java - Difference of two Joda LocalDateTimes

Question

I've got 2 Joda LocalDateTime objects and need to produce a 3rd that represents the difference between them:

LocalDateTime start = getStartLocalDateTime();
LocalDateTime end = getEndLocalDateTime();

LocalDateTime diff = ???

The only way I can figure is to painstakingly go through each date/time field and performs its respective minus operation:

LocalDateTime diff = end;

diff.minusYears(start.getYear());
diff.minusMonths(start.getMonthOfYear());
diff.minusDays(start.getDayOfMonth());
diff.minusHours(start.getHourOfDay());
diff.minusMinutes(start.getMinuteOfHour());
diff.minusSeconds(start.getSecondsOfMinute());

The end result would simply be to call diff's toString() method and get something meaningful. For instance if start.toString() produces 2012/02/08T15:05:00, and end.toString() produces 2012/02/08T16:00:00, then diff.toString() would be the difference (55 minutes) and might look like 2012/02/08T00:55:00.

And, if this is a terrible abuse of LocalDateTime, then I just need to know how to take the time difference between the two and put that difference into an easy-to-read (human friendly) format.

Thanks in advance!

Answer 1

You can use org.joda.time.Period class for this - in particular the fieldDifference method.

Example:

LocalDateTime endOfMonth = now.dayOfMonth().withMaximumValue();
LocalDateTime firstOfMonth = now.dayOfMonth().withMinimumValue();
Period period = Period.fieldDifference(firstOfMonth, endOfMonth)