servlet is not working properly

Greenhorn

Posts: 6

posted 14 years ago

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please need help dealling with this problem.i have a Controll servlet that user id from a jsp page.the id is used to delete user data from a database and when i run my jsp page,the servlet does not use the id to delete user data from the database.i can figure what the problem could be.thanks for your usual attension
the jsp code

<%@page contentType="text/html"%>
<%@page pageEncoding="UTF-8"%>
<%@ page language="java" import="java.sql.*"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd">

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>JSP Page</title>
    </head>
    <body>
            <table align="center" cellspacing="0" cellpadding="0" bgcolor="1">                
                <form method="get" action="/webdb/ControlServlet">
                <tr>
                    <td align="center" bgcolor="lightblue">id</td>
                    <td align="center" bgcolor="pink">Surname</td>
                    <td align="center" bgcolor="lightblue">Other Names</td>
                    <td align="center" bgcolor="pink">Last Name</td>
                    <td align="center" bgcolor="lightblue">Email</td>
                </tr>
                <%
                    Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
                    Connection con = DriverManager.getConnection("jdbc:odbc:kham");
                    Statement st = con.createStatement();
                    ResultSet rs = st.executeQuery("select*from kham_rec");
                    while(rs.next()){
                %>
                <tr bgcolor="lightgray">
                    <td><input type="radio" value="<%=rs.getString(1)%>" name="id"></td>
                    <td><%=rs.getString(2)%></td>
                    <td><%=rs.getString(3)%></td>
                    <td><%=rs.getString(4)%></td>
                    <td><%=rs.getString(6)%></td>
                </tr>
                  <%}%>
                <tr bgcolor="lightgray">
                    <td align="right"><input type="submit" value="delet"></td>
                    <td align="right"></td>
                    <td align="right"></td>
                    <td align="right"></td>
                    <td align="right"></td>
                </tr>
            </form>
           
        </table> 
       
    </body>
</html>

the servlet code

/*
 * ControlServlet.java
 *
 * 
 */

package com.db;

import java.io.*;
import java.net.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

import javax.servlet.*;
import javax.servlet.http.*;

/**
 *
 * @author Administrator
 * @version
 */
public class ControlServlet extends HttpServlet {
    private Connection con;
    private Statement st;    
    private ResultSet rs;       
    private static String driver = "sun.jdbc.odbc.JdbcOdbcDriver";
    private static String url = "jdbc:odbc:kham";
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
       response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        int id = Integer.parseInt(request.getParameter("id"));
        try{
            Class.forName(driver);
            con = DriverManager.getConnection(url);
            st = con.createStatement();
            rs= st.executeQuery("delete from kham_rec where id="+"\'"+id+"\'");
            rs.next();
        }catch(Exception e){
            e.printStackTrace();
        }
        RequestDispatcher rd = request.getRequestDispatcher("index.jsp"); 
        rd.forward(request,response);
        /* TODO output your page here
        out.println("<html>");
        out.println("<head>");
        out.println("<title>Servlet ControlServlet</title>");
        out.println("</head>");
        out.println("<body>");
        out.println("<h1>Servlet ControlServlet at " + request.getContextPath () + "</h1>");
        out.println("</body>");
        out.println("</html>");
         */
        out.close();
    }
      
    /** Returns a short description of the servlet.
     */
    public String getServletInfo() {
        return "Short description";
    }
    // </editor-fold>
}

William Brogden

Author and all-around good cowpoke

Posts: 13078

posted 14 years ago

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I have no idea if this is related to your immediate problem, but your use of instance variables:

to hold user request specific data is bound to cause trouble eventually since any number of request threads could be executing the servlet code "at the same time."

Bill

srinivas srinivasmeenavalli

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Posts: 65

posted 14 years ago

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Issue would be using

request.getParameter("id")

. Id returns more than one record.
You may have to use .Try to print "id" value before using.

Mohamed Inayath

Ranch Hand

Posts: 124

posted 14 years ago

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srinivas srinivasmeenavalli wrote:Issue would be using

request.getParameter("id")

. Id returns more than one record.
You may have to use java.lang.String[] getParameterValues("id").Try to print "id" value before using.

Its a radio button option any point time it will hold only one value.

Efekodo Kingsley, You are using Database connection within JSP its not a good practice.
JSP is for rendering views, you do retrieving of data in servlet and then use it in JSP.

Between are you getting any errors?

Don't get me started about those stupid light bulbs.