-- Learning not just technology, but dreams! Home HTML JAVASCRIPT CSS VUE REACT PYTHON3 JAVA C C++ C# AI GO SQL LINUX VS CODE BOOTSTRAP GIT Local Bookmarks JSP Tutorial JSP Tutorial JSP Introduction JSP Development Environment Setup Eclipse JSP/Servlet JSP Structure JSP Life Cycle JSP Syntax JSP Directives JSP Action Elements JSP Implicit Objects JSP Client Request 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 JSP Cookie Handling JSP File Upload Deep Dive Scripts Scripting Languages Web Design & Development Computer Science Programming Software Web Service Development Tools Web Services Programming Languages JSP Session HTTP is a stateless protocol, which means that each time a client retrieves a webpage, a separate server connection must be opened, so the server does not record any information from previous client requests. There are three methods to maintain the session between the client and the server: Cookies The web server can specify a unique session ID as a cookie to represent each client, used to identify the client's subsequent requests. This may not be an effective method, because many times browsers do not necessarily support cookies, so we do not recommend using this method to maintain sessions. Hidden Form Fields A web server can send a hidden HTML form field and a unique session ID, like this: This entry means that when the form is submitted, the specified name and value will be automatically included in the GET or POST data. Whenever the browser sends a request, the value of session_id can be used to keep track of different browsers. This method may be an effective way, but clicking a hyperlink in an tag does not generate a form submission event, so hidden form fields also do not support general session tracking. URL Rewriting You can add some extra data to each URL to distinguish sessions, and the server can associate session identifiers based on this data. For example, http://w3cschool.cc/file.htm;sessionid=12345, the session identifier is sessionid=12345, and the server can use this data to identify the client. In comparison, URL rewriting is a better method, as it works even if the browser does not support cookies, but the drawback is that you must dynamically specify the session ID for each URL, even for a simple HTML page. Session Object In addition to the above methods, JSP uses the HttpSession interface provided by servlets to identify a user and store all access information for that user. By default, JSP allows session tracking, and a new HttpSession object will be automatically instantiated for a new client. To disable session tracking, you need to explicitly turn it off by setting the session attribute value in the page directive to false, like this: The JSP engine exposes the implicit session object to developers. With the session object, developers can conveniently store or retrieve data. The following table lists some important methods of the session object: S.N. Method & Description 1 public Object getAttribute(String name) Returns the object bound to the specified name in the session object, or null if it does not exist. 2 public Enumeration getAttributeNames() Returns all object names in the session object. 3 public long getCreationTime() Returns the time when the session object was created, in milliseconds since midnight, January 1, 1970. 4 public String getId() Returns the ID of the session object. 5 public long getLastAccessedTime() Returns the last time the client accessed, in milliseconds since midnight, January 1, 1970. 6 public int getMaxInactiveInterval() Returns the maximum time interval, in seconds, that the servlet container will keep the session open. 7 public void invalidate() Invalidates the session and unbinds any objects bound to it. 8 public boolean isNew() Returns whether this is a new client, or whether the client has refused to join the session. 9 public void removeAttribute(String name) Removes the object with the specified name from the session. 10 public void setAttribute(String name, Object value) Creates an object with the specified name and value and binds it to the session. 11 public void setMaxInactiveInterval(int interval) Specifies the time, in seconds, that the servlet container will keep the session valid. JSP Session Application This example describes how to use the HttpSession object to get the creation time and last access time. We will associate a new session object with the request object if it does not already exist.

Session Tracking

Session Information	Value
id
Creation Time
Last Access Time
User ID
Visit Count

Try accessing http://localhost:8080/testjsp/main.jsp, and when you run it for the first time, you will get the following result: When you visit again, you will get the following result: Deleting Session Data After processing a user's session data, you have the following options: Remove a specific attribute: Call the public void removeAttribute(String name) method to remove the specified attribute. Delete the entire session: Call the public void invalidate() method to invalidate the entire session. Set session validity period: Call the public void setMaxInactiveInterval(int interval) method to set the session timeout. Log out the user: Servers supporting servlet 2.4 can call the logout() method to log out the user and invalidate all related sessions. Configure the web.xml file: If you are using Tomcat, you can configure the web.xml file like this: 15 The timeout is in minutes, and the default timeout in Tomcat is 30 minutes. The getMaxInactiveInterval() method in Servlet returns the timeout in seconds. If configured as 15 minutes in web.xml, the getMaxInactiveInterval() method will return 900. JSP Cookie Handling JSP File Upload ByteArk Coding Plan Supports mainstream large models like Doubao, GLM, DeepSeek, Kimi, MiniMax, officially supplied, stable and reliable. Configuration Guide ¥9.9 / Month Activate Now iFlytek Star Coding Plan Includes free model call quota, DeepSeek, GLM, Kimi, MiniMax, one-stop experience and deployment platform. Configuration Guide ¥3.9 / Month Activate Now Click 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 Building Advertisement JSP Tutorial JSP Tutorial JSP Introduction JSP Development Environment Setup Eclipse JSP/Servlet JSP Structure JSP Life Cycle JSP Syntax JSP Directives JSP Action Elements JSP Implicit Objects JSP Client Request 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