单列模式

1. package com.cvicse.daofactory;  
2. public class SingleSpoon {  
3.     private static SingleSpoon instance;  
4.     private SingleSpoon(){  
5.         //内部可以做一些初始化成员变量的操作  
6.     }  
7.     public static synchronized SingleSpoon getInstance(){  
8.          if (instance == null) {         
9.                instance = new SingleSpoon();         
10.            }         
11.            return instance;     
12.     }   
13. }