import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
public class LoginServlet extends HttpServlet {
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
sendLoginForm(response, false);
}
private void sendLoginForm(HttpServletResponse response,
boolean withErrorMessage)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("");
out.println("");
out.println("Login");
out.println("");
out.println("");
out.println("");
if (withErrorMessage)
out.println("Login failed. Please try again.
");
out.println("
");
out.println("
Login Page
");
out.println("
");
out.println("
Please enter your user name and password.");
out.println("
");
out.println("
");
out.println("");
out.println("");
out.println("");
}
public void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
String userName = request.getParameter("userName");
String password = request.getParameter("password");
if (login(userName, password)) {
RequestDispatcher rd =
request.getRequestDispatcher("AnotherServlet");
rd.forward(request, response);
}
else {
sendLoginForm(response, true);
}
}
boolean login(String userName, String password) {
try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection con =
DriverManager.getConnection("jdbc:odbc:JavaWeb");
System.out.println("got connection");
Statement s = con.createStatement();
String sql = "SELECT UserName FROM Users" +
" WHERE UserName='" + userName + "'" +
" 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;
}
}