辅助工具，日期计算

DateUtil.java

package org.jar.tools.util;

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

/**
 * 日期操作: 性能不高. 线程安全
 */
public class DateUtil {

	protected static final ThreadLocal<Calendar> CALENDAR = new ThreadLocal<Calendar>() {
		@Override
		protected Calendar initialValue() {
			return Calendar.getInstance();
		}
	};

	protected static final ThreadLocal<Date> DATE = new ThreadLocal<Date>() {
		@Override
		protected Date initialValue() {
			return new Date();
		}
	};

	static final ThreadLocal<SimpleDateFormat> _buildSDF(final String fmt) {
		return new ThreadLocal<SimpleDateFormat>() {
			@Override
			protected SimpleDateFormat initialValue() {
				return new SimpleDateFormat(fmt);
			}
		};
	}

	protected static final ThreadLocal<SimpleDateFormat> DATE_FORMAT_YYYYMM = _buildSDF("yyyyMM");
	protected static final ThreadLocal<SimpleDateFormat> DATE_FORMAT_DAY_ONLY = _buildSDF("yyyyMMdd");
	protected static final ThreadLocal<SimpleDateFormat> DATE_FORMAT_YYYY_MM_DD = _buildSDF("yyyy-MM-dd");
	protected static final ThreadLocal<SimpleDateFormat> DATE_FORMAT_YYYY_MM = _buildSDF("yyyy-MM");
	protected static final ThreadLocal<SimpleDateFormat> DATE_FORMAT_FULL = _buildSDF("yyyy/MM/dd HH:mm:ss");
	protected static final ThreadLocal<SimpleDateFormat> DATE_FORMAT_FULL2 = _buildSDF("yyyy-MM-dd HH:mm:ss");
	protected static final ThreadLocal<SimpleDateFormat> DATE_FORMAT_FULL3 = _buildSDF("yyyyMMddHHmmss");

	/** 当前月的天数 */
	public static int kit_daysOfMonth(Date date) {
		return kit_daysOfMonth(date, true);
	}

	/**
	 * 指定日期所在月的天数
	 *
	 * @param date       日期
	 * @param resetEarly 是否初始化到月初
	 * @return 天数
	 */
	public static int kit_daysOfMonth(Date date, boolean resetEarly) {
		Calendar c = CALENDAR.get();

		c.setTime(date);
		if (resetEarly)
			c.set(Calendar.DAY_OF_MONTH, 1);
		final long t1 = c.getTimeInMillis();
		c.add(Calendar.MONTH, 1);
		c.set(Calendar.DAY_OF_MONTH, 1);
		final long t2 = c.getTimeInMillis();
		return (int) ((t2 - t1) / DateTimeUtil.MILLIS_ONE_DAY);
	}

	/** 获取加减后的日期 */
	public static Date kit_dateAdd(Date date, int year, int month, int days) {
		Calendar c = CALENDAR.get();

		c.setTime(date);
		c.add(Calendar.YEAR, year);
		c.add(Calendar.MONTH, month);
		c.add(Calendar.DAY_OF_MONTH, days);
		return c.getTime();
	}

	/**
	 * 日期增加，并截断尾巴（以非0字段截断）
	 *
	 * @param date  当前日期
	 * @param year  年
	 * @param month 月
	 * @param days  日
	 */
	public static Date kit_dateAddToStart(Date date, int year, int month, int days) {
		Calendar c = CALENDAR.get();

		c.setTime(date);
		int level = 0;
		boolean last = false;
		if (year != 0) {
			c.add(Calendar.YEAR, year);
			level = Calendar.YEAR;
			last = year < 0 && c.get(Calendar.MONTH) != 0;
		}
		if (month != 0) {
			c.add(Calendar.MONTH, month);
			level = Calendar.MONTH;
			//inc = month;
			last = month < 0 && c.get(Calendar.DAY_OF_MONTH) != 1;
		}
		if (days != 0) {
			c.add(Calendar.DAY_OF_MONTH, days);
			level = Calendar.DAY_OF_MONTH;
			last = false;
		}
		if (level != 0) {
			if (last)
				c.add(level, 1);
			if (level <= Calendar.DAY_OF_MONTH) {
				c.set(Calendar.HOUR_OF_DAY, 0);
				c.set(Calendar.MINUTE, 0);
				c.set(Calendar.SECOND, 0);
			}
			if (level <= Calendar.MONTH)
				c.set(Calendar.DAY_OF_MONTH, 1);
			if (level <= Calendar.YEAR)
				c.set(Calendar.MONTH, 0);
		}
		return c.getTime();
	}

	/** 获取下一个月的月初日期(1号) */
	public static Date kit_dateNextMonthStart(Date date) {
		Calendar c = CALENDAR.get();

		c.setTime(date);
		c.add(Calendar.MONTH, 1);
		c.set(Calendar.DAY_OF_MONTH, 1);
		return c.getTime();
	}

	/** 获取下一个季度 */
	public static Date kit_dateNextQuarterlyStart(Date date) {
		Calendar c = CALENDAR.get();

		c.setTime(date);
		int m = c.get(Calendar.MONTH);
		m += 3 - m % 3;
		c.set(Calendar.MONTH, m);
		c.set(Calendar.DAY_OF_MONTH, 1);
		return c.getTime();
	}

	/** 获取下一年初始日期 */
	public static Date kit_dateNextYearStart(Date date) {
		Calendar c = CALENDAR.get();

		c.setTime(date);
		c.add(Calendar.YEAR, 1);
		c.set(Calendar.MONTH, 0);
		c.set(Calendar.DAY_OF_MONTH, 1);
		return c.getTime();
	}

	public static String kit_nextMonthStart_yyyyMMdd(String s) {
		Date d1 = kit_parseYYYYMMdd(s);
		if (d1 != null) {
			Date d2 = kit_dateNextMonthStart(d1);
			return kit_dateYYYYMMdd(d2);
		}
		return null;
	}

	/** 获取当月初始日期 */
	public static Date kit_dateMonthStart(Date date) {
		Calendar c = CALENDAR.get();

		c.setTime(date);
		c.set(Calendar.DAY_OF_MONTH, 1);
		return c.getTime();
	}

	/** 获取当年初始日期 */
	public static Date kit_dateYearStart(Date date) {
		Calendar c = CALENDAR.get();

		c.setTime(date);
		c.set(Calendar.MONTH, 0);
		c.set(Calendar.DAY_OF_MONTH, 1);
		return c.getTime();
	}

	/** 返回 b-a 的天数 */
	public static int kit_daysDiff(Date a, Date b) {
		long s_day = DateTimeUtil.second2Day(a.getTime());
		long e_day = DateTimeUtil.second2Day(b.getTime());
		return (int) (e_day - s_day);
	}

	/** 返回 b-a 的月份(不足1月也凑整) */
	public static int kit_monthDiff(Date a, Date b) {
		Calendar c = CALENDAR.get();

		c.setTime(a);
		int aY = c.get(Calendar.YEAR);
		int aM = c.get(Calendar.MONTH);
		int aD = c.get(Calendar.DAY_OF_MONTH);
		c.setTime(b);
		int bY = c.get(Calendar.YEAR);
		int bM = c.get(Calendar.MONTH);
		int bD = c.get(Calendar.DAY_OF_MONTH);
		int sum = (bY - aY) * 12 + (bM - aM);
		if (sum >= 0 && bD > aD) sum++;
		if (sum <= 0 && bD < aD) sum--;
		return sum;
	}

	/** 返回 b-a 的季度(不足1月也凑整) */
//	public static int kit_quarterlyDiff(Date a, Date b) {
//		return 0;
//	}

	/** 返回 b-a 的年份(不足1年也凑整) */
	public static int kit_yearDiff(Date a, Date b) {
		Calendar c = CALENDAR.get();
		c.setTime(a);
		int aY = c.get(Calendar.YEAR);
		int aD = c.get(Calendar.DAY_OF_YEAR);
		c.setTime(b);
		int bY = c.get(Calendar.YEAR);
		int bD = c.get(Calendar.DAY_OF_YEAR);
		int sum = bY - aY;
		if (aD != bD) {
			if (aD < bD && sum > 0) sum++;
			if (aD > bD && sum < 0) sum--;
		}
		return sum;
	}


	/** 日期加减 */
	public static Date kit_addDay(Date date, int days) {
		return kit_dateAdd(date, 0, 0, days);
	}

	public static Date kit_addMonth(Date date, int months) {
		return kit_dateAdd(date, 0, months, 0);
	}

	public static int get_hour(Date date) {
		Calendar c = CALENDAR.get();
		c.setTime(date);
		return c.get(Calendar.HOUR_OF_DAY);
	}

	public static int get_day(Date date) {
		Calendar c = CALENDAR.get();
		c.setTime(date);
		return c.get(Calendar.DAY_OF_MONTH);
	}

	/** 取较早的日期 */
	public static Date min(Date a, Date b) {
		return a.before(b) ? a : b;
	}

	public static Date max(Date a, Date b) {
		return b.after(a) ? b : a;
	}

	/*- - - - - - - - - - - - - - - - - 日期解析 - - - - - - - - - - - - - - - -*/


	private static Pattern PATTERN_DATA_ONLY_DAY = Pattern.compile("^(\\d{1,2})\\D(\\d{1,2})\\D?$");

	/**
	 * 按 月？日？ 格式解析
	 */
	protected static Date kit_dateParseMissYear(int year, String sDay) {
		Matcher m = PATTERN_DATA_ONLY_DAY.matcher(sDay);
		if (m.find()) {
			Calendar c = CALENDAR.get();
			int month = Integer.parseInt(m.group(1)) - 1;
			int date = Integer.parseInt(m.group(2));
			c.set(year, month, date, 0, 0, 0);
			return c.getTime();
		}
		return null;
	}

	protected static String kit_dateFormat(SimpleDateFormat sdf, Date date) {
		return sdf.format(date);
	}

	protected static String kit_dateFormat(ThreadLocal<SimpleDateFormat> sdf, Date date) {
		return kit_dateFormat(sdf.get(), date);
	}

	protected static Date kit_dateParse(SimpleDateFormat sdf, String s) {
		if (s != null && s.length() > 0) {
			try {
				return sdf.parse(s.trim());
			} catch (ParseException e) {
				System.err.println("s=" + s);
				e.printStackTrace();
			}
		}
		return null;
	}

	protected static Date kit_dateParse(ThreadLocal<SimpleDateFormat> sdf, String s) {
		return kit_dateParse(sdf.get(), s);
	}

	/** 格式: yyyyMMdd */
	public static String kit_dateYYYYMMdd(Date date) {
		return kit_dateFormat(DATE_FORMAT_DAY_ONLY, date);
	}

	/** 格式: yyyyMMdd */
	public static Date kit_parseYYYYMMdd(String s) {
		return kit_dateParse(DATE_FORMAT_DAY_ONLY, s);
	}

	/** 按天解析 yyyy-MM-dd */
	public static String kit_dateYYYY_MM_dd(Date date) {
		return kit_dateFormat(DATE_FORMAT_YYYY_MM_DD, date);
	}

	/** 格式: yyyy-MM-dd */
	public static Date kit_parseYYYY_MM_dd(String s) {
		return kit_dateParse(DATE_FORMAT_YYYY_MM_DD, s);
	}

	/** 按月,格式: yyyyMM */
	public static String kit_dateYYYYMM(Date date) {
		return kit_dateFormat(DATE_FORMAT_YYYYMM, date);
	}

	/** 按月解析,格式: yyyyMM */
	public static Date kit_parseYYYYMM(String s) {
		return kit_dateParse(DATE_FORMAT_YYYYMM, s);
	}

	/** 按月,格式: yyyy-MM */
	public static String kit_dateYYYY_MM(Date date) {
		return kit_dateFormat(DATE_FORMAT_YYYY_MM, date);
	}

	/** 按月解析,格式: yyyy-MM */
	public static Date kit_parseYYYY_MM(String s) {
		return kit_dateParse(DATE_FORMAT_YYYY_MM, s);
	}

	/** 完整时间,格式: yyyy/MM/dd HH:mm:ss */
	public static Date parseDate_Full(String s) {
		return kit_dateParse(DATE_FORMAT_FULL, s);
	}

	/** 完整时间,格式: yyyy/MM/dd HH:mm:ss */
	public static String kit_dateFull(Date date) {
		return kit_dateFormat(DATE_FORMAT_FULL, date);
	}

	/** 完整时间,格式: yyyy/MM/dd HH:mm:ss */
	public static String kit_dateFull(long tick) {
		Date d = DATE.get();
		d.setTime(tick);
		return kit_dateFull(d);
	}

	/** 完整时间2,格式: yyyy-MM-dd HH:mm:ss */
	public static Date parseDate_Full2(String s) {
		return kit_dateParse(DATE_FORMAT_FULL2, s);
	}

	/** 完整时间2,格式: yyyy-MM-dd HH:mm:ss */
	public static String kit_dateFull2(Date date) {
		return kit_dateFormat(DATE_FORMAT_FULL2, date);
	}

	/** 完整时间3,格式: yyyyMMddHHmmss */
	public static Date parseDate_Full3(String s) {
		return kit_dateParse(DATE_FORMAT_FULL3, s);
	}

	/** 完整时间3,格式: yyyyMMddHHmmss */
	public static String kit_dateFull3(Date date) {
		return kit_dateFormat(DATE_FORMAT_FULL3, date);
	}

	/** 完整时间3,格式: yyyyMMddHHmmss */
	public static String kit_dateFull3(long tick) {
		Date d = DATE.get();
		d.setTime(tick);
		return kit_dateFull3(d);
	}


	/** 解析紧凑型日期，如 yyyy（年） 或 yyyyMM（月） 或 yyyyMMdd（天），如果 wantNext 为 true，则根据类型，找到下一周期的日期 */
	public static Date parseDate_compact(String s, boolean wantNext) {
		if (s != null) {
			if (s.length() == 8) { // yyyyMMdd
				Date d = DateUtil.kit_parseYYYYMMdd(s);
				if (wantNext)
					d = DateUtil.kit_addDay(d, 1);
				return d;
			}
			if (s.length() == 6) { // yyyyMM
				Date d = DateUtil.kit_parseYYYYMM(s);
				if (wantNext)
					d = DateUtil.kit_dateNextMonthStart(d);
				return d;
			}
			if (s.length() == 4) { // yyyy
				Calendar c = CALENDAR.get();
				c.clear();
				c.set(Integer.parseInt(s), 0, 1);
				if (wantNext)
					c.add(Calendar.YEAR, 1);
				return c.getTime();
			}
		}
		return null;
	}

	public static Date kit_parseDate(String fmt, String s) {
		return kit_dateParse(new SimpleDateFormat(fmt), s);
	}

	public static String kit_formatDate(String fmt, Date d) {
		return kit_dateFormat(new SimpleDateFormat(fmt), d);
	}

	/*- - - - - - - - - - - - - - - - - 调试辅助 - - - - - - - - - - - - - - - - */

	public static long debug_tick() {
		return System.currentTimeMillis();
	}

	public static float debug_tick(long t0) {
		return (System.currentTimeMillis() - t0) / 1000f;
	}

	/*- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -*/

	public static void main(String[] args) {


//		System.out.println(kit_dateFlag(kit_parseYYYYMM("201501"), kit_parseYYYYMM("201709"), DATE_FORMAT_DAY_ONLY.get()));
//		System.out.println("days="+kit_daysOfMonth(kit_parseYYYYMMdd("20180229"),false));
//		System.out.println("month="+kit_monthDiff( kit_parseYYYYMMdd("20171128"),kit_parseYYYYMMdd("20180321")));
//		System.out.println("month="+kit_monthDiff( kit_parseYYYYMMdd("20171128"),kit_parseYYYYMMdd("20180328")));
//		System.out.println("month="+kit_monthDiff( kit_parseYYYYMMdd("20171128"),kit_parseYYYYMMdd("20180329")));
//		System.out.println("month="+kit_monthDiff( kit_parseYYYYMMdd("20180430"),kit_parseYYYYMMdd("20180329")));
//		System.out.println("month=" + kit_dateYYYYMMdd(kit_dateNextQuarterlyStart(kit_parseYYYYMMdd("20180129"))));
//		System.out.println("month=" + kit_dateYYYYMMdd(kit_dateNextQuarterlyStart(kit_parseYYYYMMdd("20180429"))));
//		System.out.println("month=" + kit_dateYYYYMMdd(kit_dateNextQuarterlyStart(kit_parseYYYYMMdd("20181129"))));

		System.out.println("day=" + kit_dateYYYYMMdd(kit_dateAddToStart(kit_parseYYYYMMdd("20181129"), 1, 0, 0)));
		System.out.println("day=" + kit_dateYYYYMMdd(kit_dateAddToStart(kit_parseYYYYMMdd("20181129"), 0, -1, 0)));
		System.out.println("day=" + kit_dateYYYYMMdd(kit_dateAddToStart(kit_parseYYYYMMdd("20181129"), 5, -2, 0)));
		System.out.println("day=" + kit_dateYYYYMMdd(kit_dateAddToStart(kit_parseYYYYMMdd("20180601"), 0, 2, 0)));
		System.out.println("day=" + kit_dateYYYYMMdd(kit_dateAddToStart(kit_parseYYYYMMdd("20180611"), 0, -2, 0)));
		System.out.println("day=" + kit_dateYYYYMMdd(kit_dateAddToStart(kit_parseYYYYMMdd("20180601"), 0, -2, 0)));

	}
}