单例模式
当我们想实例化一个类,并可以一直使用这个类,可以使用单例模式:
方式一:
1 package com.kunhong.design.test; 2 3 public class Singleton { 4 private static Singleton instance = new Singleton(); 5 6 private Singleton() { 7 8 } 9 10 public static Singleton getInstance() { 11 return instance; 12 } 13 }
方法二:
1 package com.kunhong.design.test; 2 3 public class Singleton { 4 private static Singleton instance = null; 5 6 private Singleton() { 7 8 } 9 public synchronized static Singleton getInstance(){ 10 if(instance == null){ 11 instance = new Singleton(); 12 } 13 return instance; 14 } 15 }