How to Convert a 2021-09-29T17:04:31.0000 +05:30 to 2021-09-29 17:04:31.0000000 Asia/Calcutta In Java?
and additional question is here-
I tried many ways to get the timezone(Asia/Calcutta) from offset(+05:30) but unable to get.
Can someone please help?
Since you cannot derive a zone from an offset (reliably), you may want to use a workaround / different approach.
Here's an example that parses the input String to an OffsetDateTime using a suitable DateTimeFormatter and then creates the desired ZoneId which it applies to the OffsetDateTime in order to create a ZonedDateTime.
public static void main(String[] args) {
// your example input
String offsetTime = "2021-09-29T17:04:31.0000 +05:30";
// define a formatter that parses a String of this format
DateTimeFormatter dtf = DateTimeFormatter.ofPattern("uuuu-MM-dd'T'HH:mm:ss.SSSS xxx");
// then parse it to an object that knows date, time and offset
OffsetDateTime odt = OffsetDateTime.parse(offsetTime, dtf);
// print the result
System.out.println(odt);
// now define the desired zone
ZoneId asiaCalcutta = ZoneId.of("Asia/Calcutta");
// and use the offset-aware object to apply the zone
ZonedDateTime zdt = odt.atZoneSameInstant(asiaCalcutta);
// print it
System.out.println(zdt);
}
This outputs
2021-09-29T17:04:31+05:30
2021-09-29T17:04:31+05:30[Asia/Calcutta]
Please note: This will only keep the same offset if the offset and the zone actually match. I don't know your concrete requirements, so only you can know if this approach is appropriate in your situation or not.
If you want to find out time zones that currently use a specific offset and then make your code decide which is the correct one, you may want to have a look at this question and its answers.
I tried to write this code to cover three possibilities String parameter , or LocalDateTime parameter and ZonedDateTime Parameter :
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
public class SpecialFormater {
// parameter : ZonedDateTime
public static String specialFormaterZonedDateTime(ZonedDateTime zdt) {
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSSSSSS");
ZoneId zid = zdt.getZone();
System.out.println("Your initial format =" + zdt);
String result = "Your expected format =" + zdt.format(formatter) + " " + zid;
return result;
}
// parameter : LocalDateTime
public static String specialFormaterLocalDateTime(LocalDateTime dt) {
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSSSSSS");
ZoneId zid = ZoneId.of("Asia/Calcutta");
System.out.println("Your initial format =" + dt);
ZonedDateTime zdt = ZonedDateTime.of(dt, zid);
System.out.println("Your zoned dateTime default format =" + zdt);
String result = "Your expected format =" + dt.format(formatter) + " " + zid;
return result;
}
// Parameter : String
public static String specialFormaterString(String localDateTime) {
System.out.println("String before formatting =" + localDateTime);
String pattern = "yyyy-MM-dd'T'HH:mm:ss.SSSS xxx";
DateTimeFormatter formatter = DateTimeFormatter.ofPattern(pattern);
LocalDateTime dt = LocalDateTime.parse(localDateTime, formatter);
ZoneId zid = ZoneId.of("Asia/Calcutta");
DateTimeFormatter formatter2 = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSSSSSS");
String result = "String after formatting =" + dt.format(formatter2) + " " + zid;
return result;
}
public static void main(String[] args) {
System.out.println("specialFormaterLocalDateTime");
System.out.println(specialFormaterLocalDateTime(LocalDateTime.now()));
System.out.println("***********");
System.out.println();
System.out.println("specialFormaterString");
System.out.println(specialFormaterString("2021-09-29T17:04:31.0000 +05:30"));
System.out.println("**********");
System.out.println();
System.out.println("specialFormaterZonedDateTime");
System.out.println(specialFormaterZonedDateTime(ZonedDateTime.now()));
}
}
Output :
specialFormaterLocalDateTime
Your initial format =2021-10-06T12:35:45.029
Your zoned dateTime default format =2021-10-06T12:35:45.029+05:30[Asia/Calcutta]
Your expected format =2021-10-06 12:35:45.0290000 Asia/Calcutta
***********
specialFormaterString
String before formatting =2021-09-29T17:04:31.0000 +05:30
String after formatting =2021-09-29 17:04:31.0000000 Asia/Calcutta
**********
specialFormaterZonedDateTime
Your initial format =2021-10-06T12:35:45.064+02:00[Europe/Paris]
Your expected format =2021-10-06 12:35:45.0640000 Europe/Paris
I tend to understand from your comment under Arvind Kumar Avinash’ answer that you have solved it by simply taking the first time zone that has the correct offset (or what you thought was the correct offset). Of course java.time, the modern Java date and time API, can do that. I wanted to show you a way.
String input = "2021-09-29T17:04:31.0000 +05:30";
// Remove space and parse
OffsetDateTime dateTime = OffsetDateTime.parse(input.replace(" ", ""));
ZoneOffset offset = dateTime.getOffset();
// Find and convert to a zone that matches the offset (there will usually be many)
ZonedDateTime zonedDateTime = ZoneId.getAvailableZoneIds()
.stream()
.map(ZoneId::of)
.map(dateTime::atZoneSameInstant)
.filter(zdt -> zdt.getOffset().equals(offset))
.findFirst()
// If all else fails, use the offset as time zone
.orElse(dateTime.atZoneSameInstant(offset));
// Convert to 2021-09-29 17:04:31.0000000 Asia/Calcutta format
String result = zonedDateTime.format(FORMATTER);
System.out.println(result);
I have used this formatter for formatting the output:
private static final DateTimeFormatter FORMATTER
= DateTimeFormatter.ofPattern("uuuu-MM-dd HH:mm:ss.SSSSSS VV", Locale.ROOT);
And the output is (on my Java 11):
2021-09-29 17:04:31.000000 Asia/Kolkata
Asia/Kolkata is the present-day name for the time zone formerly known as Asia/Calcutta. Is that close enough?
In my code I have taken the case into account where no suitable time zone exists. Let’s see this with an offset that I don’t think is used in any real time zone:
String input = "2021-10-06T18:54:31.0000 +00:30";
2021-10-06 18:54:31.000000 +00:30
If you didn’t want this, you will at least need to change the line with the call to orElse().
