编辑“︁HTTP 301”︁

{{NoteTA
|G1=IT
}}
{{HTTP}}

'''301 Move Permanently''' 是[[HTTP协议]]中的一个状态码（Status Code）。可以简单地理解为该资源已经被永久改变了位置<ref>{{cite web|url=http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html|title=HTTP/1.1: Status Code Definitions|accessdate=2014-06-01|archive-date=2010-03-16|archive-url=https://web.archive.org/web/20100316011642/http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html|dead-url=no}}</ref>，通常会发送[[HTTP Location]]来[[重定向]]到正确的新位置。

返回301状态码进行跳转被[[Google]]认为是将网站地址由HTTP迁移到[[HTTPS]]的最佳方法。<ref>{{cite web|title=Secure your site with HTTPS|url=https://support.google.com/webmasters/answer/6073543?hl=en|website=Google 用户中心|publisher=Google|accessdate=6 February 2016|archive-date=2017-12-15|archive-url=https://web.archive.org/web/20171215041903/https://support.google.com/webmasters/answer/6073543?hl=en|dead-url=no}}</ref> 

==定义==
根据定义： <ref name="h1">{{cite web|last1=T.|first1=Fielding, Roy|last2=Tim|first2=Berners-Lee,|last3=Henrik|first3=Frystyk,|title=Hypertext Transfer Protocol -- HTTP/1.0|url=https://tools.ietf.org/html/rfc1945#section-9.3|language=en|accessdate=2017-07-04|archive-date=2010-11-30|archive-url=https://web.archive.org/web/20101130120327/http://tools.ietf.org/html/rfc1945#section-9.3|dead-url=no}}</ref><ref name="h1.1">{{cite web|last1=C.|first1=Mogul, Jeffrey|last2=Jim|first2=Gettys,|last3=Tim|first3=Berners-Lee,|last4=Henrik|first4=Frystyk,|title=Hypertext Transfer Protocol -- HTTP/1.1|url=https://tools.ietf.org/html/rfc2068#section-10.3.2|website=IETF|language=en|accessdate=2017-07-04|archive-date=2018-06-07|archive-url=https://web.archive.org/web/20180607164335/https://tools.ietf.org/html/rfc2068#section-10.3.2|dead-url=no}}</ref><ref>{{cite web|last1=J.|first1=Leach, Paul|last2=Tim|first2=Berners-Lee,|last3=C.|first3=Mogul, Jeffrey|last4=Larry|first4=Masinter,|last5=T.|first5=Fielding, Roy|last6=James|first6=Gettys,|title=Hypertext Transfer Protocol -- HTTP/1.1|url=https://tools.ietf.org/html/rfc2616#section-10.3.2|language=en|accessdate=2017-07-04|archive-date=2011-03-07|archive-url=https://web.archive.org/web/20110307142107/http://tools.ietf.org/html/rfc2616#section-10.3.2|dead-url=no}}</ref>
* 如果一个客户端有链接编辑能力，其应当把所有的引用链接重定向到新的URL上。
* 这个响应代码是可以被缓存的。<ref>{{cite web|title=How long do browsers cache HTTP 301s?|url=http://stackoverflow.com/questions/9130422/how-long-do-browsers-cache-http-301s|website=StackOverflow|accessdate=2016-01-21|archive-date=2016-01-27|archive-url=https://web.archive.org/web/20160127030845/http://stackoverflow.com/questions/9130422/how-long-do-browsers-cache-http-301s|dead-url=no}}</ref><ref>{{cite web|last1=Mark|first1=Nottingham,|last2=Roy|first2=Fielding,|last3=Julian|first3=Reschke,|title=Hypertext Transfer Protocol (HTTP/1.1): Caching|url=https://tools.ietf.org/html/rfc7234#section-4.2.2|language=en|accessdate=2017-07-04|archive-date=2017-07-07|archive-url=https://web.archive.org/web/20170707155139/https://tools.ietf.org/html//rfc7234#section-4.2.2|dead-url=no}}</ref>
* 除非请求方法是HEAD，否则响应实体应该包含一个小型的超文本，标注一个超链接到新的URL。
* 如果是除了GET和HEAD之外的请求方法，客户端必须在重定向之前询问用户。

==例子==
客户端发出请求:
<syntaxhighlight lang="http">
GET /blog HTTP/1.1
Host: www.example.com
</syntaxhighlight>
服务器回应，不带Cache-Control头部:
<syntaxhighlight lang="http">
HTTP/1.1 301 Moved Permanently
Location: http://www.example.org/index.asp
</syntaxhighlight>
服务器回应，带Cache-Control头部:
<syntaxhighlight lang="http">
HTTP/1.1 301 Moved Permanently
Location: http://www.example.org/index.asp
Cache-control: private; max-age=600
</syntaxhighlight>

==客户端实现问题==
当某些HTTP/1.0客户端收到该状态码时，可能会将POST方法改为GET方法，继续向新地址发出请求，这是错误的实现——故而后续标准引入了[[HTTP 307]]。<ref>{{cite web|last1=Roy|first1=Fielding,|last2=Julian|first2=Reschke,|title=Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content|url=https://tools.ietf.org/html/rfc7231#section-6.4.2|language=en|accessdate=2017-07-04|archive-date=2017-05-25|archive-url=https://web.archive.org/web/20170525004653/https://tools.ietf.org/html/rfc7231#section-6.4.2|dead-url=no}}</ref>

==搜索引擎优化==
由于该代码表示页面地址发生了较长久的改变，故[[必应|Bing]]<ref>{{cite web|title=How to Use the Site Move Tool|url=https://www.bing.com/webmaster/help/how-to-use-the-site-move-tool-bb8f5112|website=Bing Webmaster Tools|accessdate=2017-07-04|archive-date=2016-03-07|archive-url=https://web.archive.org/web/20160307042000/https://www.bing.com/webmaster/help/how-to-use-the-site-move-tool-bb8f5112|dead-url=no}}</ref>和[[谷歌|Google]]<ref>{{cite web|title=Change page URLs with 301 redirects - Search Console Help|url=https://support.google.com/webmasters/answer/93633?hl=en|website=Google Help|language=en|accessdate=2017-07-05|archive-date=2017-07-24|archive-url=https://web.archive.org/web/20170724151015/https://support.google.com/webmasters/answer/93633?hl=en|dead-url=no}}</ref>等搜索引擎都推荐使用301重定向，以改变搜索引擎中的实际页面地址。

== 相關條目 ==
* [[.htaccess]]
* [[HTTP狀態碼]]
* [[URL重寫]]
* [[HTTP 302]]
* [[HTTP 303]]
* [[HTTP 307]]
* [[HTTP Location]]

== 参考文献 ==
<references />

== 外部連結 ==
* [http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html HTTP/1.1 Error codes in RFC 2616]{{Wayback|url=http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html |date=20100316011642 }} {{en icon}}
* RFC 1945
* RFC 2068

[[Category:計算機錯誤]]
[[Category:HTTP]]