public class AesUtil {
    public static final String UTF_8 = "UTF-8";
    /**
     * 必須16位
     */
    private static final String S_KEY ="0123456789ABCDEF";

    /**
     * 必須16位
     */
    private static final String IV_PARAMETER = "0123456789ABCDEF";
    /**
     * 演算法名稱
     */
    private static final String KEY_ALGORITHM_AES = "AES";
    /**
     * 演算法/模式/填充
     **/
    private static final String CIPHER_MODE = "AES/CBC/PKCS5Padding";

    /**
     * 加密(結果為16進位制字串)
     **/
    public static String encrypt(String content) throws UnsupportedEncodingException,
            NoSuchPaddingException,
            NoSuchAlgorithmException,
            InvalidAlgorithmParameterException,
            InvalidKeyException,
            BadPaddingException,
            IllegalBlockSizeException {
        if (content == null) {
            return null;
        }
        SecretKeySpec secretKey = new SecretKeySpec(S_KEY.getBytes(UTF_8), KEY_ALGORITHM_AES);
        IvParameterSpec ivParameterSpec = getIv();
        Cipher cipher = Cipher.getInstance(CIPHER_MODE);
        cipher.init(Cipher.ENCRYPT_MODE, secretKey, ivParameterSpec);
        byte[] data = cipher.doFinal(content.getBytes(UTF_8));
        String result = byte2hex(data);
        return result;
    }

    /**
     * 解密(輸出結果為字串)
     **/
    public static String decrypt(String content) throws UnsupportedEncodingException,
            NoSuchPaddingException,
            NoSuchAlgorithmException,
            InvalidAlgorithmParameterException,
            InvalidKeyException,
            BadPaddingException,
            IllegalBlockSizeException {
        if (content == null) {
            return null;
        }
        SecretKeySpec secretKey = new SecretKeySpec(S_KEY.getBytes(UTF_8), KEY_ALGORITHM_AES);
        IvParameterSpec ivParameterSpec = getIv();
        Cipher cipher = Cipher.getInstance(CIPHER_MODE);
        cipher.init(Cipher.DECRYPT_MODE, secretKey, ivParameterSpec);

        byte[] hexBytes = hex2byte(content);
        byte[] data = cipher.doFinal(hexBytes);
        return new String(data, UTF_8);
    }

    /**
     * 位元組陣列轉成16進位制字串
     **/
    public static String byte2hex(byte[] b) { // 一個位元組的數，
        StringBuffer sb = new StringBuffer(b.length * 2);
        String tmp = "";
        for (int n = 0; n < b.length; n++) {
            // 整數轉成十六進位制表示
            tmp = (Integer.toHexString(b[n] & 0XFF));
            if (tmp.length() == 1) {
                sb.append("0");
            }
            sb.append(tmp);
        }
        return sb.toString().toUpperCase(); // 轉成大寫
    }

    /**
     * 將hex字串轉換成位元組陣列
     **/
    private static byte[] hex2byte(String inputString) {
        if (inputString == null || inputString.length() < 2) {
            return new byte[0];
        }
        inputString = inputString.toLowerCase();
        int l = inputString.length() / 2;
        byte[] result = new byte[l];
        for (int i = 0; i < l; ++i) {
            String tmp = inputString.substring(2 * i, 2 * i + 2);
            result[i] = (byte) (Integer.parseInt(tmp, 16) & 0xFF);
        }
        return result;
    }

    public static IvParameterSpec getIv() throws UnsupportedEncodingException {
        IvParameterSpec ivParameterSpec = new IvParameterSpec(IV_PARAMETER.getBytes("utf-8"));
//    System.out.println("偏移量："+byte2hex(ivParameterSpec.getIV()));
        return ivParameterSpec;
    }

}