Java日期工具类DateUtils实例详解

在项目开发中，日期是我们必不可少的的一部分，本文将总结代码开发中的关于日期常用的一些方法，以方便自己后期使用。下面直接上菜了：

package com.example.util; 

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

/**
 * 日期常用方法
 *
 * @author
 *
 */
public class DateUtils { 

  /**
   * 常用变量
   */
  public static final String DATE_FORMAT_FULL = "yyyy-MM-dd HH:mm:ss";
  public static final String DATE_FORMAT_YMD = "yyyy-MM-dd";
  public static final String DATE_FORMAT_HMS = "HH:mm:ss";
  public static final String DATE_FORMAT_HM = "HH:mm";
  public static final String DATE_FORMAT_YMDHM = "yyyy-MM-dd HH:mm";
  public static final String DATE_FORMAT_YMDHMS = "yyyyMMddHHmmss";
  public static final long ONE_DAY_MILLS = 3600000 * 24;
  public static final int WEEK_DAYS = 7;
  private static final int dateLength = DATE_FORMAT_YMDHM.length(); 

  /**
   * 日期转换为制定格式字符串
   *
   * @param time
   * @param format
   * @return
   */
  public static String formatDateToString(Date time, String format) {
    SimpleDateFormat sdf = new SimpleDateFormat(format);
    return sdf.format(time);
  } 

  /**
   * 字符串转换为制定格式日期
   * (注意：当你输入的日期是2014-12-21 12:12，format对应的应为yyyy-MM-dd HH:mm
   * 否则异常抛出)
   * @param date
   * @param format
   * @return
   * @throws ParseException
   *       @
   */
  public static Date formatStringToDate(String date, String format) {
    SimpleDateFormat sdf = new SimpleDateFormat(format);
    try {
      return sdf.parse(date);
    } catch (ParseException ex) {
      ex.printStackTrace();
      throw new RuntimeException(ex.toString());
    }
  } 

  /**
   * 判断一个日期是否属于两个时段内
   * @param time
   * @param timeRange
   * @return
   */
  public static boolean isTimeInRange(Date time, Date[] timeRange) {
    return (!time.before(timeRange[0]) && !time.after(timeRange[1]));
  } 

  /**
   * 从完整的时间截取精确到分的时间
   *
   * @param fullDateStr
   * @return
   */
  public static String getDateToMinute(String fullDateStr) {
    return fullDateStr == null ? null
        : (fullDateStr.length() >= dateLength ? fullDateStr.substring(
            0, dateLength) : fullDateStr);
  } 

  /**
   * 返回指定年度的所有周。List中包含的是String[2]对象 string[0]本周的开始日期,string[1]是本周的结束日期。
   * 日期的格式为YYYY-MM-DD 每年的第一个周，必须包含星期一且是完整的七天。
   * 例如：2009年的第一个周开始日期为2009-01-05，结束日期为2009-01-11。 星期一在哪一年，那么包含这个星期的周就是哪一年的周。
   * 例如：2008-12-29是星期一，2009-01-04是星期日，哪么这个周就是2008年度的最后一个周。
   *
   * @param year
   *      格式 YYYY ，必须大于1900年度 小于9999年
   * @return @
   */
  public static List<String[]> getWeeksByYear(final int year) {
    int weeks = getWeekNumOfYear(year);
    List<String[]> result = new ArrayList<String[]>(weeks);
    int start = 1;
    int end = 7;
    for (int i = 1; i <= weeks; i++) {
      String[] tempWeek = new String[2];
      tempWeek[0] = getDateForDayOfWeek(year, i, start);
      tempWeek[1] = getDateForDayOfWeek(year, i, end);
      result.add(tempWeek);
    }
    return result;
  } 

  /**
   * 计算指定年、周的上一年、周
   *
   * @param year
   * @param week
   * @return @
   */
  public static int[] getLastYearWeek(int year, int week) {
    if (week <= 0) {
      throw new IllegalArgumentException("周序号不能小于1！！");
    }
    int[] result = { week, year };
    if (week == 1) {
      // 上一年
      result[1] -= 1;
      // 最后一周
      result[0] = getWeekNumOfYear(result[1]);
    } else {
      result[0] -= 1;
    }
    return result;
  } 

  /**
   * 下一个[周，年]
   *
   * @param year
   * @param week
   * @return @
   */
  public static int[] getNextYearWeek(int year, int week) {
    if (week <= 0) {
      throw new IllegalArgumentException("周序号不能小于1！！");
    }
    int[] result = { week, year };
    int weeks = getWeekNumOfYear(year);
    if (week == weeks) {
      // 下一年
      result[1] += 1;
      // 第一周
      result[0] = 1;
    } else {
      result[0] += 1;
    }
    return result;
  } 

  /**
   * 计算指定年度共有多少个周。(从周一开始)
   *
   * @param year
   * @return @
   */
  public static int getWeekNumOfYear(final int year) {
    return getWeekNumOfYear(year, Calendar.MONDAY);
  } 

  /**
   * 计算指定年度共有多少个周。
   *
   * @param year
   *      yyyy
   * @return @
   */
  public static int getWeekNumOfYear(final int year, int firstDayOfWeek) {
    // 每年至少有52个周 ，最多有53个周。
    int minWeeks = 52;
    int maxWeeks = 53;
    int result = minWeeks;
    int sIndex = 4;
    String date = getDateForDayOfWeek(year, maxWeeks, firstDayOfWeek);
    // 判断年度是否相符，如果相符说明有53个周。
    if (date.substring(0, sIndex).equals(year)) {
      result = maxWeeks;
    }
    return result;
  } 

  public static int getWeeksOfWeekYear(final int year) {
    Calendar cal = Calendar.getInstance();
    cal.setFirstDayOfWeek(Calendar.MONDAY);
    cal.setMinimalDaysInFirstWeek(WEEK_DAYS);
    cal.set(Calendar.YEAR, year);
    return cal.getWeeksInWeekYear();
  } 

  /**
   * 获取指定年份的第几周的第几天对应的日期yyyy-MM-dd(从周一开始)
   *
   * @param year
   * @param weekOfYear
   * @param dayOfWeek
   * @return yyyy-MM-dd 格式的日期 @
   */
  public static String getDateForDayOfWeek(int year, int weekOfYear,
      int dayOfWeek) {
    return getDateForDayOfWeek(year, weekOfYear, dayOfWeek, Calendar.MONDAY);
  } 

  /**
   * 获取指定年份的第几周的第几天对应的日期yyyy-MM-dd，指定周几算一周的第一天（firstDayOfWeek）
   *
   * @param year
   * @param weekOfYear
   * @param dayOfWeek
   * @param firstDayOfWeek
   *      指定周几算一周的第一天
   * @return yyyy-MM-dd 格式的日期
   */
  public static String getDateForDayOfWeek(int year, int weekOfYear,
      int dayOfWeek, int firstDayOfWeek) {
    Calendar cal = Calendar.getInstance();
    cal.setFirstDayOfWeek(firstDayOfWeek);
    cal.set(Calendar.DAY_OF_WEEK, dayOfWeek);
    cal.setMinimalDaysInFirstWeek(WEEK_DAYS);
    cal.set(Calendar.YEAR, year);
    cal.set(Calendar.WEEK_OF_YEAR, weekOfYear);
    return formatDateToString(cal.getTime(), DATE_FORMAT_YMD);
  } 

  /**
   * 获取指定日期星期几
   *
   * @param datetime
   * @throws ParseException
   *       @
   */
  public static int getWeekOfDate(String datetime) throws ParseException {
    Calendar cal = Calendar.getInstance();
    cal.setFirstDayOfWeek(Calendar.MONDAY);
    cal.setMinimalDaysInFirstWeek(WEEK_DAYS);
    Date date = formatStringToDate(datetime, DATE_FORMAT_YMD);
    cal.setTime(date);
    return cal.get(Calendar.DAY_OF_WEEK); 

  } 

  /**
   * 计算某年某周内的所有日期(从周一开始 为每周的第一天)
   *
   * @param yearNum
   * @param weekNum
   * @return @
   */
  public static List<String> getWeekDays(int yearNum, int weekNum) {
    return getWeekDays(yearNum, weekNum, Calendar.MONDAY);
  } 

  /**
   * 计算某年某周内的所有日期(七天)
   *
   * @param yearNum
   * @param weekNum
   * @return yyyy-MM-dd 格式的日期列表
   */
  public static List<String> getWeekDays(int year, int weekOfYear,
      int firstDayOfWeek) {
    List<String> dates = new ArrayList<String>();
    int dayOfWeek = firstDayOfWeek;
    for (int i = 0; i < WEEK_DAYS; i++) {
      dates.add(getDateForDayOfWeek(year, weekOfYear, dayOfWeek++,
          firstDayOfWeek));
    }
    return dates;
  } 

  /**
   * 获取目标日期的上周、或本周、或下周的年、周信息
   *
   * @param queryDate
   *      传入的时间
   * @param weekOffset
   *      -1:上周 0:本周 1:下周
   * @param firstDayOfWeek
   *      每周以第几天为首日
   * @return
   * @throws ParseException
   */
  public static int[] getWeekAndYear(String queryDate, int weekOffset,
      int firstDayOfWeek) throws ParseException { 

    Date date = formatStringToDate(queryDate, DATE_FORMAT_YMD);
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(date);
    calendar.setFirstDayOfWeek(firstDayOfWeek);
    calendar.setMinimalDaysInFirstWeek(WEEK_DAYS);
    int year = calendar.getWeekYear();
    int week = calendar.get(Calendar.WEEK_OF_YEAR);
    int[] result = { week, year };
    switch (weekOffset) {
    case 1:
      result = getNextYearWeek(year, week);
      break;
    case -1:
      result = getLastYearWeek(year, week);
      break;
    default:
      break;
    }
    return result;
  } 

  /**
   * 计算个两日期的天数
   *
   * @param startDate
   *      开始日期字串
   * @param endDate
   *      结束日期字串
   * @return
   * @throws ParseException
   */
  public static int getDaysBetween(String startDate, String endDate)
      throws ParseException {
    int dayGap = 0;
    if (startDate != null && startDate.length() > 0 && endDate != null
        && endDate.length() > 0) {
      Date end = formatStringToDate(endDate, DATE_FORMAT_YMD);
      Date start = formatStringToDate(startDate, DATE_FORMAT_YMD);
      dayGap = getDaysBetween(start, end);
    }
    return dayGap;
  } 

  private static int getDaysBetween(Date startDate, Date endDate) {
    return (int) ((endDate.getTime() - startDate.getTime()) / ONE_DAY_MILLS);
  } 

  /**
   * 计算两个日期之间的天数差
   * @param startDate
   * @param endDate
   * @return
   */
  public static int getDaysGapOfDates(Date startDate, Date endDate) {
    int date = 0;
    if (startDate != null && endDate != null) {
      date = getDaysBetween(startDate, endDate);
    }
    return date;
  } 

  /**
   * 计算两个日期之间的年份差距
   *
   * @param firstDate
   * @param secondDate
   * @return
   */ 

  public static int getYearGapOfDates(Date firstDate, Date secondDate) {
    if (firstDate == null || secondDate == null) {
      return 0;
    }
    Calendar helpCalendar = Calendar.getInstance();
    helpCalendar.setTime(firstDate);
    int firstYear = helpCalendar.get(Calendar.YEAR);
    helpCalendar.setTime(secondDate);
    int secondYear = helpCalendar.get(Calendar.YEAR);
    return secondYear - firstYear;
  } 

  /**
   * 计算两个日期之间的月份差距
   *
   * @param firstDate
   * @param secondDate
   * @return
   */
  public static int getMonthGapOfDates(Date firstDate, Date secondDate) {
    if (firstDate == null || secondDate == null) {
      return 0;
    } 

    return (int) ((secondDate.getTime() - firstDate.getTime())
        / ONE_DAY_MILLS / 30); 

  } 

  /**
   * 计算是否包含当前日期
   *
   * @param datys
   * @return
   */
  public static boolean isContainCurrent(List<String> dates) {
    boolean flag = false;
    SimpleDateFormat fmt = new SimpleDateFormat(DATE_FORMAT_YMD);
    Date date = new Date();
    String dateStr = fmt.format(date);
    for (int i = 0; i < dates.size(); i++) {
      if (dateStr.equals(dates.get(i))) {
        flag = true;
      }
    }
    return flag;
  } 

  /**
   * 从date开始计算time天后的日期
   *
   * @param date
   * @param time
   * @return
   * @throws ParseException
   */
  public static String getCalculateDateToString(String startDate, int time)
      throws ParseException {
    String resultDate = null;
    if (startDate != null && startDate.length() > 0) {
      Date date = formatStringToDate(startDate, DATE_FORMAT_YMD);
      Calendar c = Calendar.getInstance();
      c.setTime(date);
      c.set(Calendar.DAY_OF_YEAR, time);
      date = c.getTime();
      resultDate = formatDateToString(date, DATE_FORMAT_YMD);
    }
    return resultDate;
  } 

  /**
   * 获取从某日期开始计算，指定的日期所在该年的第几周
   *
   * @param date
   * @param admitDate
   * @return
   * @throws ParseException
   *       @
   */
  public static int[] getYearAndWeeks(String date, String admitDate)
      throws ParseException {
    Calendar c = Calendar.getInstance();
    c.setTime(formatStringToDate(admitDate, DATE_FORMAT_YMD));
    int time = c.get(Calendar.DAY_OF_WEEK);
    return getWeekAndYear(date, 0, time);
  } 

  /**
   * 获取指定日期refDate，前或后一周的所有日期
   *
   * @param refDate
   *      参考日期
   * @param weekOffset
   *      -1:上周 0:本周 1:下周
   * @param startDate
   *      哪天算一周的第一天
   * @return yyyy-MM-dd 格式的日期
   * @throws ParseException
   *       @
   */
  public static List<String> getWeekDaysAroundDate(String refDate,
      int weekOffset, String startDate) throws ParseException {
    // 以startDate为一周的第一天
    Calendar c = Calendar.getInstance();
    c.setTime(formatStringToDate(startDate, DATE_FORMAT_YMD));
    int firstDayOfWeek = c.get(Calendar.DAY_OF_WEEK);
    // 获取相应周
    int[] weekAndYear = getWeekAndYear(refDate, weekOffset, firstDayOfWeek);
    // 获取相应周的所有日期
    return getWeekDays(weekAndYear[1], weekAndYear[0], firstDayOfWeek);
  } 

  /**
   * 根据时间点获取时间区间
   *
   * @param hours
   * @return
   */
  public static List<String[]> getTimePointsByHour(int[] hours) {
    List<String[]> hourPoints = new ArrayList<String[]>();
    String sbStart = ":00:00";
    String sbEnd = ":59:59";
    for (int i = 0; i < hours.length; i++) {
      String[] times = new String[2];
      times[0] = hours[i] + sbStart;
      times[1] = (hours[(i + 1 + hours.length) % hours.length] - 1)
          + sbEnd;
      hourPoints.add(times);
    }
    return hourPoints;
  } 

  /**
   *
   * 根据指定的日期，增加或者减少天数
   *
   * @param date
   * @param amount
   * @return
   */
  public static Date addDays(Date date, int amount) {
    return add(date, Calendar.DAY_OF_MONTH, amount);
  } 

  /**
   * 根据指定的日期，类型，增加或减少数量
   *
   * @param date
   * @param calendarField
   * @param amount
   * @return
   */
  public static Date add(Date date, int calendarField, int amount) {
    if (date == null) {
      throw new IllegalArgumentException("The date must not be null");
    }
    Calendar c = Calendar.getInstance();
    c.setTime(date);
    c.add(calendarField, amount);
    return c.getTime();
  } 

  /**
   * 获取当前日期的最大日期 时间2014-12-21 23:59:59
   * @return
   */
  public static Date getCurDateWithMaxTime() {
    Calendar c = Calendar.getInstance();
    c.set(Calendar.HOUR_OF_DAY, 23);
    c.set(Calendar.MINUTE, 59);
    c.set(Calendar.SECOND, 59);
    return c.getTime();
  } 

  /**
   * 获取当前日期的最小日期时间 2014-12-21 00:00:00
   * @return
   */
  public static Date getCurDateWithMinTime() {
    Calendar c = Calendar.getInstance();
    c.set(Calendar.HOUR_OF_DAY, 0);
    c.set(Calendar.MINUTE, 0);
    c.set(Calendar.SECOND, 0);
    c.set(Calendar.MILLISECOND, 0);
    return c.getTime();
  } 

} 

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