singleton_JAVA_编程开发_程序员俱乐部

package com.renpeng.singleton;/** * 同步单例模式(延迟实例化) * @author administrator * */public class singleton {	private static singleton singleton;		private singleton(){}		public synchronized singleton getinstance(){		if(singleton==null){			singleton=new singleton();		}		return singleton;	}	}

package com.renpeng.singleton;/** * 急切单例模式（非延迟实例话） * @author administrator * */public class singleton1 {    private static singleton1 singleton1=new singleton1();        private singleton1(){}        public singleton1 getinstance(){    	return singleton1;    }}

package com.renpeng.singleton;/** * 双层检测单例模式 * @author administrator * */public class singleton2 {	private volatile singleton2 singleton2;		private singleton2(){}		public singleton2 getinstance(){		if(singleton2==null){			//同步块，首次创建才同步			synchronized (singleton2.class) {				if(singleton2==null){					singleton2=new singleton2();				}			}		}		return singleton2;	}}