Convert epoch String to Java date

Question

I am getting an epoch String from my DB which looks something like this : 1391328000000

I am having a hard time trying to convert it to Java Date.

I tried the following :

private String buildDate(String dateString){
        System.out.println("dateString " + dateString);

        DateFormat format = new SimpleDateFormat("dd/MM/yyyy HH:mm:ss");
        format.setTimeZone(TimeZone.getTimeZone("Etc/UTC"));
        String formatted = format.format(Integer.parseInt(dateString));

        return formatted;
    }

Well what date is that meant to represent? And do you really have to get it as a string rather than as a number? (I suspect it's actually milliseconds since the unix epoch.) — Jon Skeet, Dec 05 '13 at 22:06

score 6 · Accepted Answer · answered Dec 05 '13 at 22:13

6

I think you're overthinking about the DateFormat. If I want to simply obtain a Date instance, what I would try is the following:

Date d = new Date(Long.parseLong(dateString));

answered Dec 05 '13 at 22:13

Andrei Nicusan

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Please note the epoch string the asker used as an example is in Milliseconds. If you are workign with epoch in seconds, you should: new Date(Long.parseLong(dateString) * 1000) – Ezequiel Adrian Oct 08 '21 at 16:51

score 3 · Answer 2 · answered Dec 05 '13 at 22:12

You need to turn it into a java.util.Date object in order for SimpleDateFormat to handle it. Also, a value like what you quoted needs to be parsed as a long, as it is too large for an int.

That is, change the line where you set formatted to be:

String formatted = format.format(new Date(Long.parseLong(dateString)));

As an aside, if the project you're working on can handle an extra external dependency, switch date/time handling over to the joda library. The stuff in java.util (that is, Date and Calendar) rapidly becomes painful and error-prone to work with.

You don't actually have to make a Date with SimpleDateFormat. The implementation of `java.text.Format#format(Object obj)` is friendly enough to convert Number to Date for you. — Affe, Dec 05 '13 at 22:16

Convert epoch String to Java date

2 Answers2