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You can refer to the HTTP protocol for more information. The following table lists some important contents of the browser-side message headers, which will be frequently encountered in future network programming: Header Description Accept Specifies the MIME types that the browser or other clients can handle. Its value is usually image/png or image/jpeg Accept-Charset Specifies the character set to be used by the browser. For example, ISO-8859-1 Accept-Encoding Specifies the encoding type. Its value is usually gzip or compress Accept-Language Specifies the client's preferred language. The servlet will prioritize returning results composed in the current language if the servlet supports this language. For example, en, en-us, ru, etc. Authorization Identifies different users when accessing password-protected webpages Connection Indicates whether the client can handle HTTP persistent connections. Persistent connections allow the client or browser to obtain multiple files in a single request. Keep-Alive indicates that persistent connections are enabled Content-Length Applies only to POST requests, indicating the number of bytes of POST data Cookie Returns cookies previously sent to the browser back to the server Host Indicates the hostname and port number in the original URL If-Modified-Since Indicates that the client only needs the webpage if it has been modified after the specified date. The server sends a 304 code to the client, indicating that there are no updated resources If-Unmodified-Since Opposite to If-Modified-Since, the operation is successful only if the document has not been modified after the specified date Referer Indicates the URL of the referring page. For example, if you are on page 1 and then click a link to page 2, the URL of page 1 will be included in the browser's request header for page 2 User-Agent Used to distinguish requests sent by different browsers or clients and return different content for different types of browsers HttpServletRequest Class The request object is an instance of the javax.servlet.http.HttpServletRequest class. Whenever a client requests a page, the JSP engine creates a new object to represent this request. The request object provides a series of methods to obtain HTTP headers, including form data, cookies, HTTP methods, etc. The following will introduce some commonly used methods for obtaining HTTP headers in JSP programming. For details, please refer to the table below: No. Method & Description 1 Cookie[] getCookies() Returns an array of all Cookies from the client 2 Enumeration getAttributeNames() Returns a collection of all attribute names of the request object 3 Enumeration getHeaderNames() Returns a collection of all HTTP header names 4 Enumeration getParameterNames() Returns a collection of all parameters in the request 5 HttpSession getSession() Returns the session object corresponding to the request, creating one if it does not exist 6 HttpSession getSession(boolean create) Returns the session object corresponding to the request, creating a new session object if it does not exist and the parameter create is true 7 Locale getLocale() Returns the Locale object of the current page, which can be set in the response 8 Object getAttribute(String name) Returns the attribute value named name, returning null if it does not exist. 9 ServletInputStream getInputStream() Returns the input stream of the request 10 String getAuthType() Returns the name of the authentication scheme used to protect the servlet, such as "BASIC" or "SSL", or null if the JSP has no protection measures set 11 String getCharacterEncoding() Returns the name of the character encoding set of the request 12 String getContentType() Returns the MIME type of the request body, returning null if unknown 13 String getContextPath() Returns the context path specified in the request URI 14 String getHeader(String name) Returns the header specified by name 15 String getMethod() Returns the HTTP method in this request, such as GET, POST, or PUT 16 String getParameter(String name) Returns the parameter specified by name in this request, returning null if it does not exist 17 String getPathInfo() Returns any additional path information related to this request URL 18 String getProtocol() Returns the protocol name and version used by this request 19 String getQueryString() Returns the query string contained in this request URL 20 String getRemoteAddr() Returns the IP address of the client 21 String getRemoteHost() Returns the full name of the client 22 String getRemoteUser() Returns the user who authenticated via login from the client, returning null if the user is not authenticated 23 String getRequestURI() Returns the URI of the request 24 String getRequestedSessionId() Returns the session ID specified by the request 25 String getServletPath() Returns the path of the requested servlet 26 String[] getParameterValues(String name) Returns all values of the parameter named name, returning null if it does not exist 27 boolean isSecure() Returns whether the request uses an encrypted channel, such as HTTPS 28 int getContentLength() Returns the number of bytes contained in the request body, returning -1 if unknown 29 int getIntHeader(String name) Returns the value of the request header specified by name 30 int getServerPort() Returns the server port number HTTP Header Example In this example, we will use the getHeaderNames() method of the HttpServletRequest class to read the HTTP headers. This method returns the header information of the current HTTP request in the form of an enumeration. After obtaining the Enumeration object, use the standard way to traverse the Enumeration object, using the hasMoreElements() method to determine when to stop, and the nextElement() method to get the name of each parameter.

HTTP Header Request Example

<% Enumeration headerNames = request.getHeaderNames(); while(headerNames.hasMoreElements()) { String paramName = (String)headerNames.nextElement(); out.print("n"); String paramValue = request.getHeader(paramName); out.println("n"); } %>

Header Name	Header Value(s)
" + paramName + "	" + paramValue + "

Accessing main.jsp will yield the following result: You can try other methods of the HttpServletRequest class in the code above. JSP Implicit Objects JSP Server Response ByteArk Coding Plan Supports mainstream large models such as Doubao, GLM, DeepSeek, Kimi, MiniMax, officially supplied, stable and reliable. Configuration Guide ¥9.9 / Month Activate Now iFlytek Xingchen Coding Plan Includes free model call quota, DeepSeek, GLM, Kimi, MiniMax, a one-stop experience and deployment platform. Configuration Guide ¥3.9 / Month Activate Now Click me to share notes Category Navigation Python / Data Science AI / Intelligent Development Front-end Development Back-end Development Database Mobile Development DevOps / Engineering Programming Languages Computer Fundamentals XML / Web Service .NET Website Construction Advertisement Deep Dive Programming Languages Programming Scripting Languages Software Network Services Web Service Scripts Computer Science JSP Tutorial JSP Tutorial JSP Introduction JSP Development Environment Setup Eclipse JSP/Servlet JSP Structure JSP Lifecycle JSP Syntax JSP Directives JSP Action Elements JSP Implicit Objects JSP Client Requests JSP Server Response JSP HTTP Status Codes JSP Form Processing JSP Filters JSP Cookie Handling JSP Session JSP File Upload JSP Date Processing JSP Page Redirection JSP Hit Counter JSP Auto Refresh JSP Sending Emails JSP Advanced Tutorial JSP Standard Tag Library (JSTL) JSP Database Connection JSP XML Data Processing JSP JavaBean JSP Custom Tags JSP Expression Language JSP Exception Handling JSP Debugging JSP Internationalization Online Examples ·HTML Examples ·CSS Examples ·JavaScript Examples ·Ajax Examples ·jQuery Examples ·XML Examples ·Java Examples Character Sets & Tools · HTML Character Set Settings · HTML ASCII Character Set · JS Obfuscation/Encryption · PNG/JPEG Image Compression · HTML Color Picker · JSON Formatting Tool · Random Number Generator Latest Updates · Large Model Multimodal (M... · Codex Advanced Configuration · AI Agent Terminology · ZCode Getting Started Tutorial · Loop Engineerin... · Claude Code Us... · Claude Code Us... Site Information · Feedback · Disclaimer · About Us · Article Archive Follow WeChat My Favorites Mark Article Browsing History Clear All No records yet