由于获取日期经常会使用到,所有我自己写了一个工具类 1、基本上能用上的都写出来了,包括:

1)获取当天的开始时间
 2)获取当天的结束时间
 3)获取昨天的开始时间
 4)获取昨天的结束时间
 5)获取明天的开始时间
 6)获取明天的结束时间
 7)获取本周的开始时间
 8)获取本周的结束时间
 9)获取上周的开始时间
 10)获取上周的结束时间
 11)获取本月的开始时间
 12)获取本月的结束时间
 13)获取上月的开始时间
 14)获取上月的结束时间
 15)获取本年的开始时间
 16)获取本年的结束时间
 17)获取某个日期的开始时间
 18)获取某个日期的结束时间
 19)获取今年是哪一年
 20)获取本月是哪一月
 21)两个日期相减得到的天数
 22)两个日期相减得到的毫秒数
 23)获取两个日期中的最大日期
 24)获取两个日期中的最小日期
 25)返回某月该季度的第一个月
 26)返回某个日期下几天的日期
 27)返回某个日期前几天的日期
 28)获取某年某月到某年某月按天的切片日期集合(间隔天数的集合)
 29)获取某年某月按天切片日期集合(某个月间隔多少天的日期集合)
/**
 * 日期工具类
 */
public class DatesUtil {
	// 获取当天的开始时间
	public static java.util.Date getDayBegin() {
		Calendar cal = new GregorianCalendar();
		cal.set(Calendar.HOUR_OF_DAY, 0);
		cal.set(Calendar.MINUTE, 0);
		cal.set(Calendar.SECOND, 0);
		cal.set(Calendar.MILLISECOND, 0);
		return cal.getTime();
	}
 
	// 获取当天的结束时间
	public static java.util.Date getDayEnd() {
		Calendar cal = new GregorianCalendar();
		cal.set(Calendar.HOUR_OF_DAY, 23);
		cal.set(Calendar.MINUTE, 59);
		cal.set(Calendar.SECOND, 59);
		return cal.getTime();
	}
 
	// 获取昨天的开始时间
	public static Date getBeginDayOfYesterday() {
		Calendar cal = new GregorianCalendar();
		cal.setTime(getDayBegin());
		cal.add(Calendar.DAY_OF_MONTH, -1);
		return cal.getTime();
	}
 
	// 获取昨天的结束时间
	public static Date getEndDayOfYesterDay() {
		Calendar cal = new GregorianCalendar();
		cal.setTime(getDayEnd());
		cal.add(Calendar.DAY_OF_MONTH, -1);
		return cal.getTime();
	}
 
	// 获取明天的开始时间
	public static Date getBeginDayOfTomorrow() {
		Calendar cal = new GregorianCalendar();
		cal.setTime(getDayBegin());
		cal.add(Calendar.DAY_OF_MONTH, 1);
		return cal.getTime();
	}
 
	// 获取明天的结束时间
	public static Date getEndDayOfTomorrow() {
		Calendar cal = new GregorianCalendar();
		cal.setTime(getDayEnd());
		cal.add(Calendar.DAY_OF_MONTH, 1);
		return cal.getTime();
	}
 
	// 获取本周的开始时间
	@SuppressWarnings("unused")
	public static Date getBeginDayOfWeek() {
		Date date = new Date();
		if (date == null) {
			return null;
		}
		Calendar cal = Calendar.getInstance();
		cal.setTime(date);
		int dayofweek = cal.get(Calendar.DAY_OF_WEEK);
		if (dayofweek == 1) {
			dayofweek += 7;
		}
		cal.add(Calendar.DATE, 2 - dayofweek);
		return getDayStartTime(cal.getTime());
	}
 
	// 获取本周的结束时间
	public static Date getEndDayOfWeek() {
		Calendar cal = Calendar.getInstance();
		cal.setTime(getBeginDayOfWeek());
		cal.add(Calendar.DAY_OF_WEEK, 6);
		Date weekEndSta = cal.getTime();
		return getDayEndTime(weekEndSta);
	}
 
	// 获取上周的开始时间
	@SuppressWarnings("unused")
	public static Date getBeginDayOfLastWeek() {
		Date date = new Date();
		if (date == null) {
			return null;
		}
		Calendar cal = Calendar.getInstance();
		cal.setTime(date);
		int dayofweek = cal.get(Calendar.DAY_OF_WEEK);
		if (dayofweek == 1) {
			dayofweek += 7;
		}
		cal.add(Calendar.DATE, 2 - dayofweek - 7);
		return getDayStartTime(cal.getTime());
	}
 
	// 获取上周的结束时间
	public static Date getEndDayOfLastWeek() {
		Calendar cal = Calendar.getInstance();
		cal.setTime(getBeginDayOfLastWeek());
		cal.add(Calendar.DAY_OF_WEEK, 6);
		Date weekEndSta = cal.getTime();
		return getDayEndTime(weekEndSta);
	}
 
	// 获取本月的开始时间
	public static Date getBeginDayOfMonth() {
		Calendar calendar = Calendar.getInstance();
		calendar.set(getNowYear(), getNowMonth() - 1, 1);
		return getDayStartTime(calendar.getTime());
	}
 
	// 获取本月的结束时间
	public static Date getEndDayOfMonth() {
		Calendar calendar = Calendar.getInstance();
		calendar.set(getNowYear(), getNowMonth() - 1, 1);
		int day = calendar.getActualMaximum(5);
		calendar.set(getNowYear(), getNowMonth() - 1, day);
		return getDayEndTime(calendar.getTime());
	}
 
	// 获取上月的开始时间
	public static Date getBeginDayOfLastMonth() {
		Calendar calendar = Calendar.getInstance();
		calendar.set(getNowYear(), getNowMonth() - 2, 1);
		return getDayStartTime(calendar.getTime());
	}
 
	// 获取上月的结束时间
	public static Date getEndDayOfLastMonth() {
		Calendar calendar = Calendar.getInstance();
		calendar.set(getNowYear(), getNowMonth() - 2, 1);
		int day = calendar.getActualMaximum(5);
		calendar.set(getNowYear(), getNowMonth() - 2, day);
		return getDayEndTime(calendar.getTime());
	}
 
	// 获取本年的开始时间
	public static Date getBeginDayOfYear() {
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.YEAR, getNowYear());
		cal.set(Calendar.MONTH, Calendar.JANUARY);
		cal.set(Calendar.DATE, 1);
		return getDayStartTime(cal.getTime());
	}
 
	// 获取本年的结束时间
	public static java.util.Date getEndDayOfYear() {
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.YEAR, getNowYear());
		cal.set(Calendar.MONTH, Calendar.DECEMBER);
		cal.set(Calendar.DATE, 31);
		return getDayEndTime(cal.getTime());
	}
 
	// 获取某个日期的开始时间
	public static Timestamp getDayStartTime(Date d) {
		Calendar calendar = Calendar.getInstance();
		if (null != d)
			calendar.setTime(d);
		calendar.set(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH),
				calendar.get(Calendar.DAY_OF_MONTH), 0, 0, 0);
		calendar.set(Calendar.MILLISECOND, 0);
		return new Timestamp(calendar.getTimeInMillis());
	}
 
	// 获取某个日期的结束时间
	public static Timestamp getDayEndTime(Date d) {
		Calendar calendar = Calendar.getInstance();
		if (null != d)
			calendar.setTime(d);
		calendar.set(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH),
				calendar.get(Calendar.DAY_OF_MONTH), 23, 59, 59);
		calendar.set(Calendar.MILLISECOND, 999);
		return new Timestamp(calendar.getTimeInMillis());
	}
 
	// 获取今年是哪一年
	public static Integer getNowYear() {
		Date date = new Date();
		GregorianCalendar gc = (GregorianCalendar) Calendar.getInstance();
		gc.setTime(date);
		return Integer.valueOf(gc.get(1));
	}
 
	// 获取本月是哪一月
	public static int getNowMonth() {
		Date date = new Date();
		GregorianCalendar gc = (GregorianCalendar) Calendar.getInstance();
		gc.setTime(date);
		return gc.get(2) + 1;
	}
 
	// 两个日期相减得到的天数
	public static int getDiffDays(Date beginDate, Date endDate) {
		if (beginDate == null || endDate == null) {
			throw new IllegalArgumentException("getDiffDays param is null!");
		}
		long diff = (endDate.getTime() - beginDate.getTime())
				/ (1000 * 60 * 60 * 24);
		int days = new Long(diff).intValue();
		return days;
	}
 
	// 两个日期相减得到的毫秒数
	public static long dateDiff(Date beginDate, Date endDate) {
		long date1ms = beginDate.getTime();
		long date2ms = endDate.getTime();
		return date2ms - date1ms;
	}
 
	// 获取两个日期中的最大日期
	public static Date max(Date beginDate, Date endDate) {
		if (beginDate == null) {
			return endDate;
		}
		if (endDate == null) {
			return beginDate;
		}
		if (beginDate.after(endDate)) {
			return beginDate;
		}
		return endDate;
	}
 
	// 获取两个日期中的最小日期
	public static Date min(Date beginDate, Date endDate) {
		if (beginDate == null) {
			return endDate;
		}
		if (endDate == null) {
			return beginDate;
		}
		if (beginDate.after(endDate)) {
			return endDate;
		}
		return beginDate;
	}
 
	// 返回某月该季度的第一个月
	public static Date getFirstSeasonDate(Date date) {
		final int[] SEASON = { 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4 };
		Calendar cal = Calendar.getInstance();
		cal.setTime(date);
		int sean = SEASON[cal.get(Calendar.MONTH)];
		cal.set(Calendar.MONTH, sean * 3 - 3);
		return cal.getTime();
	}
 
	// 返回某个日期下几天的日期
	public static Date getNextDay(Date date, int i) {
		Calendar cal = new GregorianCalendar();
		cal.setTime(date);
		cal.set(Calendar.DATE, cal.get(Calendar.DATE) + i);
		return cal.getTime();
	}
 
	// 返回某个日期前几天的日期
	public static Date getFrontDay(Date date, int i) {
		Calendar cal = new GregorianCalendar();
		cal.setTime(date);
		cal.set(Calendar.DATE, cal.get(Calendar.DATE) - i);
		return cal.getTime();
	}
 
	// 获取某年某月到某年某月按天的切片日期集合(间隔天数的集合)
	@SuppressWarnings({ "rawtypes", "unchecked" })
	public static List getTimeList(int beginYear, int beginMonth, int endYear,
			int endMonth, int k) {
		List list = new ArrayList();
		if (beginYear == endYear) {
			for (int j = beginMonth; j <= endMonth; j++) {
				list.add(getTimeList(beginYear, j, k));
			}
		} else {
			{
				for (int j = beginMonth; j < 12; j++) {
					list.add(getTimeList(beginYear, j, k));
				}
				for (int i = beginYear + 1; i < endYear; i++) {
					for (int j = 0; j < 12; j++) {
						list.add(getTimeList(i, j, k));
					}
				}
				for (int j = 0; j <= endMonth; j++) {
					list.add(getTimeList(endYear, j, k));
				}
			}
		}
		return list;
	}
 
	// 获取某年某月按天切片日期集合(某个月间隔多少天的日期集合)
	@SuppressWarnings({ "unchecked", "rawtypes" })
	public static List getTimeList(int beginYear, int beginMonth, int k) {
		List list = new ArrayList();
		Calendar begincal = new GregorianCalendar(beginYear, beginMonth, 1);
		int max = begincal.getActualMaximum(Calendar.DATE);
		for (int i = 1; i < max; i = i + k) {
			list.add(begincal.getTime());
			begincal.add(Calendar.DATE, k);
		}
		begincal = new GregorianCalendar(beginYear, beginMonth, max);
		list.add(begincal.getTime());
		return list;
	}