Getting unix timestamp from Date()

I can convert a unix timestamp to a Date() object by putting the long value into the Date() constructor. For eg: I could have it as new Date(1318762128031).

But after that, how can I get back the unix timestamp from the Date() object?

Solution 1:

getTime() retrieves the milliseconds since Jan 1, 1970 GMT passed to the constructor. It should not be too hard to get the Unix time (same, but in seconds) from that.

Solution 2:

To get a timestamp from Date(), you'll need to divide getTime() by 1000, i.e. :

Date currentDate = new Date();
currentDate.getTime() / 1000;
// 1397132691

or simply:

long unixTime = System.currentTimeMillis() / 1000L;

Solution 3:

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.TimeZone;

public class Timeconversion {
    private DateFormat dateFormat = new SimpleDateFormat("yyyyMMddHHmm", Locale.ENGLISH); //Specify your locale

    public long timeConversion(String time) {
        long unixTime = 0;
        dateFormat.setTimeZone(TimeZone.getTimeZone("GMT+5:30")); //Specify your timezone
        try {
            unixTime = dateFormat.parse(time).getTime();
            unixTime = unixTime / 1000;
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return unixTime;
    }
}

Solution 4:

In java 8, it's convenient to use the new date lib and getEpochSecond method to get the timestamp (it's in second)

Instant.now().getEpochSecond();