JAVA 日期工具类备用！

package cn.cowboy.common.util;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.regex.Pattern;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class DateUtil {
	protected static Log logger = LogFactory.getLog(DateUtil.class);

	// 格式：年－月－日 小时：分钟：秒
	public static final String FORMAT_ONE = "yyyy-MM-dd HH:mm:ss";

	// 格式：年－月－日 小时：分钟
	public static final String FORMAT_TWO = "yyyy-MM-dd HH:mm";

	// 格式：年月日 小时分钟秒
	public static final String FORMAT_THREE = "yyyyMMdd-HHmmss";
	
	// 格式：年月日小时分钟秒
	public static final String FORMAT_FOUR = "yyyyMMddHHmmss";
	
	// 格式：月日小时分钟
	public static final String FORMAT_FIVE = "MM-dd HH:mm";

	// 格式：年－月－日
	public static final String LONG_DATE_FORMAT = "yyyy-MM-dd";

	// 格式：年月日
	public static final String EIGHT_STYLE_DATE_FORMAT = "yyyyMMdd";

	// 格式：月－日
	public static final String SHORT_DATE_FORMAT = "MM-dd";

	// 格式：小时：分钟：秒
	public static final String LONG_TIME_FORMAT = "HH:mm:ss";
	
	// 格式：小时分钟秒
	public static final String SHORT_TIME_FORMAT = "HHmmss";

	// 格式：年-月
	public static final String MONTG_DATE_FORMAT = "yyyy-MM";
	
	// 格式: 年/月
	public static final String MONTH_DATE_FORMAT_2 = "yyyy/MM";

	// 年的加减
	public static final int SUB_YEAR = Calendar.YEAR;

	// 月加减
	public static final int SUB_MONTH = Calendar.MONTH;

	// 天的加减
	public static final int SUB_DAY = Calendar.DATE;

	// 小时的加减
	public static final int SUB_HOUR = Calendar.HOUR;

	// 分钟的加减
	public static final int SUB_MINUTE = Calendar.MINUTE;

	// 秒的加减
	public static final int SUB_SECOND = Calendar.SECOND;
	
	// 格式：年月日小时分钟秒
	public static final String FORMAT_Five_New = "yyyyMMddHHmmssSS";

	static final String dayNames[] = { "星期日", "星期一", "星期二", "星期三", "星期四",
			"星期五", "星期六" };

	@SuppressWarnings("unused")
	private static final SimpleDateFormat timeFormat = new SimpleDateFormat(
			FORMAT_ONE);

	public DateUtil() {
	}

	/**
	 * 把符合日期格式的字符串转换为日期类型
	 */

	public static java.util.Date toDate(String dateStr) {
		Date d = null;
		SimpleDateFormat formater = new SimpleDateFormat(FORMAT_ONE);
		try {
			formater.setLenient(false);
			d = formater.parse(dateStr);
		} catch (Exception e) {
			d = null;
		}
		return d;
	}

	public static java.util.Date toDate(String dateStr, String format) {
		Date d = null;
		SimpleDateFormat formater = new SimpleDateFormat(format);
		try {
			formater.setLenient(false);
			d = formater.parse(dateStr);
		} catch (Exception e) {
			d = null;
		}
		return d;
	}

	/**
	 * 把日期转换为字符串
	 * 
	 * @param date
	 * @return
	 */
	public static String formatDateTime(java.util.Date date) {
		String result = "";
		SimpleDateFormat formater = new SimpleDateFormat(FORMAT_ONE);
		try {
			result = formater.format(date);
		} catch (Exception e) {
			// log.error(e);
		}
		return result;
	}

	public static String formatDateTime(java.util.Date date, String format) {
		String result = "";
		SimpleDateFormat formater = new SimpleDateFormat(format);
		try {
			result = formater.format(date);
		} catch (Exception e) {
			// log.error(e);
		}
		return result;
	}

	/**
	 * 获取当前时间的指定格式
	 * 
	 * @param format
	 * @return
	 */
	public static String getCurrDate(String format) {
		return formatDateTime(new Date(), format);
	}

	/**
	 * 
	 * @param dateStr
	 * @param amount
	 * @return
	 */
	public static String dateSub(int dateKind, String dateStr, int amount) {
		Date date = toDate(dateStr, FORMAT_ONE);
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(date);
		calendar.add(dateKind, amount);
		return formatDateTime(calendar.getTime(), FORMAT_ONE);
	}

	/**
	 * 两个日期相减
	 * 
	 * @param firstTime
	 * @param secTime
	 * @return 相减得到的秒数
	 */
	public static long timeSub(String firstTime, String secTime) {
		long first = toDate(firstTime, FORMAT_ONE).getTime();
		long second = toDate(secTime, FORMAT_ONE).getTime();
		return (second - first) / 1000;
	}
	
	/**
	 * 两个日期相减
	 * 
	 * @param firstTime
	 * @param secTime
	 * @return 相减得到的秒数
	 */
	public static long timeSub(Date firstTime, Date secTime) {
		long first = firstTime.getTime();
		long second = secTime.getTime();
		return (second - first) / 1000;
	}

	/**
	 * 两个日期相减
	 * 
	 * @param firstTime
	 * @param secTime
	 * @return 相减得到的分钟
	 */
	public static long minSub(Date firstTime, Date secTime) {
		long first = firstTime.getTime();
		long second = secTime.getTime();
		return (second - first) / 60 / 1000;
	}
	
	/**
	 * 获得某月的天数
	 * 
	 * @param year
	 *            int
	 * @param month
	 *            int
	 * @return int
	 */
	public static int getDaysOfMonth(String year, String month) {
		int days = 0;
		if (month.equals("1") || month.equals("3") || month.equals("5")
				|| month.equals("7") || month.equals("8") || month.equals("10")
				|| month.equals("12")) {
			days = 31;
		} else if (month.equals("4") || month.equals("6") || month.equals("9")
				|| month.equals("11")) {
			days = 30;
		} else {
			if ((Integer.parseInt(year) % 4 == 0 && Integer.parseInt(year) % 100 != 0)
					|| Integer.parseInt(year) % 400 == 0) {
				days = 29;
			} else {
				days = 28;
			}
		}

		return days;
	}

	/**
	 * 获取某年某月的天数
	 * 
	 * @param year
	 *            int
	 * @param month
	 *            int 月份[1-12]
	 * @return int
	 */
	public static int getDaysOfMonth(int year, int month) {
		Calendar calendar = Calendar.getInstance();
		calendar.set(year, month - 1, 1);
		return calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
	}

	/**
	 * 获得当前日期
	 * 
	 * @return int
	 */
	public static int getToday() {
		Calendar calendar = Calendar.getInstance();
		return calendar.get(Calendar.DATE);
	}

	/**
	 * 获得当前月份
	 * 
	 * @return int
	 */
	public static int getToMonth() {
		Calendar calendar = Calendar.getInstance();
		return calendar.get(Calendar.MONTH) + 1;
	}

	/**
	 * 获得当前年份
	 * 
	 * @return int
	 */
	public static int getToYear() {
		Calendar calendar = Calendar.getInstance();
		return calendar.get(Calendar.YEAR);
	}

	/**
	 * 返回日期的天
	 * 
	 * @param date
	 *            Date
	 * @return int
	 */
	public static int getDay(Date date) {
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(date);
		return calendar.get(Calendar.DATE);
	}

	/**
	 * 返回日期的年
	 * 
	 * @param date
	 *            Date
	 * @return int
	 */
	public static int getYear(Date date) {
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(date);
		return calendar.get(Calendar.YEAR);
	}

	/**
	 * 返回日期的月份，1-12
	 * 
	 * @param date
	 *            Date
	 * @return int
	 */
	public static int getMonth(Date date) {
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(date);
		return calendar.get(Calendar.MONTH) + 1;
	}

	/**
	 * 计算两个日期相差的天数，如果date2 > date1 返回正数，否则返回负数
	 * 
	 * @param date1
	 *            Date
	 * @param date2
	 *            Date
	 * @return long
	 */
	public static long dayDiff(Date date1, Date date2) {
		return (date2.getTime() - date1.getTime()) / 86400000;
	}
	
	/**
	 * 计算两个日期0点时，相差的天数，如果date2 > date1 返回正数，否则返回负数
	 * @param date1
	 * @param date2
	 * @return
	 */
	public static long daySubtraction(Date date1, Date date2) {
		return (getStartOfDay(date2).getTime() - getStartOfDay(date1).getTime()) / 86400000;
	}

	/**
	 * 比较两个日期的年差
	 * 
	 * @param befor
	 * @param after
	 * @return
	 */
	public static int yearDiff(String before, String after) {
		Date beforeDay = toDate(before, LONG_DATE_FORMAT);
		Date afterDay = toDate(after, LONG_DATE_FORMAT);
		return getYear(afterDay) - getYear(beforeDay);
	}

	/**
	 * 比较指定日期与当前日期的差
	 * 
	 * @param befor
	 * @param after
	 * @return
	 */
	public static int yearDiffCurr(String after) {
		Date beforeDay = new Date();
		Date afterDay = toDate(after, LONG_DATE_FORMAT);
		return getYear(beforeDay) - getYear(afterDay);
	}

	/**
	 * 比较指定日期与当前日期的差
	 * 
	 * @param before
	 * @return
	 * @author chenyz
	 */
	public static long dayDiffCurr(String before) {
		Date currDate = DateUtil.toDate(currDay(), LONG_DATE_FORMAT);
		Date beforeDate = toDate(before, LONG_DATE_FORMAT);
		return (currDate.getTime() - beforeDate.getTime()) / 86400000;

	}

	/**
	 * 获取每月的第一周
	 * 
	 * @param year
	 * @param month
	 * @return
	 * @author chenyz
	 */
	public static int getFirstWeekdayOfMonth(int year, int month) {
		Calendar c = Calendar.getInstance();
		c.setFirstDayOfWeek(Calendar.SATURDAY); // 星期天为第一天
		c.set(year, month - 1, 1);
		return c.get(Calendar.DAY_OF_WEEK);
	}

	/**
	 * 获取每月的最后一周
	 * 
	 * @param year
	 * @param month
	 * @return
	 * @author chenyz
	 */
	public static int getLastWeekdayOfMonth(int year, int month) {
		Calendar c = Calendar.getInstance();
		c.setFirstDayOfWeek(Calendar.SATURDAY); // 星期天为第一天
		c.set(year, month - 1, getDaysOfMonth(year, month));
		return c.get(Calendar.DAY_OF_WEEK);
	}

	/**
	 * 获得当前日期字符串，格式"yyyy-MM-dd HH:mm:ss"
	 * 
	 * @return
	 */
	public static String getNow() {
		Calendar today = Calendar.getInstance();
		return formatDateTime(today.getTime(), FORMAT_ONE);
	}

	/**
	 * 根据生日获取星座
	 * 
	 * @param birth
	 *            YYYY-mm-dd
	 * @return
	 */
	public static String getAstro(String birth) {
		if (!isDate(birth)) {
			birth = "2000" + birth;
		}
		if (!isDate(birth)) {
			return "";
		}
		int month = Integer.parseInt(birth.substring(birth.indexOf("-") + 1,
				birth.lastIndexOf("-")));
		int day = Integer.parseInt(birth.substring(birth.lastIndexOf("-") + 1));
		String s = "魔羯水瓶双鱼牡羊金牛双子巨蟹狮子处女天秤天蝎射手魔羯";
		int[] arr = { 20, 19, 21, 21, 21, 22, 23, 23, 23, 23, 22, 22 };
		int start = month * 2 - (day < arr[month - 1] ? 2 : 0);
		return s.substring(start, start + 2) + "座";
	}

	/**
	 * 判断日期是否有效,包括闰年的情况
	 * 
	 * @param date
	 *            YYYY-mm-dd
	 * @return
	 */
	public static boolean isDate(String date) {
		StringBuffer reg = new StringBuffer(
				"^((\\d{2}(([02468][048])|([13579][26]))-?((((0?");
		reg.append("[13578])|(1[02]))-?((0?[1-9])|([1-2][0-9])|(3[01])))");
		reg.append("|(((0?[469])|(11))-?((0?[1-9])|([1-2][0-9])|(30)))|");
		reg.append("(0?2-?((0?[1-9])|([1-2][0-9])))))|(\\d{2}(([02468][12");
		reg.append("35679])|([13579][01345789]))-?((((0?[13578])|(1[02]))");
		reg.append("-?((0?[1-9])|([1-2][0-9])|(3[01])))|(((0?[469])|(11))");
		reg.append("-?((0?[1-9])|([1-2][0-9])|(30)))|(0?2-?((0?[");
		reg.append("1-9])|(1[0-9])|(2[0-8]))))))");
		Pattern p = Pattern.compile(reg.toString());
		return p.matcher(date).matches();
	}

	/**
	 * 取得指定日期过 months 月后的日期 (当 months 为负数表示指定月之前);
	 * 
	 * @param date
	 *            日期 为null时表示当天
	 * @param month
	 *            相加(相减)的月数
	 */
	public static Date nextMonth(Date date, int months) {
		Calendar cal = Calendar.getInstance();
		if (date != null) {
			cal.setTime(date);
		}
		cal.add(Calendar.MONTH, months);
		return cal.getTime();
	}

	/**
	 * 取得指定日期过 day 天后的日期 (当 day 为负数表示指日期之前);
	 * 
	 * @param date
	 *            日期 为null时表示当天
	 * @param month
	 *            相加(相减)的月数
	 */
	public static Date nextDay(Date date, int day) {
		Calendar cal = Calendar.getInstance();
		if (date != null) {
			cal.setTime(date);
		}
		cal.add(Calendar.DAY_OF_YEAR, day);
		return cal.getTime();
	}

	/**
	 * 取得距离今天 day 日的日期
	 * 
	 * @param day
	 * @param format
	 * @return
	 * @author chenyz
	 */
	public static String nextDay(int day, String format) {
		Calendar cal = Calendar.getInstance();
		cal.setTime(new Date());
		cal.add(Calendar.DAY_OF_YEAR, day);
		return formatDateTime(cal.getTime(), format);
	}

	/**
	 * 取得指定日期过 day 周后的日期 (当 day 为负数表示指定月之前)
	 * 
	 * @param date
	 *            日期 为null时表示当天
	 */
	public static Date nextWeek(Date date, int week) {
		Calendar cal = Calendar.getInstance();
		if (date != null) {
			cal.setTime(date);
		}
		cal.add(Calendar.WEEK_OF_MONTH, week);
		return cal.getTime();
	}

	/**
	 * 获取当前的日期(yyyy-MM-dd) 
	 */
	public static String currDay() {
		return DateUtil.formatDateTime(new Date(), DateUtil.LONG_DATE_FORMAT);
	}
	
	/**
	 * 获取当前的日期(yyyy-MM-dd HH:mm:ss ) 
	 */
	public static String currDays() {
		return DateUtil.formatDateTime(new Date(), DateUtil.FORMAT_ONE);
	}
	
	/**
	 * 获取昨天的日期
	 * 
	 * @return
	 */
	public static String befoDay() {
		return befoDay(DateUtil.LONG_DATE_FORMAT);
	}

	/**
	 * 根据时间类型获取昨天的日期
	 * 
	 * @param format
	 * @return
	 * @author chenyz
	 */
	public static String befoDay(String format) {
		return DateUtil
				.formatDateTime(DateUtil.nextDay(new Date(), -1), format);
	}

	/**
	 * 根据时间类型获取上月的月份
	 * 
	 * @param format
	 * @return
	 * @author chenyz
	 */
	public static String befoMonth(String format) {
		Calendar cal = Calendar.getInstance();
		cal.setTime(new Date());
		cal.add(Calendar.MONTH, -1);
		return DateUtil.formatDateTime(cal.getTime(), format);
	}

	/**
	 * 获取明天的日期
	 */
	public static String afterDay() {
		
		return DateUtil.formatDateTime(DateUtil.nextDay(new Date(), 1),
				DateUtil.LONG_DATE_FORMAT);
	}

	/**
	 * 取得当前时间距离1900/1/1的天数
	 * 
	 * @return
	 */
	public static int getDayNum() {
		int daynum = 0;
		GregorianCalendar gd = new GregorianCalendar();
		Date dt = gd.getTime();
		GregorianCalendar gd1 = new GregorianCalendar(1900, 1, 1);
		Date dt1 = gd1.getTime();
		daynum = (int) ((dt.getTime() - dt1.getTime()) / (24 * 60 * 60 * 1000));
		return daynum;
	}

	/**
	 * getDayNum的逆方法(用于处理Excel取出的日期格式数据等)
	 * 
	 * @param day
	 * @return
	 */
	public static Date getDateByNum(int day) {
		GregorianCalendar gd = new GregorianCalendar(1900, 1, 1);
		Date date = gd.getTime();
		date = nextDay(date, day);
		return date;
	}

	/** 针对yyyy-MM-dd HH:mm:ss格式,显示yyyymmdd */
	public static String getYmdDateCN(String datestr) {
		if (datestr == null)
			return "";
		if (datestr.length() < 10)
			return "";
		StringBuffer buf = new StringBuffer();
		buf.append(datestr.substring(0, 4)).append(datestr.substring(5, 7))
				.append(datestr.substring(8, 10));
		return buf.toString();
	}

	/**
	 * 获取本月第一天
	 * 
	 * @param format
	 * @return
	 */
	public static String getFirstDayOfMonth(String format) {
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.DATE, 1);
		return formatDateTime(cal.getTime(), format);
	}
	
	/**
	 * 获取某月第一天
	 * 
	 * @param format
	 * @return
	 */
	public static Date getFirstDayOfMonth(Date date) {
		if (date == null) {
			date = new Date();
		}
		Calendar cal = Calendar.getInstance();
		cal.setTime(date);
		cal.set(Calendar.DATE, 1);
		return cal.getTime();
	}

	/**
	 * 获取本月最后一天
	 * 
	 * @param format
	 * @return
	 */
	public static String getLastDayOfMonth(String format) {
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.DATE, 1);
		cal.add(Calendar.MONTH, 1);
		cal.add(Calendar.DATE, -1);
		return formatDateTime(cal.getTime(), format);
	}
	
	/**
	 * 获取某月最后一天
	 * 
	 * @param format
	 * @return
	 */
	public static Date getLastDayOfMonth(Date date) {
		if (date == null)
			date = new Date();
		Calendar cal = Calendar.getInstance();
		cal.setTime(date);
		cal.set(Calendar.DATE, 1);
		cal.add(Calendar.MONTH, 1);
		cal.add(Calendar.DATE, -1);
		return cal.getTime();
	}

	/**
	 * Returns a Date set to the first possible millisecond of the day, just
	 * after midnight. If a null day is passed in, a new Date is created.
	 * midnight (00m 00h 00s)
	 */
	public static Date getStartOfDay(Date day) {
		return getStartOfDay(day, Calendar.getInstance());
	}

	public static Date getTodayStart(){
		return getStartOfDay( new Date() );
	}
	
	public static Date getBeforeDate(Date mirror, int dayNum) {
		Calendar current = Calendar.getInstance();
		current.setTime(mirror);

		current.add(Calendar.HOUR, -24 * dayNum);
		return current.getTime();
	}
	
	/**
	 * Returns a Date set to the first possible millisecond of the day, just
	 * after midnight. If a null day is passed in, a new Date is created.
	 * midnight (00m 00h 00s)
	 */
	public static Date getStartOfDay(Date day, Calendar cal) {
		if (day == null)
			day = new Date();
		cal.setTime(day);
		cal.set(Calendar.HOUR_OF_DAY, cal.getMinimum(Calendar.HOUR_OF_DAY));
		cal.set(Calendar.MINUTE, cal.getMinimum(Calendar.MINUTE));
		cal.set(Calendar.SECOND, cal.getMinimum(Calendar.SECOND));
		cal.set(Calendar.MILLISECOND, cal.getMinimum(Calendar.MILLISECOND));
		return cal.getTime();
	}

	/**
	 * Returns a Date set to the last possible millisecond of the day, just
	 * before midnight. If a null day is passed in, a new Date is created.
	 * midnight (00m 00h 00s)
	 */
	public static Date getEndOfDay(Date day) {
		return getEndOfDay(day, Calendar.getInstance());
	}

	public static Date getEndOfDay(Date day, Calendar cal) {
		if (day == null)
			day = new Date();
		cal.setTime(day);
		cal.set(Calendar.HOUR_OF_DAY, cal.getMaximum(Calendar.HOUR_OF_DAY));
		cal.set(Calendar.MINUTE, cal.getMaximum(Calendar.MINUTE));
		cal.set(Calendar.SECOND, cal.getMaximum(Calendar.SECOND));
		cal.set(Calendar.MILLISECOND, cal.getMaximum(Calendar.MILLISECOND));
		return cal.getTime();
	}

	/**
	 * 判断2个时间相差多少天<br>
	 * <br>
	 * 
	 * @param pBeginTime
	 *            请假开始时间<br>
	 * @param pEndTime
	 *            请假结束时间<br>
	 * @return String 计算结果<br>
	 * @throws ParseException
	 * @Exception 发生异常<br>
	 */
	public static Long timeDiffForDay(Date pBeginTime, Date pEndTime)
			throws ParseException {
		Long beginL = pBeginTime.getTime();
		Long endL = pEndTime.getTime();
		Long day = (endL - beginL) / 86400000;
		return day;
	}

	/**
	 * 判断2个时间相差多少小时<br>
	 * <br>
	 * 
	 * @param pBeginTime
	 *            请假开始时间<br>
	 * @param pEndTime
	 *            请假结束时间<br>
	 * @return String 计算结果<br>
	 * @throws ParseException
	 * @Exception 发生异常<br>
	 */
	public static Long timeDiffForHour(Date pBeginTime, Date pEndTime)
			throws ParseException {
		Long beginL = pBeginTime.getTime();
		Long endL = pEndTime.getTime();
		Long hour = ((endL - beginL) % 86400000) / 3600000;
		return hour;
	}

	/**
	 * 判断2个时间相差多少分<br>
	 * <br>
	 * 
	 * @param pBeginTime
	 *            请假开始时间<br>
	 * @param pEndTime
	 *            请假结束时间<br>
	 * @return String 计算结果<br>
	 * @throws ParseException
	 * @Exception 发生异常<br>
	 */
	public static Long timeDiffForMin(Date pBeginTime, Date pEndTime)
			throws ParseException {
		Long beginL = pBeginTime.getTime();
		Long endL = pEndTime.getTime();
		Long min = ((endL - beginL) % 86400000 % 3600000) / 60000;
		return min;
	}
	
	/**
	 * 返回指定时间与当前时间差多少天(小时, 分钟, 刚才) 
	 * @param time 要比较的时间
	 * @return 多少天(小时, 分钟, 刚才)
	 */
	public static String getTime(Date time) {
		String result = null;
		Long temp = null;
		final Date currentDate = new Date();
		
		do {
			try {
				// 看差多少天
				temp = timeDiffForDay(time, currentDate);
				if (temp > 0l) {
					result = temp + "天前";
					break;
				}
				
				// 看差多少时
				temp = timeDiffForHour(time, currentDate);
				if (temp > 0l) {
					result = temp + "小时前";
					break;
				}
				
				// 看差多少分
				temp = timeDiffForMin(time, currentDate);
				if (temp > 0l) {
					result = temp + "分种前";
					break;
				}
			} catch (ParseException e) {
				e.printStackTrace();
			}
		} while (false);
		
		return result == null ? "刚才" : result;
	}
	
	public static Date getMonthDelay(Date currentDay, int month) {
		Calendar current = Calendar.getInstance();
		current.setTime(currentDay);

		current.add(Calendar.MONTH, month);
		current.add(Calendar.HOUR, -24);
		return current.getTime();
	}
	
	public static Date getStartOfLastMonth() {
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.HOUR_OF_DAY, cal.getMinimum(Calendar.HOUR_OF_DAY));
		cal.set(Calendar.MINUTE, cal.getMinimum(Calendar.MINUTE));
		cal.set(Calendar.SECOND, cal.getMinimum(Calendar.SECOND));
		cal.set(Calendar.MILLISECOND, cal.getMinimum(Calendar.MILLISECOND));
		cal.set(Calendar.DAY_OF_MONTH, 1);
		cal.add(Calendar.MONTH, -1);
		return cal.getTime();
	}
	
	public static Date getStartOfToday() {
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.HOUR_OF_DAY, cal.getMinimum(Calendar.HOUR_OF_DAY));
		cal.set(Calendar.MINUTE, cal.getMinimum(Calendar.MINUTE));
		cal.set(Calendar.SECOND, cal.getMinimum(Calendar.SECOND));
		cal.set(Calendar.MILLISECOND, cal.getMinimum(Calendar.MILLISECOND));
		return cal.getTime();
	}
	
	public static Date getEndOfLastMonth() {
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.HOUR_OF_DAY, cal.getMaximum(Calendar.HOUR_OF_DAY));
		cal.set(Calendar.MINUTE, cal.getMaximum(Calendar.MINUTE));
		cal.set(Calendar.SECOND, cal.getMaximum(Calendar.SECOND));
		cal.set(Calendar.MILLISECOND, cal.getMaximum(Calendar.MILLISECOND));
		cal.set(Calendar.DAY_OF_MONTH, 1);
		cal.add(Calendar.DAY_OF_MONTH, -1);
		return cal.getTime();
	}
	
	public static Date getMinEndOfLastMonth() {
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.HOUR_OF_DAY, cal.getMinimum(Calendar.HOUR_OF_DAY));
		cal.set(Calendar.MINUTE, cal.getMinimum(Calendar.MINUTE));
		cal.set(Calendar.SECOND, cal.getMinimum(Calendar.SECOND));
		cal.set(Calendar.MILLISECOND, cal.getMinimum(Calendar.MILLISECOND));
		cal.set(Calendar.DAY_OF_MONTH, 1);
		cal.add(Calendar.DAY_OF_MONTH, -1);
		return cal.getTime();
	}
	
	public static int getDaysOfLastMonth() {
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.DAY_OF_MONTH, 1);
		cal.add(Calendar.DAY_OF_MONTH, -1);
		return cal.get(Calendar.DAY_OF_MONTH);
	}

	// 获得本月第一天，比如：2014-02-01 00:00:00
	public static Date getStartOfMonth() {
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.HOUR_OF_DAY, cal.getMinimum(Calendar.HOUR_OF_DAY));
		cal.set(Calendar.MINUTE, cal.getMinimum(Calendar.MINUTE));
		cal.set(Calendar.SECOND, cal.getMinimum(Calendar.SECOND));
		cal.set(Calendar.MILLISECOND, cal.getMinimum(Calendar.MILLISECOND));
		cal.set(Calendar.DAY_OF_MONTH, 1);
		return cal.getTime();
	}
	
	// 获得本月最后一天，比如：2014-02-28 23:59:59
	public static Date getEndOfMonth() {
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.HOUR_OF_DAY, cal.getMaximum(Calendar.HOUR_OF_DAY));
		cal.set(Calendar.MINUTE, cal.getMaximum(Calendar.MINUTE));
		cal.set(Calendar.SECOND, cal.getMaximum(Calendar.SECOND));
		cal.set(Calendar.MILLISECOND, cal.getMaximum(Calendar.MILLISECOND));
		cal.set(Calendar.DAY_OF_MONTH, 1);
		cal.add(Calendar.MONTH, 1);
		cal.add(Calendar.DAY_OF_MONTH, -1);
		return cal.getTime();
	}

	/**
	 * 获取两个日期中间的工作日
	 * 
	 * @param starttime yyyy-MM-dd
	 * @param endtime yyyy-MM-dd
	 * @return
	 */
	public static int getWorkTime(String starttime, String endtime) {
		// 设置时间格式
		SimpleDateFormat dateFormat = new SimpleDateFormat(LONG_DATE_FORMAT);
		// 开始日期
		Date dateFrom = null;
		Date dateTo = null;
		try {
			dateFrom = dateFormat.parse(starttime);
			dateTo = dateFormat.parse(endtime);
		} catch (ParseException e) {
			e.printStackTrace();
		}
		int workdays = 0;
		Calendar cal = null;
		while (dateFrom.before(dateTo) || dateFrom.equals(dateTo)) {
			cal = Calendar.getInstance();
			// 设置日期
			cal.setTime(dateFrom);
			if ((cal.get(Calendar.DAY_OF_WEEK) != Calendar.SATURDAY)
					&& (cal.get(Calendar.DAY_OF_WEEK) != Calendar.SUNDAY)) {
				// 进行比较，如果日期不等于周六也不等于周日，工作日+1
				workdays++;
			}
			// 日期加1
			cal.add(Calendar.DAY_OF_MONTH, 1);
			dateFrom = cal.getTime();
		}
		return workdays;
	}

	/**
	 * 获取两个日期中间的工作日
	 * 
	 * @param starttime yyyy-MM-dd
	 * @param endtime yyyy-MM-dd
	 * @return
	 */
	public static int getYearDays(Calendar cal) {
		cal.set(Calendar.DAY_OF_YEAR, 1);
		cal.roll(Calendar.DAY_OF_YEAR, -1);
		int yearDays = cal.get(Calendar.DAY_OF_YEAR);
		return yearDays;
	}
	
	/**
	 * 获取本周第一天
	 * 
	 * @return
	 */
	public static Date getFirstDayOfWeek(Date date){
		Calendar cal = new GregorianCalendar();
		cal.setFirstDayOfWeek(Calendar.MONDAY);
		if (date != null) {
			cal.setTime(date);
		}else {
			cal.setTime(new Date());
		}
		cal.set(Calendar.HOUR_OF_DAY, 0);  
		cal.set(Calendar.MINUTE, 0);  
		cal.set(Calendar.SECOND, 0);  
		
		cal.set(Calendar.DAY_OF_WEEK, cal.getFirstDayOfWeek());// Monday
		return cal.getTime();
	}
	
	/**
	 * 获取本周最后一天
	 * 
	 * @return
	 */
	public static Date getLastDayOfWeek(Date date){
		Calendar cal = new GregorianCalendar();
		cal.setFirstDayOfWeek(Calendar.MONDAY);
		cal.setTime(new Date());
		cal.set(Calendar.DAY_OF_WEEK, cal.getFirstDayOfWeek() + 6);// Sunday
		return cal.getTime();
	}
	
	/**
	 * 获取某月次月的最后一天
	 * 
	 * @return
	 */
	public static String  getNextMonth0fDay(Date date,String format){
		Calendar cal = Calendar.getInstance();
		cal.setTime(date);
		cal.set(Calendar.DATE, 1);
		cal.add(Calendar.MONTH,2);
		cal.add(Calendar.DATE, -1);
		return formatDateTime(cal.getTime(),format);
	
	}
	
	/**
	 * 当前时间减去38年的 毫秒数.
	 */
	public static long getRecentTimeVal() {
		// 38 年的 毫秒数
		long millisecondsIn38 = 86400 * 365 * 38;
		
		return System.currentTimeMillis() / 1000 - millisecondsIn38;
	}
	
	/**
	 * 获得某一天是星期几, 默认是当前日期.
	 * @return 1 -> SUNDAY 
	 *         2 -> MONDAY 
	 *         3 -> TUESDAY 
	 *         4 -> WEDNESDAY 
	 *         5 -> THURSDAY 
	 *         6 -> FRIDAY
	 *         7 -> SATURDAY
	 */
	public static int getDayOfWeek(Date date) {
		final Calendar cal = Calendar.getInstance();
		if (date != null) {
			cal.setTime(date);
		}
		
		return cal.get(Calendar.DAY_OF_WEEK);
	}
	
	/**
	 * 获得某一天的下周一的日期, 默认是当天.
	 */
	public static Date getNextMonday(Date date) {
		final Calendar cal = Calendar.getInstance();
		if (date != null) {
			cal.setTime(date);
		}
		
		final int dayOfWeek = cal.get(Calendar.DAY_OF_WEEK);
		
   	    cal.add(Calendar.DATE, (7 - dayOfWeek + 2) % 7);
   	    
   	    return cal.getTime();
	}
	
	/**
	 * 拿某一时间的 24小时计时法中的小时数, 默认当前时间,
	 * E.g., at 10:04:15.250 PM the HOUR_OF_DAY is 22.
	 */
	public static int getHourOfDay(Date date) {
    	final Calendar cal = Calendar.getInstance();  
		if (date != null) {
			cal.setTime(date);
		}
		
    	return cal.get(Calendar.HOUR_OF_DAY);
	}

	public static void main(String[] args) throws ParseException {
		
//		Date today = new Date();
//		Calendar c = Calendar.getInstance();
//		c.setTime(today);
//		c.add(Calendar.MONTH, 1); // 这个意思是得到下个月 想得到3个月后就加3 半年加6
//		int i = c.get(Calendar.MONTH);
//		while (c.get(Calendar.MONTH) != (i == 11 ? 0 : i + 1)) {
//			c.add(Calendar.DAY_OF_MONTH, 1);
//		}
//		c.add(Calendar.DAY_OF_MONTH, -1);
//		System.out.println("下个月是" + c.get(Calendar.DAY_OF_MONTH) + "天");
		
		String ds = "2011-11-18";
		Date d = new SimpleDateFormat("yyyy-MM-dd").parse(ds);
		Calendar cal = Calendar.getInstance();
		cal.setTime(d);
		int i1 = cal.get(Calendar.MONTH);
		while (cal.get(Calendar.MONTH) != (i1 == 11 ? 0 : i1 + 1)) {
			cal.add(Calendar.DAY_OF_MONTH, 1);
		}
		cal.add(Calendar.DAY_OF_MONTH, -1);
		System.out.println("这个月是" + cal.get(Calendar.DAY_OF_MONTH) + "天");
		
		String ds1 = ds.substring(0, ds.lastIndexOf("-") + 1) + 1;
		String ds2 = ds.substring(0, ds.lastIndexOf("-") + 1) + cal.get(Calendar.DAY_OF_MONTH);
		System.out.println(ds1);
		System.out.println(ds2);
		System.out.println(getWorkTime(ds1, ds2));
		
		
		System.out.println("--------------------");
		System.out.println(DateUtil.getBeforeDate( new Date(), 1));
		
		
		System.out.println("-----------本周第一天-------------");
		System.out.println(formatDateTime(getFirstDayOfWeek(new Date())));
	}

}