Java HTML/XML - 如何设置输出方法和缩进

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;

public class Main {
  public static void main(String[] args) throws Exception {
    DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
    DocumentBuilder parser = factory.newDocumentBuilder();

    Document doc;
    doc = parser.parse(args[0]);

    TransformerFactory transFactory = TransformerFactory.newInstance();
    System.out.println(transFactory.getClass().getName());
    transFactory.setAttribute("indent-number", 2);
    Transformer idTransform = transFactory.newTransformer();
    idTransform.setOutputProperty(OutputKeys.METHOD, "xml");
    idTransform.setOutputProperty(OutputKeys.INDENT, "yes");
    Source input = new DOMSource(doc);
    Result output = new StreamResult(System.out);
    idTransform.transform(input, output);
  }
}