Java：单例模式

饿汉式

class SingleTonHungry {private static final SingleTonHungry instance = new SingleTonHungry();private SingleTonHungry() {}public static SingleTonHungry getInstance() {return instance;}
}
public class Demo17 {public static void main(String[] args) {SingleTonHungry hungry = SingleTonHungry.getInstance();}
}

懒汉式

class SingleTonLazy {private static volatile SingleTonLazy instance;private SingleTonLazy() {}public static SingleTonLazy getInstance() {if (instance == null) {synchronized (SingleTonLazy.class) {if (instance == null) {instance = new SingleTonLazy();}}}return instance;}
}
public class Demo18 {public static void main(String[] args) {SingleTonLazy singleTonLazy = SingleTonLazy.getInstance();}
}