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| 设计模式,单例这个模式用得应该很频繁 
 直接介绍几种线程安全的且我觉得还比较不错的方式:
 
 1、是不是号称恶汉,就是类加载就初始化了
 
 [java] view plaincopy在CODE上查看代码片派生到我的代码片
 package com.zhy.pattern.singlton;
 
 public class Singleton
 {
 private static Singleton instance = new Singleton();
 
 public static Singleton getInstance()
 {
 return instance ;
 }
 }
 2、懒汉,我喜欢这种,需要双重判断
 [java] view plaincopy在CODE上查看代码片派生到我的代码片
 package com.zhy.pattern.singlton;
 
 
 public class Singleton02
 {
 private static Singleton02 instance;
 
 public static Singleton02 getInstance()
 {
 if (instance == null)
 {
 synchronized (Singleton02.class)
 {
 if (instance == null)
 {
 instance = new Singleton02();
 }
 }
 }
 return instance;
 }
 }
 
 3、使用Java的枚举,还是很推荐的,简单的跟神马一样,如果对枚举不熟悉,小google一下
 [java] view plaincopy在CODE上查看代码片派生到我的代码片
 public enum Singleton03
 {
 INSTANCE;
 }
 
 4、使用一个持有类,主要是为了不在初始化的时候加载
 [java] view plaincopy在CODE上查看代码片派生到我的代码片
 package com.zhy.pattern.singlton;
 
 public class Singleton04
 {
 private static final class InstanceHolder
 {
 private static Singleton04 INSTANCE = new Singleton04();
 }
 
 public static Singleton04 getInstance()
 {
 return InstanceHolder.INSTANCE;
 }
 }
 
 
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