File last modified date wrong

[Marc Mendez]

Hi,

Under W2003 (and once under XP Pro), I can't get the right last modified
date of a file.

I use :
long lastmodified = file.lastModified();
long currentTime = new GregorianCalendar().getTimeInMillis();

to know how long a file was changed.

To trace the routine, I do :

log.println("Last modified date : " + lastmodified);
GregorianCalendar t = new GregorianCalendar();
t.setTimeInMillis(lastmodified);
log.println("Last modified date (readable) :
"+t.get(Calendar.DAY_OF_MONTH)+"/"+t.get(Calendar.MONTH)+"/"+t.get(Calendar.YEAR));
log.println("Current date : " + currentTime);

A file modified on 16/07/2007 looks modified on le
16/06/2007 ! I use JRE 1.4.2. On my home computer (XP Pro), no problem.

Any idea ?

 

[Gordon Beaton]

A file modified on 16/07/2007 looks modified on le 16/06/2007 ! I
use JRE 1.4.2.

The months are numbered starting from 0, so 6 is July, not June.

On my home computer (XP Pro), no problem.

Can't explain that.

/gordon

--

 

[Marc Mendez]

Yes you're right. But if so, it should occur on any system. Some systems
give me the right month, the other the wrong one...

 

[Roedy Green]

long lastmodified = file.lastModified();
long currentTime = new GregorianCalendar().getTimeInMillis();

I would do it like this:

long currentTime = System..currentTimeMillis();

long filetime = file.lastModified();

static final SimpleDateFormat sdf =
new SimpleDateFormat( "EEEE yyyy/MM/dd hh:mm:ss aa zz :
zzzzzz" );

String dateString = sdf.format( new Date( filetime ) );

This way you see the time zone being used. Most often problems with
date/time are displaying in a different time zone, DST than you
thought you were.

Also check how both machines are configured in the OS.
See http://mindprod.com/applet/tz.html

see http://mindprod.com/jgloss/timezone.html
http://mindprod.com/jgloss/calendar.html
http://mindprod.com/jgloss/time.html
http://mindprod.com/jgloss/timestamp.html

 

[Marc Mendez]

That's a good idea, but a different TMZ can give a difference up to one day,
not a month

 

[Roedy Green]

That's a good idea, but a different TMZ can give a difference up to one day,
not a month

That was not obvious to me . I did not know if you meant DDMMYYYYY or
MMDDYYYY.

I use ISO format YYYY-MM-DD since it is unambiguous.

 

[Roedy Green]

Under W2003 (and once under XP Pro), I can't get the right last modified
date of a file.

I presume you are not showing us the exact code. Could some sort of
exception leave the lastModified set to an old value?

 

[Marc Mendez]

No, it was exactly the code. About the TMZ, it's DD/MM/YYYY.

 

[Roedy Green]

To get one possible source of confusion out the way, use SetClock to
set your time and let you know the timezone you have configured on the
various machines.


See http://mindprod.com/webstarts/setclock.html