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javax.servlet.ServletException: PWC1381: Error allocating a servlet instance

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posted 13 years ago

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Hi all,

I am trying to extract value from database in a filtered way. I am trying to get value as per emp_id.

Html Code

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <title></title>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  </head>
  <body bgcolor="Yellow">
      <form action="HomeController.do" method="get">
          <table align="center"><tr><td><h1><font face='Verdana' size='9' color="green">Employee Details System</font></h1></td></tr></table>
          <br><br>
              
          <font face='Verdana' size='6' color="green">What Do you want to do :</font>
          <br><br>
                      
          <font face='Verdana' size='4' color="green">
            <input type="radio" name="options" value="all" checked="checked" /> See details of every employee
          </font>
        <input type="text" name="txt" value="" size="4" />
                      
          <input type="submit" value="  Enter   " />
      </form>
  </body>
</html>

Servlet COde

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package cont;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.*;

/**
 *
 * @author Suvojit
 */
public class HomeController extends HttpServlet {

protected void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        try {
            String s=request.getParameter("options");
             if(s.equalsIgnoreCase("all"))
             {
                 RequestDispatcher allRd = request.getRequestDispatcher("/getAll.view");
                 allRd.forward(request, response);
             }

} finally {
            out.close();
        }
    }

// <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /**
     * Handles the HTTP <code>GET</code> method.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }

/**
     * Handles the HTTP <code>POST</code> method.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }

/**
     * Returns a short description of the servlet.
     * @return a String containing servlet description
     */
    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>

}

Database connectivity code:

package view;

public class getAll extends HttpServlet {

static int j;
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();

Connection con1 = null;
        PreparedStatement stmt1 = null;
        ResultSet rs1 = null;

try {

out.println("<html>");
            out.println("<head>");
            out.println("<title>Servlet getAll</title>");
            out.println("</head>");
            out.println("<body bgcolor='Yellow'>");

try
                {
                    String s=request.getParameter("idtxt");
                    Class.forName("com.mysql.jdbc.Driver");
                    con1 =DriverManager.getConnection ("jdbc:mysql://127.0.0.1:3306/empdata","root", "passadmin");
                    stmt1 = con1.prepareStatement("SELECT * FROM employee LIMIT 15 OFFSET 0 where emp_id = ?");
                    stmt1.setString(1,s);
                    rs1 = stmt1.executeQuery();

// Initial Heading

out.print("<table border='0' align='center'>");
                    out.print("<thead align='center'>");
                    out.print("<tr><td><h1><font face='Verdana' size='9' color='green'>");
                    out.print("Employee Details System");

out.print("</font></h1></td></tr>");
                    out.print("</thead><tbody></tbody></table>");

// Employee details table

out.print("<table border='1' cellspacing='12' cellpadding='8'>");
                    out.print("<thead align='center'>");
                    out.print("<tr>");
                    out.print("<td COLSPAN=6><h1>");
                    out.print("<font face='Verdana' size='4' color='green'>");
                    out.print("Details Of All Employees : ");
                    out.print("</font></h1></td></tr>");
                    out.print("</thead>");
                    out.print("<tbody align='center'");
                    out.print("<tr>");
                    out.print("<td><b>Employee ID</b></td>");
                    out.print("<td><b>Employee Name</b></td>");
                    out.print("<td><b>Street</b></td>");
                    out.print("<td><b>City</b></td>");
                    out.print("<td><b>State</b></td>");
                    out.print("<td><b>Pin Code</b></td>");
                    out.print("</tr>");

//Populating with database data

while(rs1.next())
                    {
                        out.print("<tr>");
                        out.print("<td>"+rs1.getObject(1).toString()+"</td>");
                        out.print("<td>"+rs1.getObject(2).toString()+"</td>");
                        out.print("<td>"+rs1.getObject(3).toString()+"</td>");
                        out.print("<td>"+rs1.getObject(4).toString()+"</td>");
                        out.print("<td>"+rs1.getObject(5).toString()+"</td>");
                        out.print("<td>"+rs1.getObject(6).toString()+"</td>");
                        //out.print("<br>");
                    }
                    out.print("</tr>");
                    out.print("</tbody></table>");
              }
              catch (SQLException e)
              {
                    out.print("Error---Servlet Could not display records.");
                    throw new ServletException("Servlet Could not display records.", e);
              }
              catch (ClassNotFoundException e)
              {
                    out.print("Error---JDBC Driver not found.");
                    throw new ServletException("JDBC Driver not found.", e);
              }

//Bottom Links
              out.print("<br><br><br><br>");
              out.print("<b>Goto : </b>");
       	      out.print("<a href=''>1</a>  ");
 	 		  out.print("<a href=''>2</a>  ");
              out.print("<a href=''>3</a>  ");
		      out.print("<a href=''>4</a>  ");
              out.print("<a href=''>Next</a>  ");
              out.print("<a href=''>Previous</a>  ");
              out.print("        <a href='home.html'>Home</a>");

out.println("</body>");
              out.println("</html>");
        }
        finally {
            try{
            rs1.close();
            stmt1.close();
            con1.close();
            }
            catch(SQLException e){}
            out.close();
        }
    }

@Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }

@Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }

@Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>

}

But executing it give following error;

HTTP Status 404 -

--------------------------------------------------------------------------------

type Status report

message

descriptionThe requested resource () is not available.

--------------------------------------------------------------------------------

Sun GlassFish Enterprise Server v2.1

Why so. Whats the error and how do I fix it??

thanks for help

David Newton

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Posts: 12617

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posted 13 years ago

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*PLEASE* remove unnecessary comments/code/whitespace/etc. in the code.

You don't provide your web.xml, so it's impossible to help much. Is there anything in the logs? Are there startup errors?

Suvojit Chakraborty

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Posts: 66

posted 13 years ago

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<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
    <servlet>
        <servlet-name>HomeController</servlet-name>
        <servlet-class>cont.HomeController</servlet-class>
    </servlet>
    <servlet>
        <servlet-name>getAll</servlet-name>
        <servlet-class>view.getAll</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>HomeController</servlet-name>
        <url-pattern>/HomeController.do</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>getAll</servlet-name>
        <url-pattern>/getAll</url-pattern>
    </servlet-mapping>
    <session-config>
        <session-timeout>
            30
        </session-timeout>
    </session-config>
    <welcome-file-list>
        <welcome-file>home.html</welcome-file>
        </welcome-file-list>
    </web-app>

->I dont know how to check logs.
-> What do you mean by startup errors, please clarify. There were no errors before this one. As soon as I click on the button this error pops up.

Suvojit Chakraborty

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Posts: 66

posted 13 years ago

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<servlet-mapping>
<servlet-name>getAll</servlet-name>
<url-pattern>/getAll</url-pattern>
</servlet-mapping>

Mr David, I think I spotted the error and fixed it. I found that in url-pattern I had /getAll instead of /getAll.view.
Perhaps it was causing the error.

Now at least the page is opening but it gives this exception : Error---Servlet Could not display records. which is actually the message I used in exception handler which mean it is throwing SQLException.
Please help me to spot.

Also can you tell me how did /getAll.view become /getAll? I dont create the web.xml it gets created automatically. I am using NetBean 6.5 iDE.

thank you

Consider Paul's rocket mass heater.