问题描述

我需要以 [+/-]hh:mm 格式保存手机的时区

I need to save the phone's timezone in the format [+/-]hh:mm

我正在使用 TimeZone 类来处理这个问题，但我能得到的唯一格式如下:

I am using TimeZone class to deal with this, but the only format I can get is the following:

PST -05:00
GMT +02:00

我宁愿不对结果进行子串化，是否可以设置任何键或选项标志以仅获取值而不是该时区的名称(GMT/CET/PST...)?

I would rather not substring the result, is there any key or option flag I can set to only get the value and not the name of that timezone (GMT/CET/PST...)?

推荐答案

我需要以 [+/-]hh:mm 格式保存手机的时区

I need to save the phone's timezone in the format [+/-]hh:mm

不，你没有.单独的偏移量是不够的，您需要存储整个时区名称/id.例如，我住在奥斯陆，我目前的偏移量是 +02:00 但在冬天(由于 dst) 它是 +01:00.标准时间和夏令时间之间的确切切换取决于您不想探索的因素.

No, you don't. Offset on its own is not enough, you need to store the whole time zone name/id. For example I live in Oslo where my current offset is +02:00 but in winter (due to dst) it is +01:00. The exact switch between standard and summer time depends on factors you don't want to explore.

所以不是存储 + 02:00(或者应该是 + 01:00?)我存储 "Europe/Oslo"在我的数据库中.现在我可以使用以下命令恢复完整配置:

So instead of storing + 02:00 (or should it be + 01:00?) I store "Europe/Oslo" in my database. Now I can restore full configuration using:

TimeZone tz = TimeZone.getTimeZone("Europe/Oslo")

想知道我今天的时区偏移量是多少?

Want to know what is my time zone offset today?

tz.getOffset(new Date().getTime()) / 1000 / 60   //yields +120 minutes

但是 12 月还是一样:

However the same in December:

Calendar christmas = new GregorianCalendar(2012, DECEMBER, 25);
tz.getOffset(christmas.getTimeInMillis()) / 1000 / 60   //yields +60 minutes

说得够多了:存储时区名称或 id 并且每次要显示日期时，检查当前偏移量(今天)是多少，而不是存储固定值.您可以使用 TimeZone.getAvailableIDs() 枚举所有支持的时区 ID.

Enough to say: store time zone name or id and every time you want to display a date, check what is the current offset (today) rather than storing fixed value. You can use TimeZone.getAvailableIDs() to enumerate all supported timezone IDs.