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
cookie
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.
how cookie work
type of cookie
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.
