Use listener to connect to database

Question

i want to use a listener to connect to an oracle database in tomcat 4, in my application web.xml y type:
<listener>
<listener-class>
ResourceManagerListener2
</listener-class>
</listener>
the class ResourceManagerListener2 which is in my web-inf/classes:
import javax.servlet.*;
import javax.servlet.http.*;
import oracle.jdbc.pool.*;
public class ResourceManagerListener2 implements
     ServletContextListener {
     private OracleConnectionCacheImpl ds = null;
     public void contextInitialized(ServletContextEvent sce) {
          ServletContext application = sce.getServletContext( );
          String jdbcURL = application.getInitParameter("jdbcURL");
          String user = application.getInitParameter("user");
          String password = application.getInitParameter("password");
          String maxLimit = application.getInitParameter("maxLimit");
          try {
          ds = new OracleConnectionCacheImpl( );
          ds.setURL(jdbcURL);
          ds.setMaxLimit(Integer.parseInt(maxLimit));
          ds.setUser("principal");
          ds.setPassword("fanta");
          catch (Exception e) {
          application.log("Failed to create data source: " +
          e.getMessage( ));
          application.setAttribute("appDataSource", ds);
     public void contextDestroyed(ServletContextEvent sce) {
          ServletContext application = sce.getServletContext( );
          application.removeAttribute("appDataSource");
          // Close the connections in the DataSource
          try {
               ds.close( );
          catch (java.sql.SQLException e) {}
          ds = null;
and then i use a servlet to get the connection but i get an error and i don't know if the listener is working ok, the error appears in the line Connection connection = ds.getConnection(); with an exception of pointer null..... if someone can help me pleasee...
this is my servlet:
import java.io.*;
import java.sql.*;
import javax.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class ConnectionServlet extends HttpServlet {
public void doGet(
HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException {
response.setContentType("text/html");
Statement statement = null;
ResultSet resultSet = null;
String userName = null;
try {
ServletContext application = getServletContext( );
DataSource ds = (DataSource) application.getAttribute("appDataSource");
Connection connection = ds.getConnection();
// Test the connection
statement = connection.createStatement( );
resultSet = statement.executeQuery(
"select rv_domain from principal.cg_ref_codes where rownum = 1");
if (resultSet.next( ))
userName = resultSet.getString(1);
catch (SQLException e) {
out.println("DedicatedConnection.doGet( ) SQLException: " +
e.getMessage( ) + "<p>");
finally {
if (resultSet != null)
try { resultSet.close( ); } catch (SQLException ignore) { }
if (statement != null)
try { statement.close( ); } catch (SQLException ignore) { }
out.println("Hello " + userName + "!<p>");
public void doPost(
HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException {
doGet(request, response);
thanks.

Answer 1

You must be joking . Please re-post that monstrosity and format it using the 'code' button above the posting window. Who on Earth can read that?
- Saish