Java atZone() method belongs to LocalDateTime class which is stored in java.time package. This method is used to combine date-time with a time-zone and create a ZonedDateTime.
LocalDateTime class represents a date-time without time-zone, so if we wish to get a date-time with time-zone then atZone() method is suitable. The Time zone can be any specific zone area like Asia/Kolkata, Asia/Tokyo, Europe/Paris, etc.
This method takes a single argument of ZoneId type to specify the time-zone and returns a zone-based date-time object(ZonedDateTime). The syntax of atZone() method is the following:
public ZonedDateTime atZone(ZoneId zone)
It takes a single ZoneId type parameter, like 'Asia/Kolkata'.
It returns a ZonedDateTime after combining the time-zone to date-time.
Let's take an example to convert date-time to ZonedDateTime. Here we are using atZone() method and specifying system default time-zone. It results in a zone-based date-time. See the example following:
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZonedDateTime;
/*
* Example to get ZonedDateTime from
* LocalDateTime's atZone() method.
*/
public class JExercise {
public static void main(String[] args) {
// Create a LocalDateTime date
LocalDateTime datetime = LocalDateTime.parse("2012-05-02T02:30:10");
// Print Date and time
System.out.println("Date and Time : "+datetime);
// Getting Day of week
ZonedDateTime zdatetime = datetime.atZone(ZoneId.systemDefault());
// Display zoned date time
System.out.println("Zoned Date and Time : "+zdatetime);
}
}Output:
Date and Time : 2012-05-02T02:30:10
Zoned Date and Time : 2012-05-02T02:30:10+05:30[Asia/Kolkata]
If we want to specify the time-zone rather than setting the system default time-zone, we can use of() method of ZoneId to set the time-zone. See, We set the Tokyo time zone to get date and time based on that area.
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZonedDateTime;
/*
* Example to get ZonedDateTime from
* LocalDateTime's atZone() method.
*/
public class JExercise {
public static void main(String[] args) {
// Create a LocalDateTime date
LocalDateTime datetime = LocalDateTime.parse("2012-05-02T02:30:10");
// Print Date and time
System.out.println("Date and Time : "+datetime);
// Getting Zoned-date-time
ZonedDateTime zdatetime = datetime.atZone(ZoneId.of("Asia/Tokyo"));
// Display zoned date time
System.out.println("Zoned Date and Time : "+zdatetime);
}
}Output:
Date and Time : 2012-05-02T02:30:10
Zoned Date and Time : 2012-05-02T02:30:10+09:00[Asia/Tokyo]
Well, in this topic, we learnt To combine time-zone with date-time to get ZonedDateTime object. We used several examples to explain the use of the atZone() method and specified zoneId, such as 'Asia/Kolkata'.
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