单列模式小练习 

 1 class SingletonClass {
 2     private static class SingletonClassInstance {
 3         private static final SingletonClass instance = new SingletonClass();
 4     }
 5     public static SingletonClass getInstance() {
 6         return SingletonClassInstance.instance;
 7     }
 8     private SingletonClass() {}    
 9 }
10 
11 class Student{
12     public Student(){}
13 }
14 
15 public class Test {
16     public static void main(String args[]){
17         Student s1 = new Student();
18         Student s2 = new Student();
19         SingletonClass sc1 = SingletonClass.getInstance();
20         SingletonClass sc2 = SingletonClass.getInstance();
21         if(s1 == s2){
22             System.out.println("s1和s2为同一个类");
23         }else{
24             System.out.println("s1和s2不是同一个类");
25         }
26         System.out.println("*******************");
27         if(sc1 == sc2){
28             System.out.println("sc1和sc2为同一个类");
29         }else{
30             System.out.println("sc1和sc2不是同一个类");
31         }
32     }
33 }

打印结果是：

s1和s2不是同一个类
*******************
sc1和sc2为同一个类

posted @ 2014-12-02 15:30  loveyuu  阅读(120)  评论(0)    收藏  举报