Separate DateTime to Date and Time with time zone `Z` at the end, in Joda-Time

Question

I have a Joda-Time DateTime object and need to have date and time separately, with time zone label at the end:

DateTime dateTime = new DateTime();
System.out.println(dateTime.toString("YYYY-MM-ddZ"));
System.out.println(dateTime.toString("HH:mm:ssZ"));

In this case the output will be:

2014-02-27+0000
15:10:36+0000

Almost exactly what I need, but it is possible to have it like this?

2014-02-27Z
15:10:36Z

Answer 1

Here's a working example

DateTime dateTime = new DateTime();
DateTimeFormatter formatter = new DateTimeFormatterBuilder()
            .appendPattern("yyyy-MM-dd")
            .appendTimeZoneOffset("Z", false, 2, 2)
            .toFormatter();
System.out.println(formatter.print(dateTime.withZone(DateTimeZone
            .forID("Zulu"))));

Basically, if the time zone offset is zero, you print Z. Since Zulu or UTC has an offset of 0, that's what will be printed.

Answer 2

If you're trying to use Military codes (i.e. Z for GMT see: http://www.timeanddate.com/library/abbreviations/timezones/military/z.html) you could so something like this:

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.TimeZone;

import java.util.Date;

public class CalendarExample {

  static final String MILITARY_OFFSETS = "YXWVUTSRQPONZABCDEFGHIKLM";
  static final int MILLIS_IN_HOUR = 1000*60*60;

  public static void main(String[] args) {
    System.out.println(formatDate(new Date(), "yyyy-MM-dd", "GMT")); // 2014-02-27Z
    System.out.println(formatDate(new Date(), "HH:mm:ss", "GMT"));
    System.out.println(formatDate(new Date(), "yyyy-MM-dd", "EST"));
    System.out.println(formatDate(new Date(), "HH:mm:ss", "EST"));
  }

  static String formatDate(Date date, String dateTimeFormat, String timezoneCode) {
    Calendar calendar = new GregorianCalendar();
    TimeZone tz = TimeZone.getTimeZone(timezoneCode);
    calendar.setTimeZone(tz);
    int offset = calendar.get(Calendar.ZONE_OFFSET)/MILLIS_IN_HOUR;

    // System.out.println(timezoneCode + " Offset is " + offset + " hours");
    String timeZoneCode = MILITARY_OFFSETS.substring(offset + 12, offset + 13);
    SimpleDateFormat dateFmt = new SimpleDateFormat(dateTimeFormat + "'" + timeZoneCode + "'");

    return dateFmt.format(date);
  }

}

output:

2014-02-27Z
11:57:44Z
2014-02-27R
11:57:44R