Subtracting days in a Calendar object [duplicate]

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Anyone know a simple way using java calendar to subtract X days to a date?

I need to minus 365 days in a given date (givenDate)-

Calendar calendar = Calendar.getInstance();
calendar.setTime(givenDate);
calendar.add(Calendar.开发者_StackOverflow中文版DATE, -365);  

Am I right?

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Calendar.DAY_OF_YEAR is the proper way to subtract days

You can also subtract a year (taking in to account leap years) by using

Calendar calendar = Calendar.getInstance();
calendar.setTime(givenDate);
calendar.add(Calendar.YEAR, -1);

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That is the correct way to subtract days.

Note that 365 days does not always equal one year because of leap days. calendar.add(Calendar.YEAR, -1) would subtract one year correctly.

You also may want to use Joda Time-library instead of java.util.Date and java.util.Calendar. Joda Time is a much nicer API for handling times and dates.

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I don't think it'll make a different, but I would use Calendar.DAY_OF_YEAR as the field.

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If you are trying to strictly subtract 365 days, then yeah, that'd do it. However, if you are trying years backward, that might not work due to leap years.

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Check out Veyder-time. It is a simple and powerful alternativ to java.util.Calendar and has simple methods for adding and subtracting both days and years, among many other things.