How can I convert a Joda's Duration to a java.time.Duration?

Question

I want to parse a string like 1d2h3m4s into a java.time.Duration. I can use a joda's PeriodFormatter to parse the string into a org.joda.time.Duration but I can't figure out how to convert that to a standard Java8's java.time.Duration.

I have to interface to some "legacy" code that already expects java.time.Duration as input, but I want to use joda's parsePeriod because the java.time.Duration.parse() only accepts ISO-8601 duration format (1d2h3m4s is not ISO-8601 duration compliant)

import org.joda.time.format.PeriodFormatter;
import org.joda.time.format.PeriodFormatterBuilder;

...

final PeriodFormatter periodFormatter = new PeriodFormatterBuilder()
        .printZeroNever()
        .appendDays().appendSuffix("d")
        .appendHours().appendSuffix("h")
        .appendMinutes().appendSuffix("m")
        .appendSeconds().appendSuffix("s").toFormatter();

org.joda.time.Duration myduration = periodFormatter.parsePeriod("1d1s").toStandardDuration(); 
java.util.time myduration2 = XXXXX

Please bear in mind that I'm not trying to remove the usage of org.joda.time.Period from my code like in Converting org.joda.time.Period to java.time.Period. I still want to have a org.joda.time.Period because I have more parsing option to generate those, and I need a java.time.Period/java.time.Duration because I interact with some other API/libraries that expect java.time.*.

So, is there a way to convert a org.joda.time.Duration to a java.time.Duration?

Does this answer your question? [Converting org.joda.time.Period to java.time.Period](https://stackoverflow.com/questions/47217098/converting-org-joda-time-period-to-java-time-period) — www.hybriscx.com, Oct 31 '19 at 07:52
Not really, in that question the OP is not trying to convert one instance of `org.joda.time.Period` to an instance of `java.time.Period` at all. He is asking how to *replace* a joda's `Period` with a `java.time.Period` , so he won't have any joda's instance at all. I want to have both a joda's `Period` (because I have more options to parse there) and a `java.time.Period` (well `java.time.Duration` ) because I have other code that expects the input in this type. — RubenLaguna, Oct 31 '19 at 08:20

Ole V.V. · Accepted Answer · 2019-10-31T11:58:55.523

I am presenting three options

Hand modify the string to ISO 8601 format so that java.time.Duration can parse it.
Convert through count of milliseconds.
Convert from joda.time.Duration.toString().

Modify the string

Personally I don’t think I would want to depend in Joda-Time for this. Instead I would modify your non-ISO 8601 string to ISO 8601 format.

    String durationString = "1d1s";
    // Convert to ISO 8601 format
    String isoString = durationString.replaceFirst("(.*?[Dd])?(.*)", "P$1T$2");
    java.time.Duration dur = java.time.Duration.parse(isoString);
    System.out.println(dur);

Output is:

PT24H1S

I admit that the regular expression is a bit hard to read. If there is an uppercase or lowercase D in the string, everything up to and including that D is placed before the T in the ISO string. Everything else is placed after the T.

Convert over milliseconds

This is an idea similar to the one in the answer by ecerulm. I didn’t want to lose the millisecond precision of the Joda-Time duration, so I rely of milliseconds rather than seconds (I know that for your example strings it will make no difference).

    final PeriodFormatter periodFormatter = new PeriodFormatterBuilder()
            .printZeroNever()
            .appendDays().appendSuffix("d")
            .appendHours().appendSuffix("h")
            .appendMinutes().appendSuffix("m")
            .appendSeconds().appendSuffix("s").toFormatter();

    org.joda.time.Duration myduration = periodFormatter.parsePeriod("1d1s").toStandardDuration(); 

    java.time.Duration dur = java.time.Duration.ofMillis(myduration.getMillis());

The result is the same as before.

Convert over a string

    java.time.Duration dur = java.time.Duration.parse(myduration.toString());

Again the result is the same. Formatting the duration into an ISO 8601 string only to parse it back feels like a waste, though.

score 0 · Answer 2 · answered Oct 31 '19 at 07:56

You can just convert the org.joda.time.Period returned by PeriodFormatter#parse() to seconds using Period#toStandardSeconds()#getSeconds(). That will give you the number of seconds as an int

Then use java.time.Duration.ofSeconds() to create a java.time.Duration from that int.

import org.joda.time.format.PeriodFormatterBuilder
import org.joda.time.format.PeriodFormatter

PeriodFormatter formatter = new PeriodFormatterBuilder()
        .printZeroNever()
        .appendDays().appendSuffix("d")
        .appendHours().appendSuffix("h")
        .appendMinutes().appendSuffix("m")
        .appendSeconds().appendSuffix("s")
        .toFormatter();

Period myPeriod = formatter.parsePeriod("1d2h3m4s");

java.time.Duration myDuration = java.time.Duration.ofSeconds(
        myPeriod.toStandardSeconds().getSeconds());

How can I convert a Joda's Duration to a java.time.Duration?

2 Answers2

Modify the string

Convert over milliseconds

Convert over a string