Convert Date/Time for given Timezone - java

Question

I want to convert this GMT time stamp to GMT+13:

2011-10-06 03:35:05

I have tried about 100 different combinations of DateFormat, TimeZone,

Answer 1

We can get the UTC/GMT time stamp from the given date.

/**
 * Get the time stamp in GMT/UTC by passing the valid time (dd-MM-yyyy HH:mm:ss)
 */
public static long getGMTTimeStampFromDate(String datetime) {
    long timeStamp = 0;
    Date localTime = new Date();

    String format = "dd-MM-yyyy HH:mm:ss";
    SimpleDateFormat sdfLocalFormat = new SimpleDateFormat(format);
    sdfLocalFormat.setTimeZone(TimeZone.getDefault());

    try {

        localTime = (Date) sdfLocalFormat.parse(datetime); 

        Calendar cal = Calendar.getInstance(TimeZone.getTimeZone("UTC"),
                Locale.getDefault());
        TimeZone tz = cal.getTimeZone();

        cal.setTime(localTime);

        timeStamp = (localTime.getTime()/1000);
        Log.d("GMT TimeStamp: ", " Date TimegmtTime: " + datetime
                + ", GMT TimeStamp : " + localTime.getTime());

    } catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    return timeStamp;

}

It will return the UTC time based on passed date.

• We can do reverse like UTC time stamp to current date and time(vice versa)

      public static String getLocalTimeFromGMT(long gmtTimeStamp) {
               try{
                      Calendar calendar = Calendar.getInstance();
                      TimeZone tz = TimeZone.getDefault();
                      calendar.setTimeInMillis(gmtTimeStamp * 1000);
      //              calendar.add(Calendar.MILLISECOND, tz.getOffset(calendar.getTimeInMillis())); 
                      SimpleDateFormat sdf = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss");
                      Date currenTimeZone = (Date) calendar.getTime();
                      return sdf.format(currenTimeZone);
                  }catch (Exception e) {
                  }
                  return "";  
              }
  

I hope this will help others. Thanks!!

Answer 2

Joda-Time

The java.util.Date/Calendar classes are a mess and should be avoided.

Update: The Joda-Time project is in maintenance mode. The team advises migration to the java.time classes.

Here's your answer using the Joda-Time 2.3 library. Very easy.

As noted in the example code, I suggest you use named time zones wherever possible so that your programming can handle Daylight Saving Time (DST) and other anomalies.

If you had placed a T in the middle of your string instead of a space, you could skip the first two lines of code, dealing with a formatter to parse the string. The DateTime constructor can take a string in ISO 8601 format.

// © 2013 Basil Bourque. This source code may be used freely forever by anyone taking full responsibility for doing so.
// import org.joda.time.*;
// import org.joda.time.format.*;

// Parse string as a date-time in UTC (no time zone offset).
DateTimeFormatter formatter = org.joda.time.format.DateTimeFormat.forPattern( "yyyy-MM-dd' 'HH:mm:ss" );
DateTime dateTimeInUTC = formatter.withZoneUTC().parseDateTime( "2011-10-06 03:35:05" );

// Adjust for 13 hour offset from UTC/GMT.
DateTimeZone offsetThirteen = DateTimeZone.forOffsetHours( 13 );
DateTime thirteenDateTime = dateTimeInUTC.toDateTime( offsetThirteen );

// Hard-coded offsets should be avoided. Better to use a desired time zone for handling Daylight Saving Time (DST) and other anomalies.
// Time Zone list… http://joda-time.sourceforge.net/timezones.html
DateTimeZone timeZoneTongatapu = DateTimeZone.forID( "Pacific/Tongatapu" );
DateTime tongatapuDateTime = dateTimeInUTC.toDateTime( timeZoneTongatapu );

Dump those values…

System.out.println( "dateTimeInUTC: " + dateTimeInUTC );
System.out.println( "thirteenDateTime: " + thirteenDateTime );
System.out.println( "tongatapuDateTime: " + tongatapuDateTime );

When run…

dateTimeInUTC: 2011-10-06T03:35:05.000Z
thirteenDateTime: 2011-10-06T16:35:05.000+13:00
tongatapuDateTime: 2011-10-06T16:35:05.000+13:00

Answer 3

display date and time for all timezones

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



static final String ISO8601 = "yyyy-MM-dd'T'HH:mm:ssZ";
DateFormat dateFormat = new SimpleDateFormat(ISO8601);
Calendar c = Calendar.getInstance();
String formattedTime;
for (String availableID : TimeZone.getAvailableIDs()) {
    dateFormat.setTimeZone(TimeZone.getTimeZone(availableID));
    formattedTime = dateFormat.format(c.getTime());
    System.out.println(formattedTime + " " + availableID);
}

Answer 4

public Timestamp convertLocalTimeToServerDatetime(String dt,String timezone){

    String clientDnT = dt ;// "2017-06-01 07:20:00";
    try{
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    Date date = sdf.parse(clientDnT);
    TimeZone tz = TimeZone.getTimeZone(timezone.trim()); // get time zone of user
    sdf.setTimeZone(tz);

    // Convert to servertime zone 
    SimpleDateFormat sdf1 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    TimeZone tzInAmerica = TimeZone.getDefault();
    sdf1.setTimeZone(tzInAmerica);

    // assign date to date
    String serverDate = sdf1.format(date);

    // Convert to servertime zone to Timestamp
    Date date2 =  sdf.parse(serverDate);
    Timestamp tsm = new Timestamp(date2.getTime());
    return  tsm;
    }
    catch(Exception e){
        System.err.println(e);
    }

    return null;
}

Answer 5

Had a look about and I don't think theres a timezone in Java that is GMT + 13. So I think you have to use:

Calendar calendar = Calendar.getInstance();
//OR Calendar.getInstance(TimeZone.getTimeZone("GMT"));

calendar.set(Calendar.HOUR_OF_DAY, calendar.get(Calendar.HOUR_OF_DAY)+13);

Date d = calendar.getTime();

(If there is then change "GMT" to that Timezone and remove the 2nd line of code)

OR

SimpleDateFormat df = new SimpleDateFormat();
df.setTimeZone(TimeZone.getTimeZone("GMT+13"));
System.out.println(df.format(c.getTime()));

If you want to set a specific time/date you can also use:

    calendar.set(Calendar.DATE, 15);
calendar.set(Calendar.MONTH, 3);
calendar.set(Calendar.YEAR, 2011);
calendar.set(Calendar.HOUR_OF_DAY, 13); 
calendar.set(Calendar.MINUTE, 45);
calendar.set(Calendar.SECOND, 00);

Answer 6

I have try this code

try{
            SimpleDateFormat sdf = new SimpleDateFormat("dd-MM-yyyy hh:mm:ss Z");
            Date datetime = new Date();

            System.out.println("date "+sdf.format(datetime));

            sdf.setTimeZone(TimeZone.getTimeZone("GMT"));

            System.out.println("GMT "+ sdf.format(datetime));

            sdf.setTimeZone(TimeZone.getTimeZone("GMT+13"));

            System.out.println("GMT+13 "+ sdf.format(datetime));

            sdf.setTimeZone(TimeZone.getTimeZone("UTC"));

            System.out.println("utc "+sdf.format(datetime));

            Calendar calendar = new GregorianCalendar(TimeZone.getTimeZone("GMT"));

            DateFormat formatter = new SimpleDateFormat("dd MMM yyyy HH:mm:ss z");    
            formatter.setTimeZone(TimeZone.getTimeZone("GMT+13"));  

            String newZealandTime = formatter.format(calendar.getTime());

            System.out.println("using calendar "+newZealandTime);

        }catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

and getting this result

date 06-10-2011 10:40:05 +0530
GMT 06-10-2011 05:10:05 +0000 // here getting 5:10:05
GMT+13 06-10-2011 06:10:05 +1300 // here getting 6:10:05
utc 06-10-2011 05:10:05 +0000
using calendar 06 Oct 2011 18:10:05 GMT+13:00