Java Generate all dates between x and y [duplicate]

Answer 1

You can use joda-time.

Days.daysBetween(fromDate, toDate);

Found at joda-time homepage.

similar question in stackoverflow with some good answers.

Answer 2

Look at the Calendar API, particularly Calendar.add().

Answer 3

Joda-Time

Calendar and Date APIs in java are really weird... I strongly suggest to consider jodatime, which is the de-facto library to handle dates. It is really powerful, as you can see from the quickstart: http://joda-time.sourceforge.net/quickstart.html.

This code solves the problem by using Joda-Time:

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

import org.joda.time.DateTime;


public class DateQuestion {

    public static List<DateTime> getDateRange(DateTime start, DateTime end) {

        List<DateTime> ret = new ArrayList<DateTime>();
        DateTime tmp = start;
        while(tmp.isBefore(end) || tmp.equals(end)) {
            ret.add(tmp);
            tmp = tmp.plusDays(1);
        }
        return ret;
    }

    public static void main(String[] args) {

        DateTime start = DateTime.parse("2012-1-1");
        System.out.println("Start: " + start);

        DateTime end = DateTime.parse("2012-12-31");
        System.out.println("End: " + end);

        List<DateTime> between = getDateRange(start, end);
        for (DateTime d : between) {
            System.out.println(" " + d);
        }
    }
}

Answer 4

You could use this function:

public static Date addDay(Date date){
   //TODO you may want to check for a null date and handle it.
   Calendar cal = Calendar.getInstance();
   cal.setTime (date);
   cal.add (Calendar.DATE, 1);
   return cal.getTime();
}

Found here. And what is the reason of fail? Why you think that your code is failed?

Answer 5

tl;dr

Year year = Year.of ( 2012 ) ;  // Represent an entire year.

year
.atDay( 1 )                     // Determine the first day of the year. Returns a `LocalDate` object.
.datesUntil(                    // Generates a `Stream<LocalDate>`.
    year
    .plusYears( 1 )             // Returns a new `Year` object, leaving the original unaltered. 
    .atDay( 1 )                 // Returns a `LocalDate`.
)                               // Returns a `Stream<LocalDate>`.
.forEach(                       // Like a `for` loop, running through each object in the stream.
    System.out :: println       // Each `LocalDate` object in stream is passed to a call of `System.out.println`.
)
;

java.time

The other Answers are outmoded as of Java 8.

The old date-time classes bundled with earlier versions of Java have been supplanted with the java.time framework built into Java 8 and later. See Tutorial.

LocalDate (date-only)

If you care only about the date without the time-of-day, use the LocalDate class. The LocalDate class represents a date-only value, without time-of-day and without time zone.

LocalDate start = LocalDate.of( 2016 , 1 , 1 ) ;
LocalDate stop = LocalDate.of( 2016 , 1 , 23 ) ;

To get the current date, specify a time zone. For any given moment, today’s date varies by time zone. For example, a new day dawns earlier in Paris than in Montréal.

LocalDate today = LocalDate.now( ZoneId.of( "America/Montreal" ) );

We can use the isEqual, isBefore, and isAfter methods to compare. In date-time work we commonly use the Half-Open approach where the beginning of a span of time is inclusive while the ending is exclusive.

List<LocalDate> localDates = new ArrayList<>();
LocalDate localDate = start;
while ( localDate.isBefore( stop ) ) {
    localDates.add( localDate );
    // Set up the next loop.
    localDate = localDate.plusDays( 1 );
}

LocalDate::datesUntil

You can obtain a stream of LocalDate objects.

Stream< LocalDate > dates = start.datesUntil( stop ) ;
dates.forEach( System.out::println ) ;

LocalDateRange

If doing much of this work, add the ThreeTen-Extra library to your project. This gives you the LocalDateRange class to represent your pair of start and stop LocalDate objects.

Instant (date-time)

If you have old java.util.Date objects, which represent both a date and a time, convert to the Instant class. An Instant is a moment on the timeline in UTC.

Instant startInstant = juDate_Start.toInstant();
Instant stopInstant = juDate_Stop.toInstant();

From those Instant objects, get LocalDate objects by:

• Applying the time zone that makes sense for your context to get ZonedDateTime object. This object is the very same moment on the timeline as the Instant but with a specific time zone assigned.
• Convert the ZonedDateTime to a LocalDate.

We must apply a time zone as a date only has meaning within the context of a time zone. As we said above, for any given moment the date varies around the world.

Example code.

ZoneId zoneId = ZoneId.of( "America/Montreal" );
LocalDate start = ZonedDateTime.ofInstant( startInstant , zoneId ).toLocalDate();
LocalDate stop = ZonedDateTime.ofInstant( stopInstant , zoneId ).toLocalDate();