How to find the number of days between two dates in java or groovy?

Question

I have a method which uses following logic to calculate difference between days.

long diff = milliseconds2 - milliseconds1;
long diffDays = diff / (24 * 60 *         


        

Answer 1

Try this:

DateFormat format = DateFormat.getDateTimeInstance();
    Date completeDate=null;
    Date postedDate=null;

    try
    {
        completeDate = format.parse("18-May-09 11:30:57");
        postedDate = format.parse("11-May-09 10:46:37");
        long res = completeDate.getTime() - postedDate.getTime();

        System.out.println("postedDate: " + postedDate);
        System.out.println("completeDate: " + completeDate);
        System.out.println("result: " + res + '\n' + "minutes: " + (double) res /  (60*1000) + '\n' 
            + "hours: " + (double) res /  (60*60*1000) + '\n' + "days: " + (double) res /  (24*60*60*1000));
    }
    catch (ParseException e)
    {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

If you want days to be an integer then just remove casting to double. HTH

Answer 2

It's a well worn line, but for Dates use JodaTime.

Here's how to calculate date intervals using JodaTime.

Days days = Days.daysBetween(new DateTime(millis1), new DateTime(millis2));
int daysBetweenDates = days.getDays();

Answer 3

This assumes times are in UTC or GMT.

long day1 = milliseconds1/ (24 * 60 * 60 * 1000);
long day2 = milliseconds2/ (24 * 60 * 60 * 1000);
// the difference plus one to be inclusive of all days
long intervalDays = day2 - day1 + 1;