session tracking

session

Session simply means a particular interval of time.
Session Tracking is a way to maintain state (data) of an user. It is also known as session management in servlet.

  • HTTP is stateless that means each request is considered as the new request. It is shown in the figure given below:

  • There are four techniques used in Session tracking:

    • Cookies
    • Hidden Form Field
    • URL Rewriting
    • HttpSession

A cookie is a small piece of information that is persisted between the multiple client requests.
A cookie has a name, a single value, and optional attributes such as a comment, path and domain qualifiers, a maximum age, and a version number.

  • Non-persistent cookie

    It is valid for single session only. It is removed each time when user closes the browser.

  • Persistent cookie

    It is valid for multiple session . It is not removed each time when user closes the browser. It is removed only if user logout or signout.

  • Advantage

    • Simplest technique of maintaining the state.
    • Cookies are maintained at client side.
  • Disadvantage
    • It will not work if cookie is disabled from the browser.
    • Only textual information can be set in Cookie object.

HttpSession Interface

  • An object of HttpSession can be used to perform two tasks:
    • bind objects
    • view and manipulate information about a session, such as the session identifier, creation time, and last accessed time.