Đề 5 KMA

import java.awt.*;
import java.awt.event.*;
import java.io.*;

public class De5 extends Frame implements ActionListener {

    private Label lbForm, lbName, lbPass;
    private TextField tfName, tfPass;
    private Button btLogin, btCancel;
    private GridBagLayout gb;
    private GridBagConstraints gbc;

    public De5(String title) {
        super(title);
        this.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent we) {
                System.exit(0);
            }
        });
        lbForm = new Label("Form Test");
        lbName = new Label("Name:");
        lbPass = new Label("Password:");
        tfName = new TextField(20);
        tfPass = new TextField(20);
        tfPass.setEchoChar('*');
        btLogin = new Button("Login");
        btCancel = new Button("Cancel");

        gb = new GridBagLayout();
        this.setLayout(gb);
        Them(lbForm,0,0,3,1);
        Them(lbName,0,1,1,1);
        Them(tfName,1,1,2,1);
        Them(lbPass,0,2,1,1);
        Them(tfPass,1,2,2,1);
        Them(btLogin,1,3,1,1);
        Them(btCancel,2,3,1,1);

        btLogin.addActionListener(this);
        btCancel.addActionListener(this);
    }

    public void Them(Component comp, int x, int y, int rong, int cao) {
        gbc = new GridBagConstraints();
        gbc.gridx = x;
        gbc.gridy = y;
        gbc.gridwidth = rong;
        gbc.gridheight = cao;
        gb.setConstraints(comp, gbc);
        this.add(comp);
    }

    public void actionPerformed(ActionEvent ae) {
        File file = new File("login.txt");
        if (ae.getSource() == btLogin) {
            DocFile(file);
        }
        if (ae.getSource() == btCancel) {
            tfName.setText("");
            tfPass.setText("");
        }
    }

    public void DocFile(File f) {
        try {
            FileReader fr = new FileReader(f);
            BufferedReader br = new BufferedReader(fr);
            StringBuilder sb = new StringBuilder();
            String strUser = br.readLine();
            sb.append("\n");
            String strPass = br.readLine();
            boolean blUser = strUser.equals(tfName.getText());
            boolean blPass = strPass.equals(tfPass.getText());
            if ((blUser == true) && (blPass == true)) {
                System.out.println ("Dang nhap thanh cong");
            } else {
                System.out.println ("Dang nhap that bai");
            }
            br.close();
            fr.close();
        }
        catch (Exception ex) {
            System.out.println ("Loi roi!");
        }
    }

    public static void main(String[] args) {
        De5 fr = new De5("De 5 - Form Test");
        fr.setSize(300,200);
        fr.setVisible(true);
    }
}