ServletRequestInterface:-
servlet interface is an interface which is used to get request information to the servlet
1. content type
2.content length
3.header name
4.parameter names and values
5.and attribute
Requset Dispatcher Interface
It is an interface which is used to dispatch the request to another resource it can be html
file or jsp file or another servlet.
they have 2 method:
1. forward:-
2. include
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sendRedirect is the predefined method of HTTP servlet response interface it is used to
redirect one servlet to the another resourese
that another resourse can be jsp,servlet, html page.
It always works on the client side.
ServletConfig is an interface which is used to get configuration information from
web.xml file.
The object of servlet config is created for each servlet.
If we do any modification in web.xml file no need to change the servlet.
Session:-
Session is a particular interval of time
to identify the particular user we use session management.
Session Management techniques:-
1. cookie- Cookie is small piece of information which persist between multiple client request.
Cookie has a name, value, maximum age, and version number.
Whenever the client send the request cookie is added with the response and it is
stored in the cached of the browser. so whenever the same user login it
automatically
added with the request. this is how particular user is identified
There are 2 types of cookies:
1. non persistent:- valid only for single session. whenever the user closes
the browser it will go
2. persistent- it is valid for multiple sessions. it will go whenever the
user will logout.
Advantages:-1. it is a very easy way to maintain the state of the user
2. cookies are maintained at client side
Disadvantages:-1. it will not work if the cookie is disabled from browser.
2. only textual information can be sent.
