How to use mysql-connector-driver with jsp

Question

I need to create a login with JSP and so, I need to use mysql-connector-java.

I insert the file jar: mysql-connector-java-5.1.38-bin.jar into WEB-INF/lib

and I use this code into the jsp file:

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

<%
    String DRIVER = "com.mysql.jdbc.Driver";
    String URL_mioDB = "jdbc:mysql://localhost:3306/ditta";

    try
    {
       Class.forName(DRIVER);
    } 
    catch (ClassNotFoundException e) 
    {
       System.err.println("Driver not found" + e);
    } 

    Connection connessione = null;
    try
    {
       // apro la connesione verso il database.
       connessione = DriverManager.getConnection(URL_mioDB,"root","");
    } 
    catch (Exception e)
    {
       System.err.println("Error during connection with db : " + e);
    } 

    String mail="",pass="",send="",query="";

    try
    {
        mail=request.getParameter("email");
        pass=request.getParameter("password");
        send=request.getParameter("send");

        out.println("<FORM name='F1' method='post' action='login.jsp'>");
            out.println("Email: <INPUT type='text' name='email' value='' placeholder='mariorossi@gmail.com'><BR><BR>");
            out.println("Password: <INPUT type='password' name='password' value=''><BR><BR>");
            out.println("<INPUT type='submit' name='send' value='Invia'>&nbsp;&nbsp;&nbsp;&nbsp;<INPUT type='reset' name='reset' value='Reset'>");
        out.println("</FORM>");
    }
    catch (Exception e)
    {
       System.err.println(e);  
    } 

    if(send!=null && mail!="" && pass!="")
    {
        query="SELECT * FROM dipendenti WHERE email="+ mail + " AND password=" + pass + "";

        Statement statement = connessione.createStatement();
        ResultSet resultSet = statement.executeQuery(query);
        ResultSetMetaData rsmd = resultSet.getMetaData();

        for(int i=0;i<=rsmd.getColumnCount();i++)
        {
            out.println(resultSet.getString(i));
            }
    }

%>

after that, When I click on the send button the page give me this error:

errors image

Somehow the error you have pasted ("... An exception occurred processing JSP page ...") should not be the only error message you get. Try to search the logs for more specific message. — Grzegorz Oledzki, Mar 08 '16 at 22:16

score 0 · Accepted Answer · edited Sep 19 '17 at 07:24

Guessing a bit here...

I guess it might be about how you pass values of the parameters into the query. So if mail is "a@a.com" and password is "a", then your query ends up being:

SELECT * FROM dipendenti WHERE email=a@a.com AND password=a

This is not a proper SQL. You are missing the quotes/apostrophes. I'd try reaching a query like this:

SELECT * FROM dipendenti WHERE email='a@a.com' AND password='a'

which requires a simple change on how you define

query=...

At the same time, I know this is not what you are asking here, but I strongly suggest you should read about SQL Injection on Wikipedia . What you are doing here is not a proper way of accepting user input into your back-end program and eventually into the database.

For this very specific use-case JDBC (and databases) has a notion of Prepared Statements: http://docs.oracle.com/javase/tutorial/jdbc/basics/prepared.html

So you would start with something similar to:

    // not tested
    query="SELECT * FROM dipendenti WHERE email=? AND password=?";
    PreparedStatement statement = connessione.prepareStatement(query);

    statement.setString(1, mail);
    statement.setString(2, pass);

    ResultSet resultSet = statement.executeQuery();

How to use mysql-connector-driver with jsp

1 Answers1