CODEWITHSUNDEEP
java
Anurag Sharma
Anurag Sharma

Reputation: 2605

Convert long epoch time for a specified Zone to long epoch time in UTC

I have a requirement to convert long epoch time for a multiple Zone (variable) to long epoch time in UTC.

I have been trying to do something like following in joda-time:

long getUTCLong(long timestamp, String timeZone) {
    DateTimeZone zone = DateTimeZone.forID(timeZone);
    DateTime dt = new DateTime(timestamp, zone);
    dt.getMillis();
}

But this does not work. How to do this with new java.time features

Upvotes: 2

Views: 145

Answers (1)

Andreas
Andreas

Reputation: 159114

Although the question code uses Joda-Time, it is actually asking for solution using Java Time API, so here it is:

static long getUTCLong(long timestamp, String timeZone) {
    return Instant.ofEpochMilli(timestamp) // process timestamp as milliseconds since 1970-01-01
                  .atZone(ZoneOffset.UTC).toLocalDateTime() // get pure date/time without timezone
                  .atZone(ZoneId.of(timeZone)) // mark the date/time as being in given timezone
                  .toInstant() // convert to UTC
                  .toEpochMilli(); // get the epoch time in milliseconds since 1970-01-01
}

Upvotes: 5

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