Get a node's inner XML as String in Java DOM

Question

I have an XML org.w3c.dom.Node that looks like this:

<variable name="variableName">
    <br /><strong>foo</strong> bar
</variable>

How do I get the <br /><strong>foo</strong> bar part as a String?

Answer 1

Same problem. To solve it I wrote this helper function:

public String innerXml(Node node) {
    DOMImplementationLS lsImpl = (DOMImplementationLS)node.getOwnerDocument().getImplementation().getFeature("LS", "3.0");
    LSSerializer lsSerializer = lsImpl.createLSSerializer();
    NodeList childNodes = node.getChildNodes();
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < childNodes.getLength(); i++) {
       sb.append(lsSerializer.writeToString(childNodes.item(i)));
    }
    return sb.toString(); 
}

Answer 2

There is no simple method on org.w3c.dom.Node for this. getTextContent() gives the text of each child node concatenated together. getNodeValue() will give you the text of the current node if it is an Attribute,CDATA or Text node. So you would need to serialize the node using a combination of getChildNodes(), getNodeName() and getNodeValue() to build the string.

You can also do it with one of the various XML serialization libraries that exist. There is XStream or even JAXB. This is discussed here: XML serialization in Java?

Answer 3

If you dont want to resort to external libraries, the following solution might come in handy. If you have a node <parent><child name="Nina"/></parent> and you want to extract the children of the parent element proceed as follows:

    StringBuilder resultBuilder = new StringBuilder();
    // Get all children of the given parent node
    NodeList children = parent.getChildNodes();
    try {

        // Set up the output transformer
        TransformerFactory transfac = TransformerFactory.newInstance();
        Transformer trans = transfac.newTransformer();
        trans.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
        trans.setOutputProperty(OutputKeys.INDENT, "yes");
        StringWriter stringWriter = new StringWriter();
        StreamResult streamResult = new StreamResult(stringWriter);

        for (int index = 0; index < children.getLength(); index++) {
            Node child = children.item(index);

            // Print the DOM node
            DOMSource source = new DOMSource(child);
            trans.transform(source, streamResult);
            // Append child to end result
            resultBuilder.append(stringWriter.toString());
        }
    } catch (TransformerException e) {
        //Error handling goes here
    }
    return resultBuilder.toString();

Answer 4

If you're using jOOX, you can wrap your node in a jquery-like syntax and just call toString() on it:

$(node).toString();

It uses an identity-transformer internally, like this:

ByteArrayOutputStream out = new ByteArrayOutputStream();
Transformer transformer = TransformerFactory.newInstance().newTransformer();
transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
Source source = new DOMSource(element);
Result target = new StreamResult(out);
transformer.transform(source, target);
return out.toString();

Answer 5

Extending on Andrey M's answer, I had to slightly modify the code to get the complete DOM document. If you just use the

 NodeList childNodes = node.getChildNodes();

It didn't include the root element for me. To include the root element (and get the complete .xml document) I used:

 public String innerXml(Node node) {
     DOMImplementationLS lsImpl = (DOMImplementationLS)node.getOwnerDocument().getImplementation().getFeature("LS", "3.0");
     LSSerializer lsSerializer = lsImpl.createLSSerializer();
     lsSerializer.getDomConfig().setParameter("xml-declaration", false);
     StringBuilder sb = new StringBuilder();
     sb.append(lsSerializer.writeToString(node));
     return sb.toString(); 
 }

Answer 6

I had the problem with the last answer that method 'nodeToStream()' is undefined; therefore, my version here:

    public static String toString(Node node){
    String xmlString = "";
    try {
        Transformer transformer = TransformerFactory.newInstance().newTransformer();
        transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
        //transformer.setOutputProperty(OutputKeys.INDENT, "yes");

        Source source = new DOMSource(node);

        StringWriter sw = new StringWriter();
        StreamResult result = new StreamResult(sw);

        transformer.transform(source, result);
        xmlString = sw.toString ();

    } catch (Exception ex) {
        ex.printStackTrace ();
    }

    return xmlString;
}

Answer 7

I want to extend the very good answer from Andrey M.:

It can happen that a node is not serializeable and this results in the following exception on some implementations:

org.w3c.dom.ls.LSException: unable-to-serialize-node: 
            unable-to-serialize-node: The node could not be serialized.

I had this issue with the implementation "org.apache.xml.serialize.DOMSerializerImpl.writeToString(DOMSerializerImpl)" running on Wildfly 13.

To solve this issue I would suggest to change the code example from Andrey M. a little bit:

private static String innerXml(Node node) {
    DOMImplementationLS lsImpl = (DOMImplementationLS) node.getOwnerDocument().getImplementation().getFeature("LS", "3.0");
    LSSerializer lsSerializer = lsImpl.createLSSerializer();
    lsSerializer.getDomConfig().setParameter("xml-declaration", false); 
    NodeList childNodes = node.getChildNodes();
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < childNodes.getLength(); i++) {
        Node innerNode = childNodes.item(i);
        if (innerNode!=null) {
            if (innerNode.hasChildNodes()) {
                sb.append(lsSerializer.writeToString(innerNode));
            } else {
                sb.append(innerNode.getNodeValue());
            }
        }
    }
    return sb.toString();
}

I also added the comment from Nyerguds. This works for me in wildfly 13.