设计模式

代码 复制代码

1. public class Singleton {
2. private Singleton(){}
3. private static Singleton instance = new Singleton();
4. public static Singleton getInstance(){
5. return instance;
6. }
7. public void sys(String s){
8. System.out.println(s+"singleton.........");
9. }
10. }
# public class TestSingletion {
#
# public static void main(String args[]){
#
# Singleton.getInstance().sys("fdsfds");
# }
# }


第二种写法：
# public class Singleton {
# private static Singleton instance = null;
# private Singleton(){
# //应该加上这个
# }
# public static synchronized Singleton getInstance(){
# if(instance==null){
# instance = new Singleton();
# }
# return instance;
# }
# public void sys(String s){
# System.out.println(s+"singleton.........");
# }
# }