HTTP——10 Status Code Definitions

HTTP状态码分为五大类。

状态码为客户端提供了一种理解事务处理结果的便捷方式。

1xx Informational100 Continue101 Switching Protocols2xx Successful 

200 OK201 Created202 Accepted203 Non-Authoritative Information204 No Content205 Reset Content206 Partial Content3xx Redirection 
300 Multiple Choices301 Moved Permanently302 Found303 See Other304 Not Modified305 Use Proxy306 (Unused)307 Temporary Redirect4xx Client Error 
400 Bad Request401 Unauthorized402 Payment Required403 Forbidden404 Not Found405 Method Not Allowed406 Not Acceptable407 Proxy Authentication Required408 Request Timeout409 Conflict410 Gone411 Length Required412 Precondition Failed413 Request Entity Too Large414 Request-URI Too Long415 Unsupported Media Type416 Requested Range Not Satisfiable417 Expectation Failed5xx Server Error 
500 Internal Server Error501 Not Implemented502 Bad Gateway503 Service Unavailable504 Gateway Timeout505 HTTP Version Not Supported

<span style="font-size:14px;">10.1 Informational 1xx   This class of status code indicates a provisional（临时的、暂时的） response,   consisting only of the Status-Line and optional headers, and is   terminated by an empty line. There are no required headers for this   class of status code. Since HTTP/1.0 did not define any 1xx status   codes, servers MUST NOT send a 1xx response to an HTTP/1.0 client   except under experimental conditions.   A client MUST be prepared to accept one or more 1xx status responses   prior to a regular response, even if the client does not expect a 100   (Continue) status message. Unexpected 1xx status responses MAY be   ignored by a user agent.   Proxies MUST forward 1xx responses, unless the connection between the   proxy and its client has been closed, or unless the proxy itself   requested the generation of the 1xx response. (For example, if a   proxy adds a "Expect: 100-continue" field when it forwards a request,   then it need not forward the corresponding 100 (Continue)   response(s).)10.1.1 100 Continue   The client SHOULD continue with its request. This interim（临时的、暂时的） response is   used to inform the client that the initial part of the request has   been received and has not yet been rejected by the server. The client   SHOULD continue by sending the remainder of the request or, if the   request has already been completed, ignore this response. The server   MUST send a final response after the request has been completed. See   section 8.2.3 for detailed discussion of the use and handling of this   status code.10.1.2 101 Switching Protocols   The server understands and is willing to comply（遵从、顺从） with the client's   request, via the Upgrade message header field (section 14.42), for a   change in the application protocol being used on this connection. The   server will switch protocols to those defined by the response's   Upgrade header field immediately after the empty line which   terminates the 101 response.   The protocol SHOULD be switched only when it is advantageous to do   so. For example, switching to a newer version of HTTP is advantageous   over older versions, and switching to a real-time, synchronous   protocol might be advantageous when delivering resources that use   such features.10.2 Successful 2xx   This class of status code indicates that the client's request was   successfully received, understood, and accepted.（接受、理解和接受）10.2.1 200 OK   The request has succeeded. The information returned with the response   is dependent on the method used in the request, for example:   GET    an entity corresponding to the requested resource is sent in          the response;   HEAD   the entity-header fields corresponding to the requested          resource are sent in the response without any message-body;   POST   an entity describing or containing the result of the action;   TRACE  an entity containing the request message as received by the          end server.10.2.2 201 Created   The request has been fulfilled and resulted in a new resource being   created. The newly created resource can be referenced by the URI(s)   returned in the entity of the response, with the most specific URI   for the resource given by a Location header field. The response   SHOULD include an entity containing a list of resource   characteristics and location(s) from which the user or user agent can   choose the one most appropriate. The entity format is specified by   the media type given in the Content-Type header field. The origin   server MUST create the resource before returning the 201 status code.   If the action cannot be carried out immediately, the server SHOULD   respond with 202 (Accepted) response instead.   A 201 response MAY contain an ETag response header field indicating   the current value of the entity tag for the requested variant just   created, see section 14.19.10.2.3 202 Accepted   The request has been accepted for processing, but the processing has   not been completed.  The request might or might not eventually be   acted upon, as it might be disallowed when processing actually takes   place. There is no facility for re-sending a status code from an   asynchronous operation such as this.   The 202 response is intentionally non-committal. Its purpose is to   allow a server to accept a request for some other process (perhaps a   batch-oriented process that is only run once per day) without   requiring that the user agent's connection to the server persist   until the process is completed. The entity returned with this   response SHOULD include an indication of the request's current status   and either a pointer to a status monitor or some estimate of when the   user can expect the request to be fulfilled.10.2.4 203 Non-Authoritative Information   The returned metainformation in the entity-header is not the   definitive set as available from the origin server, but is gathered   from a local or a third-party copy. The set presented MAY be a subset   or superset of the original version. For example, including local   annotation information about the resource might result in a superset   of the metainformation known by the origin server. Use of this   response code is not required and is only appropriate when the   response would otherwise be 200 (OK).10.2.5 204 No Content   The server has fulfilled the request but does not need to return an   entity-body, and might want to return updated metainformation. The   response MAY include new or updated metainformation in the form of   entity-headers, which if present SHOULD be associated with the   requested variant.   If the client is a user agent, it SHOULD NOT change its document view   from that which caused the request to be sent. This response is   primarily intended to allow input for actions to take place without   causing a change to the user agent's active document view, although   any new or updated metainformation SHOULD be applied to the document   currently in the user agent's active view.   The 204 response MUST NOT include a message-body, and thus is always   terminated by the first empty line after the header fields.10.2.6 205 Reset Content   The server has fulfilled the request and the user agent SHOULD reset   the document view which caused the request to be sent. This response   is primarily intended to allow input for actions to take place via   user input, followed by a clearing of the form in which the input is   given so that the user can easily initiate another input action. The   response MUST NOT include an entity.10.2.7 206 Partial Content   The server has fulfilled the partial GET request for the resource.   The request MUST have included a Range header field (section 14.35)   indicating the desired range, and MAY have included an If-Range   header field (section 14.27) to make the request conditional.   The response MUST include the following header fields:      - Either a Content-Range header field (section 14.16) indicating        the range included with this response, or a multipart/byteranges        Content-Type including Content-Range fields for each part. If a        Content-Length header field is present in the response, its        value MUST match the actual number of OCTETs transmitted in the        message-body.      - Date      - ETag and/or Content-Location, if the header would have been sent        in a 200 response to the same request      - Expires, Cache-Control, and/or Vary, if the field-value might        differ from that sent in any previous response for the same        variant   If the 206 response is the result of an If-Range request that used a   strong cache validator (see section 13.3.3), the response SHOULD NOT   include other entity-headers. If the response is the result of an   If-Range request that used a weak validator, the response MUST NOT   include other entity-headers; this prevents inconsistencies between   cached entity-bodies and updated headers. Otherwise, the response   MUST include all of the entity-headers that would have been returned   with a 200 (OK) response to the same request.   A cache MUST NOT combine a 206 response with other previously cached   content if the ETag or Last-Modified headers do not match exactly,   see 13.5.4.   A cache that does not support the Range and Content-Range headers   MUST NOT cache 206 (Partial) responses.10.3 Redirection 3xx   This class of status code indicates that further action needs to be   taken by the user agent in order to fulfill the request.  The action   required MAY be carried out by the user agent without interaction   with the user if and only if the method used in the second request is   GET or HEAD. A client SHOULD detect infinite redirection loops, since   such loops generate network traffic（网络流量） for each redirection.      Note: previous versions of this specification recommended a      maximum of five redirections. Content developers should be aware      that there might be clients that implement such a fixed      limitation.10.3.1 300 Multiple Choices   The requested resource corresponds to any one of a set of   representations（表现、代表）, each with its own specific location, and agent-   driven negotiation information (section 12) is being provided so that   the user (or user agent) can select a preferred representation and   redirect its request to that location.   Unless it was a HEAD request, the response SHOULD include an entity   containing a list of resource characteristics and location(s) from   which the user or user agent can choose the one most appropriate. The   entity format is specified by the media type given in the Content-   Type header field. Depending upon the format and the capabilities of   the user agent, selection of the most appropriate choice MAY be   performed automatically. However, this specification does not define   any standard for such automatic selection.   If the server has a preferred choice of representation, it SHOULD   include the specific URI for that representation in the Location   field; user agents MAY use the Location field value for automatic   redirection. This response is cacheable unless indicated otherwise.10.3.2 301 Moved Permanently   The requested resource has been assigned a new permanent URI and any   future references to this resource SHOULD use one of the returned   URIs.  Clients with link editing capabilities ought to automatically   re-link references to the Request-URI to one or more of the new   references returned by the server, where possible. This response is   cacheable unless indicated otherwise.   The new permanent URI SHOULD be given by the Location field in the   response. Unless the request method was HEAD, the entity of the   response SHOULD contain a short hypertext note with a hyperlink to   the new URI(s).   If the 301 status code is received in response to a request other   than GET or HEAD, the user agent MUST NOT automatically redirect the   request unless it can be confirmed by the user, since this might   change the conditions under which the request was issued.      Note: When automatically redirecting a POST request after      receiving a 301 status code, some existing HTTP/1.0 user agents      will erroneously change it into a GET request.10.3.3 302 Found   The requested resource resides temporarily（临时驻留） under a different URI.   Since the redirection might be altered on occasion, the client SHOULD   continue to use the Request-URI for future requests.  This response   is only cacheable if indicated by a Cache-Control or Expires header   field.   The temporary URI SHOULD be given by the Location field in the   response. Unless the request method was HEAD, the entity of the   response SHOULD contain a short hypertext note with a hyperlink to   the new URI(s).   If the 302 status code is received in response to a request other   than GET or HEAD, the user agent MUST NOT automatically redirect the   request unless it can be confirmed by the user, since this might   change the conditions under which the request was issued.      Note: RFC 1945 and RFC 2068 specify that the client is not allowed      to change the method on the redirected request.  However, most      existing user agent implementations treat 302 as if it were a 303      response, performing a GET on the Location field-value regardless      of the original request method. The status codes 303 and 307 have      been added for servers that wish to make unambiguously clear which      kind of reaction is expected of the client.10.3.4 303 See Other   The response to the request can be found under a different URI and   SHOULD be retrieved using a GET method on that resource. This method   exists primarily to allow the output of a POST-activated script to   redirect the user agent to a selected resource. The new URI is not a   substitute reference for the originally requested resource. The 303   response MUST NOT be cached, but the response to the second   (redirected) request might be cacheable.   The different URI SHOULD be given by the Location field in the   response. Unless the request method was HEAD, the entity of the   response SHOULD contain a short hypertext note with a hyperlink to   the new URI(s).      Note: Many pre-HTTP/1.1 user agents do not understand the 303      status. When interoperability with such clients is a concern, the      302 status code may be used instead, since most user agents react      to a 302 response as described here for 303.10.3.5 304 Not Modified   If the client has performed a conditional GET request and access is   allowed, but the document has not been modified, the server SHOULD   respond with this status code. The 304 response MUST NOT contain a   message-body, and thus is always terminated by the first empty line   after the header fields.   The response MUST include the following header fields:      - Date, unless its omission is required by section 14.18.1   If a clockless origin server obeys these rules, and proxies and   clients add their own Date to any response received without one (as   already specified by [RFC 2068], section 14.19), caches will operate   correctly.      - ETag and/or Content-Location, if the header would have been sent        in a 200 response to the same request      - Expires, Cache-Control, and/or Vary, if the field-value might        differ from that sent in any previous response for the same        variant   If the conditional GET used a strong cache validator (see section   13.3.3), the response SHOULD NOT include other entity-headers.   Otherwise (i.e., the conditional GET used a weak validator), the   response MUST NOT include other entity-headers; this prevents   inconsistencies between cached entity-bodies and updated headers.   If a 304 response indicates an entity not currently cached, then the   cache MUST disregard the response and repeat the request without the   conditional.   If a cache uses a received 304 response to update a cache entry, the   cache MUST update the entry to reflect any new field values given in   the response.10.3.6 305 Use Proxy   The requested resource MUST be accessed through the proxy given by   the Location field. The Location field gives the URI of the proxy.   The recipient is expected to repeat this single request via the   proxy. 305 responses MUST only be generated by origin servers.      Note: RFC 2068 was not clear that 305 was intended to redirect a      single request, and to be generated by origin servers only.  Not      observing these limitations has significant security consequences.10.3.7 306 (Unused)   The 306 status code was used in a previous version of the   specification, is no longer used, and the code is reserved.10.3.8 307 Temporary Redirect   The requested resource resides temporarily under a different URI.   Since the redirection MAY be altered on occasion, the client SHOULD   continue to use the Request-URI for future requests.  This response   is only cacheable if indicated by a Cache-Control or Expires header   field.   The temporary URI SHOULD be given by the Location field in the   response. Unless the request method was HEAD, the entity of the   response SHOULD contain a short hypertext note with a hyperlink to   the new URI(s) , since many pre-HTTP/1.1 user agents do not   understand the 307 status. Therefore, the note SHOULD contain the   information necessary for a user to repeat the original request on   the new URI.   If the 307 status code is received in response to a request other   than GET or HEAD, the user agent MUST NOT automatically redirect the   request unless it can be confirmed by the user, since this might   change the conditions under which the request was issued.<strong>10.4 Client Error 4xx</strong>   The 4xx class of status code is intended for cases in which the   client seems to have erred. Except when responding to a HEAD request,   the server SHOULD include an entity containing an explanation of the   error situation, and whether it is a temporary or permanent   condition. These status codes are applicable to any request method.   User agents SHOULD display any included entity to the user.   If the client is sending data, a server implementation using TCP   SHOULD be careful to ensure that the client acknowledges receipt of   the packet(s) containing the response, before the server closes the   input connection. If the client continues sending data to the server   after the close, the server's TCP stack will send a reset packet to   the client, which may erase the client's unacknowledged input buffers   before they can be read and interpreted by the HTTP application.10.4.1 400 Bad Request   The request could not be understood by the server due to malformed   syntax. The client SHOULD NOT repeat the request without   modifications.10.4.2 401 Unauthorized   The request requires user authentication. The response MUST include a   WWW-Authenticate header field (section 14.47) containing a challenge   applicable to the requested resource. The client MAY repeat the   request with a suitable Authorization header field (section 14.8). If   the request already included Authorization credentials, then the 401   response indicates that authorization has been refused for those   credentials. If the 401 response contains the same challenge as the   prior response, and the user agent has already attempted   authentication at least once, then the user SHOULD be presented the   entity that was given in the response, since that entity might   include relevant diagnostic information. HTTP access authentication   is explained in "HTTP Authentication: Basic and Digest Access   Authentication" [43].10.4.3 402 Payment Required（付费要求）   This code is reserved for future use.10.4.4 403 Forbidden   The server understood the request, but is refusing to fulfill it.   Authorization will not help and the request SHOULD NOT be repeated.   If the request method was not HEAD and the server wishes to make   public why the request has not been fulfilled, it SHOULD describe the   reason for the refusal in the entity.  If the server does not wish to   make this information available to the client, the status code 404   (Not Found) can be used instead.10.4.5 404 Not Found   The server has not found anything matching the Request-URI. No   indication is given of whether the condition is temporary or   permanent. The 410 (Gone) status code SHOULD be used if the server   knows, through some internally configurable mechanism, that an old   resource is permanently unavailable and has no forwarding address.   This status code is commonly used when the server does not wish to   reveal（显示、揭露） exactly why the request has been refused, or when no other   response is applicable.10.4.6 405 Method Not Allowed   The method specified in the Request-Line is not allowed for the   resource identified by the Request-URI. The response MUST include an   Allow header containing a list of valid methods for the requested   resource.10.4.7 406 Not Acceptable   The resource identified by the request is only capable of generating   response entities which have content characteristics（特征、特性） not acceptable   according to the accept headers sent in the request.   Unless it was a HEAD request, the response SHOULD include an entity   containing a list of available entity characteristics and location(s)   from which the user or user agent can choose the one most   appropriate. The entity format is specified by the media type given   in the Content-Type header field. Depending upon the format and the   capabilities of the user agent, selection of the most appropriate   choice MAY be performed automatically. However, this specification   does not define any standard for such automatic selection.      Note: HTTP/1.1 servers are allowed to return responses which are      not acceptable according to the accept headers sent in the      request. In some cases, this may even be preferable to sending a      406 response. User agents are encouraged to inspect the headers of      an incoming response to determine if it is acceptable.   If the response could be unacceptable, a user agent SHOULD   temporarily stop receipt of more data and query the user for a   decision on further actions.10.4.8 407 Proxy Authentication Required   This code is similar to 401 (Unauthorized), but indicates that the   client must first authenticate itself with the proxy. The proxy MUST   return a Proxy-Authenticate header field (section 14.33) containing a   challenge applicable to the proxy for the requested resource. The   client MAY repeat the request with a suitable Proxy-Authorization   header field (section 14.34). HTTP access authentication is explained   in "HTTP Authentication: Basic and Digest Access Authentication"   [43].10.4.9 408 Request Timeout   The client did not produce a request within the time that the server   was prepared to wait. The client MAY repeat the request without   modifications at any later time.10.4.10 409 Conflict   The request could not be completed due to a conflict with the current   state of the resource. This code is only allowed in situations where   it is expected that the user might be able to resolve the conflict   and resubmit the request. The response body SHOULD include enough   information for the user to recognize the source of the conflict.   Ideally, the response entity would include enough information for the   user or user agent to fix the problem; however, that might not be   possible and is not required.   Conflicts are most likely to occur in response to a PUT request. For   example, if versioning were being used and the entity being PUT   included changes to a resource which conflict with those made by an   earlier (third-party) request, the server might use the 409 response   to indicate that it can't complete the request. In this case, the   response entity would likely contain a list of the differences   between the two versions in a format defined by the response   Content-Type.10.4.11 410 Gone   The requested resource is no longer available at the server and no   forwarding address is known. This condition is expected to be   considered permanent. Clients with link editing capabilities SHOULD   delete references to the Request-URI after user approval. If the   server does not know, or has no facility to determine, whether or not   the condition is permanent, the status code 404 (Not Found) SHOULD be   used instead. This response is cacheable unless indicated otherwise.   The 410 response is primarily intended to assist the task of web   maintenance by notifying the recipient that the resource is   intentionally unavailable and that the server owners desire that   remote links to that resource be removed. Such an event is common for   limited-time, promotional services and for resources belonging to   individuals no longer working at the server's site. It is not   necessary to mark all permanently unavailable resources as "gone" or   to keep the mark for any length of time -- that is left to the   discretion of the server owner.10.4.12 411 Length Required   The server refuses to accept the request without a defined Content-   Length. The client MAY repeat the request if it adds a valid   Content-Length header field containing the length of the message-body   in the request message.10.4.13 412 Precondition Failed   The precondition given in one or more of the request-header fields   evaluated to false when it was tested on the server. This response   code allows the client to place preconditions on the current resource   metainformation (header field data) and thus prevent the requested   method from being applied to a resource other than the one intended.？10.4.14 413 Request Entity Too Large   The server is refusing to process a request because the request   entity is larger than the server is willing or able to process. The   server MAY close the connection to prevent the client from continuing   the request.   If the condition is temporary, the server SHOULD include a Retry-   After header field to indicate that it is temporary and after what   time the client MAY try again.10.4.15 414 Request-URI Too Long   The server is refusing to service the request because the Request-URI   is longer than the server is willing to interpret. This rare   condition is only likely to occur when a client has improperly   converted a POST request to a GET request with long query   information, when the client has descended into a URI "black hole" of   redirection (e.g., a redirected URI prefix that points to a suffix of   itself), or when the server is under attack by a client attempting to   exploit security holes present in some servers using fixed-length   buffers for reading or manipulating the Request-URI.10.4.16 415 Unsupported Media Type   The server is refusing to service the request because the entity of   the request is in a format not supported by the requested resource   for the requested method.10.4.17 416 Requested Range Not Satisfiable   A server SHOULD return a response with this status code if a request   included a Range request-header field (section 14.35), and none of   the range-specifier values in this field overlap the current extent   of the selected resource, and the request did not include an If-Range   request-header field. (For byte-ranges, this means that the first-   byte-pos of all of the byte-range-spec values were greater than the   current length of the selected resource.)   When this status code is returned for a byte-range request, the   response SHOULD include a Content-Range entity-header field   specifying the current length of the selected resource (see section   14.16). This response MUST NOT use the multipart/byteranges content-   type.10.4.18 417 Expectation Failed   The expectation given in an Expect request-header field (see section   14.20) could not be met by this server, or, if the server is a proxy,   the server has unambiguous evidence that the request could not be met   by the next-hop server.10.5 Server Error 5xx   Response status codes beginning with the digit "5" indicate cases in   which the server is aware that it has erred or is incapable of   performing the request. Except when responding to a HEAD request, the   server SHOULD include an entity containing an explanation of the   error situation, and whether it is a temporary or permanent   condition. User agents SHOULD display any included entity to the   user. These response codes are applicable to any request method.10.5.1 500 Internal Server Error   The server encountered an unexpected condition which prevented it   from fulfilling the request.10.5.2 501 Not Implemented   The server does not support the functionality required to fulfill the   request. This is the appropriate response when the server does not   recognize the request method and is not capable of supporting it for   any resource.10.5.3 502 Bad Gateway   The server, while acting as a gateway or proxy, received an invalid   response from the upstream server it accessed in attempting to   fulfill the request.10.5.4 503 Service Unavailable   The server is currently unable to handle the request due to a   temporary overloading or maintenance of the server. The implication   is that this is a temporary condition which will be alleviated（缓解、减轻） after   some delay. If known, the length of the delay MAY be indicated in a   Retry-After header. If no Retry-After is given, the client SHOULD   handle the response as it would for a 500 response.      Note: The existence of the 503 status code does not imply that a      server must use it when becoming overloaded. Some servers may wish      to simply refuse the connection.10.5.5 504 Gateway Timeout   The server, while acting as a gateway or proxy, did not receive a   timely response from the upstream server specified by the URI (e.g.   HTTP, FTP, LDAP) or some other auxiliary（辅助的、附加的） server (e.g. DNS) it needed   to access in attempting to complete the request.      Note: Note to implementors: some deployed proxies are known to      return 400 or 500 when DNS lookups time out.10.5.6 505 HTTP Version Not Supported   The server does not support, or refuses to support, the HTTP protocol   version that was used in the request message. The server is   indicating that it is unable or unwilling to complete the request   using the same major version as the client, as described in section   3.1, other than with this error message. The response SHOULD contain   an entity describing why that version is not supported and what other   protocols are supported by that server.</span>