chapter 6 之日期

package chapter6;import java.text.dateformat;import java.text.parseexception;import java.util.*;public class ioelseclass {		//date类的大多数方法已经不推荐使用了，它现在主要用作calendar类和format类的桥梁	//在内部，日期和时间被存储为long类型，表示的日期是与1970.1.1之间的毫秒数（1万亿毫秒==31年8个月）	public void datemethod(){		date d1 =new date(1000000000000l);		system.out.println("1st "+d1.tostring());//tostring()方法默认已经被重写过了		d1.settime(d1.gettime()+3600000);//1hour=3600s		system.out.println("2st "+d1.tostring());		date nowdate =new date();//无变元构造函数，返回的是当前时间		system.out.println("3st "+nowdate.tostring());		//output is:		//1st sun sep 09 09:46:40 gmt+08:00 2001		//2st sun sep 09 10:46:40 gmt+08:00 2001		//3st sat may 22 11:53:55 gmt+08:00 2010	}		//calendar类,字段按域考虑	public void calendarmethod(){		date d1 =new date();		system.out.println(d1.tostring());		calendar c =calendar.getinstance();		c.settime(d1);//calendar.sunday，返回的是int值==1		if(calendar.sunday == c.getfirstdayofweek()){//如果是美国的星期制			system.out.println("sunday is the first day of the week");		}		system.out.println("the day of week is "+c.get(calendar.day_of_week));//星期几其实是一周的第几天		system.out.println(c.get(calendar.year)+" "+c.get(calendar.month)+" "+c.get(calendar.date));//月份的起始值是0		c.add(calendar.month, 1);//前面是域，后面是值		system.out.println(c.get(calendar.year)+" "+c.get(calendar.month)+" "+c.get(calendar.date));		date d2 =c.gettime();//返回已被修改的date对象		system.out.println(d2.tostring());		//略roll方法，增加的数，不会递增。(exp：增加月数超12了，不会对年数产生增加)		//output is:		//sat may 22 12:28:49 gmt+08:00 2010		//sunday is the first day of the week		//the day of week is 7		//2010 4 22		//2010 5 22		//tue jun 22 12:28:49 gmt+08:00 2010	}		//dateformat类，格式化日期	public void dateformatmethod(){//dateformat在java.text包里		date d1 =new date();		system.out.println("d1 ="+d1.tostring());		dateformat df =dateformat.getdateinstance(dateformat.short);//如果需要记住时间，要调用getdatetimeinstance()		string s=df.format(d1);		system.out.println("s ="+s.tostring());				try {			date d2 =df.parse(s);			system.out.println("d2 ="+d2.tostring());		} catch (parseexception e) {			e.printstacktrace();		}		//output is:		//d1 =sat may 29 20:24:14 gmt+08:00 2010		//s =10-5-29		//d2 =sat may 29 00:00:00 gmt+08:00 2010	}	//略locale和numberformat		public static void main(string[] args) {		ioelseclass iec =new ioelseclass();		//iec.datemethod();		//iec.calendarmethod();		//iec.dateformatmethod();	}}