Question

I need to use java xpath to return by id an xml element as a string.

given…

<svg>
    <g id="Background">
    </g>
    <g id="Outline">
        <polygon fill="none" stroke="#000000" stroke-linecap="round" stroke-linejoin="round"     stroke-miterlimit="10" points=" 119.813,57.875 119.188,57.87" />
    </g>
    <g id="Base_Colour" transform="matrix(0.25 0 0 0.25 0 0)">
        <path fill="#ADB1AF" d="M112.25,208l-8,20.25l-0.5-1.75l0.75-0.5v-1.5l0.75-0.5v-1.5L106,222v-1.5l0.75-0.5v-1.5l0.75-0.5v-1.5"/>
        <path fill="#625595" d="M112.25,208l5.25-14.5l30-30.25l2.25-1.5l41.5-20.5l49.75-9.5h4.25l49,3l48.75"/>
    </g>
</svg>

the value returned needs to be…

<g id="Outline">
    <polygon fill="none" stroke="#000000" stroke-linecap="round" stroke-linejoin="round"     stroke-miterlimit="10" points=" 119.813,57.875 119.188,57.87" />
</g> 

I have googled extensively and nothing I have tried has been able to return the whole element. Xpath is desired because I want to query g tags at any level by id.

Answer 1

The solution I found was to get the org.w3c.dom.Node with xpath (DOM would work too). Then I created a javax.xml.transform.dom.DOMSource from the node and transformed that to a string with javax.xml.transform.TransformerFactory.

Node node = // the node you want to serialize
xmlOutput = new StreamResult(new StringWriter());
transformer = TransformerFactory.newInstance().newTransformer();
transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
transformer.transform(new DOMSource(node), xmlOutput);
String nodeAsAString = xmlOutput.getWriter().toString();

This is easily factored into a class for reuse. Unfortunately, the is no .OuterXml property in Java as there is in .NET. All you .NETer’s can smirk now.