如何在Java中编写AES-40加密程序？

import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;

public class AESExample {
    public static void main(String[] args) throws Exception {
        // 创建KeyGenerator对象
        KeyGenerator keyGen = KeyGenerator.getInstance("AES");
        // 设置密钥长度为40位
        keyGen.init(40);
        // 生成AES密钥
        SecretKey secretKey = keyGen.generateKey();
        // 将密钥转换为字节数组
        byte[] keyBytes = secretKey.getEncoded();
        // 打印密钥
        System.out.println("AES密钥：" + bytesToHex(keyBytes));
    }

    // 将字节数组转换为十六进制字符串
    private static String bytesToHex(byte[] bytes) {
        StringBuilder sb = new StringBuilder();
        for (byte b : bytes) {
            sb.append(String.format("%02X", b));
        }
        return sb.toString();
    }
}

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

public class AESExample {
    public static void main(String[] args) throws Exception {
        // AES密钥（示例）
        byte[] keyBytes = hexToBytes("0123456789ABCDEF0123456789ABCDEF01234567");
        // 待加密的数据
        byte[] data = "Hello, AES!".getBytes("UTF-8");

        // 创建AES密钥对象
        SecretKey secretKey = new SecretKeySpec(keyBytes, "AES");
        // 创建Cipher对象
        Cipher cipher = Cipher.getInstance("AES");
        // 初始化Cipher对象为加密模式
        cipher.init(Cipher.ENCRYPT_MODE, secretKey);
        // 执行加密操作
        byte[] encryptedData = cipher.doFinal(data);
        // 打印加密后的数据
        System.out.println("加密后的数据：" + bytesToHex(encryptedData));
    }

    // 将十六进制字符串转换为字节数组
    private static byte[] hexToBytes(String hexString) {
        int len = hexString.length();
        byte[] bytes = new byte[len / 2];
        for (int i = 0; i < len; i += 2) {
            bytes[i / 2] = (byte) ((Character.digit(hexString.charAt(i), 16) << 4)
                    + Character.digit(hexString.charAt(i + 1), 16));
        }
        return bytes;
    }

    // 将字节数组转换为十六进制字符串
    private static String bytesToHex(byte[] bytes) {
        StringBuilder sb = new StringBuilder();
        for (byte b : bytes) {
            sb.append(String.format("%02X", b));
        }
        return sb.toString();
    }
}