Date in to UTC format Java

Question

I have a string like this 2013-10-22T01:37:56. I Need to change this string into UTC Date format like this MM/dd/yyyy KK:mm:ss a. I have tried some code but it is not returning the UTC datetime.

My code is

        String[] time = itsAlarmDttm.split("T");
        String aFormatDate = time[0]+ " "+time[1];
        String aRevisedDate = null;
        try {
            final SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            final Date dateObj = sdf.parse(aFormatDate);
            aRevisedDate = new SimpleDateFormat("MM/dd/yyyy KK:mm:ss a").format(dateObj);
            System.out.println(aRevisedDate);
        } catch (ParseException e) {
            itsLogger.error("Error occured in Parsing the Data Time Object:  " +e.getMessage());
        } catch (Exception e) {
            itsLogger.error("Error occured in Data Time Objecct:  " +e.getMessage());
        }

I am getting the output is MM/dd/yyyy KK:mm:ss a format. But Not UTC time format. How to solve this issue?

Answer 1

Try this... Worked for me and printed 10/22/2013 01:37:56 AM Ofcourse this is your code only with little modifications.

final SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");
sdf.setTimeZone(TimeZone.getTimeZone("UTC"));   // This line converts the given date into UTC time zone
final java.util.Date dateObj = sdf.parse("2013-10-22T01:37:56");

aRevisedDate = new SimpleDateFormat("MM/dd/yyyy KK:mm:ss a").format(dateObj);
System.out.println(aRevisedDate);

Answer 2

Try to format your date with the Z or z timezone flags:

new SimpleDateFormat("MM/dd/yyyy KK:mm:ss a Z").format(dateObj);

Answer 3

SimpleDateFormat sdf = new SimpleDateFormat( "yyyy-MM-dd HH:mm:ss" );
// or SimpleDateFormat sdf = new SimpleDateFormat( "MM/dd/yyyy KK:mm:ss a Z" );
sdf.setTimeZone( TimeZone.getTimeZone( "UTC" ) );
System.out.println( sdf.format( new Date() ) );

Answer 4

What Time Zones?

No where in your question do you mention time zone. What time zone is implied that input string? What time zone do you want for your output? And, UTC is a time zone (or lack thereof depending on your mindset) not a string format.

ISO 8601

Your input string is in ISO 8601 format, except that it lacks an offset from UTC.

Joda-Time

Here is some example code in Joda-Time 2.3 to show you how to handle time zones. Joda-Time has built-in default formatters for parsing and generating String representations of date-time values.

String input = "2013-10-22T01:37:56";
DateTime dateTimeUtc = new DateTime( input, DateTimeZone.UTC );
DateTime dateTimeMontréal = dateTimeUtc.withZone( DateTimeZone.forID( "America/Montreal" );
String output = dateTimeMontréal.toString();

As for generating string representations in other formats, search StackOverflow for "Joda format".