is it true? (about getRequestDispatcher())

[Sreeraj G Harilal]

ServletContext.getRequestDispatcher("/MyTestServlet.do")

I want to know that the ServletContext's getRequestDispatcher() method will not take URL pattern of a servlet as a parameter?

[Sayak Banerjee]

I want to know that the ServletContext's getRequestDispatcher() method will not take URL pattern of a servlet as a parameter?

Your question is not quite clear...however, if you're looking for a similar method which does not take a url-pattern as an argument....it is ServletContext.getNamedDispatcher(String ServletName) where ServletName is the name you've declared in the DD for the servlet

[Sreeraj G Harilal]

MyServlet.TestSession

package MyServlets;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
public class TestSession extends HttpServlet
{
 
public void doGet(HttpServletRequest request,HttpServletResponse response) throws IOException,ServletException
{
response.setContentType("text/html");
RequestDispatcher rd = getServletContext().getRequestDispatcher("red");
rd.forward(request,response);
}
public void doPost(HttpServletRequest req,HttpServletResponse res) throws IOException,ServletException
{
doGet(req,res);
}
}
 

web.xml

<servlet>
        <servlet-name>TestSession</servlet-name>
        <servlet-class>MyServlets.TestSession</servlet-class>
</servlet>
<servlet-mapping>
        <servlet-name>TestSession</servlet-name>
        <url-pattern>/TestSession.do</url-pattern>
</servlet-mapping>
 
<servlet>
<servlet-name>RedServlet</servlet-name>
<servlet-class>MyServlets.RedServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>RedServlet</servlet-name>
<url-pattern>/red/*</url-pattern>
</servlet-mapping>

RequestDispatcher rd = getServletContext().getRequestDispatcher("red");
rd.forward(request,response);

it will not work because we must pass the url starting with / to ServletContext's getRequestDispatcher() method.right?

But if want to invoke a servlet through url pattern then you must avoid the / before the url paramete.

RequestDispatcher rd = request.getRequestDispatcher("red");
rd.forward(request,response);

it works fine.

[Sayak Banerjee]

But if want to invoke a servlet through url pattern then you must avoid the / before the url paramete.

Where do you want to avoid that? You're not supposed to avoid using "/" if you're ServletContext.getRequestDiapatcher() method.

Therefore
RequestDispatcher rd = getServletContext().getRequestDispatcher("/red");
rd.forward(request,response);
Would work fine here

[Sreeraj G Harilal]

No Sayak, it will not invoke the RedServlet servlet if put "/red".

RequestDispatcher rd = getServletContext().getRequestDispatcher("/red");

Its will try to locate any resource like [Application Path]/red

Please run my code, you will get error.

[Sayak Banerjee]

Its will try to locate any resource like [Application Path]/red

That's what it is supposed to do.... "/" means the context root(application)...By the way I ran the code with
RequestDispatcher rd = getServletContext().getRequestDispatcher("/red");
and got no errors...it's workin' fine...check if you're goin' wrong somewhere

[Sreeraj G Harilal]

Yes Sayak its working. You make my eye open. Thank you.

[Firas Zuriekat]

So the following is working:

RequestDispatcher rd = getServletContext().getRequestDispatcher("/red");

because "/red" matches pattern "/red/*" that's declared in web.xml above, right?

Or is it working because it looks in the Context and finds "red" there with disregards with the DD above?

Thanks
[ December 23, 2006: Message edited by: Firas Zuriekat ]

[Sayak Banerjee]

The former one
[ December 23, 2006: Message edited by: Sayak Banerjee ]