CODEWITHSUNDEEP
javadateparsingtimeutc
internethulk
internethulk

Reputation: 92

Convert Time with offset to UTC and return localdatetime

I have a Method which parses a String according to Iso8601 and returns a LocalDateTime. Now I accept possible offsets. The Problem now is I have to convert the offset to UTC and return it as LocalDateTime.

So far I have tried working with Instant, OffsetDateTime, ZonedDateTime. I always get the opposite. Instead of +06:00 my result will be shown as -06:00.

return LocalDateTime.ofInstant(Instant.from(OffsetDateTime.parse(date, buildIso8601Formatter())), ZoneOffset.UTC);

This is the solution which works the same as my other tried ones I mentioned above.

I know this is not the common way to do it and I did a lot of research because of that but the current architecture only allows me to do it that way.

EDIT example: With an implementation like this: 

OffsetDateTime offsetDateTime = OffsetDateTime.parse(date, buildIso8601Formatter()); 
Instant instant = offsetDateTime.toInstant();


return LocalDateTime.ofInstant(instant, ZoneOffset.UTC);

Let's say I get "2020-01-12T08:30+06:00" as input for my method. I HAVE to return LocalDateTime.

As a result I want to have "2020-01-12T14:30" instead my best solution was to get it the opposite way: "2020-01-12T02:30".

Upvotes: 1

Views: 756

Answers (1)

MC Emperor
MC Emperor

Reputation: 22977

The behavior of java.time is correct. The string 2020-01-12T08:30+06:00 means that the datetime part of this string is a datetime local to some region, which exists in an area with an offset of +06:00 from UTC.

Your interpretation is different from the abovementioned case. In your case, you interpret 08:30 as a time in sync with UTC, and then concatenate the timezone offset string for the desired region.

So if you really want to do this – think again.

One way to achieve this, is simply by parsing the datetime as an offset datetime and negate the offset.

Upvotes: 4

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