设计模式 单例模式

public class Singleton {

    private static Singleton instance;
    private Singleton()
    {

    }

    public static Singleton GetInstance()
    {
        if(instance == null)
        {
            instance = new Singleton();
        }
        return instance;
    }
}

public class Program {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Singleton s1=Singleton.GetInstance();
        Singleton s2=Singleton.GetInstance();

        if(s1==s2)
        {
            System.out.println("两个对象是相同的实例");
        }
        else
        {
            System.out.println("两个对象是不同实例");
        }
    }

}