java基礎學習總結——監聽當資料發生變化時要做的操作
阿新 • • 發佈：2019-01-31
1，我們先定義一個介面，可以讓多個監聽者實現
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public interface IDataListen {
public void update(Object event,Object msg);
}
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2，實現一監聽者
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public class DataListen implements IDataListen{
@Override
public void update(Object event, Object arg) {
// TODO Auto-generated method stubSystem.out.println("資料發生了變化");
}
}
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3，被監聽者
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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");
}
}
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