如何在Java中将时区字符串转换为TimeZone对象? [英] How can i convert time zone string to the TimeZone Object in java?

问题描述

我有几个UTC格式的时区字符串，例如"UTC + 08:00"，"UTC-05:00" ，问题是如何转换这些utc格式Java中 java.util.TimeZone 的字符串?

I have several time zone strings in UTC format, such as "UTC+08:00", "UTC-05:00", the question is how can i convert these utc format strings to the java.util.TimeZone in Java?

我曾尝试通过 ZoneId 进行如下转换，但没有成功:

I have tried to convert by ZoneId as follows, but it did not work:

ZoneId zoneId = ZoneId.of("UTC+08:00");
TimeZone timeZone = TimeZone.getTimeZone(zoneId);

我知道 TimeZone timeZone = TimeZone.getTimeZone("Asia/Shanghai"); 可以工作，但是我不知道"UTC + 08:00" 和亚洲/上海"

I know TimeZone timeZone = TimeZone.getTimeZone("Asia/Shanghai"); would work, but I do not know the mapping between "UTC+08:00" and "Asia/Shanghai"

推荐答案

tl; dr

• 不要不使用 TimeZone 类(现在是旧版).
• 改为使用 ZoneOffset 和 ZoneId .

tl;dr

• Do not use TimeZone class (now legacy).
• Use ZoneOffset and ZoneId instead.

示例:

ZoneOffset.of( "+08:00" )

使用 java.time.ZoneId ，而不是 TimeZone

与最早的Java版本捆绑在一起的麻烦的旧日期时间类现在已被遗留，由java.time类取代.这些旧的旧类中有 TimeZone ，现在已由 ZoneId 和 ZoneOffset .

Use java.time.ZoneId, not TimeZone

The troublesome old date-time classes bundled with the earliest versions of Java are now legacy, supplanted by the java.time classes. Among these old legacy classes is TimeZone, now supplanted by ZoneId and ZoneOffset.

UTC偏移量是指提前数小时和数分钟的调整，或后面的 UTC .这由 ZoneOffset 类表示.

An offset-from-UTC is a number of hours and minutes adjustment ahead of, or behind, UTC. This is represented by the ZoneOffset class.

时区是偏移量的集合，即偏移量的变化历史由特定区域在确定其挂钟时间时使用.这由 ZoneId 类表示.

A time zone is a collection of offsets, the history of changes in the offset used by a particular region in determining their wall-clock time. This is represented by the ZoneId class.

使用时区始终比偏移量更可取，因为一个时区具有偏移量以及更多的信息.但是您的示例仅是补偿.因此，在删除字符 UTC 后，使用 ZoneOffset 解析字符串.

Using a time zone is always preferable to an offset as a zone has the offset plus so much more information. But your examples are only mere offsets. So use the ZoneOffset to parse the strings after deleting the characters UTC.

String input = "UTC+08:00".replace( "UTC" , "" ) ;
ZoneOffset offset = ZoneOffset.of( input ) ;

不要猜时区

您不能假设特定的偏移量意味着特定的时区.许多区域可能在过去，现在或将来使用了特定的偏移量.因此，您不应该猜测区域.

Do not guess the time zone

You cannot assume that a particular offset implies a particular time zone. Many zones may have used a particular offset in the past, present, or future. So you should not guess the zone.

以例如 +08:00 的偏移量为例.目前，几个不同的时区(包括亚洲/上海，亚洲/澳门和 Australia/Perth .

Take, for example, the offset of +08:00. That offset is currently used by several different time zones including Asia/Shangai, Asia/Macao, and Australia/Perth.

如果您确定某个特定区域打算用于日期时间值，则将其应用于获取

If you are certain a particular zone was intended for a date-time value, apply it to get a ZonedDateTime. But do not guess.

Instant 类表示UTC时间轴上的时刻，其分辨率为纳秒.

The Instant class represents a moment on the timeline in UTC with a resolution of nanoseconds.

Instant instant = Instant.now() ;
ZoneId z = ZoneId.of( "Asia/Shanghai" ) ; 
ZonedDateTime zdt = instant.atZone( z ) ;

如果您不确定特定的预期时区并且只有一个偏移量，请使用该偏移量获取

If you do not know for certain the intended time zone and have only an offset, use the offset to get an OffsetDateTime.

Instant instant = Instant.now() ;
ZoneOffset offset = ZoneOffset.of( "+08:00" ) ; 
OffsetDateTime odt = instant.atOffset( offset ) ;

转换

最好避免使用旧的旧类 TimeZone .但是，如果必须使用该类来处理尚未为java.time类更新的旧代码，则可以转换为 ZoneId .使用添加到旧类中的新转换方法.

Convert

Best to avoid the old legacy class TimeZone. But if you must use that class to work with old code not yet updated for the java.time classes, you can convert to/from a ZoneId. Use the new conversion methods added to the old classes.

TimeZone myLegacyTimeZone = TimeZone.getTimeZone( myModernZoneId ); 

…和…

ZoneId z = myLegacyTimeZone.toZoneId() ;

请注意， ZoneOffset 是 ZoneId 的子类.通常，我们忽略该继承关系.如果只有偏移量，例如 +08:00 ，请使用 ZoneOffset .如果您有一个完整的时区，例如 Asia/Shanghai ，请使用 ZoneId .此规则的一个例外是这种与 TimeZone 之间的转换，其中仅超类 ZoneId 被识别.

Note that ZoneOffset is a subclass of ZoneId. Normally, we ignore that inheritance relationship. If you have only a mere offset such as +08:00, use ZoneOffset. If you have a full time zone such as Asia/Shanghai, use ZoneId. One exception to this rule is for this conversion to/from TimeZone where only the superclass ZoneId is recognized.

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