How can I “pretty print” a Duration in Java?

Question

Does anyone know of a Java library that can pretty print a number in milliseconds in the same way that C# does?

E.g., 123456 ms as a long would be printed as 4d1h3m5

Answer 1

org.threeten.extra.AmountFormats.wordBased

The ThreeTen-Extra project, which is maintained by Stephen Colebourne, the author of JSR 310, java.time, and Joda-Time, has an AmountFormats class which works with the standard Java 8 date time classes. It's fairly verbose though, with no option for more compact output.

Duration d = Duration.ofMinutes(1).plusSeconds(9).plusMillis(86);
System.out.println(AmountFormats.wordBased(d, Locale.getDefault()));

1 minute, 9 seconds and 86 milliseconds

Answer 2

JodaTime has a Period class that can represent such quantities, and can be rendered (via IsoPeriodFormat) in ISO8601 format, e.g. PT4D1H3M5S, e.g.

Period period = new Period(millis);
String formatted = ISOPeriodFormat.standard().print(period);

If that format isn't the one you want, then PeriodFormatterBuilder lets you assemble arbitrary layouts, including your C#-style 4d1h3m5s.

Answer 3

Java 9+

Duration d1 = Duration.ofDays(0);
        d1 = d1.plusHours(47);
        d1 = d1.plusMinutes(124);
        d1 = d1.plusSeconds(124);
System.out.println(String.format("%s d %sh %sm %ss", 
                d1.toDaysPart(), 
                d1.toHoursPart(), 
                d1.toMinutesPart(), 
                d1.toSecondsPart()));

2 d 1h 6m 4s

Answer 4

Here's how you can do it using pure JDK code:

import javax.xml.datatype.DatatypeFactory;
import javax.xml.datatype.Duration;

long diffTime = 215081000L;
Duration duration = DatatypeFactory.newInstance().newDuration(diffTime);

System.out.printf("%02d:%02d:%02d", duration.getDays() * 24 + duration.getHours(), duration.getMinutes(), duration.getSeconds()); 

Answer 5

I realize this might not fit your use case exactly, but PrettyTime might be useful here.

PrettyTime p = new PrettyTime();
System.out.println(p.format(new Date()));
//prints: “right now”

System.out.println(p.format(new Date(1000*60*10)));
//prints: “10 minutes from now”

Answer 6

With Java 8 you can also use the toString() method of java.time.Duration to format it without external libraries using ISO 8601 seconds based representation such as PT8H6M12.345S.