abc.java

/*** Koneksi.java ***/
private static Connection koneksi;
public static Connection koneksiDatabase(){
    if(koneksi==null){
        MysqlDataSource dataSource = new MysqlDataSource();
        dataSource.setURL("jdbc:mysql://localhost:3306/db_helpdesk");
        dataSource.setUser("root");
        dataSource.setPassword("");

        try{
            koneksi = dataSource.getConnection();
        } catch (SQLException ex) {
           JOptionPane.showMessageDialog(null, "Error Koneksi : " + ex.getMessage());
        }
    }
    return koneksi;
}

/*** FormLogin.java ***/
public FormLogin() {
    initComponents();
    setLocationRelativeTo(null);
}

public void validasi(String user, String pass){
    String query = "SELECT * FROM tbl_user WHERE tu_user=? AND tu_pass=?";
    PreparedStatement statement;

    Connection connection;
    try {
        connection = Koneksi.koneksiDatabase();
        statement = connection.prepareStatement(query);
        statement.setString(1, user);
        statement.setString(2, pass);

        ResultSet rs = statement.executeQuery();
        if(rs.next()){
            this.dispose();
            new FormMenuUtama().setVisible(true);
        } else {
            JOptionPane.showMessageDialog(this, "Username dan password salah");
        }
    } catch (SQLException err){
        JOptionPane.showMessageDialog(this, "Terjadi Kesalahan " + err.getMessage());
    }
}

private void bSubmitActionPerformed(java.awt.event.ActionEvent evt) {
    String user = tfUsername.getText();
    String pass = String.valueOf(tfPassword.getPassword());
    if(user.trim().equals("")){
        JOptionPane.showMessageDialog(this, "Username tidak boleh kosong");
    } else if(pass.trim().equals("")) {
        JOptionPane.showMessageDialog(this, "Paasword tidak boleh kosong");
    } else {
        validasi(user, pass);
    }
}