javax. servlet.Servlet Exception: Initialization failed, Unable to get DB connection

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October 31, 2008 at 4:54 PM

Hi friend,

<html>

<head>
<title>login form application</title>
</head>

<body>
<center><h1>XYZ Company Ltd.</h1></center>
<table border="1" width="100%" height="100%">
<tr>
<td width="15%" valign="top" align="center">
<br/><a href="Login.html">Login</a><br/>
<br/><a href="Register.html">Register</a><br/>
</td>
<td valign="top" align="center"><br/>
<form method="POST" action="">

<h2 align="center"><font color="black">Login Application</font></h2>
<table border="0" width="100%" cellspacing="0" callpadding="0">
<tr>
<td width="50%" align="right"><b><font color="black">User Name:</b></font></td>
<td width="50%"><input type="text" name="uname" size="20"/> </td>
</tr>
<tr>
<td width="50%" align="right"><b><font color="black">Password:</b></font></td>
<td width="50%"><input type="password" name="pass" size="20"></td>
</tr>
</table>
<p><center><input type="submit" value="Submit" name="submit">
<input type="reset" value="Reset" name="reset"></p></center>

</form>
</td>
</tr>
</table>

</body>

</html>

October 31, 2008 at 5:13 PM

Hi friend,

Home.html

<html><body>
<center><h1>XYZ Company Ltd.</h1></center>
<table border="1" width="100%" height="100%">
<tr>
<td width="15%" valign="top" align="center">
<br/><a href="Login.html">Login</a><br/>
<br/><a href="Register.html">Register</a><br/>
</td>
<td valign="top" align="center"><br/>
Welcome to xyz.com
</td>
</tr>
</table>
</body></html>

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

Login form

<html>

<head>
<title>login form application</title>
</head>

<body>
<center><h1>XYZ Company Ltd.</h1></center>
<table border="1" width="100%" height="100%">
<tr>
<td width="15%" valign="top" align="center">
<br/><a href="Login.html">Login</a><br/>
<br/><a href="Register.html">Register</a><br/>
</td>
<td valign="top" align="center"><br/>
<form method="POST" action="loginServlet">

<h2 align="center"><font color="black">Login Application</font></h2>
<table border="0" width="100%" cellspacing="0" callpadding="0">
<tr>
<td width="50%" align="right"><b><font color="black">User Name:</b></font></td>
<td width="50%"><input type="text" name="uname" size="20"/> </td>
</tr>
<tr>
<td width="50%" align="right"><b><font color="black">Password:</b></font></td>
<td width="50%"><input type="password" name="pass" size="20"></td>
</tr>
</table>
<p><center><input type="submit" value="Submit" name="submit">
<input type="reset" value="Reset" name="reset"></p></center>

</form>
</td>
</tr>
</table>

</body>

</html>

October 31, 2008 at 5:15 PM

login action.

package javacode;

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

public class loginServlet extends GenericServlet {

private Connection con;
private PreparedStatement ps=null;

public void init() throws ServletException {
System.out.println("In init");
try {
ServletContext ctxt=getServletContext();
//Getting the Driver class name from context parameter
String driverClassName=ctxt.getInitParameter("driverClassName");
Class.forName(driverClassName);
//Getting the JDBC URL from context parameter
String url=ctxt.getInitParameter("url");

//Getting the DB Username, password & sqlstatement from servlet init parameter
String dbuser=getInitParameter("dbuser");
String dbpass=getInitParameter("dbpass");
String sqlst=getInitParameter("sqlstatement");

con=DriverManager.getConnection(url, dbuser, dbpass);
ps=con.prepareStatement(sqlst);
}//try
catch(Exception e){
e.printStackTrace();
throw new ServletException("Initialization failed, Unable to get DB connection");
}//catch
}//init

public void service (ServletRequest req, ServletResponse res) throws ServletException, IOException {

System.out.println("In service");

res.setContentType("text/html");
PrintWriter out=res.getWriter();
try {

String uname=req.getParameter("uname");
System.out.println("username>>>>>>>>>>>>: " + uname);
String pass= req.getParameter("pass");
System.out.println("pass>>>>>>>>>> :" + pass);

if (uname==null||uname.equals("")||pass==null||pass.equals("")) {

out.println("<html><body><center>");
out.println("<li><i>User Name and Password cannot be empty</i></li><br/>");
out.println("<li><i>We cannot log you into your account at this time. Please try again later</i>");
out.println("</center></body></html>");
return;
}//if

ps.setString(1,uname);
ps.setString(2,pass);
ResultSet rs=ps.executeQuery();

if (rs.next()){
out.println("<html><body>");
out.println("<center><h1>XYZ Company Ltd.</h1></center>");
out.println("<table border='1' width='100%' height='100%'>");
out.println("<tr>");
out.println("<td width='15%' valign='top' align='center'>");
out.println("<br/><a href='Login.html'>Login</a><br/>");
out.println("<br/><a href='Register.html'>Register</a>");
out.println("</td>");
out.println("<td valign='top' align='center'><br/>");
out.println("<h3>Welcome, "+uname+"</h3><br/>");
out.println("<h2>Enjoy browsing the Site</h2>");
out.println("</td></tr></table>");
out.println("</body></html>");
}
else{
out.println("<html><body><center>");
out.println("Given username and password are incorrect<br/>");
out.println("<li><i>We cannot log you into your account at this time. Please try again later</i>");
out.println("</center></body></html>");
}
}//try
catch(Exception e){
out.println("<html><body><center>");
out.println("<h2>Unable to the process the request try after some time</h2>");
out.println("</center></body></html>");
}//catch
}//service

public void destroy () {
System.out.println("In destroy");
try {
con.close();
}
catch(Exception e){
System.out.println("error : " + e);
}
}//destroy
}//class

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

October 31, 2008 at 5:18 PM

if you have any problem then check database connection code web.xml.

Visit for more information.

http://www.roseindia.net/jsp/jsp-authentication.shtml

Thanks.