如何将秒转换以这种格式＆QUOT; HH：MM：SS＆QUOT; [英] How to convert the seconds in this format "HH:mm:ss"

问题描述

欲第二/毫秒转换这种格式HH：MM：SS（用于esamples，从5秒到0点○○分05秒）。我试图让这样的格式：

I want to convert the second/milliseconds in this format "HH:mm:ss" (for esamples, from 5 seconds to 00:00:05). I tried to get that format in this way:

int millis = 5000;
SimpleDateFormat df = new SimpleDateFormat("HH:mm:ss");
String time = df.format(millis);

在这种方式，我得到1点00分05秒，而不是00:00:05。我在哪里错了？

In that way, I get "01:00:05" and not "00:00:05". Where am I wrong?

推荐答案

时区。

长值 5000 指时代后5秒。对于大多数时区，时代在5秒钟之内没有5秒过去当地时间的午夜。

The long value 5000 means 5 seconds after the epoch. For the majority of timezones, 5 seconds after the epoch is not 5 seconds past midnight local time.

8的Java更新

java.time.LocalTime 将处理墙上时钟一天中的时间的想法而不必担心时区和天隐含在 java.util.Date 。如果您可以使用Java 8，和你的持续时间将永远是不到一天的时间，然后一个正确版本的例子可以非常简单，如：

java.time.LocalTime will handle the idea of a wall-clock "time of day" without you having to worry about the timezones and days implicit in java.util.Date. If you can use Java 8, and your durations will always be less than a day, then a correct version of your example can be as simple as:

int millis = 5000;
int seconds = millis / 1000; // Maybe no need to divide if the input is in seconds
LocalTime timeOfDay = LocalTime.ofSecondOfDay(seconds);
String time = timeOfDay.toString();

（我猜严格来说， java.time.Duration 是一个更好的模式的你想要的东西，因为它重新presents若干秒，而不是时间，一天的，但它是一个痛苦的格式化为HH：MM：SS，所以如果你总是处理子24小时值的TimeOfDay给你这个格式的自由和在其他等价的。）

(I guess strictly speaking, java.time.Duration is a better model of what you want, in that it represents a certain number of seconds, rather than a time-of-day. But it's a pain to format into hh:mm:ss, so if you're always dealing with sub-24hour values, TimeOfDay gives you this formatting for free and is otherwise equivalent.)

如果你坚持使用Java 7或以下，则显式指定在你的榜样code GMT 的时区应该给你你所期望的输出。

If you're stuck with Java 7 or below, then explicitly specifying a timezone of GMT in your example code should give you the output you expect.

下面是一个斯卡拉REPL会话演示问题，以及Java 7的解决方案，我的机器上：

Here's a Scala REPL session demonstrating the problem, and Java 7 solution, on my machine:

scala> val millis = 5000
millis: Int = 5000

scala> val df = new java.text.SimpleDateFormat("HH:mm:ss")
df: java.text.SimpleDateFormat = java.text.SimpleDateFormat@8140d380

scala> df.format(millis)
res0: java.lang.String = 01:00:05

scala> df.getTimeZone.getID
res1: java.lang.String = GB

scala> df.getTimeZone.getOffset(millis)
res2: Int = 3600000

scala> df.setTimeZone(java.util.TimeZone.getTimeZone("GMT"))

scala> df.format(millis)
res3: java.lang.String = 00:00:05

所以，你可以看到，我的默认时区是 GB ，其中有1小时，从格林尼治时间记为时间5000L 。设置时区为GMT gievs的期望输出 00:00:05 。

So you can see that my default time zone is GB, which has a 1 hour offset from GMT at the time denoted by 5000L. Setting the timezone to GMT gievs the expected output of 00:00:05.

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