Changing TimeZone of Date.

[R K Singh]

I want to convert my Date timezone from local setting to say Zulu.

First of all Date class does not support setting of TimeZone [method is depricated.]

I have found a way to change the timeZone, but I am not very sure if its the best way to change the TimeZone.

Following is the code which currently works fine.

  
        final String DATE_FORMAT = "yyyy-MM-dd hh:mm:ss.SSS";
        final String ZULU_TIMEZONE = "Zulu";
 
        SimpleDateFormat dateFormatori = new SimpleDateFormat(DATE_FORMAT);
        TimeZone zuluTimeZoneori = TimeZone.getTimeZone(ZULU_TIMEZONE);
        dateFormatori.setTimeZone(zuluTimeZoneori);
 
        // get current Date/time
        java.util.Date tempDate = new java.util.Date();
        String dateTimestampFormat = dateFormatori.format(tempDate); // NOTE: pay attention to this line.
 
        System.out.println("\n\n Ori " + Timestamp.valueOf(dateTimestampFormat));
 

I am not comfortable with the idea of first getting String and then actually getting the changed date.

Is there any better way to change the TimeZone ???

Thanks in advance.

This following program is my test program, in case if one wants to run the code.

  
import java.util. *;  
import java.text.*;
import java.sql.Timestamp;
 

public class DateTimeZone {
 
    public static void main(String[] args) throws Exception{
 
        {
            // announcement of the current default time belt:
            System.out.println("default time belt = "+  TimeZone.getDefault().getID());
 
            // e.g..  ' euro PE/Berlin '
            TimeZone zuluTimeZone = TimeZone.getTimeZone("Zulu");
 
             // create a GregorianCalendar with the Pacific Daylight time zone
             // and the current date and time
             Calendar calendar = new GregorianCalendar(TimeZone.getDefault());
 
             Date trialTime = new Date();
             calendar.setTime(trialTime);
             System.out.println("time = "+  calendar.getTime());
             System.out.println("time belt = "+  calendar.getTimeZone().getID());
 
             Calendar zuluCalendar = new GregorianCalendar(zuluTimeZone);
             //calendar.setTime(trialTime);
            System.out.println("\n\nzulu time belt = "+  zuluCalendar.getTimeZone().getID());
            System.out.println("zulu time = "+  zuluCalendar.getTime());
 

            //System.out.println("\n\n new Date = "+  new Date());
            SimpleDateFormat dateFormatTest = new SimpleDateFormat();
            dateFormatTest.setCalendar(calendar);
            System.out.println("\n\ndateFormatTest : " + dateFormatTest.format(trialTime));
            System.out.println("dateFormatTest Pattern: " + dateFormatTest.toPattern());
 
            //DateFormat dateFormat = DateFormat.getDateTimeInstance();
            SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss.SSS");
            //SimpleDateFormat dateFormat = new SimpleDateFormat();
            System.out.println("\npattern: " + dateFormat.toPattern());
 
            //dateFormat.setCalendar(calendar);
            System.out.println("\n\nBefore Zulu dateFormat : " + dateFormat.format(trialTime));
            System.out.println("Before Zulu date : " + dateFormat.parse(dateFormat.format(trialTime)));
            System.out.println("Before Zulu SQltimeStamp Using TimeStamp: " + Timestamp.valueOf(dateFormat.format(trialTime)));
 
            dateFormat.setTimeZone(zuluTimeZone);
            //dateFormat.setCalendar(zuluCalendar);
            System.out.println("\n\nAfter Zulu dateFormat : " + dateFormat.format(trialTime));
            System.out.println("After Zulu SQltimeStamp : " + dateFormat.parse(dateFormat.format(trialTime)));
            System.out.println("After Zulu SQltimeStamp Using TimeStamp: " + Timestamp.valueOf(dateFormat.format(trialTime)));
            System.out.println("After Zulu SQltimeStamp Using TimeStamp: " + new Timestamp(zuluCalendar.getTime().getTime()));
        }
 
        final String DATE_FORMAT = "yyyy-MM-dd hh:mm:ss.SSS";
        final String ZULU_TIMEZONE = "Zulu";
 
        SimpleDateFormat dateFormatori = new SimpleDateFormat(DATE_FORMAT);
        TimeZone zuluTimeZoneori = TimeZone.getTimeZone(ZULU_TIMEZONE);
        dateFormatori.setTimeZone(zuluTimeZoneori);
 
        // get current Date/time
        java.util.Date tempDate = new java.util.Date();
        String dateTimestampFormat = dateFormatori.format(tempDate);
 
//      // set the time zone in GMT
//      int offset = 2 * tempDate.getTimezoneOffset();
//      tempDate.setTimezoneOffset(offset);
 
        System.out.println("\n\n Ori " + Timestamp.valueOf(dateTimestampFormat));
 

 

    }
 
}

[R K Singh]

still wondering, I doubt that its the best way to change the timezone?

I think, its not necessary to first convert to String and then get the changed timeZone.
I will really appreciate if someone has used or know any other alternate way to change the timezone.

Thanks in advance.