Today is 2014-04-06 (Sunday).
The output I get from using the code below is:
Start Date = 2014-04-07
End Date = 2014-04-13
This is the output I would like to get instead:
Start Date = 2014-03-31
End Date = 2014-04-06
How can I achieve this?
This is the code I have completed so far:
// Get calendar set to current date and time
Calendar c = GregorianCalendar.getInstance();
System.out.println("Current week = " + Calendar.DAY_OF_WEEK);
// Set the calendar to monday of the current week
c.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
System.out.println("Current week = " + Calendar.DAY_OF_WEEK);
// Print dates of the current week starting on Monday
DateFormat df = new SimpleDateFormat("yyyy-MM-dd", Locale.getDefault());
String startDate = "", endDate = "";
startDate = df.format(c.getTime());
c.add(Calendar.DATE, 6);
endDate = df.format(c.getTime());
System.out.println("Start Date = " + startDate);
System.out.println("End Date = " + endDate);
Using Java 8 and keeping the same principle as before (the first day of the week depends on your Locale
), you should consider using the following:
DayOfWeek
for a specific Locale
final DayOfWeek firstDayOfWeek = WeekFields.of(locale).getFirstDayOfWeek();
final DayOfWeek lastDayOfWeek = DayOfWeek.of(((firstDayOfWeek.getValue() + 5) % DayOfWeek.values().length) + 1);
LocalDate.now(/* tz */).with(TemporalAdjusters.previousOrSame(firstDayOfWeek)); // first day
LocalDate.now(/* tz */).with(TemporalAdjusters.nextOrSame(lastDayOfWeek)); // last day
Consider the following class
:
private static class ThisLocalizedWeek {
// Try and always specify the time zone you're working with
private final static ZoneId TZ = ZoneId.of("Pacific/Auckland");
private final Locale locale;
private final DayOfWeek firstDayOfWeek;
private final DayOfWeek lastDayOfWeek;
public ThisLocalizedWeek(final Locale locale) {
this.locale = locale;
this.firstDayOfWeek = WeekFields.of(locale).getFirstDayOfWeek();
this.lastDayOfWeek = DayOfWeek.of(((this.firstDayOfWeek.getValue() + 5) % DayOfWeek.values().length) + 1);
}
public LocalDate getFirstDay() {
return LocalDate.now(TZ).with(TemporalAdjusters.previousOrSame(this.firstDayOfWeek));
}
public LocalDate getLastDay() {
return LocalDate.now(TZ).with(TemporalAdjusters.nextOrSame(this.lastDayOfWeek));
}
@Override
public String toString() {
return String.format( "The %s week starts on %s and ends on %s",
this.locale.getDisplayName(),
this.firstDayOfWeek,
this.lastDayOfWeek);
}
}
We can demonstrate its usage as follows:
final ThisLocalizedWeek usWeek = new ThisLocalizedWeek(Locale.US);
System.out.println(usWeek);
// The English (United States) week starts on SUNDAY and ends on SATURDAY
System.out.println(usWeek.getFirstDay()); // 2018-01-14
System.out.println(usWeek.getLastDay()); // 2018-01-20
final ThisLocalizedWeek frenchWeek = new ThisLocalizedWeek(Locale.FRANCE);
System.out.println(frenchWeek);
// The French (France) week starts on MONDAY and ends on SUNDAY
System.out.println(frenchWeek.getFirstDay()); // 2018-01-15
System.out.println(frenchWeek.getLastDay()); // 2018-01-21
Simply use:
c.setFirstDayOfWeek(Calendar.MONDAY);
Right now, your first day of week is set on Calendar.SUNDAY
. This is a setting that depends on your Locale
.
Thus, a better alternative would be to initialise your Calendar
specifying the Locale
you're interested in.
For example:
Calendar c = GregorianCalendar.getInstance(Locale.US);
... would give you your current output, while:
Calendar c = GregorianCalendar.getInstance(Locale.FRANCE);
... would give you your expected output.