Getting the correct GMT format using DateFormat Object

Question

If i have a File object how can i get the lastModified() date of this file in this GMT format: Mon, 23 Jun 2011 17:40:23 GMT.

For example, when i call the java method lastModified() on a file and use a DateFormat object to getDateTimeInstance(DateFormat.Long, DateFormat.Long) and also set the TimeZone to GMT, the file date displays in different format:

File fileE = new File("/Some/Path");
Date fileDate = new Date (fileE.lastModified());
DateFormat dateFormat = DateFormat.getDateTimeInstance(DateFormat.Long, DateFormat.Long);
dateFormat.setTimeZone(TimeZone.getTimeZone("GMT"));
System.out.println("file date " + dateFormat.format(fileDate));

This prints in this format:

January 26, 2012 7:11:46 PM GMT

I feel like i am close to getting it in the format above and i am only missing the day. Do i have to use instead the SimpleDateFormat object?

jtahlborn · Answer 1 · 2012-01-26T20:04:57.753

2

Yes, the DateFormat static instances will be locale specific. If you want a specific format, you should use SimpleDateFormat with the appropriate format pattern.

If you want to compare 2 file modified times to the second granularity, then just divide them both by 1000, e.g.:

long t1InSeconds = f1.lastModified() / 1000L;
long t2InSeconds = f2.lastModified() / 1000L;

// which one is sooner
if(t1InSeconds < t2InSeconds) {
  // f1 is older ...
}

edited Jan 26 '12 at 20:04

answered Jan 26 '12 at 19:52

jtahlborn

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I have tried using the simpleDateFormat in many ways to get the above format. Is it possible to get a java date object in the format above? To clarify, I'm sure there is a format that i can use to print the date but what if i want to compare two dates to the second granularity and they need to be in the format i stated above. Do you have any examples? – Warz Jan 26 '12 at 19:56
Date objects don't have a format, they are just a millisecond value in UTC time. – jtahlborn Jan 26 '12 at 20:01

Bhesh Gurung · Accepted Answer · 2012-01-26T20:13:26.143

1

Use the SimpleDateFormat with the pattern as follows:

DateFormat dateFormat = new SimpleDateFormat("EEE, dd MMM yyyy hh:mm:ss z");

Update:

Date d1 = new Date(file1.lastModified());
Date d2 = new Date(file2.lastModified());

You can compare them as follows:

d1.compareTo(d2);
d1.before(d2);
d1.after(d2);

Why do you want to compare them at seconds granularity?

If you want to get the difference in seconds:

int diffInSeconds = (int) (d1.getTime() - d2.getTime()) / 1000;

edited Jan 26 '12 at 20:13

answered Jan 26 '12 at 19:53

Bhesh Gurung

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This format is great and prints my date object the way i want it to. Is it possible to get Date Objects that are in this format for comparison? – Warz Jan 26 '12 at 19:58
To print (display) you use it to format the Date object and if you have two different dates (string) that are in this format then parse and compare (using Date.compareTo(), Date.before(), or Date.after()) – Bhesh Gurung Jan 26 '12 at 20:01
Make sure to use Locale.US on your SimpleDateFormat – samottenhoff Mar 19 '15 at 20:11
[Never use SimpleDateFormat or DateTimeFormatter without a Locale](https://stackoverflow.com/a/65544056/10819573) – Arvind Kumar Avinash May 16 '21 at 13:21

Getting the correct GMT format using DateFormat Object

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