# Time With Zone

类似 Ruby 内置的 [Time](http://ruby-doc.org/core-2.1.0/Time.html)，但 Ruby 内置的 Time 所创建的实例对象局限于 UTC 和系统的 ENV\['TZ'] 时区。这里的实例没有此局限，你可以用你想用的时区。

你不能直接使用 new 创建 TimeWithZone 实例对象，但可以用 local, parse, at 和 now 创建 `TimeZone` 实例对象，或者 in\_time\_zone 创建 `Time` 和 `DateTime` 实例对象。

```ruby
Time.zone = 'Eastern Time (US & Canada)'
# => 'Eastern Time (US & Canada)'

Time.zone.local(2007, 2, 10, 15, 30, 45)
# => Sat, 10 Feb 2007 15:30:45 EST -05:00

Time.zone.parse('2007-02-10 15:30:45')
# => Sat, 10 Feb 2007 15:30:45 EST -05:00

Time.zone.at(1170361845)
# => Sat, 10 Feb 2007 15:30:45 EST -05:00

Time.zone.now
# => Sun, 18 May 2008 13:07:55 EDT -04:00

Time.utc(2007, 2, 10, 20, 30, 45).in_time_zone
# => Sat, 10 Feb 2007 15:30:45 EST -05:00
```

查询 Time 和 TimeZone 的 API 可以对这些方法有更多的了解。

TimeWithZone 创建的实例对象和 Ruby 内置的 Time 创建的实例对象完全兼容，也就是说它们是等价关系。

```ruby
t = Time.zone.now                    # => Sun, 18 May 2008 13:27:25 EDT -04:00
t.hour                               # => 13
t.dst?                               # => true
t.utc_offset                         # => -14400
t.zone                               # => "EDT"
t.to_s(:rfc822)                      # => "Sun, 18 May 2008 13:27:25 -0400"
t + 1.day                            # => Mon, 19 May 2008 13:27:25 EDT -04:00
t.beginning_of_year                  # => Tue, 01 Jan 2008 00:00:00 EST -05:00
t > Time.utc(1999)                   # => true

# 完全兼容，它们是等价关系。
t.is_a?(Time)                        # => true
t.is_a?(ActiveSupport::TimeWithZone) # => true
```

相关：Date, Time, DateTime, DateAndTime 以及 TimeZone.

实例方法：

```
+, -, <=>

acts_like_time?, advance, ago, as_json

between?, blank?

comparable_time

dst?

eql?

formatted_offset, freeze, future?

getgm, getlocal, getutc, gmt?, gmt_offset, gmtime, gmtoff

hash, httpdate

in_time_zone, inspect, is_a?, isdst, iso8601

kind_of?

localtime

marshal_dump, marshal_load, method_missing

name

past?, period

respond_to?, respond_to_missing?, rfc2822, rfc822

since, strftime

time

to_a, to_datetime, to_f, to_formatted_s, to_i, to_r, to_s, to_time

today?, tv_sec

utc, utc?, utc_offset

xmlschema

zone
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://kelby.gitbook.io/rails-beginner-s-guide/activesupport_core_ext/activesupport_timewithzone.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.