CODEWITHSUNDEEP
java
Sore Finger Tips
Sore Finger Tips

Reputation: 343

Java - Convert Unix epoch time to date

I need to convert some epoch time stamps to the real date and have used some of the methods I found on stack overflow, but they give the wrong answer.

As an example, one date is "129732384262470907" in epoch time, which is "Mon, 20 Jan 6081 05:24:22 GMT" using http://www.epochconverter.com/

However, my code generates: "Wed Dec 24 14:54:05 CST 19179225"

  String epochString = token.substring(0, comma);
  long epoch = Long.parseLong(epochString);
  Date logdate = new Date(epoch * 1000);
  BufferedWriter timewrite = new BufferedWriter(new FileWriter(tempfile, true));
  timewrite.write(logdate);
  timewrite.flush();
  timewrite.close();

The initial timestamp is in miliseconds, which in the examples I saw here I am supposed to multiply by 1000.

If I don't multiply by 1000, I get: "Mon Aug 08 01:14:30 CDT 4113025"

Both of which are wrong.

So where have I made my error?

Upvotes: 1

Views: 1073

Answers (2)

Jon Skeet
Jon Skeet

Reputation: 1503974

129732384262470907 is actually in microseconds since the epoch if it's meant to be 6081, so you need to divide by 1000 if that's real input.

Note that epochconverter.com doesn't even handle that value - it only allows you to enter 129732384262470 which it then treats as milliseconds since the epoch.

You need to multiply by 1000 if your data is seconds since the epoch. Basically all you need to know is that Java expects milliseconds since the epoch; the rest should be plain sailing, assuming you know what your input data actually means.

If you could provide your real data, and what it's meant to represent, it's probably going to be easy to fix your problems.

Upvotes: 2

dty
dty

Reputation: 18998

If you look carefully, epochconverter.com truncated that number because it was too long for the entry field.

I suggest you print the current value of System.currentMillis() to see what approximate range a "current" epoch-based timestamp has, and re-scale your input number to match. I think you'll probably have to divide by 1000.

In fact, looking closer, if you divide by 10,000, you get 1297323842624, which comes out to a date in 2011. So it's not at all clear what units the number you've given are in.

Upvotes: 0

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