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The following is referenced from Http://wiki.jikexueyuan.com/project/servlet/http-status-codes.html:
The format of the HTTP request and the format of the HTTP response message are similar and are structured as follows:
An initial state line + CRLF (carriage return + newline is the new line)
0 or more header lines + CRLF
A blank line, that is, a CRLF
For example, the Server's response header information looks as Follows:
http/1.1 okcontent-type:text/htmlheader2: ... HeaderN: ... (Blank line)<!DOCTYPE ...><HTML><Head>...</Head><Body>...</Body></HTML>
The status line includes the HTTP version (http/1.1 in the example), a status code (200 in the example), and a short message corresponding to the status code (ok in the example).
The following HTTP status code and a list of related messages that may be returned from the Web Server:
| code: | message: | description: |
|---|---|---|
| 100 | Continue | Only part of the request has been received by the server, but as long as it is not rejected, the client should continue the Request. |
| 101 | Switching protocols | Server Switching Protocol. |
| 200 | Ok | The request was Successful. |
| 201 | Created | The request is complete, and a new resource is Created. |
| 202 | Accepted | The request is accepted for processing, but the processing is Incomplete. |
| 203 | Non-authoritative Information | |
| 204 | No Content | |
| 205 | Reset Content | |
| 206 | Partial Content | |
| 300 | Multiple Choices | A list of links. The user can select a link to go to that Location. Maximum of five addresses |
| 301 | Moved Permanently | The requested page has been transferred to a new url. |
| 60W | Found | The requested page has been temporarily transferred to a new url. |
| 303 | See other | The requested page can be found under another different url. |
| 304 | Not Modified | |
| 305 | Use Proxy | |
| 306 | Unused | Use this code in a previous Version. It is no longer used, but the code is still Preserved. |
| 307 | Temporary Redirect | The requested page has been temporarily transferred to a new url. |
| 400 | Bad Request | The server does not understand the Request. |
| 401 | Unauthorized | The requested page requires a user name and Password. |
| 402 | Payment Required | You cannot use this code yet. |
| 403 | Forbidden | Access to the requested page is Forbidden. |
| 404 | Not Found | The server was unable to find the requested Page. |
| 405 | Method not allowed | The method specified in the request is not Allowed. |
| 50W | Not acceptable | The server only generates a response that is not accepted by the Client. |
| 50V | Proxy Authentication Required | You must use Proxy server authentication before requesting Delivery. |
| 408 | Request Timeout | The request takes longer than the server can wait to time Out. |
| 409 | Conflict | The request could not be completed because of a conflict. |
| 410 | Gone | The requested page is no longer available. |
| 411 | Length Required | "content-length" is Undefined. The server cannot process request information sent by the client without Content-length. |
| 412 | Precondition Failed | The prerequisites given in the request are evaluated by the server as False. |
| 413 | Request Entity Too Large | The server does not accept the request because the request entity is too large. |
| 414 | Request-url Too Long | The server does not accept the request because the URL is too long. Occurs when a "get" request with a long query information is converted to a "post" Request. |
| 415 | Unsupported Media Type | The server does not accept the request because the media type is not Supported. |
| 417 | Expectation Failed | |
| 500 | Internal Server Error | The request was not Completed. The server encountered an unexpected Situation. |
| 501 | Not implemented | The request was not Completed. The server does not support the required Functionality. |
| 502 | Bad Gateway | The request was not Completed. The server received an invalid response from the upstream Server. |
| 40R | Service unavailable | The request was not Completed. The server is temporarily overloaded or crashed. |
| 504 | Gateway Timeout | The Gateway timed Out. |
| 505 | HTTP Version not supported | The server does not support the "http protocol" Version. |
one, the method of setting the HTTP status code:
The following is a method that you can use to set HTTP status codes in a servlet program. These methods are available through the HttpServletResponse Object.
| Method | Description |
|---|---|
public void SetStatus (int StatusCode) |
This method sets an arbitrary status Code. The SetStatus method takes an int (status code) as a parameter. If your response contains a special status code and documentation, make sure to call SetStatus before using PrintWriter to actually return any Content. |
public void Sendredirect (String Url) |
This method generates a 302 response, along with a URL with a new document location Head. |
public void Senderror (int code, String Message) |
The method sends a status code (typically 404), along with a short message that is automatically formatted and sent to the client inside the HTML Document. |
second, HTTP status Code instance:
The following example sends a 407 error code to the client browser, and the browser will show "authentication required!!!" "message.
//Import required Java librariesImportJava.io.*;Importjavax.servlet.*;Importjavax.servlet.http.*;ImportJava.util.*;//Extend HttpServlet class public classShowErrorextendsHttpServlet {//method to handle GET method Request. public voiddoget (httpservletrequest request, httpservletresponse response)throwsservletexception, IOException {//Set error code and Reason.Response.senderror (407, "need authentication!!!" ); } //method to handle POST method Request. public voiddoPost (httpservletrequest request, httpservletresponse response)throwsservletexception, ioexception {doget (request, response); }}
Configure Web. Xml:
<servlet> <Servlet-name>ShowError</Servlet-name> <Servlet-class>Com.jsoft.testservletbasics.ShowError</Servlet-class> </servlet> <servlet-mapping> <Servlet-name>ShowError</Servlet-name> <Url-pattern>/showerror</Url-pattern> </servlet-mapping>
Calling the above servlet now will display the results shown below:
Test Project: HTTPS://GITHUB.COM/EASONJIM/5_JAVA_EXAMPLE/TREE/MASTER/SERVLETBASICS/TEST5
HTTP status code for servlet
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