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

DateFormat df = new SimpleDateFormat("HH:mm:ss");
String formatted = df.format(aDateObject);

Answer 2

Going by Bohemian's answer we need need not use TimeUnit to find a known value. Much more optimal code would be

String hms = String.format("%02d:%02d:%02d", millisLeft/(3600*1000),
                    millisLeft/(60*1000) % 60,
                    millisLeft/1000 % 60);

Hope it helps

Answer 3

Java 9

    Duration timeLeft = Duration.ofMillis(3600000);
    String hhmmss = String.format("%02d:%02d:%02d", 
            timeLeft.toHours(), timeLeft.toMinutesPart(), timeLeft.toSecondsPart());
    System.out.println(hhmmss);

This prints:

01:00:00

You are doing right in letting library methods do the conversions involved for you. java.time, the modern Java date and time API, or more precisely, its Duration class does it more elegantly and in a less error-prone way than TimeUnit.

The toMinutesPart and toSecondsPart methods I used were introduced in Java 9.

Java 6, 7 and 8

    long hours = timeLeft.toHours();
    timeLeft = timeLeft.minusHours(hours);
    long minutes = timeLeft.toMinutes();
    timeLeft = timeLeft.minusMinutes(minutes);
    long seconds = timeLeft.toSeconds();
    String hhmmss = String.format("%02d:%02d:%02d", hours, minutes, seconds);
    System.out.println(hhmmss);

The output is the same as above.

Question: How can that work in Java 6 and 7?

• In Java 8 and later and on newer Android devices (from API level 26, I’m told) java.time comes built-in.
• In Java 6 and 7 get the ThreeTen Backport, the backport of the modern classes (ThreeTen for JSR 310; see the links at the bottom).
• On (older) Android use the Android edition of ThreeTen Backport. It’s called ThreeTenABP. And make sure you import the date and time classes from org.threeten.bp with subpackages.

Links

• Oracle tutorial: Date Time explaining how to use java.time.
• Java Specification Request (JSR) 310, where java.time was first described.
• ThreeTen Backport project, the backport of java.timeto Java 6 and 7 (ThreeTen for JSR-310).
• ThreeTenABP, Android edition of ThreeTen Backport
• Question: How to use ThreeTenABP in Android Project, with a very thorough explanation.

Answer 4

Test results for the 4 implementations

Having to do a lot of formatting for huge data, needed the best performance, so here are the (surprising) results:

for (int i = 0; i < 1000000; i++) { FUNCTION_CALL }

Durations:

• combinationFormatter: 196 millis
• formatDuration: 272 millis
• apacheFormat: 754 millis

• formatTimeUnit: 2216 millis

  public static String apacheFormat(long millis) throws ParseException {
      return DurationFormatUtils.formatDuration(millis, "HH:mm:ss");
  }
  
  public static String formatTimeUnit(long millis) throws ParseException {
  String formatted = 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)));
      return formatted;
  }
  
  public static String formatDuration(final long millis) {
      long seconds = (millis / 1000) % 60;
      long minutes = (millis / (1000 * 60)) % 60;
      long hours = millis / (1000 * 60 * 60);
  
      StringBuilder b = new StringBuilder();
      b.append(hours == 0 ? "00" : hours < 10 ? String.valueOf("0" + hours) : 
      String.valueOf(hours));
      b.append(":");
      b.append(minutes == 0 ? "00" : minutes < 10 ? String.valueOf("0" + minutes) :     
      String.valueOf(minutes));
      b.append(":");
      b.append(seconds == 0 ? "00" : seconds < 10 ? String.valueOf("0" + seconds) : 
      String.valueOf(seconds));
      return b.toString();
  }
  
  public static String combinationFormatter(final long millis) {
      long seconds = TimeUnit.MILLISECONDS.toSeconds(millis)
              - TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millis));
      long minutes = TimeUnit.MILLISECONDS.toMinutes(millis)
              - TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(millis));
      long hours = TimeUnit.MILLISECONDS.toHours(millis);
  
      StringBuilder b = new StringBuilder();
      b.append(hours == 0 ? "00" : hours < 10 ? String.valueOf("0" + hours) : 
      String.valueOf(hours));
      b.append(":");
      b.append(minutes == 0 ? "00" : minutes < 10 ? String.valueOf("0" + minutes) : 
      String.valueOf(minutes));
          b.append(":");
      b.append(seconds == 0 ? "00" : seconds < 10 ? String.valueOf("0" + seconds) : 
      String.valueOf(seconds));
      return b.toString(); 
   }
  

Answer 5

        String string = String.format("%02d:%02d:%02d.%03d",
            TimeUnit.MILLISECONDS.toHours(millisecend), TimeUnit.MILLISECONDS.toMinutes(millisecend) - TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(millisecend)),
            TimeUnit.MILLISECONDS.toSeconds(millisecend) - TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millisecend)), millisecend - TimeUnit.SECONDS.toMillis(TimeUnit.MILLISECONDS.toSeconds(millisecend)));

Format: 00:00:00.000

Example: 615605 Millisecend

00:10:15.605

Answer 6

this worked for me, with kotlin

fun formatToDigitalClock(miliSeconds: Long): String {
        val hours = TimeUnit.MILLISECONDS.toHours(miliSeconds).toInt() % 24
        val minutes = TimeUnit.MILLISECONDS.toMinutes(miliSeconds).toInt() % 60
        val seconds = TimeUnit.MILLISECONDS.toSeconds(miliSeconds).toInt() % 60
        return when {
            hours > 0 -> String.format("%d:%02d:%02d", hours, minutes, seconds)
            minutes > 0 -> String.format("%02d:%02d", minutes, seconds)
            seconds > 0 -> String.format("00:%02d", seconds)
            else -> {
                "00:00"
            }
        }
    }