When a series of requests from the same User (i.e., requests coming from the same browser) occurs over an extended period of time, servlets employ a mechanism known as session tracking to maintain state about the requests. Each servlet that a client accesses uses a shared session.
Servlets are Java applications that run on a web server or application server that supports Java. They take care of the request that was sent to them by the web server, manage it, process it, create the response, and then send the web server a response.
By employing the "stateless" HTTP protocol, each time a client requests a web page, a new connection is made to the web server, which does not keep note of previous requests.
- A session is the period of time during which a user converts. It often refers to a specific amount of time.
- The practice of recognizing and documenting customer conversions over time is known as session tracking. Managing sessions is another name for it.
- The recording of the item in session is called tracking.
- An online application that remembers and keeps track of client conversions over time is called a "stateful web application."
Why is it required to track sessions?
- Due of the statelessness of the HTTP protocol, users require session tracking to make the client-server relationship stateful.
- Since the HTTP protocol has no state, every request is assumed to be a fresh one.
- Session tracking is crucial to track conversions in e-commerce, mailing, and online shopping apps.
Data deletion for sessions
Once User has finished handling a user's session data, the Userhas a lot of options.
- Take away a specific quality. Calling the public void removeAttribute(String name) function will remove the value connected to a particular key.
- Remove the entire session. The public void invalidates () function can be used to terminate a full session.
- Session Timeout Setting By executing the public void setMaxInactiveInterval(int interval) function, you can set the timeout for each session.
- User signing out You can log the client off of the Web server and invalidate every User's session on servers that support servlets version 2.4 by using the logout function.
- Configuration of web.xml In addition to the methods mentioned above, if you're using Tomcat, you can also set the session timeout in the web.xml file.
The timeout, set in minutes, overrides Tomcat's 30-minute default timeout.
The getMaxInactiveInterval() function in a servlet returns the session timeout value in seconds. If your session's web.xml value is set to 20 minutes, the GetMaxInactiveInterval() function returns 900.
Session Tracking Uses Four Distinct Methods
- Hidden form Field
- URL Rewriting
- Cookies: Cookies are little data packets that the web server delivers in the response header and that the browser stores. A web server can provide each web client with their unique session ID. Cookies are used to keep the session running smoothly.
- Hidden form Field: The data is entered into the web pages and sent to the server through a hidden form field. These fields are not visible to users.
<input type = hidden' name = 'session' value = '95159' >
- URL Rewriting: Add more information as request parameters via the URL to each request and response. To keep session management and browser activities in sync, URL rewriting is a superior method.
- HttpSession: An illustration of a user session is the HttpSession object. A user session is a grouping of user data spread across numerous HTTP requests.
HttpSession session = request.getSession( );
The user must make the request. The user must call getSession before transmitting any document content to the client (). The HttpSession object offers the following list of the most important methods:
What is utilized to track sessions?
The most common tool for tracking sessions is cookies. The server sends the browser key-value pairs of data called cookies. The browser must save this to its location on the client's PC. The cookie is sent along with every request the browser makes to that server.
What benefits does session tracking offer?
The ease of implementation is the main benefit of employing user authorization to monitor sessions. Simply specify a collection of pages to be protected and use getRemoteUser() to determine who is using which page. Another benefit is that the method still works when a person visits your website from various devices.