Sunday, December 24, 2017

RequestDispatcher interface

RequestDispatcher is a interface of Servlet API. Implementation of which provided by vendors. This interface provides methods for including contents of a resource (Such as Servlet/html page etc.) to the response of current Servlet or forward the request to another web resource(Such as Servlet/html page etc.).

Methods:
1- getRequestDispatcher():
                                              
Method of ServletRequest interface is used to obtain a RequestDispatcher object.
public RequestDispatcher getRequestDispatcher(String URL of Resource);

RequestDispatcher interface provides include() and forward() method for including contents of a resource and to forward the request to another response respectively.

I) include():
                  Is used to include the content of the resource to the response of the current Servlet.
public void include(ServletRequest, ServletResponse) throws ServletException, IOException;

II) forward():
                     
Is used to forward request to another resource.
public void forward(ServletRequest, ServletResponse) throws ServletException, IOException;


Note:
Real life example (Cases for request handling):
Assume counselor is acts as a Servlet
Case1:
Self give result if any one ask about course CourseName/fee/CourseDuration.
Case2:
For Some technical Enquiry (such as version of hibernate) ask the Technical Trainer ( Take a Help of another person on same enquiry)  and then give the information (result).
Case3:
Forward the call direct to the Trainer (Now information (result) is produce by Trainer) .

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