在芬兰湾的科特林:

fun FUNCTION_NAME(milliSeconds: Long): String {
    val s: Long = milliSeconds / 1000 % 60

    val m: Long = milliSeconds / (1000*60) % 60

    val h: Long = milliSeconds / (1000*60*60) % 24

    return String.format("%02d:%02d:%02d", h, m, s)
}

下面的代码以两种方式进行转换

23:59:58:999到86398999

和比

86398999到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;
    }
}

Java 9

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

这个打印:

01:00:00

让库方法为您完成相关的转换是正确的。java。time是现代Java日期和时间API，或者更准确地说，它的Duration类比TimeUnit更优雅，更不容易出错。

我使用的toMinutesPart和toSecondsPart方法是在Java 9中引入的。

Java 6、7和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);

输出与上面相同。

问题:这在Java 6和7中如何工作?

在Java 8及以上版本和更新的Android设备上(我被告知从API级别26开始)。时间是与生俱来的。 在Java 6和7中获得ThreeTen Backport，现代类的后端口(JSR 310的ThreeTen;参见底部的链接)。 在(旧的)Android上使用ThreeTen Backport的Android版本。叫做ThreeTenABP。并确保从org.three .bp导入带有子包的日期和时间类。

链接

Oracle教程:Date Time解释如何使用java.time。 Java规范请求(JSR) 310，其中Java。时间是最早被描述的。 ThreeTen Backport项目，java的Backport。timeto Java 6和7 (JSR-310为ThreeTen)。 ThreeTenABP, Android版的ThreeTen Backport 问:如何在Android项目中使用ThreeTenABP，并有一个非常详细的解释。

在芬兰湾的科特林:

fun FUNCTION_NAME(milliSeconds: Long): String {
    val s: Long = milliSeconds / 1000 % 60

    val m: Long = milliSeconds / (1000*60) % 60

    val h: Long = milliSeconds / (1000*60*60) % 24

    return String.format("%02d:%02d:%02d", h, m, s)
}

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

这对我来说很管用，用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"
            }
        }
    }