Java Calendar 类的时间操作

注意事项：

Calendar 的 month 从 0 开始，也就是全年 12 个月由 0 ~ 11 进行表示。

而 Calendar.DAY_OF_WEEK 定义和值如下：

Calendar.SUNDAY = 1
Calendar.MONDAY = 2
Calendar.TUESDAY = 3
Calendar.WEDNESDAY = 4
Calendar.THURSDAY = 5
Calendar.FRIDAY = 6
Calendar.SATURDAY = 7

package com.zhaogang.test;

import org.junit.Test;

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

/**
* Created by weixiang.wu on 2017/9/26.
*/
public class CalendarTest {

@Test
public void CalendarTest1() {
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss:SSS");
Calendar cal = Calendar.getInstance(); // 初始化

int year = cal.get(Calendar.YEAR);//年
int month = cal.get(Calendar.MONTH) + 1;//月
int day = cal.get(Calendar.DATE);//日
int hour = cal.get(Calendar.HOUR_OF_DAY);//时
int minute = cal.get(Calendar.MINUTE);//分
int second = cal.get(Calendar.SECOND);//秒
int weekday = cal.get(Calendar.DAY_OF_WEEK);//星期   周日-周六对应1-7
int last = cal.getActualMaximum(cal.DAY_OF_MONTH); // 获取本月最大天数
int DAY_OF_YEAR = cal.get(Calendar.DAY_OF_YEAR);//今年的第几天
int DAY_OF_MONTH = cal.get(Calendar.DAY_OF_MONTH);//本月的第几天
System.out.println("现在是: " + year + " 年 " + month + " 月 " + day +
" 日 " + hour + " 时 " + minute + " 分 " + second + " 秒 " + "\nweekday: " + weekday
+ " 本月天数 :" + last + " 今年的第几天:" + DAY_OF_YEAR + " 本月第几天:" + DAY_OF_MONTH);

cal.set(2013, 5, 4, 13, 44, 51);//年月日时分秒（月份0代表1月）  ，毫秒不会自动清零
System.out.println(sdf.format(cal.getTime()));
cal.set(Calendar.MILLISECOND, 0);//毫秒清零
System.out.println(sdf.format(cal.getTime()));
cal.set(Calendar.YEAR, 2014);//年
cal.set(Calendar.MONTH, 7);//月（月份0代表1月）
cal.set(Calendar.DATE, 11);//日
cal.set(Calendar.HOUR_OF_DAY, 15);//时
cal.set(Calendar.MINUTE, 33);//分
cal.set(Calendar.SECOND, 32);//秒
System.out.println(sdf.format(cal.getTime()));

cal.setTime(new Date());
System.out.println(sdf.format(cal.getTime()));

cal.add(Calendar.YEAR, 1);//年
cal.add(Calendar.MONTH, 1);//月
cal.add(Calendar.DATE, 1);//日
cal.add(Calendar.HOUR_OF_DAY, -1);//时
cal.add(Calendar.MINUTE, 1);//分
cal.add(Calendar.SECOND, 1);//秒
System.out.println(sdf.format(cal.getTime()));

Calendar calendarNew = Calendar.getInstance();
calendarNew.add(Calendar.HOUR, -2);
System.out.println("时间比较：" + calendarNew.compareTo(cal));
}

}