Java Date utility functions

java_date_ex

/**
 * 
 */
package com.newcoresys.utils;

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

/**
 * 日期工具类
 * 
 * @author joeymac
 *
 */
public class DateEx {

	private static SimpleDateFormat sdf = new SimpleDateFormat("yyyy年MM月dd日");
	
	private static SimpleDateFormat simpltsdf = new SimpleDateFormat("yyyyMMdd");

	/**
	 * 获得两个日期相差的天数
	 * @param date1
	 * @param date2
	 * @return
	 */
	public static int getAlterDays(Date date1, Date date2) {
		int days = (int) ((date1.getTime() - date2.getTime()) / (24*60*60*1000));
		return Math.abs(days);
	}
	
	/**
	 * 解析 整数 20150505 为对应的date
	 * @param yyyyMMdd
	 * @return
	 */
	public static Date parseInt(int yyyyMMdd) {
		try {
			return simpltsdf.parse(String.valueOf(yyyyMMdd));
		} catch (ParseException e) {
			e.printStackTrace();
			return null;
		}
	}
	
	/**
	 * 获得两个日期相差的交易日天数
	 * @param date1
	 * @param date2
	 * @return
	 */
	public static int getAlterDealDays(Date date1, Date date2) {
		int days = (int) ((date1.getTime() - date2.getTime()) / (24*60*60*1000));
		return Math.abs(days);
	}
	
	/**
	 * 返回对应当前时间的date对象
	 * @return
	 */
	public static Date now() {
		return new Date();
	}
	
	/**
	 * 几秒后的工具函数，
	 * @param count		允许为负值，表示几秒之前
	 * @return
	 */
	public static Date secondsLater(int count) {
		return new Date(now().getTime() + count * 1000);
	}
	
	/**
	 * date的几天后
	 * @param date
	 * @param days	允许为负值，表示几天之前
	 * @return
	 */
	public static Date daysLater(Date date, int days) {
		Calendar cal = Calendar.getInstance();
		cal.setTime(date);
		cal.add(Calendar.DAY_OF_MONTH, days);
		cal.set(cal.get(Calendar.YEAR), cal.get(Calendar.MONTH),
				cal.get(Calendar.DATE), cal.get(Calendar.HOUR_OF_DAY),
				cal.get(Calendar.MINUTE), cal.get(Calendar.SECOND));
		return cal.getTime();
	}
	
	/**
	 * 判断source是否在dest之后
	 * @param source
	 * @param dest
	 * @return 如果相等，返回false
	 */
	public static boolean isAfter(Date source, Date dest) {
		return source.getTime() > dest.getTime();
	}
	
	/**
	 * 判断source是否在dest之前
	 * @param source
	 * @param dest
	 * @return	如果相等，返回false
	 */
	public static boolean isBefore(Date source, Date desc) {
		return desc.getTime() > source.getTime();
	}
	
	public static String toChineseFormat(Date date) {
		return sdf.format(date);
	}
	
	public static String toYYYYMMDDFormat(Date date) {
		return simpltsdf.format(date);
	}
	
	public static int getDayOfYear(Date date) {
		Calendar cal = Calendar.getInstance();
		cal.setTime(date);
		return cal.get(Calendar.DAY_OF_YEAR);
	}
	
	/**
	 * 获取某年（自从2015年）的第多少天
	 * 		比如：20150101，(2015-2015)*366【防止出现366天】
	 * @param date
	 * @return
	 */
	public static int getDayAfter20150101(Date date) {
		Calendar cal = Calendar.getInstance();
		cal.setTime(date);
		int dayofyear = cal.get(Calendar.DAY_OF_YEAR);
		return (cal.get(Calendar.YEAR) - 2015) * 366 + dayofyear;
	}
	
	/**
	 * 获取指定date明天00:00:00
	 * @param date
	 * @return
	 */
	public static Date tomorrowStart(Date date) {
		return dayStart(daysLater(date, 1));
	}
	
	/**
	 * 获取指定date的00:00:00
	 * @param date
	 * @return
	 */
	public static Date dayStart(Date date) {
		Calendar cal = Calendar.getInstance();
		cal.setTime(date);
		cal.set(cal.get(Calendar.YEAR), cal.get(Calendar.MONTH),
				cal.get(Calendar.DATE), 0, 0, 0);
		return cal.getTime();
	}
	
	/**
	 * 获取指定date的23:59:59
	 * @param date
	 * @return
	 */
	public static Date dayEnd(Date date) {
		Calendar cal = Calendar.getInstance();
		cal.setTime(date);
		cal.set(cal.get(Calendar.YEAR), cal.get(Calendar.MONTH),
				cal.get(Calendar.DATE), 23, 59, 59);
		return cal.getTime();
	}
	
	public static void main(String[] args) {
		Calendar cal = Calendar.getInstance();
		cal.set(2015, 0, 1);
	 	System.out.println(DateEx.getDayAfter20150101(cal.getTime()));
	 	Date date = DateEx.parseInt(20150331);
	 	System.out.println(DateEx.dayEnd(date));
	}
	
}