CODEWITHSUNDEEP
javajava-8
Santosh Kamat
Santosh Kamat

Reputation: 25

Convert timestamp belonging to a particular timezone into Timestamp for another timezone

Consider Timestamp sourceTimestamp belonging to Timezone sourceTimezone . I want to convert sourceTimestamp to a new Timestamp belonging to Timezone newTimezone.
How do I get this new Timestamp?

Basically I want a function like

Timestamp myFunction(Timestamp sourceTimestamp , Timezone sourceTimezone , Timezone newTimezone){
        ...
        ...
    return newTimestamp
}

Timestamp belongs to package java.sql.Timestamp and Timezone belongs to import java.util.TimeZone.

Upvotes: 0

Views: 44

Answers (1)

deHaar
deHaar

Reputation: 18568

If Java 8 is available to you, you will be best advised to use java.time.

Fortunately, a java.sql.Timestamp has methods to convert its values from and to objects/classes from java.time

You could write a method that takes a Timestamp and two ZoneIds:

public static Timestamp convertZone(Timestamp time, ZoneId originZone, ZoneId targetZone) {
    // create a zone-aware datetime object to fully represent the input
    ZonedDateTime originZdt = time.toLocalDateTime().atZone(originZone);
    /*
     * then change its zone, keeping the epoch millis
     * (only time of day changes according to the zone)
     */
    ZonedDateTime targetZdt = originZdt.withZoneSameInstant(targetZone);
    // and return a Timestamp of the date and time of the adjusted
    return Timestamp.valueOf(targetZdt.toLocalDateTime());
}

and then use it somehow like this:

public static void main(String[] args) throws Exception {
    // create some example Timestamp
    Timestamp sourceTimestamp = Timestamp.from(Instant.now());
    // define the zones
    ZoneId sourceTimezone = ZoneId.of("Europe/Amsterdam");
    ZoneId newTimezone = ZoneId.of("Asia/Kolkata");
    // use the method to convert the values
    Timestamp adjusted = convertZone(sourceTimestamp, sourceTimezone, newTimezone);
    // print them
    System.out.println("source: " + sourceTimestamp);
    System.out.println("target: " + adjusted);
}

Some moments (Instants ;-) ) ago, the output on my machine was:

source: 2021-08-04 08:50:22.913429
target: 2021-08-04 12:20:22.913429

Upvotes: 1

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