Java EE (Java Enterprise Edition) General Discussion

Examples*

This code works well:

public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		String url = "/jsp/pageStart.jsp";

                /* requestDispatcher is NOT null */
		RequestDispatcher requestDispatcher = getServletContext()
				.getRequestDispatcher(url); 
		
		requestDispatcher.forward(request, response);

	}

This code doesn't work, get NullPointerException, requestDispatcher is null:

public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		String url = "http://localhost:8080/mymvc/jsp/pageStart.jsp";

                /* requestDispatcher is null */
		RequestDispatcher requestDispatcher = getServletContext()
				.getRequestDispatcher(url)
		
		requestDispatcher.forward(request, response);

	}

Notes*

- JSP path is \src\main\webapp\jsp\pageStart.jsp
- I am sure, I can manually open 'http://localhost:8080/mymvc/jsp/pageStart.jsp', just copy and paste this url into address of new browser window.
- Base url is http://localhost:8080/mymvc/servlet/ControllerServlet
- I use Servlet mapping:

<servlet-mapping>
	<servlet-name>ControllerServlet</servlet-name>
	<url-pattern>/servlet/*</url-pattern>
</servlet-mapping>

<servlet>
	<servlet-name>ControllerServlet</servlet-name>
	<servlet-class>controller.ControllerServlet</servlet-class>
</servlet>

Questions*

1. Why getRequestDispatcher method cannot accept full URL?
2. Could you please explain to me the reason why ? and please provide me the better resolutions.

Thanks u in advance!