I am developing a Java application that will be used by people from around the world. One feature requires it to display the current time in Melbourne, Australia.
I have found this answer and adapted the code as follows, but it returns my current time (as expected). It uses the Apache Commons Net library:
try {
String TIME_SERVER = "time-a.nist.gov";
NTPUDPClient timeClient = new NTPUDPClient();
InetAddress inetAddress = InetAddress.getByName(TIME_SERVER);
TimeInfo timeInfo = timeClient.getTime(inetAddress);
long returnTime = timeInfo.getMessage().getTransmitTimeStamp().getTime();
return new Date(returnTime);
} catch (Exception e) {
System.out.println(e.getMessage());
return null;
}
How can I modify this code to return the time in Melbourne, rather than my time? I am open to other solutions to solve this problem as well.
Thank you!
EDIT:
Taking Jon's advice, I have used the JodaTime library and built the following code to solve the problem. It can be used for other time zones by changing Australia/Melbourne to any timezone found here.
try {
//Get the time for the current time zone.
String TIME_SERVER = "time-a.nist.gov";
NTPUDPClient timeClient = new NTPUDPClient();
InetAddress inetAddress = InetAddress.getByName(TIME_SERVER);
TimeInfo timeInfo = timeClient.getTime(inetAddress);
long returnTime = timeInfo.getMessage().getTransmitTimeStamp().getTime();
//Format it to the Melbourne TimeZone.
DateTimeZone tzMelbourne = DateTimeZone.forID("Australia/Melbourne");
return new DateTime(returnTime).toDateTime(tzMelbourne);
} catch (Exception e) {
System.out.println(e.getMessage());
return null;
}
You're currently returning a java.util.Date
- that doesn't have a time zone. It's just an instant in time. It's not in your time zone, or some other time zone - it's just an instant. When you call toString()
, that will give you a textual representation in your local time zone, but that's not part of the data in the object.
If you need to represent "a date/time in a particular time zone" then you should use the Calendar
class, or ideally use Joda Time which is a much better date/time API.
Alternatively, if you're just trying to format the date/time in a particular time zone, you can use SimpleDateFormat
- set the time zone, and then format the Date
value you're already returning.