Login system in java

Question

So I made this code but it’s not passing, it goes straight to LSE even with the correct user and password.

I made the changes and I instated the class where the checkLogin method is, but when I run and put the data it gives that the data is incorrect even the data is correct

BTNLOGAR

   package login;

    import cadastro.TelaCadastro;
    import javax.swing.JOptionPane;
    import view.TelaPrincipal;
    import model.dao.UsuarioDAO;

    public class TelaLogin extends javax.swing.JFrame {

        public TelaLogin() {
            initComponents();

        }

        @SuppressWarnings("unchecked")
        // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
        private void initComponents() {

            jPanel1 = new javax.swing.JPanel();
            txt_user = new javax.swing.JLabel();
            txt_senha = new javax.swing.JLabel();
            campo_usuario = new javax.swing.JTextField();
            campo_senha = new javax.swing.JPasswordField();
            btn_logar = new javax.swing.JButton();
            btn_cadastrar = new javax.swing.JButton();

            setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

            jPanel1.setBackground(new java.awt.Color(255, 255, 255));

            txt_user.setText("Usuario:");

            txt_senha.setText("Senha:");

            campo_usuario.addActionListener(new java.awt.event.ActionListener() {
                public void actionPerformed(java.awt.event.ActionEvent evt) {
                    campo_usuarioActionPerformed(evt);
                }
            });

            btn_logar.setText("Entrar");
            btn_logar.addActionListener(new java.awt.event.ActionListener() {
                public void actionPerformed(java.awt.event.ActionEvent evt) {
                    btn_logarActionPerformed(evt);
                }
            });

            btn_cadastrar.setText("Cadastrar");
            btn_cadastrar.addActionListener(new java.awt.event.ActionListener() {
                public void actionPerformed(java.awt.event.ActionEvent evt) {
                    btn_cadastrarActionPerformed(evt);
                }
            });

            javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
            jPanel1.setLayout(jPanel1Layout);
            jPanel1Layout.setHorizontalGroup(
                jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(jPanel1Layout.createSequentialGroup()
                    .addGap(76, 76, 76)
                    .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                        .addGroup(jPanel1Layout.createSequentialGroup()
                            .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                                .addComponent(txt_senha)
                                .addComponent(txt_user))
                            .addGap(43, 43, 43)
                            .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                                .addComponent(campo_senha, javax.swing.GroupLayout.DEFAULT_SIZE, 110, Short.MAX_VALUE)
                                .addComponent(campo_usuario))
                            .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                        .addGroup(jPanel1Layout.createSequentialGroup()
                            .addGap(6, 6, 6)
                            .addComponent(btn_logar)
                            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 89, Short.MAX_VALUE)
                            .addComponent(btn_cadastrar)
                            .addGap(85, 85, 85))))
            );
            jPanel1Layout.setVerticalGroup(
                jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(jPanel1Layout.createSequentialGroup()
                    .addGap(115, 115, 115)
                    .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                        .addComponent(txt_user)
                        .addComponent(campo_usuario, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addGap(41, 41, 41)
                    .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                        .addComponent(txt_senha)
                        .addComponent(campo_senha, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 46, Short.MAX_VALUE)
                    .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                        .addComponent(btn_logar)
                        .addComponent(btn_cadastrar))
                    .addGap(35, 35, 35))
            );

            javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
            getContentPane().setLayout(layout);
            layout.setHorizontalGroup(
                layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            );
            layout.setVerticalGroup(
                layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addComponent(jPanel1, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            );

            pack();
        }// </editor-fold>                        

        private void campo_usuarioActionPerformed(java.awt.event.ActionEvent evt) {                                              
            // TODO add your handling code here:
        }                                             

        private void btn_logarActionPerformed(java.awt.event.ActionEvent evt) {                                          

           //instancie a classe onde está o checkLogin, pois ele pedia para criar um metodo checkLogin e o metodo já existe

            UsuarioDAO dao = new UsuarioDAO();

       String strUsuario = campo_usuario.getText();
       String strSenha = new String(campo_senha.getPassword());

    if(dao.checkLogin(strUsuario, strSenha)){

    TelaPrincipal tela = new TelaPrincipal();
    tela.setVisible(true);
    dispose();


}else{
    JOptionPane.showMessageDialog(null, "Dados incorretos!");
}

        }                                         

        private void btn_cadastrarActionPerformed(java.awt.event.ActionEvent evt) {                                              
           new TelaCadastro().setVisible(true);
            dispose();
        }                                             

        public static void main(String args[]) {

            try {
                for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                    if ("Nimbus".equals(info.getName())) {
                        javax.swing.UIManager.setLookAndFeel(info.getClassName());
                        break;
                    }
                }
            } catch (ClassNotFoundException ex) {
                java.util.logging.Logger.getLogger(TelaLogin.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
            } catch (InstantiationException ex) {
                java.util.logging.Logger.getLogger(TelaLogin.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
            } catch (IllegalAccessException ex) {
                java.util.logging.Logger.getLogger(TelaLogin.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
            } catch (javax.swing.UnsupportedLookAndFeelException ex) {
                java.util.logging.Logger.getLogger(TelaLogin.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
            }
            //</editor-fold>


            java.awt.EventQueue.invokeLater(new Runnable() {
                public void run() {
                    new TelaLogin().setVisible(true);
                }
            });
        }

        // Variables declaration - do not modify                     
        private javax.swing.JButton btn_cadastrar;
        private javax.swing.JButton btn_logar;
        private javax.swing.JPasswordField campo_senha;
        private javax.swing.JTextField campo_usuario;
        private javax.swing.JPanel jPanel1;
        private javax.swing.JLabel txt_senha;
        private javax.swing.JLabel txt_user;

    }

login check

public boolean checkLogin(String email, String senha){

    Connection con = Conexao.getConnection(); 
    PreparedStatement stmt = null;
    ResultSet rs = null;
    boolean check = false;


    try {
        stmt = con.prepareStatement("SELECT * FROM cadastro_user WHERE email = ?, and senha = ?");
        stmt.setString(1, email);
        stmt.setString(2, senha);
        rs = stmt.executeQuery();

        if (rs.next()){

          check = false;

        }

    } catch (SQLException ex) {
        //Logger.getLogger(UserDAO.class.getEmail()).log(Level.SEVERE, null, ex);
    }finally{
        Conexao.closeConnection(con, stmt, rs);
    }        
    return check;

}

Answer 1

There’s a problem with the logic of if, will only fall into it when both fields are blank.

Another problem is with your method checkLogin, he will never return true. Instead of checking if the field came blank still on the screen, leave this responsibility for this method, since its purpose is to check login, which also implies checking if the information is coming blank.

It is unnecessary to check if a field is empty, since you will not store a blank login and password in your database, but if the goal is to avoid allocation of communication resources with the bank, it further reinforces the idea of checking this in the method.

With the suggested changes, the code would now look like this:

String strUsuario = campo_usuario.getText().trim();
String strSenha = new String(campo_senha.getPassword()).trim();

if(checkLogin(strUsuario, strSenha)){

    TelaPrincipal tela = new TelaPrincipal();
    tela.setVisible(true);
    dispose();


}else{
    JOptionPane.showMessageDialog(null, "Dados incorretos!");
}

And the method checklogin:

public boolean checkLogin(String email, String senha){

    Connection con = Conexao.getConnection(); 
    PreparedStatement stmt = null;
    ResultSet rs = null;
    boolean check = false;

    if(!email.isEmpty() && !senha.isEmpty()) {

        try {
            stmt = con.prepareStatement("SELECT * FROM cadastro_user WHERE email = ?, and senha = ?");
            stmt.setString(1, email);
            stmt.setString(2, senha);
            rs = stmt.executeQuery();

            if (rs.next()){

              check = true;

            }

        } catch (SQLException ex) {
        //Logger.getLogger(UserDAO.class.getEmail()).log(Level.SEVERE, null, ex);
        }finally{
        Conexao.closeConnection(con, stmt, rs);
        }

    }

    return check;

}

Answer 2

Is there no such comma after email = ? stmt = con.prepareStatement("SELECT * FROM cadastro_user WHERE email = ? , and password = ?");

Stay like this stmt = con.prepareStatement("SELECT * FROM cadastro_user WHERE email = ? and password = ?");