Login App Java

LoginLogic.java

package sk.loginapp;

import java.sql.ResultSet;
import java.sql.SQLException;

public class LoginLogic {

    LoginUI lu;

    public LoginLogic() {
        lu = new LoginUI();

    }

    public LoginLogic(ResultSet rs) {
        process(rs);
    }

    private void process(ResultSet rs) {
        try {
            if (rs.next()) {
                lu.loginSuccess();

            } else {
                lu.loginFailed();
            }
        } catch (SQLException e) {
            // TODO: handle exception
        }
    }

    public static void main(String[] args) {

        new LoginLogic();

    }

}

LoginUI.java

package sk.loginapp;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class LoginUI {

    // Container declarations
    JFrame frame;
    JPanel panel;

    // Component declarations
    JLabel lblUname, lblPwd;
    JTextField tfUname, tfPwd;
    JButton btnLogin, btnCancel;

    public LoginUI() {
        this.createFrame();
    }

    private void createFrame() {

        // set native OS UI
        try {
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        } catch (ClassNotFoundException | UnsupportedLookAndFeelException | IllegalAccessException
                | InstantiationException e) {

        }

        frame = new JFrame("Login App");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        panel = new JPanel();
        frame.add(panel);
        this.placePanelComponents(panel);

        frame.setSize(300, 160);
        frame.setResizable(false);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);

    }

    private void placePanelComponents(JPanel panel) {

        panel.setLayout(null);

        lblUname = new JLabel("Username: ");
        lblUname.setBounds(50, 20, 120, 20);
        lblPwd = new JLabel("Password: ");
        lblPwd.setBounds(50, 50, 120, 20);

        tfUname = new JTextField(10);
        tfUname.setBounds(120, 20, 120, 20);
        tfPwd = new JTextField(10);
        tfPwd.setBounds(120, 50, 120, 20);

        btnLogin = new JButton("Login");
        btnLogin.setBounds(50, 85, 90, 25);
        btnCancel = new JButton("Cancel");
        btnCancel.setBounds(150, 85, 90, 25);

        panel.add(lblUname);
        panel.add(lblPwd);
        panel.add(tfUname);
        panel.add(tfPwd);
        panel.add(btnLogin);
        panel.add(btnCancel);

        btnLogin.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {

                try {
                    String uname = tfUname.getText().trim();
                    String pwd = tfPwd.getText().trim();
                    new LoginDbConn(uname, pwd);//startDB after user presses the login button
                } catch (Exception ex) {
                    // TODO: handle exception
                }

            }
        });

        btnCancel.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                try {
                    System.exit(0);
                } catch (Exception ex) {
                    // TODO: handle exception
                }

            }
        });

    }

    void loginSuccess() {
        JOptionPane.showMessageDialog(null, "Login Successful!");
    }

    void loginFailed() {
        JOptionPane.showMessageDialog(null, "Login Failed!");
    }

}


LoginDBConn.java

package sk.loginapp;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
//import java.sql.Statement;

public class LoginDbConn {

    /*public LoginDbConn() {
        // TODO Auto-generated constructor stub
    }*/

    public LoginDbConn(String uname, String pwd) {
        this.getConn(uname, pwd);
    }

    private void getConn(String uname, String pwd) {
        try {
            // 0. Register the JDBC drivers
            String driverClass = "oracle.jdbc.driver.OracleDriver";
            Class.forName(driverClass);
            // or DriverManager.registerDriver(new oracle.jdbc.OracleDriver());

            // 1. Get a connection to the Database
            String dbUrl = "jdbc:oracle:thin:@localhost:1521:xe";
            String dbuname = "scott";
            String dbpwd = "tiger";
            Connection conn = DriverManager.getConnection(dbUrl, dbuname, dbpwd);

            // 2. Create a statement
            // String sql = "SELECT * FROM users WHERE name = '"+uname+"' and
            // password = '"+pwd+"'";
            // Statement st = conn.createStatement();
            String sql = "select * from users where name = ? and password = ?";
            PreparedStatement pst = conn.prepareStatement(sql);

            pst.setString(1, uname);
            pst.setString(2, pwd);

            // 3. Execute SQL query
            ResultSet rs = pst.executeQuery();

            // 4. Process the result set
            new LoginLogic(rs);

            // 5. Close Connection
            conn.close();
        } catch (SQLException | ClassNotFoundException e) {

        }

    }

}