java 监测 java 监测数据变化

1，我们先定义一个接口，可以让多个监听者实现

public  interface  IDataListen {
 
public  void  update(Object event,Object msg);
}

2，实现一监听者

public  class  DataListen  implements  IDataListen{
 
     @Override
     public  void  update(Object event, Object arg) {
         // TODO Auto-generated method stub
         System.out.println( "数据发生了变化" );
     }
 
}

3，被监听者

public  class  DataManager{
 
     private  List<IDataListen> listenList =  new  ArrayList<>();
     
     public  void  notifyListen(Object event,Object msg){
         for (IDataListen dataListen : listenList){
             dataListen.update( null ,  null );
         }
     }
     
     public  void  addListen(IDataListen dataListen){
         listenList.add(dataListen);
     }
     
     public  void  updateData(Object msg){
         this .notifyListen( null , msg);
     }
 
 
     public  static  void  main(String[] args) {
         DataManager dataManager =  new  DataManager();
         IDataListen dataListen1 =  new  DataListen();
         IDataListen dataListen2 =  new  DataListen();
         
         dataManager.addListen(dataListen1);
         dataManager.addListen(dataListen2);
         dataManager.updateData( "aaa" );
     }
}