Timezone conversion in Java | Code Factory

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1. Convert ZonedDateTime between timezones

LocalDateTimeExample.java

package com.codeFactory;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
/**
 * @author code.factory
 *
 */
public class LocalDateTimeExample {
private static final String DATE_FORMAT = "yyyy-M-dd hh:mm:ss a z";
 private static final DateTimeFormatter FORMATTER = DateTimeFormatter.ofPattern(DATE_FORMAT);
 private static final String souce = "Asia/Kolkata";
 private static final String target = "Australia/Sydney";
public static void main(String[] args) {
  ZoneId sourceTimeZone = ZoneId.of(souce);
  ZoneId targetTimeZone = ZoneId.of(target);
LocalDateTime today = LocalDateTime.now();
// Zoned date time at source timezone
  ZonedDateTime sourceTime = today.atZone(sourceTimeZone);
// Zoned date time at target timezone
  ZonedDateTime targetTime = sourceTime.withZoneSameInstant(targetTimeZone);
System.out.println(FORMATTER.format(sourceTime));
  System.out.println(FORMATTER.format(targetTime));
 }
}

Output :

2019-11-30 09:14:27 PM IST
2019-12-01 02:44:27 AM AEDT

2. Convert Date between timezones

DateExample.java

package com.codeFactory;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimeZone;
/**
 * @author code.factory
 *
 */
public class DateExample {
private static final String DATE_FORMAT = "yyyy-M-dd hh:mm:ss a z";
 private static final SimpleDateFormat FORMATTER = new SimpleDateFormat(DATE_FORMAT);
 private static final String souce = "Asia/Kolkata";
 private static final String target = "Australia/Sydney";
public static void main(String[] args) {
  TimeZone sourceTimeZone = TimeZone.getTimeZone(souce);
  TimeZone targetTimeZone = TimeZone.getTimeZone(target);
Date currentDate = new Date();
// Date in source timezone
  FORMATTER.setTimeZone(sourceTimeZone);
  System.out.println(FORMATTER.format(currentDate));
// Date in target timezone
  FORMATTER.setTimeZone(targetTimeZone);
  System.out.println(FORMATTER.format(currentDate));
 }
}

Output :

2019-11-30 09:15:01 PM IST
2019-12-01 02:45:01 AM AEDT

3. Convert Calendar between timezones

package com.codeFactory;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.TimeZone;
/**
 * @author code.factory
 *
 */
public class CalendarExample {
private static final String DATE_FORMAT = "yyyy-M-dd hh:mm:ss a z";
 private static final SimpleDateFormat FORMATTER = new SimpleDateFormat(DATE_FORMAT);
 private static final String souce = "Asia/Kolkata";
 private static final String target = "Australia/Sydney";
public static void main(String[] args) {
  TimeZone sourceTimeZone = TimeZone.getTimeZone(souce);
  TimeZone targetTimeZone = TimeZone.getTimeZone(target);
Calendar today = Calendar.getInstance(sourceTimeZone);
// Date in source timezone
  System.out.println(FORMATTER.format(today.getTime()));
// Date in target timezone
  FORMATTER.setTimeZone(targetTimeZone);
  System.out.println(FORMATTER.format(today.getTime()));
 }
}

Output :

2019-11-30 09:15:36 PM IST
2019-12-01 02:45:36 AM AEDT

Reference Links :

All ZoneId : Get All ZoneId.