Baseelements time zone offset8/17/2023 ![]() ZoneOffset zoneOffsetXmas = zdtXmas.getOffset() ![]() ZonedDateTime zdtXmas = ld.atStartOfDay( z ) LocalDate ld = LocalDate.of( 2017, 12, 25 ) ZoneId z = ZoneId.of( "America/Montreal" ) Specify the time zone America/Montreal, get a ZonedDateTime, ask for its offset as a ZoneOffset object. int offsetSeconds = zoneOffset.getTotalSeconds () Īnother example: Perhaps you want to know what the offset will be on Christmas Day this year in Québec. You can ask the offset for its amount of time as a total number of seconds. If important, ask the user for their intended time zone. ZoneId.systemDefault().toString(): America/Los_AngelesĪ caution about depending on the default zone: This default can be changed at any moment by any code in any thread within the JVM. OffsetDateTime odt = OffsetDateTime.now ( ZoneId.systemDefault () ) Eliminate the ambiguity about whether you intended the default or failed to consider time zone as so often happens with programmers. Even if you want the current default zone, say so explicitly to make your intentions clear. I suggest you always make that explicit by specifying your desired/expected time zone. That now method is actually applying implicitly the JVM’s current default time zone. ZoneOffset zoneOffset = odt.getOffset () OffsetDateTime odt = OffsetDateTime.now () So let's specify a moment as an OffsetDateTime, and then extract the ZoneOffset. In America/Los_Angeles, for example in part of this year the offset is -08:00 but in another part of the year it is -07:00 during DST. So it really makes no sense to ask for an offset without a date-time. The entire purpose of a time zone is to document those shifts in offset. For example, DST in the United States shifts the offset by an hour for about half the year and then restoring that hour back to the offset during the other half of the year. The offset for any region varies over time. Anomalies such as Daylight Saving Time (DST) causing shifts in the offset over specific periods of time are tracked over time, in the past as they happened, and in the future when politicians have announced planned changes. For example, -08:00 means eight hours behind the UTC, and +05:45 means five hours and forty-five minutes ahead of UTC.Ī time zone is a history of past, present, and future changes to the offset used by the people of a particular region. ZoneId.systemDefault()Īn offset-from-UTC is merely a number of hour, minutes, and seconds - nothing more. But you likely should be using a time zone rather than a mere offset-from-UTC.
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