How to convert ZonedDateTime/OffsetDateTime to Date using ThreeTenABP?

Question

Using the ThreeTen Android Backport library, what is the simplest way to convert a ZonedDateTime or OffsetDateTime into an old-school java.util.Date instance?

If I had full Java 8 libs at my disposal, this of course would be the way to do it (as in this question):

Date.from(zonedDateTime.toInstant());

But I cannot use that on Android; specifically Date.from(Instant instant) is missing.

score 42 · Answer 1 · answered Jan 05 '17 at 09:00

42

Well, one straightforward way is to get milliseconds since epoch and create the Date from that:

long epochMilli = zonedDateTime.toInstant().toEpochMilli();
Date date = new Date(epochMilli);

Feel free to point out if there's some preferable way.

answered Jan 05 '17 at 09:00

Jonik

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or even a one-liner `new Date(zonedDateTime.toInstant().toEpochMilli());` – kiedysktos Oct 09 '17 at 10:56
@Sten's answer in https://stackoverflow.com/a/72392825/1880761 is even simpler. – trebor Jun 26 '22 at 18:28

score 18 · Accepted Answer · edited Oct 29 '18 at 18:22

18

See DateTimeUtils which handles the methods added to classes like java.util.Date: http://www.threeten.org/threetenbp/apidocs/org/threeten/bp/DateTimeUtils.html

Edit: using that, the complete code would be:

DateTimeUtils.toDate(zonedDateTime.toInstant())

edited Oct 29 '18 at 18:22

Jonik

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answered Jan 05 '17 at 17:43

JodaStephen

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Nice, this utility class is what I had missed. So the exact code would be `DateTimeUtils.toDate(zonedDateTime.toInstant())`. Also good to note (looking at ThreeTenABP sources) that under the hood it uses just [what I had thought](http://stackoverflow.com/a/41480812/56285), i.e. `new Date(instant.toEpochMilli())`. – Jonik Jan 09 '17 at 10:36

How to convert ZonedDateTime/OffsetDateTime to Date using ThreeTenABP?

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