hi andres,
as for me,everything is correct.instead of checking like
rs.next,store database data into some variable and check it.
bye,
hari
At 04:13 PM 12/2/99 +0200, you wrote:
>Hi there,
>
>although a novice, I am trying to develop a room booking system using
>servlets and JDBC. Currently I am trying to get my LoginServlet to work.
>This system is a project from a university so things like multiuser access
>and connection pools are not of my interest at the moment.
>
>The loginServlet I developed is part of the following:
>
>1. First the user accesses an HTML form in order to provide Login and
>Password. He/she then submits the query that is sent via GET to the servlet
>in order to authenticate user access via the database connection.
>2. Here comes the servlet that opens a connection with the db and executes a
>query that checks a table with the user details, username/password. If it
>finds ANY row in the db table then user access is granted and the user is
>redirected to another URL that accomodates my booking form(which is still
>under construction).
>3. If on the other hand there are no matches from the table the user is
>thrown an Html error message(from within servlet via out.println()s..).
>
>My problems started when I was getting SQL exception messages notifying me
>of something wrong in my query statement. I solved that but now everytime I
>run the servlet via JWS1.1.3 I always get the Html error message mentioned
>above even if in the Login form I provide the exact user details from the
>database.
>
>Just to add some more info on the problem, I am using:
>
>- JavaWebServer1.1.3 to run/accomodate servlets and to store Html files in
>public_html
>- everything runs locally on WIN98 machine
>- Java2 SDK
>- javax.servlet API
>- standard java.sql db connectivity classes once my db code is simple..
>
>The following code is my servlet code as a whole:
>
> import java.io.*;
>import java.util.*;
>import java.sql.*;
>import javax.servlet.*;
>import javax.servlet.http.*;
>
>public class LoginServlet extends HttpServlet {
>
> static String username = "";
> static String password = "";
>
> public void doGet(HttpServletRequest req, HttpServletResponse res)
> throws ServletException, IOException {
>
> username = req.getParameter("username"); //via req parameter grab username
>(textfield)input from form
> password = req.getParameter("password"); //via " " " password
>(textfield)input " "
>
> //set the output stream that goes back to the browser to HTML
> res.setContentType("text/html");
>
> //get a handle to the writer going back to the client
> PrintWriter out = res.getWriter();
>
> //Create a connection object
> Connection con = null;
>
> //Create a statement object
> Statement stmt = null;
>
> //Create a ResultSet object to encapsulate retrieved data
> ResultSet rs = null;
>
> try {
>
> //Load the jdbc:odbc bridge/driver
> Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
>
> //Get a connection to the Access database
> con = DriverManager.getConnection("jdbc:odbc:RoomBookDB", "andreas",
>"stellatos");
>
> //Create a statement object that is used for querying the database
> stmt = con.createStatement();
>
> //Execute SQL query and get a result set
> rs = stmt.executeQuery("SELECT username, password FROM Lecturers
>WHERE username = '+ username +' AND password = '+ password +'" );
>
>
> //If the query returns ANY ROW from the db, then grant access, if
>not, show error message
> if(rs.next()) {
> res.sendRedirect("http://andreas:8080/BookingForm.html"); }
> else {
> out.println("<HTML>");
> out.println("<HEAD><TITLE>Login Error</TITLE></HEAD>");
> out.println("<BODY>");
> out.println("<P>Error Message!</P>");
> out.println("<P>Your PASSWORD or USERNAME is incorrect. Please return
>to the Login Screen to re-enter your details.</P>");
> out.println("</BODY></HTML>");
> }
>
> }
> //Handle a series of exceptions
> catch(ClassNotFoundException e) {
> out.println("Couldn't load the database driver: " + e.getMessage());
> }
> catch(SQLException e) {
> out.println("SQLException caught: " + e.getMessage());
> }
> finally {
> //Close the database connection
> try {
> if (con != null) con.close();
> }
> catch(SQLException ignored) { }
> }
>
> }
>
>}
>
>
>What I am worried about now is whether the reDirection code I have used is
>wrong, but still, it's very simple:
>
>if match in the db then
> go to URL:....BookingForm
> else
> throw error
>
>I have been getting some help so far but is it possible to have a collective
>view(!) from the SERVLET-INTEREST mailing list? I'm quite desperate now as I
>am trying to continue writing my other servlet(s) and this problem keeps
>persisting.. What am I doing wrong? I have also attached the file Login.html
>to check the source even though I think there's nothing wrong with it.
>
>Thanks,
>
>Andreas Stellatos
>
>
>Attachment Converted: "c:\eudora\attach\Login.html"
>
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