Count Days Between Dates

sha2484

I need help to count days between 2 dates,where i want to count the days between current date and registeration date.Here is the code that i have write but it only compare the days , it do not compare the month and the year, where it will return 0 if the day of the second date is the same as the first date even the month or year are different, plz help me...

my code:
public static int dayDiff(java.sql.Date date1, java.sql.Date date2)throws Exception
{
long diff = date1.getTime()-date2.getTime();
return (int)diff/1000/60/60/24;
}

r035198x

Always first consider using the GregorianCalendar class whenever you need to fiddle with dates.

chaarmann

Your calculation is not correct!
Some days have 23 or 25 hours (daylight saving)
Also as what i have heard (but not verified), the day before new year is a few minutes and seconds shorter or longer than 24 hours.

GregorianCalendar is your friend to do the correct calulation for you.

Gregorian calendar:
365.2425 days has a year here.
the error rate to the real value is -0.0003.

JosAH

Quote:

Originally Posted by chaarmann

Your calculation is not correct!
Some days have 23 or 25 hours (daylight saving)
Also as what i have heard (but not verified), the day before new year is a few minutes and seconds shorter or longer than 24 hours.

Not that much! The braking effect of the tides does cause a slow down in the
earth rotation but not by several minutes per year; we'd all fall over yearly ;-)
Leap seconds are injected once or twice a year to compensate for the slow down.
Read this: http://tycho.usno.navy.mil/leapsec.html

kind regards,

Jos

chaarmann

Quote:

Originally Posted by JosAH

Not that much! The braking effect of the tides does cause a slow down in the
earth rotation but not by several minutes per year; we'd all fall over yearly ;-)
Leap seconds are injected once or twice a year to compensate for the slow down.
Read this: http://tycho.usno.navy.mil/leapsec.html

kind regards,

Jos

Thanks for the link, Jos.
I searched for such a link before, but couldn't find anything.
It is interesting to know that a leap second is mostly, but not always inserted at first January. From 1973 to now it was always either first January or July or no insertion every year. From 1961 to 1973 it was at different months. Before 1961 it did not happen.

Also very interesting that the GPS is already 14 seconds ahead of our time (UTC), because it is not adjusted for leap seconds.

JosAH

I haven't found any regularity in whether or not a second was inserted. I think it's
a matter of important old men that aye or naye for a second. It's the continuous
slow down of earth's rotation that complicates matters.

The good side of the medal is that they insert that second at night: we can sleep
longer then ;-)

kind regards,

Jos

sha2484

sory im really a beginner..can u help me by giving code with some explanation?plz...urgent

r035198x

Read about that GregorianCalendar class. No one is going to write the code for you here.

myusernotyours

Quote:

Originally Posted by r035198x

Read about that GregorianCalendar class. No one is going to write the code for you here.

r0, You may add that the OP shouldn't take advantage of the one added second to sleep longer if they want to learn how to use the GregorianCalendar. :)

Regards,

Alex.

r035198x

Yes, that would be a waste of time, wouldn't it?

Count Days Between Dates

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