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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