problem: How to get last month date

[Peter Primrose]

Hi all,

quick question:
I have a date (Date, 2006-05-12) and i would like to get the same date last month: 2005-04-12.

right now I'm using:

int future= -30 ;

Calendar c = Calendar.getInstance();
c.setTime(someDay);
c.add(Calendar.DATE, future);

the problem is that a month can have 28,30,31 days, and as a result the previuos month will be incorrect.

any idea?

[Ernest Friedman-Hill]

Any solution would also have to account for the fact that the date might be the "31st", and many months don't have one of those.

In any case, the method Calendar.roll() does exactly what you want.

[Paul Clapham]

And so does the method Calendar.add(), which you should use instead of roll() if you want to get December 2005 (not 2006) as the month before January 2006.

[Peter Primrose]

thanks for your reply but i don't think i fully understand it.

I am attaching a code sample, my question is how would you use the roll.
I read the sun documentation on the roll but could plug it in the code.

thanks

  import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
 
public class MyDate
{
public static void main(String args[])
{
final int YEAR = -365;
final int MONTH = -30;

Date date = new Date();

System.out.println(getPastDate(date, YEAR));
System.out.println(getPastDate(date, MONTH));

}

public static String getPastDate(Date day, int interval)
{
try{

SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");

Calendar c = Calendar.getInstance();
c.setTime(day);

c.add(Calendar.DATE,interval);  //not sure

return dateFormat.format(c.getTime());


}catch (Exception exp)
{
return null;
}
}
}  

[Jesper de Jong]

Why don't you just subtract 1 month from the date instead of 30 days?

Calendar c = Calendar.getInstance();
c.add(Calendar.MONTH, -1);

[kittu vadde]

i think this will solve ur prob, if i understood correctly

    
Calendar c = Calendar.getInstance();
c.add(Calendar.YEAR, -1); //one year back
c.add(Calendar.MONTH, -1);// then one month

[ May 16, 2006: Message edited by: kittu vadde ]