如何在Java中将当前日期添加到工作日？

Question

如何在Java中将当前日期添加到工作日？

public Calendar addBusinessDate(Calendar cal, int days) {
//
// code goes over here
//
}

注意:

它也应该考虑周末.

Answer 1

您可能需要考虑使用ObjectLab Kit为您做繁重的工作.

假设要求只是在计算日期属于非工作日时返回下一个工作日:

package bizdays.example;

import java.time.LocalDate;
import java.util.HashSet;
import net.objectlab.kit.datecalc.common.DateCalculator;
import net.objectlab.kit.datecalc.common.DefaultHolidayCalendar;
import net.objectlab.kit.datecalc.common.HolidayHandlerType;
import net.objectlab.kit.datecalc.jdk8.LocalDateKitCalculatorsFactory;
import static org.junit.Assert.assertThat;
import org.junit.Before;
import org.junit.Test;
import static org.hamcrest.Matchers.equalTo;

public class BizDayTest {
    private DateCalculator<LocalDate> dateCalculator;
    private final LocalDate startDate = LocalDate.of(2009, 12, 23);

    @Before
    public void setUp() {
        HashSet<LocalDate> holidays = new HashSet<LocalDate>();
        holidays.add(LocalDate.of(2009, 12, 25));  // Friday

        DefaultHolidayCalendar<LocalDate> holidayCalendar =
            new DefaultHolidayCalendar<LocalDate>(holidays);

        LocalDateKitCalculatorsFactory.getDefaultInstance()
                .registerHolidays("example", holidayCalendar);
        dateCalculator = LocalDateKitCalculatorsFactory.getDefaultInstance()
                .getDateCalculator("example", HolidayHandlerType.FORWARD);
        dateCalculator.setStartDate(startDate);
    }

    @Test
    public void should_not_change_calendar_start_date_even_after_moving() {
        assertThat(
            dateCalculator.moveByBusinessDays(6).getStartDate(),
            equalTo(startDate));
    }

    @Test
    public void moveByBusinessDays_will_return_24_dec_2009_as_next_business_day() {
        assertThat(
            dateCalculator.moveByBusinessDays(1).getCurrentBusinessDate(),
            equalTo(LocalDate.of(2009, 12, 24)));
    }

    @Test
    public void moveByBusinessDays_will_return_28_dec_2009_as_two_business_days_later() {
        assertThat(
            dateCalculator.moveByBusinessDays(2).getCurrentBusinessDate(),
            equalTo(LocalDat.of(2009, 12, 28)));

    }

    @Test
    public void moveByDays_will_also_return_28_dec_2009_as_two_business_days_later() {
        assertThat(
            dateCalculator.moveByDays(2).getCurrentBusinessDate(),
            equalTo(LocalDate.of(2009, 12, 28)));
    }

    @Test
    public void moveByBusinessDays_will_exclude_25_26_and_27_dec_when_computing_business_days() {
        assertThat(
            dateCalculator.moveByBusinessDays(5).getCurrentBusinessDate(),
            equalTo(LocalDate.of(2009, 12, 31)));
    }


    @Test
    public void moveByDays_will_include_25_26_and_27_dec_when_computing_business_days() {
        assertThat(
            dateCalculator.moveByDays(5).getCurrentBusinessDate(),
            equalTo(LocalDate.of(2009, 12, 28)));
    }
}

库默认的工作周,从周一到周五,但你可以通过提供一个自定义更改默认设置WorkingWeek来DateCalculator的setWorkingWeek().

如前两个示例所示,moveByDays()包括周末移动时,而不moveByBusinessDays()包括周末.

该库还允许您使用java.util.Calendar或Joda Time的LocalDate.这些示例使用JDK8,java.time.LocalDate因为它是自JDK8以来的首选方式.

编辑:更新要使用的示例 java.time.LocalDate

Answer 2

使用:

public Calendar addBusinessDate(Calendar cal, int numBusinessDays) {
  int numNonBusinessDays = 0;

  for(int i = 0; i < numBusinessDays; i++) {
    cal.add(Calendar.DATE, 1);

    /*
       It's a Canadian/American custom to get the Monday (sometimes Friday) off
       when a holiday falls on a weekend.
    */
    for(int j = 0; j < holidays; j++) { //holidays is list of dates
      if(cal.getTime() == (Date)holidays.get(j)) {
        numNonBusinessDays++;
      }
    }

    if(cal.get(Calendar.DAY_OF_WEEK) == 1 ||
       cal.get(Calendar.DAY_OF_WEEK) == 7) {
      numNonBusinessDays++;
    }
  }

  if(numNonBusinessDays > 0) {
    cal.add(Calendar.DATE, numNonBusinessDays);
  }

  return cal;
}

您必须填写日期列表才能处理假期.像新年这样的常见品,但感恩节在加拿大和美国之间是不同的.还要注意假期可能会在周末出现,因此周末将成为3天的周末.

参考:

• 日历
• 日历常量值

PS:如果您正在更新示例中的值,则实际上不需要返回Calendar实例.但是如果要创建单独的Calendar实例,则有效:

public Calendar addBusinessDate(Calendar cal, int numBusinessDays) {
  Calendar cal2 = Calendar.getInstance();
  cal2.setTime(cal.getTime());

  int numNonBusinessDays = 0;

  for(int i = 0; i < numBusinessDays; i++) {
    cal2.add(Calendar.DATE, 1);

    /*
       It's a Canadian/American custom to get the Monday (sometimes Friday) off
       when a holiday falls on a weekend.
    */
    for(int j = 0; j < holidays; j++) { //holidays is list of dates
      if(cal2.getTime() == (Date)holidays.get(j)) {
        numNonBusinessDays++;
      }
    }

    if(cal2.get(Calendar.DAY_OF_WEEK) == 1 ||
       cal2.get(Calendar.DAY_OF_WEEK) == 7) {
      numNonBusinessDays++;
    }
  }

  if(numNonBusinessDays > 0) {
    cal2.add(Calendar.DATE, numNonBusinessDays);
  }

  return cal2;
}

Answer 3

以下是查找日期计算的修改版本.

public  Calendar algorithm2(int businessDays){
    Calendar cal2 = Calendar.getInstance();
    Calendar cal = Calendar.getInstance(); 
    int totalDays= businessDays/5*7;
    int remainder = businessDays % 5;
    cal2.add(cal2.DATE, totalDays); 

    switch(cal.get(Calendar.DAY_OF_WEEK)){
        case 1:
                break;
        case 2: 
                break;
        case 3: 
                if(remainder >3)
                cal2.add(cal2.DATE,2);
                break;
        case 4: 
                if(remainder >2)
                cal2.add(cal2.DATE,2);
                break;
        case 5: 
                if(remainder >1)
                cal2.add(cal2.DATE,2);
                break;
        case 6: 
                if(remainder >1)
                cal2.add(cal2.DATE,2);
                break;
        case 7: 
                if(remainder >1)
                cal2.add(cal2.DATE,1);
                break;
    }

    cal2.add(cal2.DATE, remainder); 
    return cal2;

}

Answer 4

//也支持负数。

private Calendar addBusinessDay(final Calendar cal, final Integer numBusinessDays)
{
    if (cal == null || numBusinessDays == null || numBusinessDays.intValue() == 0)
    {
        return cal;
    }
    final int numDays = Math.abs(numBusinessDays.intValue());
    final int dateAddition = numBusinessDays.intValue() < 0 ? -1 : 1;//if numBusinessDays is negative
    int businessDayCount = 0;
    while (businessDayCount < numDays)
    {
        cal.add(Calendar.DATE, dateAddition);

        //check weekend
        if (cal.get(Calendar.DAY_OF_WEEK) == Calendar.SATURDAY || cal.get(Calendar.DAY_OF_WEEK) == Calendar.SUNDAY)
        {
            continue;//adds another day
        }

        //check holiday
        if (isHoliday(cal))//implement isHoliday yourself
        {
            continue;//adds another day
        }

        businessDayCount++;
    }
    return cal;
}