Java日期工具类DateUtils实例详解

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,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,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 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 firstDayOfWeek) { 
    List<String> dates = new ArrayList<String>(); 
    int dayOfWeek = firstDayOfWeek; 
    for (int i = 0; i < WEEK_DAYS; i++) { 
      dates.add(getDateForDayOfWeek(year,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,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,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(); 
  } 
 
}