Calling getRequestDispatcher method ??

[Bikash Paul]

Hi,

I am confused about calling getRequestDispatcher method we can call this method in two below ways :

RequestDispatcher dispatcher = this.getServletConfig().getServletContext().getRequestDispatcher("/servlet/Test");
if (dispatcher != null)
dispatcher.forward(req, res);

and another way is :

RequestDispatcher dispatcher = req.getRequestDispatcher("/servlet/Test");
if (dispatcher != null)
dispatcher.forward(req, res);

where req is the object of HttpServletRequest.

Can any one please explain me what is the difference between this two ways.

Thanks & Regards
Bikash

[Mike Nightsky]

the HttpServletRequest.getRequestDispatcher()could take a relative path.
quote from the api: "The pathname specified may be relative, although it cannot extend outside the current servlet context. If the path begins with a "/" it is interpreted as relative to the current context root. This method returns null if the servlet container cannot return a RequestDispatcher."

the ServletContext.getRequestDispatcher() could only take an absolute path.
quote from the api: "The pathname must begin with a "/" and is interpreted as relative to the current context root. Use getContext to obtain a RequestDispatcher for resources in foreign contexts. This method returns null if the ServletContext cannot return a RequestDispatcher."