将相同时间转换为不同时区 [英] Convert same time to different time zone

问题描述

我正在尝试将时间转换为不同的时区，但不是您想的那样.例如，我需要将美国东部标准时间上午 9 点的日期时间转换为 UTC 时间上午 9 点.时区是可变的，因此仅添加/减去时间似乎不是使用 NodaTime 的正确方法

I am trying to convert times to different time zones, but not the way you're thinking. I need to convert a DateTime that is 9am EST to 9am CST on the UTC for example. The timezones are variable so just adding/subtracting hours doesn't seem correct way to do it with NodaTime

Fri, 21 Feb 2014 21:00:00 EST = 1393034400 Epoch Timestamp
convert to
Fri, 21 Feb 2014 21:00:00 CST = 1393030800 Epoch Timestamp

推荐答案

如果我正确理解了这个问题，那么听起来您像是在尝试将一个时区中的日期/时间转换为具有相同本地时间的另一个时区和不同的时区；也就是说，不同的时间点.

If I understand the question correctly, it sounds like you're trying to convert a date/time in one time zone to another one that has the same local time and a different time zone; that is, a different point in time.

您可以通过将 LocalDateTime 与新区域结合使用 Noda Time 来实现这一点.例如，给定如下内容:

You can do this with Noda Time by combining the LocalDateTime with the new zone. For example, given something like the following:

Instant now = SystemClock.Instance.Now;
DateTimeZone eastern = DateTimeZoneProviders.Tzdb["America/New_York"];
ZonedDateTime nowEastern = now.InZone(eastern);

nowEastern 是 America/New_York 时区的现在时间.如果我们将 nowEastern 直接打印到控制台，我们会看到类似 2014-02-22T05:18:50 America/New_York (-05) 的内容.

nowEastern is the time now in the America/New_York time zone. If we print nowEastern directly to the console, we'll see something like 2014-02-22T05:18:50 America/New_York (-05).

顺便说一句，EST"和CST"不是时区:它们是时区内特定偏移量的非唯一缩写；America/New_York 和 America/Chicago 可能代表了我们认为的东部"和中部"(或者你可以使用类似 UTC-05:00 如果您真的想要 EST，即使在夏令时生效的情况下).

As an aside, "EST" and "CST" aren't time zones: they're non-unique abbreviations for a particular offset within a time zone; America/New_York and America/Chicago are probably representative of what we think of as "Eastern" and "Central", though (or you could use something like UTC-05:00 if you really wanted EST even when daylight savings time was in effect).

给定一个在任何时区的ZonedDateTime，我们可以将其转换为一个具有相同本地时间和指定时区的ZonedDateTime，如下所示:

Given a ZonedDateTime in any time zone, we can convert it to a ZonedDateTime with the same local time and a specified time zone as follows:

DateTimeZone central = DateTimeZoneProviders.Tzdb["America/Chicago"];
ZonedDateTime sameLocalTimeCentral = nowEastern.LocalDateTime.InZoneStrictly(central);

这为我们提供了一个具有相同本地时间但不同时区的 ZonedDateTime.使用上面的输入，结果将是 2014-02-22T05:18:50 America/Chicago (-06).

This gives us a ZonedDateTime with the same local time, but a different time zone. With the input above, the result would be 2014-02-22T05:18:50 America/Chicago (-06).

请注意，我使用的是 InZoneStrictly.如果本地时间不明确或无效(例如，在白天储蓄过渡).如果这是不可接受的，您可以使用 InZoneLeniently，它在给定的本地时间或之后选择最早的有效 ZonedDateTime，或 InZone，它允许您在这些情况下指定您自己的规则.

Note that I'm using InZoneStrictly. This will throw an exception if the local time is ambiguous or invalid (for example, during daylight savings transitions). If that's unacceptable, you could use InZoneLeniently, which picks the earliest valid ZonedDateTime on or after the given local time, or InZone, which allows you to specify your own rules in those cases.

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