date - Java 8: Calculate difference between two ZonedDateTime

Question

I'm trying to write a method to print the time difference between two ZonedDateTimes, regarding the difference between time zones.

I found some solutions but all of them were written to work with LocalDateTime.

Answer 1

You can use method between from ChronoUnit.

This method converts those times to same zone (zone from the first argument) and after that, invokes until method declared in Temporal interface:

static long zonedDateTimeDifference(ZonedDateTime d1, ZonedDateTime d2, ChronoUnit unit){
    return unit.between(d1, d2);
}

Since both ZonedDateTime and LocalDateTime implements Temporal interface, you can write also universal method for those date-time types:

static long dateTimeDifference(Temporal d1, Temporal d2, ChronoUnit unit){
    return unit.between(d1, d2);
}

But keep in mind, that invoking this method for mixed LocalDateTime and ZonedDateTime leads to DateTimeException.

Hope it helps.