那么下面的函数呢 + H: MM: SS 或 + H: MM: SS.sss

public static String formatInterval(final long interval, boolean millisecs )
{
    final long hr = TimeUnit.MILLISECONDS.toHours(interval);
    final long min = TimeUnit.MILLISECONDS.toMinutes(interval) %60;
    final long sec = TimeUnit.MILLISECONDS.toSeconds(interval) %60;
    final long ms = TimeUnit.MILLISECONDS.toMillis(interval) %1000;
    if( millisecs ) {
        return String.format("%02d:%02d:%02d.%03d", hr, min, sec, ms);
    } else {
        return String.format("%02d:%02d:%02d", hr, min, sec );
    }
}

这是一个可行的选择。

public static String showDuration(LocalTime otherTime){          
    DateTimeFormatter df = DateTimeFormatter.ISO_LOCAL_TIME;
    LocalTime now = LocalTime.now();
    System.out.println("now: " + now);
    System.out.println("otherTime: " + otherTime);
    System.out.println("otherTime: " + otherTime.format(df));

    Duration span = Duration.between(otherTime, now);
    LocalTime fTime = LocalTime.ofNanoOfDay(span.toNanos());
    String output = fTime.format(df);

    System.out.println(output);
    return output;
}

使用

System.out.println(showDuration(LocalTime.of(9, 30, 0, 0)));

产生如下内容:

otherTime: 09:30
otherTime: 09:30:00
11:31:27.463
11:31:27.463

我使用Apache common的DurationFormatUtils，就像这样:

DurationFormatUtils.formatDuration(millis, "**H:mm:ss**", true);

下面是在Kotlin中将java.time.Duration转换为一个漂亮的字符串的一行代码:

duration.run {
   "%d:%02d:%02d.%03d".format(toHours(), toMinutesPart(), toSecondsPart(), toMillisPart())
}

示例输出: 120:56:03.004

在java8中还有另一种方法。但如果持续时间不超过24小时，则有效

public String formatDuration(Duration duration) {
    DateTimeFormatter formatter = DateTimeFormatter.ofPattern("h:mm.SSS");
    return LocalTime.ofNanoOfDay(duration.toNanos()).format(formatter);
}

long duration = 4 * 60 * 60 * 1000;
SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss.SSS", Locale.getDefault());
log.info("Duration: " + sdf.format(new Date(duration - TimeZone.getDefault().getRawOffset())));