Display elapsed time with month an day support in JAVA

Question

I need to display elapsed time in my application form.
I currently do this using this code:

    AppTimer = new Timer();
    AppTimer.scheduleAtFixedRate(new java.util.TimerTask() {
        SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");
        public void run() {
            sdf.setTimeZone(java.util.TimeZone.getTimeZone("GMT+0"));
            lblAppRunTime.setText(""+sdf.format(new Date(AppTimeCounter*1000)));
            AppTimeCounter++;
        }
    },1000, 1000);

This Code shows hours,minutes & seconds properly but how can I show DAYS & MONTHS? new SimpleDateFormat("M D HH:mm:ss") can't do this and for example when 5 seconds elapsed it shows 1 month and 1 days too!

How can I show month and day too?

Thanks

Answer 1

You should not use the Date class for it, because a date is an instant of time, but you are using it as a duration. Please read carefully joda time documentation about it. And then you could use Period and PeriodFormatter for you task. Or write something similar if you don't want use the library.

Answer 2

Avoid legacy date-time classes

Never use the legacy classes Date, Calendar, SimpleDateFormat, etc. These were years ago supplanted by the modern java.time classes defined in JSR 310, and built into Java 8 and later.

java.time

Always use java.time classes for your date-time handling.

Duration

To store a span-of-time unattached to the timeline, on a scale of generic 24-hour days, hours, minutes, seconds, and nanoseconds, use Duration class.

Duration duration = Duration.ofHours( 5 ).plusMinutes( 4 ).plusSeconds( 3 );

Generate a standard ISO 8601 formatted text.

String iso8601Text = duration.toString() ;

Parse such standard text.

Duration duration = Duration.parse ( "PT5H4M3S" ) ;

You can specify days as well, but these are days unrelated to the calendar. They are generic chunks of 24-hours. For example, specifying two of these “days” is exactly the same as specifying forty-eight hours.

Duration duration = Duration.ofDays( 2 ) ;  // 48 hours, not calendar days.
Duration theSame = Duration.ofHours( 48 ) ;  // 2 days.

You will find methods such as Thread.sleep have been updated to accept Duration object as an argument.

Period

If you wish to represent a span-of-time on the scale of years-months-days, use Period class.

org.threeten.extra.PeriodDuration

Combining years-months-days with hours-minutes-seconds-nanos does not really make sense, if you think about it. But if you insist on going that route, see the PeriodDuration class in the ThreeTen-Extra library.

ScheduledExecutorService

By the way, the Timer & TimerTask classes are now legacy, as mentioned in their Javadoc.

In Java 5+, we got the Executors framework to relieve us of the chore of juggling threads. Define your task as a Runnable or Callable. Then submit an object of that type to an ExecutorService to be run.

In particular, to schedule a task to run after a delay, use ScheduledExecutorService. You can even ask that interface to run a task repeatedly, with a specified gap of time.