Web Application problem

Question

Hello everyone. I have been debuging this for the past three days with no positive result. My problem is that I have a web application with the following "web.xml" configuration
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE web-app
PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app>
     <!-- Define the controller servlet -->
     <servlet>
          <servlet-name>ControllerServlet</servlet-name>
          <servlet-class>com.org.ControllerServlet</servlet-class>
     <!-- Define initial parameter that will load into the servletContext object
     in the controller servlet -->
     <init-param>
          <param-name>base</param-name>
          <param-value>http:/domainName/shopping/ControllerServlet</param-value>
     </init-param>
     <init-param>
          <param-name>imageUrl</param-name>
          <param-value>http://domainName/shopping/images/</param-value>
     </init-param>
     <init-param>
          <param-name>jdbcDriver</param-name>
          <param-value>sun.jdbc.odbc.JdbcOdbcDriver</param-value>
     </init-param>
     <init-param>
          <param-name>dbUrl</param-name>
          <param-value>jdbc:odbc:shopping</param-value>
     </init-param>
     <init-param>
          <param-name>dbUsername</param-name>
          <param-value></param-value>
     </init-param>
     <init-param>
          <param-name>dbPassword</param-name>
          <param-value></param-value>
     </init-param>
     </servlet>
     <welcome-file-list>
     <welcome-file>Default.jsp</welcome-file>
     </welcome-file-list>
</web-app>
My servlet loads the initial parameters into the ServletContext configuration i.e.
package com.org;
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import com.org.DbBean;
public class ControllerServlet extends HttpServlet{
/**Initialize global variables*/
public void init(ServletConfig config) throws ServletException {
super.init( config );
System.out.println("initializing controller servlet.");
ServletContext context = config.getServletContext();
context.setAttribute("base", config.getInitParameter("base"));
context.setAttribute("imageUrl", config.getInitParameter("imageUrl"));
// instantiating the DbBean
DbBean dbBean = new DbBean();
// initialize the DbBean's fields
dbBean.setDbUrl(config.getInitParameter("dbUrl"));
dbBean.setDbUserName(config.getInitParameter("dbUserName"));
dbBean.setDbPassword(config.getInitParameter("dbPassword"));
// put the bean in the servlet context
// the bean will be accessed from JSP pages
context.setAttribute("dbBean", dbBean);
try {
// loading the database JDBC driver
Class.forName(config.getInitParameter("jdbcDriver"));
}catch (ClassNotFoundException e) {
System.out.println(e.toString());
/**Process the HTTP Get request*/
public void doGet(HttpServletRequest request, HttpServletResponse
response) throws ServletException, IOException {
doPost(request, response);
/**Process the HTTP Post request*/
public void doPost(HttpServletRequest request, HttpServletResponse
response) throws ServletException, IOException {
String base = "/jsp/";
String url = base + "Default.jsp";
String action = request.getParameter("action");
if (action != null) {
if (action.equals("search"))
url = base + "SearchResults.jsp";
else if (action.equals("browseCatalog"))
url = base + "BrowseCatalog.jsp";
else if (action.equals("productDetails"))
url = base + "ProductDetails.jsp";
else if (action.equals("productDetails"))
url = base + "ProductDetails.jsp";
else if (action.equals("addShoppingItem") ||
action.equals("updateShoppingItem") ||
action.equals("deleteShoppingItem") ||
action.equals("displayShoppingCart"))
url = base + "ShoppingCart.jsp";
else if (action.equals("checkOut"))
url = base + "CheckOut.jsp";
else if (action.equals("order"))
url = base + "Order.jsp";
RequestDispatcher requestDispatcher =
getServletContext().getRequestDispatcher(url);
requestDispatcher.forward(request, response);
I have a simple jsp page here i.e.
<%@ page import="java.util.*" %>
<jsp:useBean id="dbBean" scope="application"
class="com.org.DbBean"/>
<%
String base = (String) application.getAttribute("base");
%>
<TABLE CELLSPACING="0" CELLPADDING="5" WIDTH="150" BORDER="0">
<TR>
<TD BGCOLOR="F6F6F6">
<FONT FACE="Verdana">Search</FONT>
<FORM>
<INPUT TYPE="HIDDEN" NAME="action" VALUE="search">
<INPUT TYPE="TEXT" NAME="keyword" SIZE="10">
<INPUT type="SUBMIT" VALUE="Go">
</FORM>
</TD>
</TR>
<TR>
<TD BGCOLOR="F6F6F6"><FONT FACE="Verdana">Categories:</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD BGCOLOR="F6F6F6">
<%
     Hashtable categories = dbBean.getCategories();
     Enumeration categoryIds = categories.keys();
          while (categoryIds.hasMoreElements()) {
               Object categoryId = categoryIds.nextElement();
               out.println("<A HREF=" + base +
               "?action=browseCatalog&categoryId=" + categoryId.toString() + ">" +
               categories.get(categoryId) +
               "</A><BR>");
%>
</TD>
</TR>
</TABLE>
The page will not load, I have tried to debug it, what I found out is that the line String base = (String) application.getAttribute( "base" );
base is null. and so do the rest of the global variables i.e.
base
imageUrl
jdbcDriver
dbUrl
Here is my url to see what I mean http://www.yexon.co.uk/shopping

Answer 1

That's because you don't have a servlet-mapping, I suggest you read the J2EE tutorial, but here's an example for your servlet.
<servlet-mapping>
  <servlet-name>ControllerServlet</servlet-name>
  <url-pattern>/ControllerServlet</url-pattern>
</servlet-mapping>