API学习GregorianCalendar

package com.wonders.api.date;import java.util.Calendar;import java.util.Date;import java.util.GregorianCalendar;import java.util.SimpleTimeZone;import java.util.TimeZone;/** * JDK1.7 * GregorianCalendar类 * (1)GregorianCalendar是一个具体的日历子类，它提供了大多数世界使用的标准日历系统 * (2)GregorianCalendar是一个混合日历，它支持Julian和Gregorian的日历系统，支持单一的不连续性，它对应于公历在公历建立时(在某些国家的1582年10月15日，后来在其他国家)的公历日期。 * (3)通过调用setGregorianChange()可以对日期进行转换。 * @author liyongyong * */public class GregorianCalendarTest {    public static void main(String[] args) {        GregorianCalendar g = new GregorianCalendar();        /**         *          */        System.out.println(g.getTimeZone());        //得到太平洋所支持的标准时间GMT-08:00的ids        String[] ids = TimeZone.getAvailableIDs(-8 * 60 * 60 * 1000);        //如果数组为空，则说明不存在对应的ids        if (ids.length == 0) {            System.out.println("不存在对应的ids");        }        System.out.println("current time");        //创建一个太平洋标准时间时区        SimpleTimeZone pdt = new SimpleTimeZone(-8 * 60 * 60 * 1000, ids[0]);        pdt.setStartRule(Calendar.APRIL, 1, Calendar.SUNDAY, 2 * 60 * 60 * 1000);        pdt.setEndRule(Calendar.OCTOBER, -1, Calendar.SUNDAY, 2 * 60 * 60 * 1000);        //创建一个与太平洋夏令时区域的GregorianCalendar ,设置当前的日期和时间        Calendar calendar = new GregorianCalendar(pdt);        Date trialTime = new Date();        calendar.setTime(trialTime);         //输出一些信息         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); // 没有被重写         calendar.set(Calendar.HOUR, 3);         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))); // 小时         System.out.println("DST_OFFSET: "                + (calendar.get(Calendar.DST_OFFSET)/(60*60*1000))); // 小时    }}