<dependency>
	<groupId>org.bouncycastle</groupId>
	<artifactId>bcprov-jdk15on</artifactId>
    <version>1.64</version>
</dependency>


public class EncryptUtils {

    private static final String SECRET = "AES";
    private static final String CIPHER_ALGORITHM = "AES/ECB/PKCS7Padding";

    static {
        Security.addProvider(new BouncyCastleProvider());
    }

    /**
     * AES加密ECB模式PKCS7Padding填充方式
     * @param str 字符串
     * @param key 密钥
     * @return 加密字符串
     * @throws Exception 异常信息
     */
    public static String aes256ECBPkcs7PaddingEncrypt(String str, String key) throws Exception {
        Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
        byte[] keyBytes = key.getBytes(StandardCharsets.UTF_8);
        cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(keyBytes, SECRET));
        byte[] doFinal = cipher.doFinal(str.getBytes(StandardCharsets.UTF_8));
        return new String(Base64.getEncoder().encode(doFinal));
    }

    /**
     * AES解密ECB模式PKCS7Padding填充方式
     * @param str 字符串
     * @param key 密钥
     * @return 解密字符串
     * @throws Exception 异常信息
     */
    public static String aes256ECBPkcs7PaddingDecrypt(String str, String key) throws Exception {
        Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
        byte[] keyBytes = key.getBytes(StandardCharsets.UTF_8);
        cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(keyBytes, SECRET));
        byte[] doFinal = cipher.doFinal(Base64.getDecoder().decode(str));
        return new String(doFinal);
    }
}

    public static void main(String[] args) throws Exception {
        String str = "a1234567";
        System.out.println("字符串：" + str);
        String encryptStr = EncryptUtils.aes256ECBPkcs7PaddingEncrypt(str, "AES454-HTJSQ9-IT");
        System.out.println("加密后字符串：" + encryptStr);
        String decryptStr = EncryptUtils.aes256ECBPkcs7PaddingDecrypt(encryptStr, "AES454-HTJSQ9-IT");
        System.out.println("解密后字符串：" + decryptStr);
    }