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; 
 
 
public class DateUtils { 
 
  
 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(); 
  
  
  
 public static String formatDateToString(Date time, String format) { 
  SimpleDateFormat sdf = new SimpleDateFormat(format); 
  return sdf.format(time); 
 } 
 
  
 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()); 
  } 
 } 
 
  
 public static boolean isTimeInRange(Date time, Date[] timeRange) { 
  return (!time.before(timeRange[0]) && !time.after(timeRange[1])); 
 } 
 
  
 public static String getDateToMinute(String fullDateStr) { 
  return fullDateStr == null ? null 
    : (fullDateStr.length() >= dateLength ? fullDateStr.substring( 
      0, dateLength) : fullDateStr); 
 } 
 
  
 public static List getWeeksByYear(final int year) { 
  int weeks = getWeekNumOfYear(year); 
  List result = new ArrayList(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; 
 } 
 
  
 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; 
 } 
 
  
 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; 
 } 
 
  
 public static int getWeekNumOfYear(final int year) { 
  return getWeekNumOfYear(year, Calendar.MONDAY); 
 } 
 
  
 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(); 
 } 
 
  
 public static String getDateForDayOfWeek(int year, int weekOfYear, 
   int dayOfWeek) { 
  return getDateForDayOfWeek(year, weekOfYear, dayOfWeek, Calendar.MONDAY); 
 } 
 
  
 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); 
 } 
 
  
 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); 
 
 } 
 
  
 public static List getWeekDays(int yearNum, int weekNum) { 
  return getWeekDays(yearNum, weekNum, Calendar.MONDAY); 
 } 
 
  
 public static List getWeekDays(int year, int weekOfYear, 
   int firstDayOfWeek) { 
  List dates = new ArrayList(); 
  int dayOfWeek = firstDayOfWeek; 
  for (int i = 0; i < WEEK_DAYS; i++) { 
   dates.add(getDateForDayOfWeek(year, weekOfYear, dayOfWeek++, 
     firstDayOfWeek)); 
  } 
  return dates; 
 } 
 
  
 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; 
 } 
 
  
 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); 
 } 
 
  
 public static int getDaysGapOfDates(Date startDate, Date endDate) { 
  int date = 0; 
  if (startDate != null && endDate != null) { 
   date = getDaysBetween(startDate, endDate); 
  } 
  return date; 
 } 
 
  
 
 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; 
 } 
 
  
 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); 
 
 } 
 
  
 public static boolean isContainCurrent(List 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; 
 } 
 
  
 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; 
 } 
 
  
 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); 
 } 
 
  
 public static List 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); 
 } 
 
  
 public static List getTimePointsByHour(int[] hours) { 
  List hourPoints = new ArrayList(); 
  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; 
 } 
 
  
 public static Date addDays(Date date, int amount) { 
  return add(date, Calendar.DAY_OF_MONTH, amount); 
 } 
 
  
 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(); 
 } 
 
  
 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(); 
 } 
 
  
 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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