Problem with Using JDBC in Applet

Question

Hi,
i have written an applet to log in (it checks the database, if the username and pasword exists it shows corresponding message). i use access or sql server and applet is started but no message is shown(i think it does not connect to database). here is my code:
import javax.swing.*;
import java.sql.*;
import java.awt.event.*;
import java.awt.*;
public class appletDatabase extends JApplet implements ActionListener {
JLabel l1;
JLabel l2;
JLabel l3;
JTextField tf1;
JPasswordField tf2;
JButton btn;
Connection cn;
Statement st;
String hostname;
public void init() {
hostname = "localhost";
l1 = new JLabel("User Name: ");
l2 = new JLabel(" Password: ");
l3 = new JLabel(" ");
tf1 = new JTextField(20);
tf2 = new JPasswordField(20);
btn = new JButton("Sign in");
Container c = getContentPane();
c.setLayout(new FlowLayout(FlowLayout.LEFT));
c.add(l1);
c.add(tf1);
c.add(l2);
c.add(tf2);
c.add(btn);
c.add(l3);
btn.addActionListener(this);
setSize(300,300);
setVisible(true);
public void actionPerformed(ActionEvent e) {
if (e.getSource()==btn) {
boolean b = check(tf1.getText(),new String(tf2.getPassword()));
if (b) {
l3.setForeground(Color.green);
l3.setText("Username and password exists. ");
else {
l3.setForeground(Color.red);
l3.setText("Username and/or password does not exist.");
public boolean check(String un, String pass) {
String query="SELECT * FROM Table1 WHERE username LIKE'"+un+"'" +
" AND password LIKE'"+pass+"'";
boolean b = false;
try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
cn = DriverManager.getConnection("jdbc:odbc:login");
st = cn.createStatement();
ResultSet rs = st.executeQuery(query);
if (!(rs==null))
if (rs.next())
b = true;
rs.close();
st.close();
cn.close();
} catch (SQLException e1) {
e1.printStackTrace();
} catch (ClassNotFoundException e1) {
e1.printStackTrace();
return b;
}

Answer 1

The first thing i notice is that there's a problem with your SQL statement.
To start with you should probably be using PreparedStatements cause it deals with the passing of variables very well and cleanly.
But if you must use a straight statement then it should be like this:
String query = "SELECT * FROM Table1 WHERE username LIKE '"+un+"'" + " AND password LIKE '"+pass+"'";
The fact that you were mising a few spaces wouldn't have helped. Although if you were to use a prepared statement, it would be a lot easier to understand where things were being passed and you don't need to worry about those single quotes for certain values.
Wes