Question

I was looking for the simplest way to convert a date an time from GMT to my local time. Of course, having the proper DST dates considered and as standard as possible.

The most straight forward code I could come up with was:

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String inpt = "2011-23-03 16:40:44";
Date inptdate = null;
try {
    inptdate = sdf.parse(inpt);
} catch (ParseException e) {e.printStackTrace();}   
Calendar tgmt = new GregorianCalendar(TimeZone.getTimeZone("GMT"));
tgmt.setTime(inptdate);

Calendar tmad = new GregorianCalendar(TimeZone.getTimeZone("Europe/Madrid"));
tmad.setTime(inptdate);

System.out.println("GMT:\t\t" + sdf.format(tgmt.getTime()));
System.out.println("Europe/Madrid:\t" + sdf.format(tmad.getTime()));

But I think I didn’t get the right concept for what getTime will return.

Answer 1

The catch here is that the DateFormat class has a timezone. Try this example instead:

    SimpleDateFormat sdfgmt = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    sdfgmt.setTimeZone(TimeZone.getTimeZone("GMT"));

    SimpleDateFormat sdfmad = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    sdfmad.setTimeZone(TimeZone.getTimeZone("Europe/Madrid"));

    String inpt = "2011-23-03 16:40:44";
    Date inptdate = null;
    try {
        inptdate = sdfgmt.parse(inpt);
    } catch (ParseException e) {e.printStackTrace();}

    System.out.println("GMT:\t\t" + sdfgmt.format(inptdate));
    System.out.println("Europe/Madrid:\t" + sdfmad.format(inptdate));