STUCK STUK STUCK- GOIN LOONEY

Question

i am really stuck i have pasted my code below in terms of bean, servlet and jsp. please could someone tell me where i am going wrong.
I am totally new to this so really stuck. When i am deploying the application the page is being displayed however when entering fields of disease and postcode nothing is being displayed it just takes me to the same page as i am alreay on but the text changes to "welcome null".
i need it to connect to my jsp.
your help is appreciated!
BEAN
* RetrieveBean.java
* To change this template, choose Tools | Template Manager
* and open the template in the editor.
package beans ;
import java.sql.*;
import javax.sql.*;
import java.util.*;
public class RetrieveBean
public String doctorpostCodeVal;
public String diseaseNameVal;
//private Connection gp_conn = null, hpu_conn=null;
private Statement gp_stmt ;
private String statusStr = "" ;
public RetrieveBean() throws InstantiationException, IllegalAccessException
try {
Class.forName("com.mysql.jdbc.Driver").newInstance();
// gp_conn = HospitalConnection.getInstance().getGPConn();
// hpu_conn = HospitalConnection.getInstance().getHPUConn();
catch(Exception e) {
System.err.println("Exception: " + e.getMessage());
e.printStackTrace();
public void closeConnection()
try
gp_stmt.close() ;
catch( SQLException e )
System.err.println( e.getMessage()) ;
e.printStackTrace();
public String getStatus()
return statusStr ;
public boolean isValiddoctorpostCode(String doctorpostCode)
String strQuery = "select distinct PostCode d from doctor where PostCode='" + doctorpostCode + "'";
String str = null;
ResultSet rs;
try {
rs = gp_stmt.executeQuery(strQuery);
while ( rs.next() )
str= rs.getString("doctorpostCode");
return true;
} catch (SQLException ex) {
ex.printStackTrace();
return false;
public String getDiseaseName(String diseaseName)
String strQuery = "select Disease_Name from disease where Disease_Name ='" + diseaseName + "'";
String str = null;
ResultSet rs;
try {
rs = gp_stmt.executeQuery(strQuery);
while ( rs.next() )
str= rs.getString("diseaseName");
return str;
} catch (SQLException ex) {
ex.printStackTrace();
str = null;
return str;
public int getCount( String givenDoctorpostCode, String givendiseaseName )
String strQuery, strCount="0";
int count = 0;
//select count(*) ct from Patient p, Consultation c, Diagnosis d where p.Post_Code= 'E176HR'
// and p.Patient_No=c.Patient_No AND c.Consultation_No=d.Consultation_No and d.Diagnosed_disease='malaria'
try
strQuery = "select Post_Code from doctor where PostCode='"+ givenDoctorpostCode + "'";
ResultSet rs = gp_stmt.executeQuery( strQuery ) ;
while ( rs.next() )
strCount = rs.getString("givenDoctorpostCode");
String[] postcode_list = new String[Integer.valueOf(strCount)];
int i = 0;
strQuery = "select PostCode pc from PostCode where doctor='"+ givenDoctorpostCode + "'";
rs = gp_stmt.executeQuery( strQuery ) ;
while ( rs.next() )
postcode_list[i++] = rs.getString("givenDoctorpostCode");
for (i =0; i<postcode_list.length;i++) {   
strQuery = "Select patient.Patient_No, patient.Surname, patient.FirstName, patient.DOB, patient.House_No, patient.Street, patient.Post_Code, doctor.PostCode, doctor.Doctor_Id, consultation.Consultation_No, diagnosis.Diagnosed_disease, disease.Disease_Name from patient, doctor, consultation, diagnosis, disease where consultation.Consultation_No = diagnosis.Consultation_No and patient.Patient_No = consultation.Patient_No and doctor.Doctor_Id = Consultation.Doctor_Id and diagnosis.Diagnosed_disease = disease.Disease_code and disease.Disease_Name = '"+diseaseNameVal+"'and doctor.PostCode = '"+doctorpostCodeVal+"'" ;
rs = gp_stmt.executeQuery( strQuery ) ;
while ( rs.next() ){
strCount= rs.getString("ct");
Integer temp = (Integer.valueOf(strCount));
count = count + temp.intValue();
return count ;
     catch (Exception ex) {
return -1 ;
SERVLET
* RetrieveServlet.java
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.* ;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.rmi.PortableRemoteObject;
// import login.ejb.*;
import beans.* ;
* @version
public class RetrieveServlet extends HttpServlet
private String statusStr = null;
/** Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods.
* @param request servlet request
* @param response servlet response
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException, InstantiationException,
SQLException, ClassNotFoundException, IllegalAccessException
HttpSession session = request.getSession();
String hpustaffIDVal = (String) session.getAttribute("hpustaffID");
String doctorpostCodeVal = request.getParameter("doctorpostCode");
String diseaseNameVal = request.getParameter("DiseaseName");
String buttonVal=request.getParameter("Button");
String responseTarget = null;
String diseaseName = null;
if (hpustaffIDVal == null){
responseTarget = new String("/accept.jsp");
request.setAttribute("Status", null);
else {
if (buttonVal.equals("Logout")) {
responseTarget = new String("/accept.jsp");
//request.setAttribute("Status", null);
session.invalidate();
else {
if( doctorpostCodeVal == null || diseaseNameVal == null ) {
//HttpSession session = request.getSession();
responseTarget = new String("/accept.jsp");
//request.setAttribute( "HPUStaffID", hpustaffIDVal ) ;
request.setAttribute("Status", "Please enter a valid doctorpostCode and Disease Name");
else if( doctorpostCodeVal.trim().equals("") || diseaseNameVal.trim().equals("") ) {
//HttpSession session = request.getSession();
responseTarget = new String("/accept.jsp");
//request.setAttribute( "HPUStaffID", hpustaffIDVal ) ;
request.setAttribute("Status", "Please enter a valid doctorpostCode and Disease Name");
else {
RetrieveBean rtBean = new RetrieveBean();
if (rtBean.isValiddoctorpostCode(doctorpostCodeVal)) {
diseaseName =rtBean.getDiseaseName(diseaseNameVal);
if (diseaseName==null){
responseTarget = new String("/retrieve.jsp");
request.setAttribute("Status", "DiseaseName is not correct. It does not have a corresponding disease entry");
} else {
int count = rtBean.getCount(doctorpostCodeVal, diseaseNameVal) ;
if (count>=0) {
responseTarget = new String("/retrieve.jsp");
request.setAttribute( "DoctorpostCode", doctorpostCodeVal ) ;
request.setAttribute("diseaseName", diseaseNameVal);
request.setAttribute( "Count", Integer.toString(count)) ;
request.setAttribute( "Status", "1") ;
else {
responseTarget = new String("/accept.jsp");
//request.setAttribute( "HPUStaffID", hpustaffIDVal ) ;
request.setAttribute("Status", "Retrieve Bean Instantiation Error");
} else {
responseTarget = new String("/accept.jsp");
request.setAttribute("Status", "Entered PostCode ID is not present in the GP database");
RequestDispatcher dispatcher = getServletContext().getRequestDispatcher( responseTarget );
dispatcher.forward( request, response );
/** Handles the HTTP <code>GET</code> method.
* @param request servlet request
* @param response servlet response
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
try
processRequest(request, response);
catch( Exception e ) { e.printStackTrace();}
/** Handles the HTTP <code>POST</code> method.
* @param request servlet request
* @param response servlet response
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
try
processRequest(request, response);
catch( Exception e ) { e.printStackTrace();}
JSP
<%@page import="Beanpackage.RetrieveBean" %>
<%@page errorPage="loginJSP.jsp"%>
<html>
<head><title>Post code search</title></head>
<body bgcolor="#ffffdd">
<%
String doctorpostCodeVal = request.getParameter("doctorpostCode");
//String hpustaffIdVal = (String) session.getAttribute("hpustaffID");
//if(session.getAttribute("hpustaffID") == nullll) {
// throw new Exception("Login error ");
%>
<%
String diseaseName = (String) request.getAttribute("DiseaseName");
String Query = (String) request.getAttribute("Query");
String hpustaffIDVal = (String) session.getAttribute("hpustaffID");
String statusVal = (String) request.getAttribute("Status");
String message = "Logged in as " + hpustaffIDVal;
%>
<center>
<h1>Data sharing project for the NHS</h1>
<h2><font color="#DC143C">Information Retrieval Screen</font></h2>
<h3><font color="blue"> <p> <%= message %> </font> </p> </h3>
<p> </p>
<form method="POST" action="RetrieveServlet">
<h1 align="center"><font color="FF7F50">Results table</font></h1>
<table border="1" cellspacing="">
<td> Disease name</td> <td><%= diseaseName %> </td>
</tr>
<tr>
<td> PostCode ID</td> <td><%= doctorpostCode %> </td>
</tr>
<tr>
<td> # of patients</td> <td><%= count %> </td>
</tr>
</table>

Answer 1

i dont get it?//request.setAttribute( "HPUStaffID", hpustaffIDVal ) ; request.setAttribute("Status", "Please enter a valid doctorpostCode and Disease Name"); } else if( doctorpostCodeVal.trim().equals("") || diseaseNameVal.trim().equals("") ) { //HttpSession session = request.getSession(); responseTarget = new String("/accept.jsp"); //request.setAttribute( "HPUStaffID", hpustaffIDVal ) ; request.setAttribute("Status", "Please enter a valid doctorpostCode and Disease Name"); } else { RetrieveBean rtBean = new RetrieveBean(); if (rtBean.isValiddoctorpostCode(doctorpostCodeVal)) { diseaseName =rtBean.getDiseaseName(diseaseNameVal); if (diseaseName==null){ responseTarget = new String("/retrieve.jsp"); request.setAttribute("Status", "DiseaseName is not correct. It does not have a corresponding disease entry"); } else { int count = rtBean.getCount(doctorpostCodeVal, diseaseNameVal) ; if (count>=0) { responseTarget = new String("/retrieve.jsp"); request.setAttribute( "DoctorpostCode", doctorpostCodeVal ) ; request.setAttribute("diseaseNamei am really stuck i hav responseTarget = new String("/accept.jsp"); //request.setAttribute("Status", null); session.invalidate(); } else { if( doctorpostCodeVal == null || diseaseNameVal == null ) { //HttpSession session = request.getSession(); responseTarget = new String("/accept.jsp"); //request.setAttribute( "HPUStaffID", hpustaffIDVal ) ; request.setAttribute("Status", "Please enter a valid doctorpostCode and Disease Name"); } else if( doctorpostCodeVal.trim().equals("") || diseaseNameVal.trim().equals("") ) { //HttpSession session = request.getSession(); responseTarget = new String("/accept.jsp"); //request.setAttribute( "HPUStaffID", hpustaffIDVal ) ; request.setAttribute("Status", "Please enter a valid doctorpostCode and Disease Name"); } else { RetrieveBean rtBean = new RetrieveBean(); if (rtBean.isValiddoctorpostCode(doctorpostCodeVal)) { diseaseName =rtBean.getDiseaseName(diseaseNameVal); if (diseaseName==null){ responseTarget = new String("/retrieve.jsp"); request.setAttribute("Status", "DiseaseName is not correct. It does not have a corresponding disease entry"); } else { int count = rtBean.getCount(doctorpostCodeVal, diseaseNameVal) ; if (count>=0) { responseTarget = new String("/retrieve.jsp"); request.setAttribute( "DoctorpostCode", doctorpostCodeVal ) ; request.setAttribute("diseaseName", diseaseNameVal); request.setAttribute( "Count", Integer.toString(count)) ; request.setAttribute( "Status", "1") ; } else { responseTarget = new String("/accept.jsp"); //request.setAttribute( "HPUStaffID", hpustaffIDVal ) ; request.setAttribute("Status", "Retrieve Bean Instantiation Error"); } } } else { responseTarget = new String("/accept.jsp"); request.setAttribute("Status", "Entered PostCode ID is not present in the GP database"); } } } } RequestDispatcher dispatcher = getServletContext().getRequestDispatcher( responseTarget ); dispatcher.forward( request, response ); } /** Handles the HTTP <code>GET</code> method. * @param request servlet request * @param response servlet response */ protected void doGet(HttpServletRequest request,//request.setAttribute( "HPUStaffID", hpustaffIDVal ) ; request.setAttribute("Status", "Please enter a valid doctorpostCode and Disease Name"); } else if( doctorpostCodeVal.trim().equals("") || diseaseNameVal.trim().equals("") ) { //HttpSession session = request.getSession(); responseTarget = new String("/accept.jsp"); //request.setAttribute( "HPUStaffID", hpustaffIDVal ) ; request.setAttribute("Status", "Please enter a valid doctorpostCode and Disease Name"); } else { RetrieveBean rtBean = new RetrieveBean(); if (rtBean.isValiddoctorpostCode(doctorpostCodeVal)) { diseaseName =rtBean.getDiseaseName(diseaseNameVal); if (diseaseName==null){ responseTarget = new String("/retrieve.jsp"); request.setAttribute("Status", "DiseaseName is not correct. It does not have a corresponding disease entry"); } else { int count = rtBean.getCount(doctorpostCodeVal, diseaseNameVal) ; if (count>=0) { responseTarget = new String("/retrieve.jsp"); request.setAttribute( "DoctorpostCode", doctorpostCodeVal ) ; request.setAttribute("diseaseNamei am really stuck i have pasted my code below in terms of bean, servlet and jsp. please could someone tell me where i am going wrong. I am totally new to this so really stuck. When i am deploying the application the page is being displayed however when entering fields of disease and postcode nothing is being displayed it just takes me to the same page as i am alreay on but the text changes to "welcome null". i need it to connect to my jsp. your help is appreciated! BEAN /* * RetrieveBean.java * * * * To change this template, choose Tools | Template Manager * and open the template in the editor. */ package beans ; import java.sql.*; import javax.sql.*; import java.util.*; public class RetrieveBean { public String doctorpostCodeVal; public String diseaseNameVal; //private Connection gp_conn = null, hpu_conn=null; private Statement gp_stmt ; private String statusStr = "" ; public RetrieveBean() throws InstantiationException, IllegalAccessException { try { Class.forName("com.mysql.jdbc.Driver").newInstance(); // gp_conn = HospitalConnection.getInstance().getGPConn(); // hpu_conn = HospitalConnection.getInstance().getHPUConn(); } catch(Exception e) { System.err.println("Exception: " + e.getMessage()); e.printStackTrace(); } } public void closeConnection() { try { gp_stmt.close() ; } catch( SQLException e ) { System.err.println( e.getMessage()) ; e.printStackTrace(); } } public String getStatus() { return statusStr ; } public boolean isValiddoctorpostCode(String doctorpostCode) { String strQuery = "select distinct PostCode d from doctor where PostCode='" + doctorpostCode + "'"; String str = null; ResultSet rs; try { rs = gp_stmt.executeQuery(strQuery); while ( rs.next() ) { str= rs.getString("doctorpostCode"); return true; } } catch (SQLException ex) { ex.printStackTrace(); } return false; } public String getDiseaseName(String diseaseName) { String strQuery = "select Disease_Name from disease where Disease_Name ='" + diseaseName + "'"; String str = null; ResultSet rs; try { rs = gp_stmt.executeQuery(strQuery); while ( rs.next() ) { str= rs.getString("diseaseName"); return str; } } catch (SQLException ex) { ex.printStackTrace(); } str = null; return str; } public int getCount( String givenDoctorpostCode, String givendiseaseName ) { String strQuery, strCount="0"; int count = 0; //select count(*) ct from Patient p, Consultation c, Diagnosis d where p.Post_Code= 'E176HR' // and p.Patient_No=c.Patient_No AND c.Consultation_No=d.Consultation_No and d.Diagnosed_disease='malaria' try { strQuery = "select Post_Code from doctor where PostCode='"+ givenDoctorpostCode + "'"; ResultSet rs = gp_stmt.executeQuery( strQuery ) ; while ( rs.next() ) strCount = rs.getString("givenDoctorpostCode"); String[] postcode_list = new String[Integer.valueOf(strCount)]; int i = 0; strQuery = "select PostCode pc from PostCode where doctor='"+ givenDoctorpostCode + "'"; rs = gp_stmt.executeQuery( strQuery ) ; while ( rs.next() ) postcode_list[i++] = rs.getString("givenDoctorpostCode"); for (i =0; i<postcode_list.length;i++) { strQuery = "Select patient.Patient_No, patient.Surname, patient.FirstName, patient.DOB, patient.House_No, patient.Street, patient.Post_Code, doctor.PostCode, doctor.Doctor_Id, consultation.Consultation_No, diagnosis.Diagnosed_disease, disease.Disease_Name from patient, doctor, consultation, diagnosis, disease where consultation.Consultation_No = diagnosis.Consultation_No and patient.Patient_No = consultation.Patient_No and doctor.Doctor_Id = Consultation.Doctor_Id and diagnosis.Diagnosed_disease = disease.Disease_code and disease.Disease_Name = '"+diseaseNameVal+"'and doctor.PostCode = '"+doctorpostCodeVal+"'" ; rs = gp_stmt.executeQuery( strQuery ) ; while ( rs.next() ){ strCount= rs.getString("ct"); Integer temp = (Integer.valueOf(strCount)); count = count + temp.intValue(); } } return count ; } catch (Exception ex) { return -1 ; } } } SERVLET /* * RetrieveServlet.java * * */ import java.io.*; import javax.servlet.*; import javax.servlet.http.*; import java.sql.* ; import javax.naming.Context; import javax.naming.InitialContext; import javax.rmi.PortableRemoteObject; // import login.ejb.*; import beans.* ; /** * * * @version */ public class RetrieveServlet extends HttpServlet { private String statusStr = null; /** Processes requests for both HTTP ><code>GET</code> and <code>POST</code> methods. * @param request servlet request * @param response servlet response */ protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException, InstantiationException, SQLException, ClassNotFoundException, IllegalAccessException { HttpSession session = request.getSession(); String hpustaffIDVal = (String) session.getAttribute("hpustaffID"); String doctorpostCodeVal = request.getParameter("doctorpostCode"); String diseaseNameVal = request.getParameter("DiseaseName"); String buttonVal=request.getParameter("Button"); String responseTarget = null; String diseaseName = null; if (hpustaffIDVal == null){ responseTarget = new String("/accept.jsp"); request.setAttribute("Status", null); } else { if (buttonVal.equals("Logout")) { responseTarget = new String("/accept.jsp"); //request.setAttribute("Status", null); session.invalidate(); } else { if( doctorpostCodeVal == null || diseaseNameVal == null ) { //HttpSession session = request.getSession(); responseTarget = new String("/accept.jsp"); //request.setAttribute( "HPUStaffID", hpustaffIDVal ) ; request.setAttribute("Status", "Please enter a valid doctorpostCode and Disease Name"); } else if( doctorpostCodeVal.trim().equals("") || diseaseNameVal.trim().equals("") ) { //HttpSession session = request.getSession(); responseTarget = new String("/accept.jsp"); //request.setAttribute( "HPUStaffID", hpustaffIDVal ) ; request.setAttribute("Status", "Please enter a valid doctorpostCode and Disease Name"); } else { RetrieveBean rtBean = new RetrieveBean(); if (rtBean.isValiddoctorpostCode(doctorpostCodeVal)) { diseaseName =rtBean.getDiseaseName(diseaseNameVal); if (diseaseName==null){ responseTarget = new String("/retrieve.jsp"); request.setAttribute("Status", "DiseaseName is not correct. It does not have a corresponding disease entry"); } else { int count = rtBean.getCount(doctorpostCodeVal, diseaseNameVal) ; if (count>=0) { responseTarget = new String("/retrieve.jsp"); request.setAttribute( "DoctorpostCode", doctorpostCodeVal ) ; request.setAttribute("diseaseName", diseaseNameVal); request.setAttribute( "Count", Integer.toString(count)) ; request.setAttribute( "Status", "1") ; } else { responseTarget = new String("/accept.jsp"); //request.setAttribute( "HPUStaffID", hpustaffIDVal ) ; request.setAttribute("Status", "Retrieve Bean Instantiation Error"); } } } else { responseTarget = new String("/accept.jsp"); request.setAttribute("Status", "Entered PostCode ID is not present in the GP database"); } } } } RequestDispatcher dispatcher = getServletContext().getRequestDispatcher( responseTarget ); dispatcher.forward( request, response ); } /** Handles the HTTP <code>GET</code> method. * @param request servlet request * @param response servlet response */ protected void doGet(HttpServletRequest request,) ct from Patient p, Consultation c, Diagnosis d where p.Post_Code= 'E176HR' // and p.Patient_No=c.Patient_No AND c.Consultation_No=d.Consultation_No and d.Diagnosed_disease='malaria' try { strQuery = "select Post_Code from doctor where PostCode='"+ givenDoctorpostCode + "'"; ResultSet rs = gp_stmt.executeQuery( strQuery ) ; while ( rs.next() ) strCount = rs.getString("givenDoctorpostCode"); String[] postcode_list = new String[Integer.valueOf(strCount)]; int i = 0; strQuery = "select PostCode pc from PostCode where doctor='"+ givenDoctorpostCode + "'"; rs = gp_stmt.executeQuery( strQuery ) ; while ( rs.next() ) postcode_list[i++] = rs.getString("givenDoctorpostCode"); for (i =0; i<postcode_list.length;i++) { strQuery = "Select patient.Patient_No, patient.Surname, patient.FirstName, patient.DOB, patient.House_No, patient.Street, patient.Post_Code, doctor.PostCode, doctor.Doctor_Id, consultation.Consultation_No, diagnosis.Diagnosed_disease, disease.Disease_Name from patient, doctor, consultation, diagnosis, disease where consultation.Consultation_No = diagnosis.Consultation_No and patient.Patient_No = consultation.Patient_No and doctor.Doctor_Id = Consultation.Doctor_Id and diagnosis.Diagnosed_disease = disease.Disease_code and disease.Disease_Name = '"+diseaseNameVal+"'and doctor.PostCode = '"+doctorpostCodeVal+"'" ; rs = gp_stmt.executeQuery( strQuery ) ; while ( rs.next() ){ strCount= rs.getString("ct"); Integer temp = (Integer.valueOf(strCount)); count = count + temp.intValue(); } } return count ; } catch (Exception ex) { return -1 ; } } } SERVLET /* * RetrieveServlet.java * * */ import java.io.*; import javax.servlet.*; import javax.servlet.http.*; import java.sql.* ; import javax.naming.Context; import javax.naming.InitialContext; import javax.rmi.PortableRemoteObject; // import login.ejb.*; import beans.* ; /** * * * @version */ public class RetrieveServlet extends HttpServlet { private String statusStr = null; /** Processes requests for both HTTP ><code>GET</code> and <code>POST</code> methods. * @param request servlet request * @param response servlet response */ protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException, InstantiationException, SQLException, ClassNotFoundException, IllegalAccessException { HttpSession session = request.getSession(); String hpustaffIDVal = (String) session.getAttribute("hpustaffID"); String doctorpostCodeVal = request.getParameter("doctorpostCode"); String diseaseNameVal = request.getParameter("DiseaseName"); String buttonVal=request.getParameter("Button"); String responseTarget = null; String diseaseName = null; if (hpustaffIDVal == null){ responseTarget = new String("/accept.jsp"); request.setAttribute("Status", null); } else { if (buttonVal.equals("Logout")) { responseTarget = new String("/accept.jsp"); //request.setAttribute("Status", null); session.invalidate(); } else { if( doctorpostCodeVal == null || diseaseNameVal == null ) { //HttpSession session = request.getSession(); responseTarget = new String("/accept.jsp"); //request.setAttribute( "HPUStaffID", hpustaffIDVal ) ; request.setAttribute("Status", "Please enter a valid doctorpostCode and Disease Name"); } else if( doctorpostCodeVal.trim().equals("") || diseaseNameVal.trim().equals("") ) { //HttpSession session = request.getSession(); responseTarget = new String("/accept.jsp"); //request.setAttribute( "HPUStaffID", hpustaffIDVal ) ; request.setAttribute("Status", "Please enter a valid doctorpostCode and Disease Name"); } else { RetrieveBean rtBean = new RetrieveBean(); if (rtBean.isValiddoctorpostCode(doctorpostCodeVal)) { diseaseName =rtBean.getDiseaseName(diseaseNameVal); if (diseaseName==null){ responseTarget = new String("/retrieve.jsp"); request.setAttribute("Status", "DiseaseName is not correct. It does not have a corresponding disease entry"); } else { int count = rtBean.getCount(doctorpostCodeVal, diseaseNameVal) ; if (count>=0) { responseTarget = new String("/retrieve.jsp"); request.setAttribute( "DoctorpostCode", doctorpostCodeVal ) ; request.setAttribute("diseaseNamei am really stuck i have pasted my code below in terms of bean, servlet and jsp. please could someone tell me where i am going wrong. I am totally new to this so really stuck. When i am deploying the application the page is being displayed however when entering fields of disease and postcode nothing is being displayed it just takes me to the same page as i am alreay on but the text changes to "welcome null". i need it to connect to my jsp. your help is appreciated! BEAN /* * RetrieveBean.java * * * * To change this template, choose Tools | Template Manager * and open the template in the editor. */ package beans ; import java.sql.*; import javax.sql.*; import java.util.*; public class RetrieveBean { public String doctorpostCodeVal; public String diseaseNameVal; //private Connection gp_conn = null, hpu_conn=null; private Statement gp_stmt ; private String statusStr = "" ; public RetrieveBean() throws InstantiationException, IllegalAccessException { try { Class.forName("com.mysql.jdbc.Driver").newInstance(); // gp_conn = HospitalConnection.getInstance().getGPConn(); // hpu_conn = HospitalConnection.getInstance().getHPUConn(); } catch(Exception e) { System.err.println("Exception: " + e.getMessage()); e.printStackTrace(); } } public void closeConnection() { try { gp_stmt.close() ; } catch( SQLException e ) { System.err.println( e.getMessage()) ; e.printStackTrace(); } } public String getStatus() { return statusStr ; } public boolean isValiddoctorpostCode(String doctorpostCode) { String strQuery = "select distinct PostCode d from doctor where PostCode='" + doctorpostCode + "'"; String str = null; ResultSet rs; try { rs = gp_stmt.executeQuery(strQuery); while ( rs.next() ) { str= rs.getString("doctorpostCode"); return true; } } catch (SQLException ex) { ex.printStackTrace(); } return false; } public String getDiseaseName(String diseaseName) { String strQuery = "select Disease_Name from disease where Disease_Name ='" + diseaseNamection.getInstance().getGPConn(); // hpu_conn = HospitalConnection.getInstance().getHPUConn(); } catch(Exception e) { System.err.println("Exception: " + e.getMessage()); e.printStackTrace(); } } public void closeConnection() { try { gp_stmt.close() ; } catch( SQLException e ) { System.err.println( e.getMessage()) ; e.printStackTrace(); } } public String getStatus() { return statusStr ; } public boolean isValiddoctorpostCode(String doctorpostCode) { String strQuery = "select distinct PostCode d from doctor where PostCode='" + doctorpostCode + "'"; String str = null; ResultSet rs; try { rs = gp_stmt.executeQuery(strQuery); while ( rs.next() ) { str= rs.getString("doctorpostCode"); return true; } } catch (SQLException ex) { ex.printStackTrace(); } return false; } public String getDiseaseName(String diseaseName) { String strQuery = "select Disease_Name from disease where Disease_Name ='" + diseaseName + "'"; String str = null; ResultSet rs; try { rs = gp_stmt.executeQuery(strQuery); while ( rs.next() ) { str= rs.getString("diseaseName"); return str; } } catch (SQLException ex) { ex.printStackTrace(); } str = null; return str; } public int getCount( String givenDoctorpostCode, String givendiseaseName ) { String strQuery, strCount="0"; int count = 0; //select count(*) ct from Patient p, Consultation c, Diagnosis d where p.Post_Code= 'E176HR' // and p.Patient_No=c.Patient_No AND c.Consultation_No=d.Consultation_No and d.Diagnosed_disease='malaria' try { strQuery = "select Post_Code from doctor where PostCode='"+ givenDoctorpostCode + "'"; ResultSet rs = gp_stmt.executeQuery( strQuery ) ; while ( rs.next() ) strCount = rs.getString("givenDoctorpostCode"); String[] postcode_list = new String[Integer.valueOf(strCount)]; int i = 0; strQuery = "select PostCode pc from PostCode where doctor='"+ givenDoctorpostCode + "'"; rs = gp_stmt.executeQuery( strQuery ) ; while ( rs.next() ) postcode_list[i++] = rs.getString("givenDoctorpostCode"); for (i =0; i<postcode_list.length;i++) { strQuery = "Select patient.Patient_No, patient.Surname, patient.FirstName, patient.DOB, patient.House_No, patient.Street, patient.Post_Code, doctor.PostCode, doctor.Doctor_Id, consultation.Consultation_No, diagnosis.Diagnosed_disease, disease.Disease_Name from patient, doctor, consultation, diagnosis, disease where consultation.Consultation_No = diagnosis.Consultation_No and patient.Patient_No = consultation.Patient_No and doctor.Doctor_Id = Consultation.Doctor_Id and diagnosis.Diagnosed_disease = disease.Disease_code and disease.Disease_Name = '"+diseaseNameVal+"'and doctor.PostCode = '"+doctorpostCodeVal+"'" ; rs = gp_stmt.executeQuery( strQuery ) ; while ( rs.next() ){ strCount= rs.getString("ct"); Integer temp = (Integer.valueOf(strCount)); count = count + temp.intValue(); } } return count ; } catch (Exception ex) { return -1 ; } } } SERVLET /* * RetrieveServlet.java * * */ import java.io.*; import javax.servlet.*; import javax.servlet.http.*; import java.sql.* ; import javax.naming.Context; import javax.naming.InitialContext; import javax.rmi.PortableRemoteObject; // import login.ejb.*; import beans.* ; /** * * * @version */ public class RetrieveServlet extends HttpServlet { private String statusStr = null; /** Processes requests for both HTTP ><code>GET</code> and <code>POST</code> methods. * @param request servlet request * @param response servlet response */ protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException, InstantiationException, SQLException, ClassNotFoundException, IllegalAccessException { HttpSession session = request.getSession(); String hpustaffIDVal = (String) session.getAttribute("hpustaffID"); String doctorpostCodeVal = request.getParameter("doctorpostCode"); String diseaseNameVal = request.getParameter("DiseaseName"); String buttonVal=request.getParameter("Button"); String responseTarget = null; String diseaseName = null; if (hpustaffIDVal == null){ responseTarget = new String("/accept.jsp"); request.setAttribute("Status", null); } else { if (buttonVal.equals("Logout")) { responseTarget = new String("/accept.jsp"); //request.setAttribute("Status", null); session.invalidate(); } else { if( doctorpostCodeVal == null || diseaseNameVal == null ) { //HttpSession session = request.getSession(); responseTarget = new String("/accept.jsp"); //request.setAttribute( "HPUStaffID", hpustaffIDVal ) ; request.setAttribute("Status", "Please enter a valid doctorpostCode and Disease Name"); } else if( doctorpostCodeVal.trim().equals("") || diseaseNameVal.trim().equals("") ) { //HttpSession session = request.getSession(); responseTarget = new String("/accept.jsp"); //request.setAttribute( "HPUStaffID", hpustaffIDVal ) ; request.setAttribute("Status", "Please enter a valid doctorpostCode and Disease Name"); } else { RetrieveBean rtBean = new RetrieveBean(); if (rtBean.isValiddoctorpostCode(doctorpostCodeVal)) { diseaseName =rtBean.getDiseaseName(diseaseNameVal); if (diseaseName==null){ responseTarget = new String("/retrieve.jsp"); request.setAttribute("Status", "DiseaseName is not correct. It does not have a corresponding disease entry"); } else { int count = rtBean.getCount(doctorpostCodeVal, diseaseNameVal) ; if (count>=0) { responseTarget = new String("/retrieve.jsp"); request.setAttribute( "DoctorpostCode", doctorpostCodeVal ) ; request.setAttribute("diseaseName", diseaseNameVal); request.setAttribute( "Count", Integer.toString(count)) ; request.setAttribute( "Status", "1") ; } else { responseTarget = new String("/accept.jsp"); //request.setAttribute( "HPUStaffID", hpustaffIDVal ) ; request.setAttribute("Status", "Retrieve Bean Instantiation Error"); } } } else { responseTarget = new String("/accept.jsp"); request.setAttribute("Status", "Entered PostCode ID is not present in the GP database"); } } } } RequestDispatcher dispatcher = getServletContext().getRequestDispatcher( responseTarget ); dispatcher.forward( request, response ); } /** Handles the HTTP <code>GET</code> method. * @param request servlet request * @param response servlet response */ protected void doGet(HttpServletRequest request,//request.setAttribute( "HPUStaffID", hpustaffIDVal ) ; request.setAttribute("Status", "Please enter a valid doctorpostCode and Disease Name"); } else if( doctorpostCodeVal.trim().equals("") || diseaseNameVal.trim().equals("") ) { //HttpSession session = request.getSession(); responseTarget = new String("/accept.jsp"); //request.setAttribute( "HPUStaffID", hpustaffIDVal ) ; request.setAttribute("Status", "Please enter a valid doctorpostCode and Disease Name"); } else { RetrieveBean rtBean = new RetrieveBean(); if (rtBean.isValiddoctorpostCode(doctorpostCodeVal)) { diseaseName =rtBean.getDiseaseName(diseaseNameVal); if (diseaseName==null){ responseTarget = new String("/retrieve.jsp"); request.setAttribute("Status", "DiseaseName is not correct. It does not have a corresponding disease entry"); } else { int count = rtBean.getCount(doctorpostCodeVal, diseaseNameVal) ; if (count>=0) { responseTarget = new String("/retrieve.jsp"); request.setAttribute( "DoctorpostCode", doctorpostCodeVal ) ; request.setAttribute("diseaseNamei am really stuck i have pasted my code below in terms of bean, servlet and jsp. please could someone tell me where i am going wrong. I am totally new to this so really stuck. When i am deploying the application the page is being displayed however when entering fields of disease and postcode nothing is being displayed it just takes me to the same page as i am alreay on but the text changes to "welcome null". i need it to connect to my jsp. your help is appreciated! BEAN /* * RetrieveBean.java * * * * To change this template, choose Tools | Template Manager * and open the template in the editor. */ package beans ; import java.sql.*; import javax.sql.*; import java.util.*; public class RetrieveBean { public String doctorpostCodeVal; public String diseaseNameVal; //private Connection gp_conn = null, hpu_conn=null; private Statement gp_stmt ; private String statusStr = "" ; public RetrieveBean() throws InstantiationException, IllegalAccessException { try { Class.forName("com.mysql.jdbc.Driver").newInstance(); // gp_conn = HospitalConnection.getInstance().getGPConn(); // hpu_conn = HospitalConnection.getInstance().getHPUConn(); } catch(Exception e) { System.err.println("Exception: " + e.getMessage()); e.printStackTrace(); } } public void closeConnection() { try { gp_stmt.close() ; } catch( SQLException e ) { System.err.println( e.getMessage()) ; e.printStackTrace(); } } public String getStatus() { return statusStr ; } public boolean isValiddoctorpostCode(String doctorpostCode) { String strQuery = "select distinct PostCode d from doctor where PostCode='" + doctorpostCode + "'"; String str = null; ResultSet rs; try { rs = gp_stmt.executeQuery(strQuery); while ( rs.next() ) { str= rs.getString("doctorpostCode"); return true; } } catch (SQLException ex) { ex.printStackTrace(); } return false; } public String getDiseaseName(String diseaseName) { String strQuery = "select Disease_Name from disease where Disease_Name ='" + diseaseName + "'"; String str = null; ResultSet rs; try { rs = gp_stmt.executeQuery(strQuery); while ( rs.next() ) { str= rs.getString("diseaseName"); return str; } } catch (SQLException ex) { ex.printStackTrace(); } str = null; return str; } public int getCount( String givenDoctorpostCode, String givendiseaseName ) { String strQuery, strCount="0"; int count = 0; //select count(*) ct from Patient p, Consultation c, Diagnosis d where p.Post_Code= 'E176HR' // and p.Patient_No=c.Patient_No AND c.Consultation_No=d.Consultation_No and d.Diagnosed_disease='malaria' try { strQuery = "select Post_Code from doctor where PostCode='"+ givenDoctorpostCode + "'"; ResultSet rs = gp_stmt.executeQuery( strQuery ) ; while ( rs.next() ) strCount = rs.getString("givenDoctorpostCode"); String[] postcode_list = new String[Integer.valueOf(strCount)]; int i = 0; strQuery = "select PostCode pc from PostCode where doctor='"+ givenDoctorpostCode + "'"; rs = gp_stmt.executeQuery( strQuery ) ; while ( rs.next() ) postcode_list[i++] = rs.getString("givenDoctorpostCode"); for (i =0; i<postcode_list.length;i++) { strQuery = "Select patient.Patient_No, patient.Surname, patient.FirstName, patient.DOB, patient.House_No, patient.Street, patient.Post_Code, doctor.PostCode, doctor.Doctor_Id, consultation.Consultation_No, diagnosis.Diagnosed_disease, disease.Disease_Name from patient, doctor, consultation, diagnosis, disease where consultation.Consultation_No = diagnosis.Consultation_No and patient.Patient_No = consultation.Patient_No and doctor.Doctor_Id = Consultation.Doctor_Id and diagnosis.Diagnosed_disease = disease.Disease_code and disease.Disease_Name = '"+diseaseNameVal+"'and doctor.PostCode = '"+doctorpostCodeVal+"'" ; rs = gp_stmt.executeQuery( strQuery ) ; while ( rs.next() ){ strCount= rs.getString("ct"); Integer temp = (Integer.valueOf(strCount)); count = count + temp.intValue(); } } return count ; } catch (Exception ex) { return -1 ; } } } SERVLET /* * RetrieveServlet.java * * */ import java.io.*; import javax.servlet.*; import javax.servlet.http.*; import java.sql.* ; import javax.naming.Context; import javax.naming.InitialContext; import javax.rmi.PortableRemoteObject; // import login.ejb.*; import beans.* ; /** * * * @version */ public class RetrieveServlet extends HttpServlet { private String statusStr = null; /** Processes requests for both HTTP ><code>GET</code> and <code>POST</code> methods. * @param request servlet request * @param response servlet response */ protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException, InstantiationException, SQLException, ClassNotFoundException, IllegalAccessException { HttpSession session = request.getSession(); String hpustaffIDVal = (String) session.getAttribute("hpustaffID"); String doctorpostCodeVal = request.getParameter("doctorpostCode"); String diseaseNameVal = request.getParameter("DiseaseName"); String buttonVal=request.getParameter("Button"); String responseTarget = null; String diseaseName = null; if (hpustaffIDVal == null){ responseTarget = new String("/accept.jsp"); request.setAttribute("Status", null); } else { if (buttonVal.equals("Logout")) { responseTarget = new String("/accept.jsp"); //request.setAttribute("Status", null); session.invalidate(); } else { if( doctorpostCodeVal == null || diseaseNameVal == null ) { //HttpSession session = request.getSession(); responseTarget = new String("