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Hi,

I'm using Java 1.5. How do I get a java.util.Date exactly one month
before today's date? I thought about converting todays date to
milliseconds and then subtracting a value, but not every month has the
same number of milliseconds.

- Dave

laredotornado wrote:
> Hi,
>
> I'm using Java 1.5. How do I get a java.util.Date exactly one month
> before today's date? I thought about converting todays date to
> milliseconds and then subtracting a value, but not every month has the
> same number of milliseconds.

Month as in "30 days" or "this day in the last calendar month"? What is
exactly one month before December 31? March 29?

Here's some code using Calendar that treats the equivalent of "November
31" as "November 30":

Calendar cal = Calendar.getInstance();
cal.setTime(date);
cal.add(Calendar.MONTH, -1);
date = cal.getTime();

--
Beware of bugs in the above code; I have only proved it correct, not
tried it. -- Donald E. Knuth

laredotornado <> wrote:

>Hi,
>
>I'm using Java 1.5. How do I get a java.util.Date exactly one month
>before today's date? I thought about converting todays date to
>milliseconds and then subtracting a value, but not every month has the
>same number of milliseconds.

Look at the add method of GregorianCalendar, that will do what you
need.

--
Tim Slattery

http://members.cox.net/slatteryt

On Oct 3, 10:37*am, Tim Slattery <Slatter...@bls.gov> wrote:
> laredotornado <laredotorn...@zipmail.com> wrote:
> >Hi,
>
> >I'm using Java 1.5. *How do I get a java.util.Date exactly one month
> >before today's date? *I thought about converting todays date to
> >milliseconds and then subtracting a value, but not every month has the
> >same number of milliseconds.
>
> Look at the add method of GregorianCalendar, that will do what you
> need.
>
> --
> Tim Slattery
> Slatter...@bls.govhttp://members.cox.net/slatteryt

What I meant by exactly one month is if today is "10-3-2008", one
month ago was "9-3-2008". Of course, I don't know what one month ago
means for "7-31-2008". But I have used GregorianCalendar's add
method, per Tim's suggestion

this.m_throughDate = new Date();
GregorianCalendar gc = new
GregorianCalendar(this.m_throughDate.getYear(),
this.m_throughDate.getMonth(), this.m_throughDate.getDate());
gc.add(Calendar.MONTH, -1);
this.m_fromDate = gc.getTime();

Thanks, - Dave

On Fri, 3 Oct 2008 07:36:55 -0700 (PDT), laredotornado
<> wrote, quoted or indirectly quoted someone
who said :

>I'm using Java 1.5. How do I get a java.util.Date exactly one month
>before today's date? I thought about converting todays date to
>milliseconds and then subtracting a value, but not every month has the
>same number of milliseconds.

That is trivial with BigDate. See TestDate examples. With Calendar is
is a bit uglier. See http://mindprod.com/products1.html#COMMON11
http://mindprod.com/jgloss/calendar.html
--
Roedy Green Canadian Mind Products
http://mindprod.com/politics/harper.html
Anyone but Harper for Prime Minister of Canada