SharkYu的专栏

【转】单例模式的七种写法[原文出处]：http://cantellow.iteye.com/blog/838473单例模式的七种写法1. 第一种（懒汉，线程不安全）：public class Singleton { private static Singleton instance; private Singleton (){} public static Singleton

import java.text.ParseException;import java.text.SimpleDateFormat;import java.util.Calendar;public class CalendarDemo { public static void main(String[] args) { try { SimpleDateFormat