent wakeUpEvent)
{
System.out.println("妈妈给小孩喂奶");
}
}
class WakeUpEvent{
}
interface WakeUpActionListener{
void wakeUpAction(WakeUpEvent wakeUpEvent);
}
class Child implements Runnable{
private List<WakeUpActionListener> listenerLists=new ArrayList<WakeUpActionListener>();
void addListener(WakeUpActionListener l){
listenerLists.add(l);
}
void wakeUp(){
System.out.println("醒来了");
for(WakeUpActionListener l:listenerLists){
l.wakeUpAction(new WakeUpEvent());
}
}
@Override
public void run()
{
try
{
Thread.sleep(5000);
} catch (InterruptedException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
wakeUp();
}
}
public class Test
{
public static void main(String[] args){
Dad d=new Dad();
Mom m=new Mom();
Child c=new Child();
c.addListener(d);
c.addListener(m);
new Thread(c).start();
}
}
用属性文件管理Observers
文件名observer.properties,里面内容：observers=ObserverMode.Dad,ObserverMode.Mom将上面代码部分的main函数换成以下
public static void main(String[] args) throws IOException, InstantiationException, IllegalAccessException, ClassNotFoundException{
Child c=new Child();
Properties props=new Properties();
//如果文件放在src下直接可以写文件名，如果放在包下写上路径
props.load(Test.class.getClassLoader().getResourceAsStream("ObserverMode/observer.properties"));
String[] observers=props.getProperty("observers").split(",");
for(String observer:observers){
c.addListener((WakeUpActionListener)Class.forName(observer).newInstance());
}
new Thread(c).start();
}