java roll back one day

Question

In a scenario i want to roll back one day from current time.It works fine when i use the function Calendar.roll() , but when it comes to 2014-1-1 00:00 it appears to be an unexpected result. here's the code:

Calendar c = Calendar.getInstance();
try {
     c.setTimeInMillis(sdf.parse("2014-1-1 00:00").getTime());
 } catch (ParseException e) {
    e.printStackTrace();
 }
 c.roll(Calendar.DAY_OF_YEAR, -1);
 c1.set(c.get(Calendar.YEAR), c.get(Calendar.MONTH), c.get(Calendar.DAY_OF_MONTH), 0, 0, 0);

System.out.println(sdf.format(c1.getTime()));

the result is: 2014-12-31 00:00

if i use Calendar.DAY_OF_MONTH instead of DAY_OF_YEAR, the result would be 2014-01-31 00:00

does anyone have a solution when rolling back one day also rolls back the year, for this example, change 2014 to 2013?

possible duplicate of [Get yesterday's date using Date](http://stackoverflow.com/questions/11425236/get-yesterdays-date-using-date) — jmj, Mar 20 '14 at 02:59

score 3 · Answer 1 · answered Mar 20 '14 at 03:01

3

as per the javadocs http://docs.oracle.com/javase/7/docs/api/java/util/Calendar.html

Roll rule. Larger fields are unchanged after the call.

so use

c.add(Calendar.DAY_OF_YEAR, -1)

answered Mar 20 '14 at 03:01

Scary Wombat

44,617
6
35
64

score 0 · Answer 2 · answered Mar 20 '14 at 03:03

0

Try using the add method instead.

c.add(Calendar.DAY_OF_YEAR, -1);

answered Mar 20 '14 at 03:03

JamesH

279
2
6

java roll back one day

2 Answers2