Converting date without time for different timezone

Question

I store the date in UTC long and displayed in user timezone. But when I try to store only days without time it misleading to different dates.

Eg: Scheduling event on 05/06/2016 (06 May 2016). This date is unique for all regions without timezone. If user from GMT+5:30 timezone trying to add a event on 05/06/2016 then it ISO-8601 format is 2016-05-05T16:00:00.000Z and milliseconds is 1462464000000.

Then user from GMT timezone try to view this event. The date will be 05/05/2016 instead of 05/06/2016.

Is there any way to convert date without any timezone.

Why don't you take time into account when computing and display only date part? E.g. you create your event date as 2016-06-05T05:30:00.000Z, convert it to target timezone (if required) and display only date part? — Aakash, May 04 '16 at 04:10
"*I store the date in UTC*" => where do you store it? In a variable? In a database? If in a database, what is the column type? etc. — assylias, May 04 '16 at 07:21

Gobinath · Answer 1 · 2016-05-04T05:08:03.817

3

Java 8 provides the solution for your problem. If you can use Java 8, use java.time.LocalDate which represents only the date without the time. Store the long value returned by toEpochDay method. A sample code is given below:

LocalDate date = LocalDate.of(2016, 5, 4);
// Store this long value
long noOfDays = date.toEpochDay(); // No of days from 1970-01-01
LocalDate newDate = LocalDate.ofEpochDay(noOfDays);
System.out.println(newDate); // 2016-05-04

edited May 04 '16 at 05:08

answered May 04 '16 at 04:55

Gobinath

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If using Java 6 or 7 you can still use this solution. `java.time`, the modern Java date and time API, has been backported. Add [ThreeTen Backport](http://www.threeten.org/threetenbp/) to your project and you’re going. – Ole V.V. May 08 '18 at 11:24

score 1 · Answer 2 · edited May 23 '17 at 12:17

Always store the whole timestap. Whenever you want to display just convert the timestamp to whichever timezone you want to convert it to & display it.

These would help in conversions: (Time-stamp to Date or viseversa)

// timestamp to Date
long timestamp = 5607059900000; //Example -> in ms
Date d = new Date(timestamp );

// Date to timestamp
long timestamp = d.getTime();

//If you want the current timestamp :
Calendar c = Calendar.getInstance();
long timestamp = c.getTimeInMillis();

Refer : convert TimeStamp to Date in Java

You may display different date formats using SimpleDateFormat.

Eg:

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class MainClass {
  public static void main(String[] args) {
    String pattern = "MM/dd/yyyy";
    SimpleDateFormat format = new SimpleDateFormat(pattern);
    try {
      Date date = format.parse("12/31/2006");
      System.out.println(date);
    } catch (ParseException e) {
      e.printStackTrace();
    }
    // formatting
    System.out.println(format.format(new Date()));
  }
}

Converting date without time for different timezone

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