Question

there are two string

String date = "9/13/2012";
String time = "5:48pm";

the time is GMT+0, I wanna change it to GMT+8,what is the simplest way to change a time to particular timezone

Answer 1

• Parse it using a SimpleDateFormat set to the UTC time zone
• Format the parsed Date value using a SimpleDateFormat set to the time zone you’re interested in. (It’s likely to be something other than just “UTC+8” – you should find out which TZDB time zone ID you really want.

For example:

SimpleDateFormat inputFormat = new SimpleDateFormat("MM/dd/yyyy h:mma", Locale.US);
inputFormat.setTimeZone(TimeZone.getTimeZone("Etc/UTC");
Date date = inputFormat.parse(date + " " + time);

// Or whatever format you want...
SimpleDateFormat outputFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm", Locale.US);
outputFormat.setTimeZone(targetTimeZone);
String outputText = outputFormat.format(date);

(If you can use Joda Time instead, that’d be great – but I understand that it’s pretty big for an Android app.)