单例模式

http://www.importnew.com/15524.html

饿汉式单例：

public class Singleton {  
    private static Singleton singleton = new Singleton();  
    private Singleton(){}  
    public static Singleton getInstance(){  
        return singleton;  
    }  
}

在java中，饿汉式单例要优于懒汉式单例。

懒汉式单例：

public class Singleton {  
    private static Singleton singleton;  
    private Singleton(){}  
       
    public static synchronized Singleton getInstance(){  
        if(singleton==null){  
            singleton = new Singleton();  
        }  
        return singleton;  
    }  
}