用java写一则代码要求有可视化界面随机生成验证码要求用户输入并能够判断输入是否正确

在Java中，我们可以利用Swing或JavaFX库来创建GUI界面，然后结合Math.random()函数生成随机验证码。这里是一个简单的例子，使用Swing：

import javax.swing.*;
import java.awt.*;
import java.util.Random;

public class CaptchaApp extends JFrame {

    private static final String CHARACTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; // 验证码字符集
    private int captchaLength = 4; // 验证码长度
    private String generatedCode; // 随机生成的验证码

    public CaptchaApp() {
        setTitle("验证码验证");
        setSize(300, 100);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        // 生成随机验证码
        generateRandomCode();

        // 创建文本框展示验证码
        JTextField textField = new JTextField(generatedCode, captchaLength);
        textField.setEditable(false); // 用户只读
        add(textField, BorderLayout.NORTH);

        // 添加提交按钮
        JButton submitButton = new JButton("验证");
        submitButton.addActionListener(e -> {
            String input = textField.getText();
            if (input.equals(generatedCode)) {
                JOptionPane.showMessageDialog(this, "输入正确", "验证结果", JOptionPane.INFORMATION_MESSAGE);
            } else {
                JOptionPane.showMessageDialog(this, "输入错误，请重试", "验证结果", JOptionPane.ERROR_MESSAGE);
            }
        });
        add(submitButton, BorderLayout.CENTER);

        setVisible(true);
    }

    private void generateRandomCode() {
        Random random = new Random();
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < captchaLength; i++) {
            int index = random.nextInt(CHARACTERS.length());
            char ch = CHARACTERS.charAt(index);
            sb.append(ch);
        }
        generatedCode = sb.toString();
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(CaptchaApp::new);
    }
}