singleton

作用：

1 保证类只实例化一次

2 提供全局访问接口

java实现

/** * 单例模式 */public class Singleton {private static Singleton singleton = null;//private Singleton(){}public static Singleton getInstance(){if(singleton==null)singleton = new Singleton();return singleton;}public static void main(String[] args) {Singleton s = Singleton.getInstance();}}

c++实现

Singleton.h

#pragma onceclass Singleton{private:static Singleton* singleton;private:Singleton(void);public:static Singleton* getInstance();};

Singleton.cpp

#include "StdAfx.h"#include "Singleton.h"Singleton* Singleton:: singleton=0;Singleton::Singleton(void){}Singleton* Singleton::getInstance(){if(singleton==0) singleton = new Singleton();return singleton;}

更多复杂用法，涉及并发访问及同步效率问题

http://www.iteye.com/topic/575052

单例模式的7种写法（基本都与线程安全相关）

http://cantellow.iteye.com/blog/838473

c++单例的几种写法，涉及自动析构和线程安全

http://blog.csdn.net/boyxiaolong/article/details/6645681