Take the following basic HTML examples.
Why do we need session tracking? Think of the scenario where a series of request and response takes place between same client and a server for example online shopping system so to maintain the conversational statesession tracking is needed.
Session API uses the other three techniques internally and provides a session tracking in much convenient and stable way. There are two types of cookies: Persistent cookies - remains on hard drive until we delete them or they expire. As we cannot hardcode the value of hidden field created for session tracking purpose, which means we cannot use this approach for static pages like HTML.
In short with this approach, HTML pages cannot participate in session tracking with this approach. Another advantage iswe need not to submit extra hidden parameter. As other approaches, this approach also has some disadvantages like we need to regenerate every url to append session identifier and this need to keep track of this identifier until the conversation completes.
Session tracking in servlet is very simple and it involves following steps Get the associated session object HttpSession using request. To get the specific value out of session object, call getAttribute String on the HttpSession object. To store any information in a session call setAttribute key,object on a session object.
To remove the session datacall removeAttribute key to discard a object with a given key. Add entry in web. Write SessionInformationServlet which will get the session object and displays its attributes package com.
Hold on for a couple of seconds and refresh the page. Now close the browser and again hit the same URL http: This time session Id is different which means new session is created because we closed the browser and opened a new one so server created a new session for the user.
This servlet will store the request parameter username in session and will increment the counter variable. Servlet will verify if counter variable in session is available or not.
If it is not available means new user has invoked the servlet and in this case store counter variable with value 1.
Later on just increment the existing counter value by 1 and update it in session. This API is most commonly used when a logged in user logs out.
Once the session is invalidated, any other call on that server will throw an error. Add Entry in web. By Default link click is a GET request so we implemented doGet method of LogoutServlet and since it will kill the session, accessing it will throw exception refer below figure Server Session By default session tracking is based on cookie session cookie which is stored in browser memory and not on hard drive.
So as soon as browser is closed, that cookie is gone and will not be retrieved again. Corresponding to this session identifier, a server session is created at server and will be available until it is invalidated or maximum inactive time has been reached.
At a first glance it looks very convenient to store attributes in session as it is available on any JSP or servlet within the same session. You have to be very careful while storing attributes in session as it can be modified by another JSP or servlet accidently which will result in undesirable behaviour.Yes and no.
Declarative security will only work if tomcat recognizes jsession id (either coming encoded in requested URL or set in JSESSIONID cookie). Without cookie support, authentication mechanism will be called for every request (one for the html/jsp page and many others for the referenced resources like images, js scripts and etc).
The jsessionid is the value that identifies the current (http) session for user. It is not only a JSF thing but every java application has to convey to the server the session id so .
In this video Scott Golightly shows how to create an pfmlures.com HttpModule to "rewrite" the URL when a request for a web page comes in. You may want to rewrite URLs to create friendly URLs or to direct an old URL to a new URL. The issue is the jsessionid encoded in the redirect url: ;jsessionid=5cr3hvcuk1ho2frvnyz When I deploy the same war file on Tomcat, I do not see the jsessionid in.
What is URL Rewriting? URL rewriting is very common with Apache Web Server (see mod_rewrite's rewriting guide) but has not been possible in most java web application pfmlures.com main things it is used for are: URL Tidyness / URL Abstraction - keep URLs tidy irrespective of the underlying technology or framework (JSP, Servlet, Struts etc).