JSP HTTP status code

The format of the HTTP request and the HTTP response are similar, and have the following structure:

  • Start with status line + CRLF (carriage return and line feed)
  • Zero-line or multi-line header module + CRLF
  • A blank line, such as CRLF
  • Optional message body such as file, query data, query output

For example, a server response header looks like this:

HTTP/1.1 200 OK
Content-Type: text/html
Header2: ...
HeaderN: ...
  (Blank Line)
<!doctype ...>

The status line contains the HTTP version, a status code, and a short message corresponding to the status code.

The following table lists the HTTP status codes and messages associated with them that may be returned from the server:

Status code Message Description
100 Continue Only part of the request is received by the server, but as long as it is not rejected by the server, the client will continue the request
101 Switching Protocols Server Switch Protocol
200 OK The request was confirmed
201 Created When requested, complete, new resources are created
202 Accepted The request was accepted but not processed
203 Non-authoritative Information  
204 No Content  
205 Reset Content  
206 Partial Content  
300 Multiple Choices A hyperlink list, the user can select a hyperlink and visit, maximum support 5 hyperlinks
301 Moved Permanently The requested page has been moved to a new URL
302 Found The requested page is temporarily moved to a new URL
303 See Other The requested page can be found under a different URL
304 Not Modified  
305 Use Proxy  
306 Unused This status code is no longer used, but the status code is retained
307 Temporary Redirect The requested page is temporarily moved to a new URL
400 Bad Request The server did not recognize the request
401 Unauthorized The requested page requires a username and password
402 Payment Required This status code is not yet available
403 Forbidden Forbid access to the requested page
404 Not Found The server could not find the requested page
405 Method Not Allowed The method specified in the request is not allowed
406 Not Acceptable The server can only create a response that the client cannot accept
407 Proxy Authentication Required A proxy server must be authenticated before the request is served
408 Request Timeout The request time exceeds the time the server can wait and the connection is disconnected
409 Conflict There are conflicts in the request
410 Gone The requested page is no longer available
411 Length Required "Content-Length" is not defined, the server refuses to accept the request
412 Precondition Failed The prerequisite of the request is evaluated as false by the server
413 Request Entity Too Large Because the requested entity is too large, the server refuses to accept the request
414 Request-url Too Long The server refused to accept the request because the URL was too long. It often appears in the large amount of query information attached when converting "POST" requests into "GET" requests
415 Unsupported Media Type The server refused to accept the request because the media type is not supported
417 Expectation Failed  
500 Internal Server Error The request was incomplete and the server encountered an unexpected condition
501 Not Implemented The request is incomplete, the server does not provide the required functions
502 Bad Gateway The request is incomplete and the server received an invalid response from the upstream server
503 Service Unavailable The request is incomplete and the server is temporarily restarted or shut down
504 Gateway Timeout Gateway timeout
505 HTTP Version Not Supported The server does not support the specified HTTP version

Method for setting HTTP status code

The following table lists the methods used to set the status code in the HttpServletResponse class:

S.N. method & Description
1 public void setStatus (int statusCode)

This method can set any status code. If your response contains a special status code and a document, make sure to call the setStatus method before returning anything with PrintWriter
2 public void sendRedirect (String url)

This method produces a 302 response and a Location The header tells the URL a new document
3 public void sendError (int code, String message)

This method automatically inserts a status code (usually 404) and a short message into the HTML document and sends it back to the client

HTTP status code program example

The following example will send a 407 error code to the browser, and then the browser will tell you "Need authentication !!!".

<title>Setting HTTP Status Code</title>
   //Set the error code and explain the reason
   response.sendError(407, "Need authentication!!!" );

Visit the above JSP page and you will get the following result´╝Ü


You can also try using other status codes to see if you get any unexpected results.