问题

Interval interval = new Interval(new DateTime("2014-01-01"), new DateTime("2014-01-30"));

Is there a way to get the weekend days numbers?

something like:

interval.toPeriod.getWeekendDays();

回答1:

Custom `Iterator`

WeekendDayIterator is an Iterator of the weekend days in the Interval specified:

class WeekendDayIterator(interval: Interval) extends Iterator[LocalDate] {
  var day = interval.getStart.toLocalDate
  private def peek = day.plusDays(1)
  def hasNext: Boolean = peek.isBefore(interval.getEnd.toLocalDate)
  private def isWeekend(ld: LocalDate): Boolean = ld.getDayOfWeek == SATURDAY || ld.getDayOfWeek == SUNDAY
  def next(): LocalDate = { val d = day; do day = peek; while (!isWeekend(day)); d }
}

def weekendLocalDates(interval: Interval): List[LocalDate] = new WeekendDayIterator(interval).toList

// The `LocalDate`s for weekend days
println(weekendLocalDates(new Interval(new DateTime("2013-10-01"), new DateTime("2014-01-30"))))

// The days of year for weekend days
println(weekendLocalDates(new Interval(new DateTime("2013-10-01"), new DateTime("2014-01-30"))).map(_.getDayOfYear))

Resulting in the following output:

List(2013-10-01, 2013-10-05, 2013-10-06, 2013-10-12, 2013-10-13, 2013-10-19, 2013-10-20, 2013-10-26, 2013-10-27, 2013-11-02, 2013-11-03, 2013-11-09, 2013-11-10, 2013-11-16, 2013-11-17, 2013-11-23, 2013-11-24, 2013-11-30, 2013-12-01, 2013-12-07, 2013-12-08, 2013-12-14, 2013-12-15, 2013-12-21, 2013-12-22, 2013-12-28, 2013-12-29, 2014-01-04, 2014-01-05, 2014-01-11, 2014-01-12, 2014-01-18, 2014-01-19, 2014-01-25, 2014-01-26)
List(274, 278, 279, 285, 286, 292, 293, 299, 300, 306, 307, 313, 314, 320, 321, 327, 328, 334, 335, 341, 342, 348, 349, 355, 356, 362, 363, 4, 5, 11, 12, 18, 19, 25, 26)

The code is written in Scala. Porting it to Java should be straightforward.

回答2:

Here is a Java implementation using Joda-Time API. You basically figure out when is the first weekend from the start date, then add 7 days and keep going in a loop till the end date. You will collect all the weekends. The trick is if the end date is on Saturday, you have to stop there.

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.List;
import org.joda.time.LocalDate;

public class DateUtil {

public static List<String> getWeekends(LocalDate fromDate, LocalDate toDate){
    List<String> weekends = new ArrayList<String>();
    SimpleDateFormat format = new SimpleDateFormat("MM-dd-yyyy");
    int fromDay = fromDate.getDayOfWeek();
    int daysToFirstWeekend = 6-fromDay;
    LocalDate nextWeekend = fromDate.plusDays(daysToFirstWeekend);
    while(nextWeekend.isBefore(toDate)){
        weekends.add(format.format(nextWeekend.toDate()));
        if(nextWeekend.plusDays(1).isBefore(toDate)){
            weekends.add(format.format(nextWeekend.plusDays(1).toDate()));
        }
        nextWeekend = nextWeekend.plusDays(7);
    }       
    return weekends;
}   

public static void main(String[] args){
    LocalDate fromDate = new LocalDate();
    LocalDate toDate = fromDate.plusDays(45);
    System.out.println(getWeekends(fromDate, toDate));
 } 
}

If you want all the weekends from today (04-16-2016) and 45 days from now, it will give output of

[04-16-2016, 04-17-2016, 04-23-2016, 04-24-2016, 04-30-2016, 05-01-2016, 05-07-2016, 05-08-2016, 05-14-2016, 05-15-2016, 05-21-2016, 05-22-2016]

回答3:

package com.test.tryings;

import java.util.ArrayList; import java.util.HashMap; import java.util.List;

import org.joda.time.DateTime; import org.joda.time.DateTimeConstants; import org.joda.time.Days; import org.joda.time.LocalDate; import org.joda.time.format.DateTimeFormat;

public class DateTest {

org.joda.time.format.DateTimeFormatter dateStringFormat = DateTimeFormat.forPattern("dd-MM-yyyy"); String firstDate = "13-12-2019"; String seconddate = "23-12-2019";

void noOfDays() {
  System.out.println("To no of dates for matches...");

  HashMap<Integer, String> totalDays = new HashMap<Integer, String>();
  System.out.println("No of days between this days..");       DateTime
start = dateStringFormat.parseDateTime(firstDate); DateTime end = dateStringFormat.parseDateTime(seconddate); for (LocalDate currentdate = start.toLocalDate(); currentdate.isBefore(end.toLocalDate()) || currentdate.isEqual(end.toLocalDate()); currentdate = currentdate.plusDays(1)) { System.out.println(currentdate.toString(dateStringFormat)); } System.out.println("To no of dates for matches...");

}

void excludeWeekEnds() {
  DateTime start = dateStringFormat.parseDateTime(firstDate);
  DateTime end = dateStringFormat.parseDateTime(seconddate);

  System.out.println("Exclude weekends for the matches...");

  for (LocalDate currentdate = start.toLocalDate();
currentdate.isBefore(end.toLocalDate()) || currentdate.isEqual(end.toLocalDate()); currentdate = currentdate.plusDays(1)) { if (currentdate.getDayOfWeek() == DateTimeConstants.SATURDAY || currentdate.getDayOfWeek() == DateTimeConstants.SUNDAY) { continue; } else { System.out.println(currentdate.toString(dateStringFormat)); } } System.out.println("Exclude weekends for the matches..."); }

void excludeWeekDays() {
  DateTime start = dateStringFormat.parseDateTime(firstDate);
  DateTime end = dateStringFormat.parseDateTime(seconddate);

  System.out.println("Exclude weekdays for the matches...");

  for (LocalDate currentdate = start.toLocalDate();
currentdate.isBefore(end.toLocalDate()) || currentdate.isEqual(end.toLocalDate()); currentdate = currentdate.plusDays(1)) { if (currentdate.getDayOfWeek() == DateTimeConstants.SATURDAY || currentdate.getDayOfWeek() == DateTimeConstants.SUNDAY) { System.out.println(currentdate.toString(dateStringFormat)); } } System.out.println("Exclude weekdays for the matches...");

}

public static void main(String[] args) {
  DateTest dt = new DateTest();       dt.noOfDays();
  dt.excludeWeekEnds();       dt.excludeWeekDays();   } }