java pretty print xml

Java 6 already has the transformer which can print xml in a pretty way.

public class XmlPrettyPrint {
	public static String getPrettyXml(String xmlStr) throws TransformerException {
		TransformerFactory transformerFactory = TransformerFactory.newInstance();
		transformerFactory.setAttribute("indent-number", 4);
		Transformer transformer = transformerFactory.newTransformer();
		transformer.setOutputProperty(OutputKeys.INDENT, "yes");
		StreamResult result = new StreamResult(new StringWriter());
		StreamSource source = new StreamSource(new StringReader(xmlStr));
		transformer.transform(source, result);
		String xmlString = result.getWriter().toString();
		return xmlString;
	}
	
	public static void main(String[] args) throws TransformerException {
		String xmlStr = "<root><child><sub>ddd</sub></child><child/></root>";
		System.out.println(XmlPrettyPrint.getPrettyXml(xmlStr));
	}
}

The result is

<?xml version="1.0" encoding="UTF-8"?>
<root>
    <child>
        <sub>ddd</sub>
    </child>
    <child/>
</root>