RequestDispatcher

RequestDispatcher

The RequestDispatcher interface provides the facility of dispatching the request to another resource it may be HTML, servlet or JSP.
This interface can also be used to include the content of another resource also. It is one of the ways of servlet collaboration.

Methods:

1. public void forward(ServletRequest request,ServletResponse response)throws ServletException,java.io.IOException:

Forwards a request from a servlet to another resource (servlet, JSP file, or HTML file) on the server.

2. public void include(ServletRequest request,ServletResponse response)throws ServletException,java.io.IOException:

Includes the content of a resource (servlet, JSP page, or HTML file) in the response.

Example of RequestDispatcher:

The getRequestDispatcher() method of ServletRequest interface returns the object of RequestDispatcher.
Syntax:

public RequestDispatcher getRequestDispatcher(String resource);

Example:

RequestDispatcher rd=request.getRequestDispatcher("servlet2");
rd.forward(request, response);//method may be include or forward

Login form Example of RequestDispatcher:

In this example, we are validating the password entered by the user.
If the password is a servlet, it will forward the request to the WelcomeServlet, otherwise, it will show an error message: sorry username or password error!.
In this program, we are checking for hardcoded information.
In this example, we have created the following files: