Converting UTC dates to other timezones

Question

I'm converting a UTC time to another timezone, using this method:

SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); Date parsed = format.parse("2011-03-01 15:10:37"); TimeZone tz = TimeZone.getTimeZone("America/Chicago"); format.setTimeZone(tz);  String result = format.format(parsed); 

So the input is 2011-03-01 15:10:37 but the output of this (value of result) is 2011-03-01 05:40:37. While it seems off, and according to this link, it should be 2011-03-01 09:10:37.

What am I doing wrong?

Answer 1

It turns out the code was almost correct, what I didn't take into account was that when parsing the String to get a Date object initially, it uses default system TimeZone, so the source date was not in UTC as I expected.

The trick was to set the timezone when parsing the date to UTC and then set it to destination TimeZone. Something like this:

SimpleDateFormat sourceFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); sourceFormat.setTimeZone(TimeZone.getTimeZone("UTC")); Date parsed = sourceFormat.parse("2011-03-01 15:10:37"); // => Date is in UTC now  TimeZone tz = TimeZone.getTimeZone("America/Chicago"); SimpleDateFormat destFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); destFormat.setTimeZone(tz);  String result = destFormat.format(parsed); 

Answer 2

Converting a date String of the format "2011-06-23T15:11:32" to out time zone.

 private String getDate(String dateString) {     SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");     formatter.setTimeZone(TimeZone.getTimeZone("UTC"));     Date value = null;     try {         value = formatter.parse(dateString);     } catch (ParseException e) {         e.printStackTrace();     }     SimpleDateFormat dateFormatter = new SimpleDateFormat("dd/MM/yyyy hh:mmaa");     dateFormatter.setTimeZone(TimeZone.getDefault());     String dt = dateFormatter.format(value);      return dt; }