Java日期工具类DateUtils实例详解

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yyhttp://yy-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(fohttp://rmat);

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 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;

}

/**

* 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 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 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;

}

/**

* 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 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 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 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;

}

/**

*

* 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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