使用特定的xpointer引用Java

Question

我需要在Java中使用以下引用URI签署XML文档：

  

的XPointer（// * [@的authenticate =＆＃39;真＆＃39;]）

所以我尝试使用此引用进行签名：

    Reference ref = fac.newReference
 ("#xpointer(//*[@authenticate='true'])", fac.newDigestMethod(DigestMethod.SHA256, null),
  Collections.singletonList
   (fac.newTransform
    ("http://www.w3.org/2001/10/xml-exc-c14n#", (TransformParameterSpec) null)),
     null, null);

我收到了这个错误：

  

找不到URI #xpointer的解析器（// * [@ authenticate =＆＃39; true＆＃39;]）和Base null

我在网上搜索我如何修复它并找到了这个类：

    public class XPointerResourceResolver extends ResourceResolverSpi
{
    private static Log log = LogFactory.getLog(XPointerResourceResolver.class);

    private static final String XP_OPEN = "xpointer(";
    private static final String XNS_OPEN = "xmlns(";

    private XPathFactory xPathFactory;
    private Node baseNode;

    public XPointerResourceResolver(Node baseNode)
    {
        this.xPathFactory = XPathFactory.newInstance();
        this.baseNode = baseNode;
    }

    /* (non-Javadoc)
     * @see org.apache.xml.security.utils.resolver.ResourceResolverSpi#engineCanResolve(org.w3c.dom.Attr, java.lang.String)
     */
    @Override
    public boolean engineCanResolve(Attr uri, String BaseURI)
    {
        String v = uri.getNodeValue();

        if (v.charAt(0) != '#')
            return false;

        String xpURI;
        try
        {
            xpURI = URLDecoder.decode(v, "utf-8");
        } catch (UnsupportedEncodingException e)
        {
            log.warn("utf-8 not a valid encoding",e);
            return false;
        }

        String parts[] = xpURI.substring(1).split("\\s");

        // plain ID reference.
        if (parts.length == 1 && !parts[0].startsWith(XNS_OPEN))
            return true;

        int i=0;

        for (;i<parts.length-1;++i)
            if (!parts[i].endsWith(")") ||  !parts[i].startsWith(XNS_OPEN))
                    return false;

        if (!parts[i].endsWith(")") || !parts[i].startsWith(XP_OPEN))
                return false;

        log.debug("xpURI="+xpURI);
        log.debug("BaseURI="+BaseURI);

        return true;
    }

    /* (non-Javadoc)
     * @see org.apache.xml.security.utils.resolver.ResourceResolverSpi#engineResolve(org.w3c.dom.Attr, java.lang.String)
     */
    @Override
    public XMLSignatureInput engineResolve(Attr uri, String BaseURI) throws ResourceResolverException
    {
        String v = uri.getNodeValue();

        if (v.charAt(0) != '#')
            return null;

        String xpURI;
        try
        {
            xpURI = URLDecoder.decode(v, "utf-8");
        } catch (UnsupportedEncodingException e)
        {
            log.warn("utf-8 not a valid encoding",e);
            return null;
        }

        String parts[] = xpURI.substring(1).split("\\s");

        int i=0;

        DSigNamespaceContext nsContext=null;

        if (parts.length > 1)
        {
            nsContext= new DSigNamespaceContext();

            for (;i<parts.length-1;++i)
            {
                if (!parts[i].endsWith(")") ||  !parts[i].startsWith(XNS_OPEN))
                    return null;

                String mapping = parts[i].substring(XNS_OPEN.length(),parts[i].length()-1);

                int pos = mapping.indexOf('=');

                if (pos <= 0 || pos >= mapping.length()-1)
                    throw new ResourceResolverException("malformed namespace part of XPointer expression",uri,BaseURI);

                nsContext.addNamespace(mapping.substring(0,pos), 
                                       mapping.substring(pos+1));
            }
        }

        try
        {
            Node node = null;
            NodeList nodes=null;

            // plain ID reference.
            if (i==0 && !parts[i].startsWith(XP_OPEN))
            {
                node = this.baseNode.getOwnerDocument().getElementById(parts[i]);
            }
            else
            {
                if (!parts[i].endsWith(")") || !parts[i].startsWith(XP_OPEN))
                    return null;

                XPath xp = this.xPathFactory.newXPath();

                if (nsContext != null)
                    xp.setNamespaceContext(nsContext);

                nodes =
                    (NodeList)xp.evaluate(parts[i].substring(XP_OPEN.length(),parts[i].length()-1),
                                          this.baseNode,
                                          XPathConstants.NODESET);

                if (nodes.getLength() == 0) return null;
                if (nodes.getLength() == 1)
                    node = nodes.item(0);
            }

            XMLSignatureInput result = null;

            if (node != null)
            {
                 result = new XMLSignatureInput(node);
            }
            else if (nodes !=null)
            {
                Set<Node> nodeSet = new HashSet<Node>(nodes.getLength());

                for (int j=0 ; j<nodes.getLength(); ++j)
                {
                    nodeSet.add(nodes.item(j));
                }

                result = new XMLSignatureInput(nodeSet);
            }
            else
                return null;

            result.setMIMEType("text/xml");
            result.setExcludeComments(true);
            result.setSourceURI((BaseURI != null) ? BaseURI.concat(v):v);      

            return result;

        } catch (XPathExpressionException e)
        {
            throw new ResourceResolverException("malformed XPath inside XPointer expression",e,uri,BaseURI);
        }
    }

}

但是我还没有找到如何使用它来使用我的xpointer签署我的XML文档。

有人有想法吗？

谢谢！