Java设计模式

  饿汉模式：

 

public class HungrySingle {
    private static  final  HungrySingle  instance = new HungrySingle();

    private HungrySingle(){

    }

    public static HungrySingle getInstance(){
         return  instance;
    }

}

 懒汉模式：

public class LazySingle {
    private static  LazySingle  instance = null;
    private LazySingle(){

    }
    public static LazySingle getInstance(){
        if(instance==null){
            synchronized (LazySingle.class){
                if (instance==null){
                    instance = new LazySingle();
                }
            }
        }
        return  instance;
    }
}