XML转换器-设置OutputKeys。具有复杂外部实体声明的DOCTYPE_SYSTEM:无法删除最后的双引号

在我的变压器中,我有这样的配置:

trans.setOutputProperty(OutputKeys.DOCTYPE_SYSTEM, "MLP_SVC_RESULT_320.DTD [<!ENTITY % extension SYSTEM \"company_mlp320_slia_extension.dtd\"> %extension;]");

这给了我一个错误:

[Fatal Error] :1:121: The document type declaration for root element type "svc_result" must end with '>'.
org.xml.sax.SAXParseException; lineNumber: 1; columnNumber: xxx; The document type declaration for root element type "svc_result" must end with '>'.

因为它增加了一个额外的 " 在我的DOCTYPE行的末尾:

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE svc_result SYSTEM "MLP_SVC_RESULT_320.DTD [<!ENTITY % extension SYSTEM "company_mlp320_slia_extension.dtd"> %extension;]">

注意最后一个 " ,它不可能存在;正确的XML不包含它。

但我不知道如何在正确的配置下删除它。

一个正确的XML示例:

<?xml version="1.0" ?>
<!DOCTYPE svc_result SYSTEM "MLP_SVC_RESULT_320.DTD" [<!ENTITY % extension SYSTEM "company_mlp320_slia_extension.dtd"> %extension;]>
<svc_result ver="3.2.0">
    <slia ver="3.0.0">
        <pos>
            <msid type="MSISDN" enc="ASC">200853000105614</msid>
            <gsm_net_param>
                <cgi>
                    <mcc>100</mcc>
                    <mnc>01</mnc>
                    <lac>2222</lac>
                    <cellid>10002</cellid>
                </cgi>
                <neid>
                    <vmscid>
                        <vmscno>00004946000</vmscno>
                    </vmscid>
                    <vlrid>
                        <vlrno>99994946000</vlrno>
                    </vlrid>
                </neid>
            </gsm_net_param>
        </pos>
        <company_mlp320_slia>
            <company_netinfo>
                <company_ms_netinfo type="CGI">
                    <msid type="MSISDN" enc="ASC">200853000105614</msid>
                    <time utc_off="+0200">20210521170211</time>
                </company_ms_netinfo>
            </company_netinfo>
        </company_mlp320_slia>
    </slia>
</svc_result>

完整代码:

    private String transformToString(Document document) {
        if (document == null) {
            return null;
        }
        document.setXmlStandalone(true); // make document to be standalone, so we can avoid outputing standalone="no" in first line
        TransformerFactory tf = TransformerFactory.newInstance();
        Transformer trans;
        try {
            trans = tf.newTransformer();
            trans.setOutputProperty(OutputKeys.INDENT, "no"); // no extra indent; file already has intent of 4
            trans.setOutputProperty(OutputKeys.DOCTYPE_SYSTEM, "MLP_SVC_RESULT_320.DTD [<!ENTITY % extension SYSTEM \"company_mlp320_slia_extension.dtd\"> %extension;]");
            StringWriter sw = new StringWriter();
            trans.transform(new DOMSource(document), new StreamResult(sw));
            // Spaces between tags are considered as text node, so when outputing we need to remove the extra empty lines
            return sw.toString().replaceAll("\\n\\s*\\n", "\n");
        } catch (TransformerException e) {
            LOG.error("Cannot transform response document to String. ", e);
            return null;
        }
    }