单例模式:
单例模式的写法: 1. 饿汉模式
public class Singleton{ private static Singleton instance=new Singletion(); private Singleton(){} public static Singleton getInstance(){ return instance; } } 懒汉模式 直接synchroinzed public class Singleton{ private static Singleton instance; private Singleton(){} public synchronized static Singleton getInstance(){ if(instance==null){ return new Sinleton(); } return instance; } }DCL
public class Singleton { private static Singleton instance; private Singleton(){} public static Singleton getInstance(){ if(instance==null){ synchronized (Singleton.class){ if(instance==null){ return new Singleton(); } } } return instance; } }内部类
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