Wrong time difference calculation

[j2me64]

hello everybody, I'm trying to calculate the time difference between two dates. here is the code

			    DateFormat df3 = DateFormat.getTimeInstance(DateFormat.MEDIUM);
			    df3.setTimeZone(TimeZone.getTimeZone("Europe/Zurich"));

			    Date dates1 = df3.parse("10:00:00");
			    Date dates2 = df3.parse("11:00:00");

			    long diff = dates2.getTime() - dates1.getTime();

			    System.out.println("Time Difference = "+df3.format(diff));

the result should be 01:00:00 but I got 02:00:00. can somebody fix this problem?

[DarrylBurke]

DST?

db

[JosAH]

It doesn't print a time difference; it prints the time at 01:00:00am in your locale; daylight saving time is active so it prints 02:00:00.

kind regards,

Jos

edit: darn, too slow again ...

[Tolls]

The date stuff in regular Java is a bit rubbish at the whole concept of durations.

[j2me64]

the diff value is 3'600'000 millis and 3600 seconds are one hour. are there any hints how to get the output in the format "01:00:00"?

[Tolls]

Calculate the hours minutes and seconds?

[j2me64]

when I use the TimeZone "Europe/Lissabon" the calculation is ok!

[Tolls]

And if you have a time difference greater than 24 hours?

[JosAH]

the diff value is 3'600'000 millis and 3600 seconds are one hour. are there any hints how to get the output in the format "01:00:00"?

Set a TimeZone without any daylight saving for your DataFormat object. (see the APIs for details). Note that it can only disply an amount of hours < 24.

kind regards,

Jos

[j2me64]

And if you have a time difference greater than 24 hours?

this shouldn't never happen, since I'm calculating the duration of our jobs on the database and there a some very slow jobs but the duration is never bigger than some hours. anyway, I will code some checks to ensure that the duration will never be grater than 24.

[DarrylBurke]

Like Jos said at #2, a Date isn't a duration; it's an instant in time.

I think the Joda time API has a Duration class.

db

[j2me64]

I got an other problem: when the duration has 0 hours 12 or 24 are displayed in the output. Because my calculations are smaller than 12 hours I will keep the java solution with date. But the class Date isn't really a good choice for calculating duration.

[JosAH]

I got an other problem: when the duration has 0 hours 12 or 24 are displayed in the output. Because my calculations are smaller than 12 hours I will keep the java solution with date. But the class Date isn't really a good choice for calculating duration.

That's what we all have been trying to tell you ;-) Hours in the range 0:00:00am up to 00:59:59am are displayed as 1:mm:ss per convention. A time value is displayed, not a duration. Better display that duration yourself ...

kind regards,

Jos