Best way to calculate differnce between two times in java?

Question

Hi, I have two times in an array and I need to calculate the difference between both of these. I have converted the hours into mins, then added the remaining mins. This gives me the total minuites overall, once I did this for both I simply minus one total mins from the other. Then converted them back to hours and minuites.

  double no1 = Double.parseDouble(array[i][4]);

  int time1_calc = (int) (no1 * 100); //Remove decimal point

  int time1hours = (time1_calc) / 100;

  int time1mins = (time1_calc) % 100;

  int time1HM = time1hours*60;

  int time1_total = time1HM + time1mins;

The above code is used for the second time, I then use:

 int total = time2_total - time1_total;

For this all the calculations "look" to work, but for example the difference betweeen 10.18 and 09.35 is 1hour 23mins or 83mins in total. My program seems to show 43mins.

I have tried other ways but still cannot get it working, any ideas?

Thanks =)

Answer 1

Have a look at the Joda library.

If you want to do it by yourself, then your code looks correct to me.

Answer 2

int time1mins = (time1_calc) % 100;

Minutes are not the remainder of hours divided by 100, but by 60. Is that what that bit of code is meant to be doing?

Also, you might be better off just using a Calendar object.

Answer 3

Use a DateFormat (probably SimpleDateFormat) object to parse your String and don't try to use parseDouble() (that's for parsing a single number, which a time is not).

Answer 4

Use the Date Object. Then Use its getTime method. It will give you the time in milliseconds(long). Then subtract the times. and then convert them to minutes and hours.

Answer 5

Calendar time1 = Calendar.getInstance(); // assign time1 date from your array

Calendar time2 = Calendar.getInstance(); // assign time2 date from your array

long diff = time1.getTimeInMills() - time2.getTimeInMills();