java中calendar的用法

Calendar 与 Date 的转换：

Calendar calendar = Calendar.getInstance();

// 从一个 Calendar 对象中获取 Date 对象

Date date = calendar.getTime();

// 将 Date 对象反应到一个 Calendar 对象中，

// 先获得一个实例，然后设置 Date 对象

calendar.setTime(date);

月份的起始值为０而不是１，所以要设置八月时，我们用７而不是8。

calendar.set(Calendar.MONTH, 7);

计算2000-01-01是星期几

calendar.get(calendar.DAY_OF_WEEK )

import Java.util.*;

　　public class ShowDate {

　　public static void main(String[] args) {

　　Calendar calendar = new GregorianCalendar();

　　Date trialTime = new Date();

　　calendar.setTime(trialTime);

　　// print out a bunch of interesting things

　　System.out.println("ERA: " + calendar.get(Calendar.ERA));

　　System.out.println("YEAR: " + calendar.get(Calendar.YEAR));

　　System.out.println("MONTH: " + calendar.get(Calendar.MONTH));

　　System.out.println("WEEK_OF_YEAR: " + calendar.get(Calendar.WEEK_OF_YEAR));

　　System.out.println("WEEK_OF_MONTH: " + calendar.get(Calendar.WEEK_OF_MONTH));

　　System.out.println("DATE: " + calendar.get(Calendar.DATE));

　　System.out.println("DAY_OF_MONTH: " + calendar.get(Calendar.DAY_OF_MONTH));

　　System.out.println("DAY_OF_YEAR: " + calendar.get(Calendar.DAY_OF_YEAR));

　　System.out.println("DAY_OF_WEEK: " + calendar.get(Calendar.DAY_OF_WEEK));

　　System.out.println("DAY_OF_WEEK_IN_MONTH: " + calendar.get(Calendar.DAY_OF_WEEK_IN_MONTH));

　　System.out.println("AM_PM: " + calendar.get(Calendar.AM_PM));

　　System.out.println("HOUR: " + calendar.get(Calendar.HOUR));

　　System.out.println("HOUR_OF_DAY: " + calendar.get(Calendar.HOUR_OF_DAY));

　　System.out.println("MINUTE: " + calendar.get(Calendar.MINUTE));

　　System.out.println("SECOND: " + calendar.get(Calendar.SECOND));

　　System.out.println("MILLISECOND: " + calendar.get(Calendar.MILLISECOND));

　　System.out.println("ZONE_OFFSET: " + (calendar.get(Calendar.ZONE_OFFSET)/(60*60*1000)));

　　System.out.println("DST_OFFSET: " + (calendar.get(Calendar.DST_OFFSET)/(60*60*1000)));

　　System.out.println("Current Time, with hour reset to 3");

　　calendar.clear(Calendar.HOUR_OF_DAY); // so doesn't override

　　calendar.set(Calendar.HOUR, 3);