How to convert milliseconds to “hh:mm:ss” format?

Question

I'm confused. After stumbling upon this thread, I tried to figure out how to format a countdown timer that had the format hh:mm:ss.

Here's my attempt -

//hh:mm:ss
String.format("%02d:%02d:%02d", 
    TimeUnit.MILLISECONDS.toHours(millis),
    TimeUnit.MILLISECONDS.toMinutes(millis) - 
    TimeUnit.MINUTES.toMinutes(TimeUnit.MILLISECONDS.toHours(millis)),
    TimeUnit.MILLISECONDS.toSeconds(millis) - 
    TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millis)));   

So, when I try a value like 3600000ms, I get 01:59:00, which is wrong since it should be 01:00:00. Obviously there's something wrong with my logic, but at the moment, I cannot see what it is!

Can anyone help?

Edit -

Fixed it. Here's the right way to format milliseconds to hh:mm:ss format -

//hh:mm:ss
String.format("%02d:%02d:%02d", 
    TimeUnit.MILLISECONDS.toHours(millis),
    TimeUnit.MILLISECONDS.toMinutes(millis) - 
    TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(millis)),
    TimeUnit.MILLISECONDS.toSeconds(millis) - 
    TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millis))));

The problem was this TimeUnit.MINUTES.toMinutes(TimeUnit.MILLISECONDS.toHours(millis)). It should have been this TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(millis)) instead.

Answer 1

I tried as shown in the first answer. It works, but minus brought me into confusion. My answer by Groovy:

import static java.util.concurrent.TimeUnit.*

...

private static String formatElapsedTime(long millis) {

    int hrs = MILLISECONDS.toHours(millis) % 24
    int min = MILLISECONDS.toMinutes(millis) % 60
    int sec = MILLISECONDS.toSeconds(millis) % 60
    int mls = millis % 1000

    sprintf( '%02d:%02d:%02d (%03d)', [hrs, min, sec, mls])
}

Answer 2

If you are using apache commons:

DurationFormatUtils.formatDuration(timeInMS, "HH:mm:ss,SSS");

Answer 3

I used this:

String.format("%1$tH:%1$tM:%1$tS.%1$tL", millis);

See description of class Formatter.

See runnable example using input of 2400 ms.

Answer 4

You were really close:

String.format("%02d:%02d:%02d", 
TimeUnit.MILLISECONDS.toHours(millis),
TimeUnit.MILLISECONDS.toMinutes(millis) -  
TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(millis)), // The change is in this line
TimeUnit.MILLISECONDS.toSeconds(millis) - 
TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millis)));   

You were converting hours to millisseconds using minutes instead of hours.

BTW, I like your use of the TimeUnit API :)

Here's some test code:

public static void main(String[] args) throws ParseException {
    long millis = 3600000;
    String hms = String.format("%02d:%02d:%02d", TimeUnit.MILLISECONDS.toHours(millis),
            TimeUnit.MILLISECONDS.toMinutes(millis) - TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(millis)),
            TimeUnit.MILLISECONDS.toSeconds(millis) - TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millis)));
    System.out.println(hms);
}

Output:

01:00:00

---

I realised that my code above can be greatly simplified by using a modulus division instead of subtraction:

String hms = String.format("%02d:%02d:%02d", TimeUnit.MILLISECONDS.toHours(millis),
    TimeUnit.MILLISECONDS.toMinutes(millis) % TimeUnit.HOURS.toMinutes(1),
    TimeUnit.MILLISECONDS.toSeconds(millis) % TimeUnit.MINUTES.toSeconds(1));

Still using the TimeUnit API for all magic values, and gives exactly the same output.

Answer 5

For Kotlin

val hours = String.format("%02d", TimeUnit.MILLISECONDS.toHours(milSecs))
val minutes = String.format("%02d",
                        TimeUnit.MILLISECONDS.toMinutes(milSecs) - TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(milSecs)))
val seconds = String.format("%02d",
                        TimeUnit.MILLISECONDS.toSeconds(milSecs) - TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(milSecs)))

where, milSecs is milliseconds

Answer 6

The code below does the conversion in both way

23:59:58:999 to 86398999

and than

86398999 to 23:59:58:999

---

import java.util.concurrent.TimeUnit;

public class TimeUtility {

    public static void main(String[] args) {

        long currentDateTime = System.currentTimeMillis();

        String strTest = "23:59:58:999";
        System.out.println(strTest);

        long l = strToMilli(strTest);
        System.out.println(l);
        l += 1;
        String str = milliToString(l);
        System.out.println(str);
    }

    /**
     * convert a time string into the equivalent long milliseconds
     *
     * @param strTime string fomratted as HH:MM:SS:MSMS i.e. "23:59:59:999"
     * @return long integer like 86399999
     */
    public static long strToMilli(String strTime) {
        long retVal = 0;
        String hour = strTime.substring(0, 2);
        String min = strTime.substring(3, 5);
        String sec = strTime.substring(6, 8);
        String milli = strTime.substring(9, 12);
        int h = Integer.parseInt(hour);
        int m = Integer.parseInt(min);
        int s = Integer.parseInt(sec);
        int ms = Integer.parseInt(milli);

        String strDebug = String.format("%02d:%02d:%02d:%03d", h, m, s, ms);
        //System.out.println(strDebug);
        long lH = h * 60 * 60 * 1000;
        long lM = m * 60 * 1000;
        long lS = s * 1000;

        retVal = lH + lM + lS + ms;
        return retVal;
    }

    /**
     * convert time in milliseconds to the corresponding string, in case of day
     * rollover start from scratch 23:59:59:999 + 1 = 00:00:00:000
     *
     * @param millis the number of milliseconds corresponding to tim i.e.
     *               34137999 that can be obtained as follows;
     *               <p>
     *               long lH = h * 60 * 60 * 1000; //hour to milli
     *               <p>
     *               long lM = m * 60 * 1000; // minute to milli
     *               <p>
     *               long lS = s * 1000; //seconds to milli
     *               <p>
     *               millis = lH + lM + lS + ms;
     * @return a string formatted as HH:MM:SS:MSMS i.e. "23:59:59:999"
     */
    private static String milliToString(long millis) {

        long hrs = TimeUnit.MILLISECONDS.toHours(millis) % 24;
        long min = TimeUnit.MILLISECONDS.toMinutes(millis) % 60;
        long sec = TimeUnit.MILLISECONDS.toSeconds(millis) % 60;
        //millis = millis - (hrs * 60 * 60 * 1000); //alternative way
        //millis = millis - (min * 60 * 1000);
        //millis = millis - (sec * 1000);
        //long mls = millis ;
        long mls = millis % 1000;
        String toRet = String.format("%02d:%02d:%02d:%03d", hrs, min, sec, mls);
        //System.out.println(toRet);
        return toRet;
    }
}