HTTP response code excerpt from Apach official website

The HTTP status List response code consists of three-bit decimal digits that appear in the first line of the response sent by the HTTP server. The response code is divided into five types, represented by their first digit: 1xx: Information, request received, continue processing 2xx: Success, Behavior is successfully accepted, understood and adopted 3xx: redirect, in order to complete the request, the action must be further performed 4xx: Client error, The request contains a syntax error or the request cannot be implemented 5XX: Server error, the server cannot implement an apparently invalid request Continue The initial request has been accepted and the customer should continue to send the remainder of the request. (HTTP 1.1 new) 101 Switching protocols server converts the client's request to another protocol (HTTP 1.1 new) OK everything is OK, the answer document for Get and post requests is followed. The 201 Created Server has created the document, and the location header gives its URL. 202 Accepted has accepted the request, but the processing has not been completed. 203 Non-authoritative Information The document has returned normally, but some of the answer headers may be incorrect because a copy of the document (HTTP 1.1 new) is being used. 204 No Content There is no new document, the browser should continue to display the original document. This status code is useful if the user refreshes the page on a regular basis and the servlet can determine that the user's document is new enough. 205 Reset content is not new, but the browser should reset what it displays. Used to force the browser to clear the form input (HTTP 1.1 new). The 206 Partial Content client sends a GET request with a range header that the server has completed (HTTP 1.1 new). Multiple Choices customer requested documents can be found in multiple locations that have been listed in the returned document. If the server wants to make a preference, it should be indicated in the location answer header. 301 Moved Permanently The document requested by the customer elsewhere, the new URL is given in the location header, and the browser should automatically access the new URL. 302 Found is similar to 301, but the new URL should be treated as a temporary replacement, not a permanent. Note that the corresponding status information in HTTP1.0 is "Moved temporatily". When the status code appears, the browser can automatically access the new URL, so it is a useful status code. Note that this status code can sometimes be used with 301 substitutions. For example, if the browser mistakenly requests Http://host/~user (the trailing slash is missing), some servers return 301, and some return 302. Strictly speaking, we can only assume that the browser will automatically redirect only if the original request is get. See 307. 303 See other is similar to 301/302, except that if the original request is the Post,location header the specified redirect target document should be fetched via get (HTTP 1.1 new). 304 Not Modified client has buffered documents and issued a conditional request (typically providing a if-modified-since header indicating that the customer only wants to update the document than the specified date). The server tells the customer that the original buffered document can continue to be used. 305 Use proxy The document requested by the client should be extracted from the agent server indicated by the location header (HTTP 1.1 is new). 307 Temporary Redirect and 302 (Found) are the same. Many browsers incorrectly respond to a 302 response for redirection, even if the original request is post, even though it can actually be redirected only if the answer to the POST request is 303. For this reason, HTTP 1.1 has been added in 307 to allow for more cleanup of the region in several status codes: When a 303 response occurs, the browser can follow the redirected get and post requests, and if the 307 answer, the browser can only follow the redirect to the GET request. (HTTP 1.1 new) The bad Request syntax error. 401 Unauthorized customer attempts to access password-protected pages without authorization. A www-authenticate header is included in the answer, and the browser displays the user name/Password dialog box, and then makes a request again after filling in the appropriate authorization header. 403 Forbidden resource is not available. The server understands the customer's request, but refuses to process it. This is usually caused by the permissions set on the file or directory on the server. 404 Not Found Could not find the resource at the specified location. This is also a common answer. The 405 method not allowed request methods (GET, POST, HEAD, Delete, PUT, trace, etc.) do not apply to the specified resource. (HTTP 1.1 new) 406 not acceptable the specified resource has been found, but its MIME type is incompatible with the client specified in the Accpet header (HTTP 1.1 new). 407 Proxy authentication Required similar to 401, indicates that the customer must be authorized by the proxy server first. (HTTP 1.1 new) 408 Request Timeout The customer has not made any requests during the waiting time of the server license. Customers can repeat the same request at a later time. (HTTP 1.1 New) 409 Conflict is usually associated with a put request. The request cannot succeed because the request conflicts with the current state of the resource. (HTTP 1.1 new) 410 Gone The requested document is no longer available, and the server does not know which address to redirect to. It differs from 404 in that returning 407 means that the document has permanently left the specified location, and 404 indicates that the document is unavailable for unknown reasons. (HTTP 1.1 New) 411 Length Required The server cannot process the request unless the client sends a content-length header. (HTTP 1.1 new) 412 precondition Failed Some of the prerequisites specified in the request header failed (HTTP 1.1 new). 413 Request Entity Too Large the size of the target document exceeds the size that the server is currently willing to handle. If the server thinks it can process the request later, it should provide a Retry-after header (HTTP 1.1 new). 414 Request Uri Too Long URI is too lengthy (HTTP 1.1 new). 416 requested range not satisfiable server does not meet the Range header specified by the customer in the request. (HTTP 1.1 new) Internal Server Error Server encountered unexpected situation, unable to complete the customer request. The 501 not implemented server does not support the functionality required to implement the request. For example, a customer sends a put request that is not supported by the server. 502 Bad Gateway server as a gateway or proxy, the server returned an illegal reply in order to complete the request to access the next server. 503 Service Unavailable Server failed to answer due to maintenance or heavy load. For example, a servlet might return 503 if the database connection pool is full. A retry-after header can be supplied when the server returns 503. 504 Gateway Timeout is used by a server acting as a proxy or gateway, indicating that it is not able to get answers from remote servers in a timely manner. (HTTP 1.1 new) 505 HTTP Version not supported server does not support the specified in the requestVersion of HTTP. (HTTP 1.1 new) The following table shows each response code and what it means: "http/1.1 Continue"//Continue 101 = "http/1.1 101 Switching Protocols"//packet switching protocol 200 =& Gt  "http/1.1-OK"//ok201 "http/1.1 201 Created"//was created 202 = "http/1.1 202 Accepted"//Adopted 203 = "http/1.1 203 Non-authoritative Information "//non-authorized information 204 =" http/1.1 204 no Content "//no contents 205 =" http/1.1 205 Reset Content "//Heavy Content 206 = "http/1.1 206 partial Content"//part Contents "http/1.1" multiple Choices "//multi-option 301 =" http/1.1 301 M Oved permanently "//permanent transmission 302 =" http/1.1 302 Found "//Find 303 =" http/1.1 303 See other "//refer to other 304 =" http/1.1 3 Modified "//Unchanged 305 =" http/1.1 305 Use Proxy "//Using proxy 307 =" http/1.1 307 temporary Redirect "//temporarily redirect to =&gt ; "http/1.1"//Error Request 401 = "http/1.1 401 Unauthorized"//unauthorized 402 = "http/1.1 402 Payment Required"//Requirements Paid 403 = "http/1.1 403 Forbidden"//Forbidden 404 = "http/1.1 404 Not Found"//did not find 405 = "http/1.1 405 Method not Allowe D "//non-permitted partiesLaw 406 = "http/1.1 406 not acceptable"//is not adopted 407 = "http/1.1 407 proxy authentication Required"//requires agent authorization 408 = "H ttp/1.1 408 Request Time-out "//Requests timed out 409 =" http/1.1 409 Conflict "//conflict 410 =" http/1.1 410 Gone "//Expired 411 =" HT tp/1.1 411 Length Required "//required lengths 412 =" http/1.1 412 precondition Failed "//Premises not established 413 =" http/1.1 413 request Ent ity Too Large "//Request instance too large 414 =" http/1.1 414 request-uri Too Large "//Request URI too large 415 =" http/1.1 415 unsupported Media T Ype "//Unsupported Media type 416 =" http/1.1 416 requested range not satisfiable "//Unmet Request Range 417 = http/1.1 417 expectation Fai LED "//failed expected $ =" http/1.1 "//Internal Server Error 501 =" http/1.1 501 Not implemented "//unused 502 =&G T "http/1.1 502 Bad Gateway"//Gateway Error 503 = "http/1.1 503 Service Unavailable"//Unavailable Service 504 = "http/1.1 504 Gateway Time" -out "//Gateway Timeout 505 =" http/1.1 505″//http version not supported

HTTP response code excerpt from Apach official website