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武林网。