What is the shortest way to pretty print a org.w3c.dom.Document to stdout?

Question

What is the easiest way to pretty print (a.k.a. formatted) a org.w3c.dom.Document to stdout?

Quota

Answer 1

Call printDocument(doc, System.out), where that method looks like this:

public static void printDocument(Document doc, OutputStream out) throws IOException, TransformerException {
    TransformerFactory tf = TransformerFactory.newInstance();
    Transformer transformer = tf.newTransformer();
    transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "no");
    transformer.setOutputProperty(OutputKeys.METHOD, "xml");
    transformer.setOutputProperty(OutputKeys.INDENT, "yes");
    transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
    transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "4");

    transformer.transform(new DOMSource(doc), 
         new StreamResult(new OutputStreamWriter(out, "UTF-8")));
}

(The indent-amount is optional, and might not work with your particular configuration)

Mishap

Isn't it ironic that that's the "easiest" way to simply print an XML document in Java? – Sabo

on the other hand you have plenty of control ;) – Mishap

Brilliant! And yes, it is a bit much text but it is crystal clear what the selected options are and Eclipse/Netbeans really help you write this. Show me a smaller version and I tell you what it cannot do. Worse, I will tell you where you need 3 debugging rounds to get it right ... – Bangka

I swear to god Java.. make me write ridiculous number of lines of code for something that can be done in one or two in other languages... with full control too.. – Impressionist

But if your XML contains astral characters, and you are using Xalan, note issues.apache.org/jira/browse/XALANJ-2419 and see also https://mcmap.net/q/196405/-serializing-supplementary-unicode-characters-into-xml-documents-with-java – Feckless

If you are seeing unexpected newlines in the output, take a look at https://mcmap.net/q/75268/-pretty-print-xml-in-java-8 – Misgovern

Answer 2

How about:

OutputFormat format = new OutputFormat(doc);
format.setIndenting(true);
XMLSerializer serializer = new XMLSerializer(System.out, format);
serializer.serialize(doc);

Gloomy

While easier, this approach requires Xerces – Concertino

I can add that today XMLSerializer and OutputFormat are deprecated – Cota

Answer 3

Try jcabi-xml with one liner:

String xml = new XMLDocument(document).toString();

This is the dependency you need:

<dependency>
  <groupId>com.jcabi</groupId>
  <artifactId>jcabi-xml</artifactId>
  <version>0.14</version>
</dependency>

Ciliary

Answer 4

private void printNode(Node rootNode, String spacer) {
    System.out.println(spacer + rootNode.getNodeName() + " -> " + rootNode.getNodeValue());
    NodeList nl = rootNode.getChildNodes();
    for (int i = 0; i < nl.getLength(); i++)
        printNode(nl.item(i), spacer + "   ");
}

Hessian

I appreciate that the Q asks for the shortest, but (for the benefit of anyone else) perhaps you could elaborate your answer to explain what's going on? – Heigho

html -> head -> meta -> title -> body -> If I place a space of string as the spacer above is the result is what I get. Is it what its intended to do? A full print of the XML is what is needed I think when it meants pretty printed. – Greenbelt

Answer 5

This will return a nicely formated output by using recursive descent/ascent.

private static boolean skipNL;
private static String printXML(Node rootNode) {
    String tab = "";
    skipNL = false;
    return(printXML(rootNode, tab));
}
private static String printXML(Node rootNode, String tab) {
    String print = "";
    if(rootNode.getNodeType()==Node.ELEMENT_NODE) {
        print += "\n"+tab+"<"+rootNode.getNodeName()+">";
    }
    NodeList nl = rootNode.getChildNodes();
    if(nl.getLength()>0) {
        for (int i = 0; i < nl.getLength(); i++) {
            print += printXML(nl.item(i), tab+"  ");    // \t
        }
    } else {
        if(rootNode.getNodeValue()!=null) {
            print = rootNode.getNodeValue();
        }
        skipNL = true;
    }
    if(rootNode.getNodeType()==Node.ELEMENT_NODE) {
        if(!skipNL) {
            print += "\n"+tab;
        }
        skipNL = false;
        print += "</"+rootNode.getNodeName()+">";
    }
    return(print);
}

Odle

This is very incomplete. – Heigho

Answer 6

if you use dom4j, it would be dom4JDOM.asString()

Azide