简单随机验证码的生成

一 代码

/**
*
* @ClassName: TestVerificationCode
*
* @Description: 随机验证码的实现
*
*/
import java.awt.*;
import java.awt.event.*;
import java.util.Random;
import javax.swing.*;
public class TestVerificationCode
{
    public static void main(String[] args)
    {
        JFrame frame = new JFrame("登录测试");
        JButton b1 = new JButton("登陆");
        JButton b2 = new JButton("注册");
        JPanel center = new JPanel();
        center.setLayout(new GridLayout(0, 1, 5, 5));
        JPanel center1 = new JPanel();
        JPanel center2 = new JPanel();
        JPanel center3 = new JPanel();
        JPanel west = new JPanel();
        JTextField t1 = new JTextField(10);
        JPasswordField t2 = new JPasswordField(10);
        JTextField t3 = new JTextField(5);
        center1.setLayout(new GridLayout(1, 0));  // 仅限1行，不限列
        center2.setLayout(new GridLayout(1, 0));
        center3.setLayout(new GridLayout(1, 0, 5, 5));
        center1.add(t1);
        center2.add(t2);
        center3.add(t3);
        ValidCode valid = new ValidCode();
        center3.add(valid);
        center.add(center1);
        center.add(center2);
        center.add(center3);
        west.setLayout(new GridLayout(0, 1));
        west.add(new JLabel("账     号:"));
        west.add(new JLabel("密     码:"));
        west.add(new JLabel("验证码:"));
        JPanel south = new JPanel();
        b1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e)
            {
                if (t3.getText().equals(valid.getCode()))
                    JOptionPane.showMessageDialog(null, "验证成功");
                else {
                    JOptionPane.showMessageDialog(null, "验证失败");
                    valid.nextCode();
                }
            }
        });
        south.add(b1);
        south.add(b2);
        frame.setSize(275, 240);
        frame.add(west, BorderLayout.WEST);
        JLabel mes = new JLabel("   欢迎登陆邮箱");
        mes.setFont(new Font("黑体", Font.BOLD, 25));
        frame.add(mes, BorderLayout.NORTH);
        frame.add(center, BorderLayout.CENTER);
        frame.add(south, BorderLayout.SOUTH);
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
}
class ValidCode extends JPanel
{
    String code;
    private Random random = new Random();

    public ValidCode()
    {
        setSize(100, 40);
        this.addMouseListener(new MouseAdapter() {
            public void mouseClicked(MouseEvent e)
            {
                setSize(100, 40);
                nextCode();
            }
        });
    }
    public String getCode()
    {
        return code;
    }
    void generateCode()
    {
        char[] codes = new char[5];
        for (int i = 0; i < 5; i++)
        {
            if (random.nextBoolean()){
                codes[i] = (char) (random.nextInt(26) + 65);
            } else {
                codes[i] = (char) (random.nextInt(26) + 97);
            }
        }
        this.code = new String(codes);
    }
    public void paint(Graphics g)
    {
        if (this.code == null)
        {
            generateCode();
        }
        Font myFont = new Font("Arial", Font.BOLD | Font.ITALIC, 25);
        g.setFont(myFont);
        g.setColor(Color.WHITE);
        g.fillRect(0, 0, 100, 40);
        g.setColor(Color.BLACK);
        g.drawRect(0, 0, 99, 39);
        g.setColor(Color.LIGHT_GRAY);
        for (int i = 0; i < 100; i++)
        {
            int x = random.nextInt(100 - 1);
            int y = random.nextInt(40 - 1);
            int x1 = random.nextInt(100 - 10) + 10;
            int y1 = random.nextInt(40 - 4) + 4;
            g.drawLine(x, y, x1, y1);
        }
        g.setColor(Color.RED);
        for (int i = 0; i < 5; i++)
        {
            g.drawString(code.charAt(i) + "", 16 * i + 10, 25);
        }
    }
    public void nextCode()
    {
        generateCode();
        repaint();
    }
}

二 运行