Formatting a Duration in Java 8 / jsr310

There is no period/duration-formatter in jsr-310, different from JodaTime. Not every feature of JodaTime was ported to JSR-310 (for example also not PeriodType). And in reverse JSR-310 has some features which are not available in JodaTime (for example localized weekday numbers or the strategy pattern approach with adjusters).

It might happen that Java 9 will introduce some kind of built-in period formatting (read something about this from S. Colebourne).

Conclusion: JSR-310 and JodaTime are not fully compatible to each other, so a lot of work can be required. I would not be so keen on migration as soon as possible. Do you need special features of JSR-310 which are not offered by JodaTime?

Additional note: You should also be aware of the fact that joda period (which includes all units from years to seconds) is not fully compatible with jsr310-period (only years, months, days) or jsr310-duration (only hours, minutes, seconds and fraction seconds).

There is no built-in method but you can access the number of hours/minutes without having to calculate them manually. Your specific format could look like:

Duration d = Duration.of(75, HOURS).plusMinutes(15);
long hours = d.toHours(); //75
long minutes = d.minusHours(hours).toMinutes(); //15
String HH_PLUS_MM = hours + "+" + minutes; //75+15
System.out.println(HH_PLUS_MM);

If the duration is guaranteed to be less than 24 hours, you can also use this trick:

String hhPlusMm = LocalTime.MIDNIGHT.plus(d).format(DateTimeFormatter.ofPattern("HH+mm"));

Java 9 and later: Duration::to…Part methods

In Java 9 the Duration class gained new to…Part methods for returning the various parts of days, hours, minutes, seconds, milliseconds/nanoseconds. See this pre-release OpenJDK source code.

Given a duration of 49H30M20.123S…

• toNanosPart() = 123000000
• toMillisPart() = 123
• toSecondsPart() = 20
• toMinutesPart() = 30
• toHoursPart() = 1
• toDaysPart() = 2

Remember that “days” here means chunks of 24-hours, ignoring dates on a calendar. If you care about dates, use Period class instead.

I do not know if any additional formatter features are added. But at least you will be able to more conveniently generate your own strings from numbers obtained via these new getter methods.

Java 8

Oddly enough, no convenient getter methods for these values were included in the first edition release of java.time in Java 8. One of very few oversights in the otherwise excellent design of the java.time framework.

See the related Question: Why can't I get a duration in minutes or hours in java.time?.