将Encoding =“ http://www.w3.org/2000/09/xmldsig#base64”设置为<ds：object>

Question

我在Java中遇到DSS ESIG标志（https://github.com/esig/dss）的问题。我的代码如下：

        DSSDocument doc = new InMemoryDocument(textToSign.getBytes(StandardCharsets.UTF_8));

        String alias = getNotExpiredAlias();
        PrivateKey privateKey = instance.getPrivateKey(alias);
        DSSPrivateKeyEntry privateKeyEntry = new KSPrivateKeyEntry(new KeyStore.PrivateKeyEntry(privateKey, new Certificate[]{instance.getCertificate(alias)}));

        XAdESSignatureParameters parameters = createSignatureParameters(privateKeyEntry, cryptoCardProvider.is64bit());
        XAdESService service = new XAdESService(new CommonCertificateVerifier());
        ToBeSigned dataToSign = service.getDataToSign(doc, parameters);

        SignatureTokenConnection token = new AbstractSignatureTokenConnection() {

            private ArrayList<DSSPrivateKeyEntry> keys;

            @Override
            public void close() {
                keys = new ArrayList<>();
            }

            @Override
            public List<DSSPrivateKeyEntry> getKeys() throws DSSException {
                keys = new ArrayList<>();
                keys.add(privateKeyEntry);
                return keys;
            }
        };

        DSSDocument dssDocument = service.signDocument(doc, parameters, token.sign(dataToSign, parameters.getDigestAlgorithm(), privateKeyEntry));
        token.close();
        return new String(DSSUtils.toByteArray(dssDocument));

这段代码的结果是：

<ds:Object Id=...>

但我需要：

<ds:Object Encoding="http://www.w3.org/2000/09/xmldsig#base64" Id=...>

如何为设置编码属性？对我而言，验证XML文档非常重要。我看不到要添加Encoding属性的设置方法。