设计模式

更加严谨的设计模式:


1.singleton

package com.swing;

public class Singleton {

	private static Singleton instance;
	
	//确保多线程可以获得同一个instance
	public static synchronized Singleton getInstance_1(){
		if(instance==null){
			return new Singleton();
		}
		return instance;
	}
	
	//多线程高并发的情况下,可以采用同步代码块进行两次检测，确保Singleton
	public static Singleton getInstance_2(){
		if(instance==null){
			synchronized(Singleton.class){
				if(instance==null){
					instance = new Singleton();
				}
			}
		}
		return instance;
	}
}