单例模式
1、私有化构造器,不能直接创建,调用方法创建对象;
public class Singleton { private static Singleton instance; private Singleton (){} public static Singleton getInstance() { if (instance == null) { instance = new Singleton(); } return instance; } }
2、饿汉式:instance在类装载时就实例化
public class Singleton { private static Singleton instance = new Singleton(); private Singleton (){} public static Singleton getInstance() { return instance; } }
3、静态内部类:
public class Singleton { private static class SingletonHolder { private static final Singleton INSTANCE = new Singleton(); } private Singleton (){} public static final Singleton getInstance() { return SingletonHolder.INSTANCE; } }
工作小总结,有错请指出,谢谢。