How to add days to a date in Java

Question

I want to add days to a date to get a new date in Java. How to achieve it using the Calender class.

Calender dom = new GregorianCalender(d, m y);

is the instance of my date of manufacture and I want to reach to date of expiry adding some 100 days to the current date and store it in doe but unable to do that.

Any help would be appreciable.

Answer 1

Make use of Calendar#add(). Here's a kickoff example.

Calendar dom = Calendar.getInstance();
dom.clear();
dom.set(y, m, d); // Note: month is zero based! Substract with 1 if needed.
Calendar expire = (Calendar) dom.clone();
expire.add(Calendar.DATE, 100);

If you want more flexibility and less verbose code, I'd recommend JodaTime though.

DateTime dom = new DateTime(y, m, d, 0, 0, 0, 0);
DateTime expire = dom.plusDays(100);

Answer 2

When using standard Java-API BalusCs answer is fine. If you use a lot of date computation it may worth the time to take a look on Joda Time. Which provides a (from mine point of view) better date handling. It also will be the base for the upcomming new Java Date API