[size=large;]
单列模式：[/size][size=small;]确保一个类只有一个实例，并提供一个
全局访问点。[/size]
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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; } }?
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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; }}?
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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; }}?
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