Java™ Phrasebook

Adding to or Subtracting from a Date or Calendar

// date arithmetic using Date objects Date date = new Date(); long time = date.getTime(); time += 5*24*60*60*1000; Date futureDate = new Date(time); // date arithmetic using Calendar objects Calendar nowCal = Calendar.getInstance(); nowCal.add(Calendar.DATE, 5);

If you are using a Date object, the technique for adding or subtracting dates is to first convert the object to a long value using the getTime() method of the Date object. The getTime() method returns the time as measured in milliseconds since the epoch (January 1, 1970, 00:00:00 GMT). You then perform the arithmetic on the long values, and finally convert back to date objects. In the phrase shown, we are adding 5 days to the date object. ...