Reference: http://www.cnblogs.com/shanyou/archive/2012/05/06/2486134.html
Common status codes for http status codes are:
200 - the server successfully returned the web page 404 - the requested web page does not exist 503 - the service is unavailable
1xx (provisional response)
status codes that indicate a provisional response and require the requester to proceed with the action.
Code Description
100 (Continue) The requester should proceed with the request. The server returns this code to indicate that the first part of the request has been received and is waiting for the rest.
101 (Switch protocol) The requester has asked the server to switch protocols, the server has confirmed and is ready to switch.
2xx (success)
Status code indicating that the request was processed successfully.
Code Description
200 (Success) The server has successfully processed the request. Typically, this means that the server served the requested web page.
201 (Created) The request was successful and the server created a new resource.
202 (Accepted) The server has accepted the request but has not yet processed it.
203 (Unauthorized Information) The server successfully processed the request, but the returned information may have come from another source.
204 (No Content) The server successfully processed the request but returned no content.
205 (Content reset) The server successfully processed the request but returned no content.
206 (Partial Content) The server successfully processed a partial GET request.
3xx (redirect)
indicates that further action is required to complete the request. Typically, these status codes are used for redirection.
Code Description
300 (multiple choice) The server can perform various actions on the request. The server may select an action based on the requestor (user agent), or provide a list of actions for the requester to choose from.
301 (Moved Permanently) The requested web page has been permanently moved to a new location. When the server returns this response (to a GET or HEAD request), it automatically redirects the requester to the new location.
302 (Moved temporarily) The server is currently responding to the request from a web page in a different location, but the requester should continue to use the original location for future requests.
303 (See other locations) The server returns this code when the requester should use separate GET requests for different locations to retrieve the response.
304 (Not Modified) The requested page has not been modified since the last request. When the server returns this response, no web page content is returned.
305 (Use Proxy) The requester can only use a proxy to access the requested web page. If the server returns this response, it also indicates that the requester should use a proxy.
307 (Temporary Redirect) The server is currently responding to the request from a web page in a different location, but the requester should continue to use the original location for future requests.
4xx (Request Error)
These status codes indicate that the request may have gone wrong, preventing the server from processing it.
代码 说明
400 （错误请求） 服务器不理解请求的语法。
401 （未授权） 请求要求身份验证。 对于需要登录的网页，服务器可能返回此响应。
403 （禁止） 服务器拒绝请求。
404 （未找到） 服务器找不到请求的网页。
405 （方法禁用） 禁用请求中指定的方法。
406 （不接受） 无法使用请求的内容特性响应请求的网页。
407 （需要代理授权） 此状态代码与 401（未授权）类似，但指定请求者应当授权使用代理。
408 （请求超时） 服务器等候请求时发生超时。
409 （冲突） 服务器在完成请求时发生冲突。 服务器必须在响应中包含有关冲突的信息。
410 （已删除） 如果请求的资源已永久删除，服务器就会返回此响应。
411 （需要有效长度） 服务器不接受不含有效内容长度标头字段的请求。
412 （未满足前提条件） 服务器未满足请求者在请求中设置的其中一个前提条件。
413 （请求实体过大） 服务器无法处理请求，因为请求实体过大，超出服务器的处理能力。
414 （请求的 URI 过长） 请求的 URI（通常为网址）过长，服务器无法处理。
415 （不支持的媒体类型） 请求的格式不受请求页面的支持。
416 （请求范围不符合要求） 如果页面无法提供请求的范围，则服务器会返回此状态代码。
417 （未满足期望值） 服务器未满足”期望”请求标头字段的要求。
5xx（服务器错误）
这些状态代码表示服务器在尝试处理请求时发生内部错误。 这些错误可能是服务器本身的错误，而不是请求出错。
代码 说明
500 （服务器内部错误） 服务器遇到错误，无法完成请求。
501 （尚未实施） 服务器不具备完成请求的功能。 例如，服务器无法识别请求方法时可能会返回此代码。
502 （错误网关） 服务器作为网关或代理，从上游服务器收到无效响应。
503 （服务不可用） 服务器目前无法使用（由于超载或停机维护）。 通常，这只是暂时状态。
504 （网关超时） 服务器作为网关或代理，但是没有及时从上游服务器收到请求。
505 （HTTP 版本不受支持） 服务器不支持请求中所用的 HTTP 协议版本。