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

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 );
    }
}

String duration(Temporal from, Temporal to) {
    final StringBuilder builder = new StringBuilder();
    for (ChronoUnit unit : new ChronoUnit[]{YEARS, MONTHS, WEEKS, DAYS, HOURS, MINUTES, SECONDS}) {
        long amount = unit.between(from, to);
        if (amount == 0) {
            continue;
        }
        builder.append(' ')
                .append(amount)
                .append(' ')
                .append(unit.name().toLowerCase());
        from = from.plus(amount, unit);
    }
    return builder.toString().trim();
}

在scala中(我看到了一些其他的尝试，并没有留下深刻的印象):

def formatDuration(duration: Duration): String = {
  import duration._ // get access to all the members ;)
  f"$toDaysPart $toHoursPart%02d:$toMinutesPart%02d:$toSecondsPart%02d:$toMillisPart%03d"
}

看起来很可怕，是吗?好吧，这就是为什么我们使用ide来编写这些东西，以便方法调用($toHoursPart等)是不同的颜色。

f"…"是一个printf/String。格式样式字符串插补器(它允许$ code注入工作) 给定输出1 14:06:32.583,f插值的字符串将等效于string。格式(“1% 02 d: % 2 d: % 2 d。%03d"， 14,6,32,583)

如果你不想拖进库，使用Formatter或相关的快捷方式就足够简单了。给定整数秒数s:

  String.format("%d:%02d:%02d", s / 3600, (s % 3600) / 60, (s % 60));

从Java 9开始，这变得更容易了。Duration仍然是不可格式化的，但是添加了获取小时、分钟和秒的方法，这使得任务更简单:

    LocalDateTime start = LocalDateTime.of(2019, Month.JANUARY, 17, 15, 24, 12);
    LocalDateTime end = LocalDateTime.of(2019, Month.JANUARY, 18, 15, 43, 33);
    Duration diff = Duration.between(start, end);
    String hms = String.format("%d:%02d:%02d", 
                                diff.toHours(), 
                                diff.toMinutesPart(), 
                                diff.toSecondsPart());
    System.out.println(hms);

这个代码片段的输出是:

24:19:21