设计模式（八） 单例设计模式

package com.anby.Singleton;


//为了创建全局唯一的对象，则使用单利模式
public class SingletonDemo
{

    /**
     * @param args
     */
    public static void main(String[] args)
    {
        SingleA singleA=SingleA.getInstance();
        
        SingleB singleB=SingleB.getInstance();

    }

}


// 懒汉式
class SingleA
{
    private static SingleA uniqueSingleA;

    private SingleA()
    {

    }

    public synchronized static SingleA getInstance()
    {
        if (uniqueSingleA == null)
        {
            uniqueSingleA=new SingleA();
        }
        return uniqueSingleA;
    }

}

//饿汉式
class SingleB
{
    private static SingleB uniqueSingleB=new SingleB();
    
    private SingleB()
    {
        
    }
    
    public synchronized static SingleB getInstance()
    {
        return uniqueSingleB;
    }
}