这里的其他答案涉及Joda API。
我想使用java.time来完成。
假设今天是2015年11月26日星期四，当我在这个日期上加2个工作日时， 我希望结果为2015年11月30日星期一。
我正在做自己的实现，但如果已经存在某些东西，那将是很好的！
编辑：
除了循环以外，还有其他方法吗？
我试图得出一个像这样的函数：
Y = f(X1,X2) where
Y is actual number of days to add,
X1 is number of business days to add,
X2 is day of the week (1-Monday to 7-Sunday)
然后，鉴于日期的星期几派生出X1和X2，我们可以找到Y，然后使用LocalDate的plusDays()方法。
到目前为止我还没能够推导出来它，它并不一致。有人能确认循环增加到需要的工作日是唯一的方法吗？
workdays的天数逐一添加工作日（跳过周末）：public LocalDate add(LocalDate date, int workdays) {
if (workdays < 1) {
return date;
}
LocalDate result = date;
int addedDays = 0;
while (addedDays < workdays) {
result = result.plusDays(1);
if (!(result.getDayOfWeek() == DayOfWeek.SATURDAY ||
result.getDayOfWeek() == DayOfWeek.SUNDAY)) {
++addedDays;
}
}
return result;
}
经过一番摸索，我想出了一个算法来计算需要增加或减少的工作日数。
/**
* @param dayOfWeek
* The day of week of the start day. The values are numbered
* following the ISO-8601 standard, from 1 (Monday) to 7
* (Sunday).
* @param businessDays
* The number of business days to count from the day of week. A
* negative number will count days in the past.
*
* @return The absolute (positive) number of days including weekends.
*/
public long getAllDays(int dayOfWeek, long businessDays) {
long result = 0;
if (businessDays != 0) {
boolean isStartOnWorkday = dayOfWeek < 6;
long absBusinessDays = Math.abs(businessDays);
if (isStartOnWorkday) {
// if negative businessDays: count backwards by shifting weekday
int shiftedWorkday = businessDays > 0 ? dayOfWeek : 6 - dayOfWeek;
result = absBusinessDays + (absBusinessDays + shiftedWorkday - 1) / 5 * 2;
} else { // start on weekend
// if negative businessDays: count backwards by shifting weekday
int shiftedWeekend = businessDays > 0 ? dayOfWeek : 13 - dayOfWeek;
result = absBusinessDays + (absBusinessDays - 1) / 5 * 2 + (7 - shiftedWeekend);
}
}
return result;
}
使用示例：
LocalDate startDate = LocalDate.of(2015, 11, 26);
int businessDays = 2;
LocalDate endDate = startDate.plusDays(getAllDays(startDate.getDayOfWeek().getValue(), businessDays));
System.out.println(startDate + (businessDays > 0 ? " plus " : " minus ") + Math.abs(businessDays)
+ " business days: " + endDate);
businessDays = -6;
endDate = startDate.minusDays(getAllDays(startDate.getDayOfWeek().getValue(), businessDays));
System.out.println(startDate + (businessDays > 0 ? " plus " : " minus ") + Math.abs(businessDays)
+ " business days: " + endDate);
示例输出：
2015-11-26 加上2个工作日：2015-11-30
2015-11-26 减去6个工作日：2015-11-18
这是一个支持正数和负数天数的版本，并将操作公开为TemporalAdjuster。这使您可以编写以下代码：
LocalDate datePlus2WorkingDays = date.with(addWorkingDays(2));
代码：
/**
* Returns the working day adjuster, which adjusts the date to the n-th following
* working day (i.e. excluding Saturdays and Sundays).
* <p>
* If the argument is 0, the same date is returned if it is a working day otherwise the
* next working day is returned.
*
* @param workingDays the number of working days to add to the date, may be negative
*
* @return the working day adjuster, not null
*/
public static TemporalAdjuster addWorkingDays(long workingDays) {
return TemporalAdjusters.ofDateAdjuster(d -> addWorkingDays(d, workingDays));
}
private static LocalDate addWorkingDays(LocalDate startingDate, long workingDays) {
if (workingDays == 0) return nextOrSameWorkingDay(startingDate);
LocalDate result = startingDate;
int step = Long.signum(workingDays); //are we going forward or backward?
for (long i = 0; i < Math.abs(workingDays); i++) {
result = nextWorkingDay(result, step);
}
return result;
}
private static LocalDate nextOrSameWorkingDay(LocalDate date) {
return isWeekEnd(date) ? nextWorkingDay(date, 1) : date;
}
private static LocalDate nextWorkingDay(LocalDate date, int step) {
do {
date = date.plusDays(step);
} while (isWeekEnd(date));
return date;
}
private static boolean isWeekEnd(LocalDate date) {
DayOfWeek dow = date.getDayOfWeek();
return dow == SATURDAY || dow == SUNDAY;
}
这是使用java.time类、一些函数式接口和lambda表达式添加工作日的方法...
IntFunction<TemporalAdjuster> addBusinessDays = days -> TemporalAdjusters.ofDateAdjuster(
date -> {
LocalDate baseDate =
days > 0 ? date.with(TemporalAdjusters.previousOrSame(DayOfWeek.MONDAY))
: days < 0 ? date.with(TemporalAdjusters.nextOrSame(DayOfWeek.FRIDAY)) : date;
int businessDays = days + Math.min(Math.max(baseDate.until(date).getDays(), -4), 4);
return baseDate.plusWeeks(businessDays / 5).plusDays(businessDays % 5);
});
LocalDate.of(2018, 1, 5).with(addBusinessDays.apply(2));
//Friday Jan 5, 2018 -> Tuesday Jan 9, 2018
LocalDate.of(2018, 1, 6).with(addBusinessDays.apply(15));
//Saturday Jan 6, 2018 -> Friday Jan 26, 2018
LocalDate.of(2018, 1, 7).with(addBusinessDays.apply(-10));
//Sunday Jan 7, 2018 -> Monday Dec 25, 2017
支持负值和任何一周的日期！
/**
* This method adds workdays (MONDAY - FRIDAY) to a given calendar object.
* If the number of days is negative than this method subtracts the working
* days from the calendar object.
*
*
* @param cal
* @param days
* @return new calendar instance
*/
public static Calendar addWorkDays(final Calendar baseDate, final int days) {
Calendar resultDate = null;
Calendar workCal = Calendar.getInstance();
workCal.setTime(baseDate.getTime());
int currentWorkDay = workCal.get(Calendar.DAY_OF_WEEK);
// test if SATURDAY ?
if (currentWorkDay == Calendar.SATURDAY) {
// move to next FRIDAY
workCal.add(Calendar.DAY_OF_MONTH, (days < 0 ? -1 : +2));
currentWorkDay = workCal.get(Calendar.DAY_OF_WEEK);
}
// test if SUNDAY ?
if (currentWorkDay == Calendar.SUNDAY) {
// move to next FRIDAY
workCal.add(Calendar.DAY_OF_MONTH, (days < 0 ? -2 : +1));
currentWorkDay = workCal.get(Calendar.DAY_OF_WEEK);
}
// test if we are in a working week (should be so!)
if (currentWorkDay >= Calendar.MONDAY && currentWorkDay <= Calendar.FRIDAY) {
boolean inCurrentWeek = false;
if (days > 0)
inCurrentWeek = (currentWorkDay + days < 7);
else
inCurrentWeek = (currentWorkDay + days > 1);
if (inCurrentWeek) {
workCal.add(Calendar.DAY_OF_MONTH, days);
resultDate = workCal;
} else {
int totalDays = 0;
int daysInCurrentWeek = 0;
// fill up current week.
if (days > 0) {
daysInCurrentWeek = Calendar.SATURDAY - currentWorkDay;
totalDays = daysInCurrentWeek + 2;
} else {
daysInCurrentWeek = -(currentWorkDay - Calendar.SUNDAY);
totalDays = daysInCurrentWeek - 2;
}
int restTotalDays = days - daysInCurrentWeek;
// next working week... add 2 days for each week.
int x = restTotalDays / 5;
totalDays += restTotalDays + (x * 2);
workCal.add(Calendar.DAY_OF_MONTH, totalDays);
resultDate = workCal;
}
}
return resultDate;
}
例子：
计算我开始工作后除了周六和周日的总天数。
public class App {
public static void main(String[] args) throws Exception {
/** I write the code when 2019-8-15 */
LocalDate now = LocalDate.now();
LocalDate startWork = LocalDate.parse("2019-06-17");
/** get all days */
long allDays = Duration.between(startWork.atStartOfDay(), now.atStartOfDay()).toDays() + 1;
System.out.println("This is the " + allDays + "th day you enter the company.");
/** variable to store day except sunday and saturday */
long workDays = allDays;
for (int i = 0; i < allDays; i++) {
if (startWork.getDayOfWeek() == DayOfWeek.SATURDAY || startWork.getDayOfWeek() == DayOfWeek.SUNDAY) {
workDays--;
}
startWork = startWork.plusDays(1);
}
System.out.println("You actually work for a total of " + workDays + " days.");
}
}
/**
This is the 60th day you enter the company.
You actually work for a total of 44 days.
*/