failing to login with jsp, bean and servlet

[size=12][size=12]Hi! I've written this code to login from jsp using a bean and servlet that checks username and password

from mysql database.

Code below:

[u]index.jsp:[/u]

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
    "http://www.w3.org/TR/html4/loose.dtd">

<html>
    <head>
        <style type="text/css">
            body {
                background-color:#AFC7C7;
                padding: 0;
                margin: 0;
            }
            div.wrapper {
                margin-left: 10%;
                margin-right: 10%;
                background-color:#6D7B8D;
                height: 620px;
                padding-top:0px;
                border: thin solid #000000;
            }

div#image{
                padding-top:1%;
                padding-bottom:1%;
            }
            div#adminlogin{
                width:35%;
                height:50%;
                background-color:#AFC7C7;
                border-width:thin;
                border-style:solid;
                border-color:#000000;
                margin: 0 auto;
                text-align:left;
                overflow: hidden;
                padding: 5px;
            }

hr {
                height:1px;
                color:#000000;
                background-color:#000000;
                width:99%;
                margin-left: 0 ;
                margin-right: auto ;
                border-style:solid;
            }

.inputtext {
                width: 350px;
                height: 30px;
                Font-Family:Arial;
                Font-Size:18px
            }

</style>

if (field.defaultValue == field.value) field.value = '';
                else if (field.value == '') field.value = field.defaultValue;

}

</script>
    </head>
    <body>
        <div class="wrapper">
            <div id="image">
                <p>
                    <img src="${pageContext.request.contextPath}/images/sms1.gif"
                         alt="banner"
                         width=98%
                         height=300
                         /></p>
            </div>
            <div id=adminlogin >
                <p>Administrator Login</p>
                <hr/>
                <form method=POST action=loginJsp.jsp>
                    <label>Username<br/>
                        <input type="text" class="inputtext" name="usrnm" value="Your Username"
                               onFocus="clearText(this)" onBlur="clearText(this)"/></label><br/>
                        <br/>
                        <label>Password<br/>
                        <input type="password" class="inputtext" name="pwd" value="Your Password"
                               onFocus="clearText(this)" onBlur="clearText(this)"/></label><br/>
                        <br/>
                    <input type="submit" value="Login"/>
                    <a href="url">Forgotten?</a>
                </form>
            </div>
        </div>
    </body>
</html>

[u]loginJsp.jsp:[/u]

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
    "http://www.w3.org/TR/html4/loose.dtd">

<%@ page language="Java" import="java.sql.*" %>

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>Login stuff</title>
    </head>
    <body>
        <jsp:useBean id="login" scope="request" class="pack1.loginHandle" >
            <jsp:setProperty name="login" property="usrnm" value = "<%=request.getParameter("usrnm")%>"/>
            <jsp:setProperty name="login" property="pwd" value = "<%=request.getParameter("pwd")%>" />
        </jsp:useBean>
        <jsp:forward page="/adminCheck">
            <jsp:param name="usrnm" value="<%=login.getUsrnm()%>" />
            <jsp:param name="pwd" value="<%=login.getPwd()%>" />
        </jsp:forward>
        <%--<h1>Hello, <jsp:getProperty name="login" property="usrnm" />!</h1>--%>
    </body>
</html>

[u]loginBean.java:[/u]

public class loginBean {

public String usrnm;
    public String pwd;
    /**
     * Get the value of usrnm
     *
     * @return the value of usrnm
     */
    public String getUsrnm() {
        return usrnm;
    }

public String getPwd() {
        return pwd;
    }
    /**
     * Set the value of usrnm
     *
     * @param usrnm new value of usrnm
     */
    public void setUsrnm(String usrnm) {
        this.usrnm = usrnm;
    }

public void setPwd(String pwd) {
        this.pwd = pwd;
    }

}

[u]adminCheck.java:[/u]

import java.io.*;
import java.sql.*;
import javax.servlet.ServletException;
import javax.servlet.http.*;

/**
 *
 * @author ken
 */
public class adminCheck extends HttpServlet {

@Override
    protected void doGet(HttpServletRequest req, HttpServletResponse res)
            throws ServletException, IOException {
    }

@Override
    protected void doPost(HttpServletRequest req, HttpServletResponse res)
            throws ServletException, IOException {

res.setContentType("text/html");
        PrintWriter pw = res.getWriter();
        System.out.println("Checking admin login");
        Connection conn = null;
        String url = "jdbc:mysql://localhost:3306/";
        String dbName = "mvs_user";
        String dbDriver = "com.mysql.jdbc.Driver";
        String dbUser = "root";
        String dbPass = "";
        String username = "";
        String userpass = "";
        String strQuery = "";
        Statement st = null;
        ResultSet rs = null;
        HttpSession session = req.getSession(true);
        try {
            Class.forName(dbDriver).newInstance();
            conn = DriverManager.getConnection(url + dbName, dbUser, dbPass);
            if (req.getParameter("usrnm") != null && req.getParameter("username") != ""
                    && req.getParameter("pwd") != null && req.getParameter("password") != "") {
                username = req.getParameter("usrnm").toString();
                userpass = req.getParameter("pwd").toString();
                strQuery = "select * from user where username='" + username + "' and  password='" + userpass + "'";
                System.out.println(strQuery);
                st = conn.createStatement();
                rs = st.executeQuery(strQuery);
                int count = 0;
                while (rs.next()) {
                    session.setAttribute("username", rs.getString(2));
                    count++;
                }
                if (count > 0) {
                    res.sendRedirect("adminHome.jsp");
                } else {
                    res.sendRedirect("index.jsp");
                }
            } else {
                res.sendRedirect("login.jsp");
            }
            System.out.println("Connected to the database");
            conn.close();
            System.out.println("Disconnected from database");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

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

[u]adminHome.jsp:[/u]

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!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>
        <h1>Hello World!</h1>
    </body>
</html>

The problem is the browser only displays a blank page of loginJsp.jsp and yet I expect it to display Hello World in

the adminHome.jsp. Where could the problem be? Please help me troubleshoot.

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Suggestion to help us answer your question: remove all the parts irrelevant to your question, and provide an example which has the bare bones of what you want to do, and displays the error.
For instance all of the styling information in this page is extraneous to your issue. We have to spend time scanning through a 2-3 page long jsp page, which we may not feel like doing. In fact you probably could have just posted the servlet for the login bit, because that appears to be the bt that is failing.

I presume you are filling in loginname/password, hitting submit, and expecting login to succeed.
There are many points in this code in which this can fail, so my suggestion would be to pepper the relevant bits with log statements. A logger like Log4j would be ideal, but System.out.println does almost as well :-)
Then check the output of your log file.

Some suggestions:
your checking if the fields are provided looks wrong to me
if (req.getParameter("usrnm") != null && req.getParameter("username") != "" && req.getParameter("pwd") != null && req.getParameter("password") != "") {

1 - You are referencing two different parameters: usrnm and username.
2 - To compare for empty string, use the .equals method, not !=

I think it should be more:

Also, when executing a query, you should use a prepared statement to pass in values rather than building a sql string in this fashion. You have opened yourself up for a SQL Injection attack.