Hi all trying to create a simple database login java servlet. It’s going straight to
Login failed. Please try again.
here is the set out of my database I have the table user–id, uniid, name, password, email
for example i have the following data in the table
uniid - 18357593
name - Jared Hoight
password - password
email - jhall@students.monash.edu.au
here is the login servlet in it’s entirety
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.RequestDispatcher;
/**
* Servlet implementation class LoginServlet
*/
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public LoginServlet() {
super();
// TODO Auto-generated constructor stub
}
private void sendLoginForm(HttpServletResponse response,
boolean withErrorMessage)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<HTML>");
out.println("<HEAD>");
out.println("<TITLE>Login</TITLE>");
out.println("</HEAD>");
out.println("<BODY>");
out.println("<CENTER>");
if (withErrorMessage)
out.println("Login failed. Please try again.<BR>");
out.println("<BR>");
out.println("<BR><H2>Login Page</H2>");
out.println("<BR>");
out.println("<BR>Please enter your user name and password.");
out.println("<BR>");
out.println("<BR><FORM METHOD=POST>");
out.println("<TABLE>");
out.println("<TR>");
out.println("<TD>User Name:</TD>");
out.println("<TD><INPUT TYPE=TEXT NAME=uniid></TD>");
out.println("</TR>");
out.println("<TR>");
out.println("<TD>Password:</TD>");
out.println("<TD><INPUT TYPE=PASSWORD NAME=password></TD>");
out.println("</TR>");
out.println("<TR>");
out.println("<TD ALIGN=RIGHT COLSPAN=2>");
out.println("<INPUT TYPE=SUBMIT VALUE=Login></TD>");
out.println("</TR>");
out.println("</TABLE>");
out.println("</FORM>");
out.println("</CENTER>");
out.println("</BODY>");
out.println("</HTML>");
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
sendLoginForm(response, false);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
public void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
String uniid = request.getParameter("uniid");
String password = request.getParameter("password");
if (login(uniid, password)) {
RequestDispatcher rd =
request.getRequestDispatcher("AnotherServlet");
rd.forward(request, response);
}
else {
sendLoginForm(response, true);
}
}
boolean login(String uniid, String password) {
try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection con =
DriverManager.getConnection("jdbc:mysql://localhost:3306/wae","root","");
System.out.println("got connection");
Statement s = con.createStatement();
String sql = "SELECT uniid FROM user" +
" WHERE uniid='" + uniid + "'" +
" AND password='" + password + "'";
ResultSet rs = s.executeQuery(sql);
if (rs.next()) {
rs.close();
s.close();
con.close();
return true;
}
rs.close();
s.close();
con.close();
}
catch (ClassNotFoundException e) {
System.out.println(e.toString());
}
catch (SQLException e) {
System.out.println(e.toString());
}
catch (Exception e) {
System.out.println(e.toString());
}
return false;
}
}
The database driver
is not the correct one for use with MySQL. It should be
When an exception occurs in your
loginmethod, the exception string is printed and it returns false.