Decrypt an hash code in Java using the PHP method

Question

I need to do something like this in Java

function my_simple_crypt( $string) 
{
    global $secret_key, $secret_iv;

    $output = false;
    $encrypt_method = "AES-256-CBC";
    $key = hash( 'sha256', $secret_key );
    $iv = substr( hash( 'sha256', $secret_iv ), 0, 16 );

    $output = openssl_decrypt( base64_decode( $string ), $encrypt_method, $key, 0, $iv );

    return $output;
}

I know the string that is an hash code containing some informations, I know the secret_key and the secret_iv (both are strings).

I tried with many examples here on SO, but no-one is working properly.

I tried to do it from myself. But I need a function that do the openssl_decrypt. This is my code for now:

final String secretKey = "****";
final String secretIv = "****";

final String decryptedString = decrypt(decodedHashCode, secretKey, secretIv);

I'm trying to write the decrypt function.

I wrote this:

private String decrypt(final String hashCode, final String key, final String iv) throws Exception
{
    InputStream cipherInputStream = null;
    try
    {
        final StringBuilder output = new StringBuilder();
        final byte[] secretKey = DigestUtils.sha256Hex(key).getBytes();
        final byte[] initVector = DigestUtils.sha256Hex(iv).substring(0, 16).getBytes();
        final byte[] decodedBytes = Base64.getDecoder().decode(hashCode);
        final String decodedString = new String(decodedBytes);
        final Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
        cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(secretKey, "AES"),
                new IvParameterSpec(initVector, 0, cipher.getBlockSize()));
        cipherInputStream = new CipherInputStream(new FileInputStream(decodedString), cipher);

        final String charsetName = "UTF-8";

        final byte[] buffer = new byte[8192];
        int read = cipherInputStream.read(buffer);

        while (read > -1)
        {
            output.append(new String(buffer, 0, read, charsetName));
            read = cipherInputStream.read(buffer);
        }

        System.out.println(output);
        return output.toString();
    }
    finally
    {
        if (cipherInputStream != null)
        {
            cipherInputStream.close();
        }
    }

}

but I get an error during the cipher initialization. The error is: java.security.InvalidKeyException: Invalid AES key length: 64 bytes

How can I do this in Java?