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

使用这个func

private static String strDuration(long duration) {
    int ms, s, m, h, d;
    double dec;
    double time = duration * 1.0;

    time = (time / 1000.0);
    dec = time % 1;
    time = time - dec;
    ms = (int)(dec * 1000);

    time = (time / 60.0);
    dec = time % 1;
    time = time - dec;
    s = (int)(dec * 60);

    time = (time / 60.0);
    dec = time % 1;
    time = time - dec;
    m = (int)(dec * 60);

    time = (time / 24.0);
    dec = time % 1;
    time = time - dec;
    h = (int)(dec * 24);
    
    d = (int)time;
    
    return (String.format("%d d - %02d:%02d:%02d.%03d", d, h, m, s, ms));
}

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));

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);
}

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

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();
}