两种比较好用的单态模式

有两种比较好用的单态模式 1.内部类的 class Singleton{ private static class SingletonHolder{ private static Singleton instance = new Singleton() } private Singleton(){} public static Singleton getInstance(){ return SingletonHolder.instance; } } 2.枚举实现的 // Enum singleton - the preferred approach public enum Elvis { INSTANCE; public void leaveTheBuilding() { ... } }