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();
 }

}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。

原文链接：http://blog.csdn.net/a123demi/article/details/42100333