How to create a Document from a Node?

Question

Howdy,
I'm cross posting this from http://forum.java.sun.com/thread.jspa?threadID=737347&tstart=0 because I didn't get a nibble after half an hour or so...
I expected this code to produce:
<?xml version="1.0" encoding="UTF-16"?>
<one>hello world</one>but instead I get Object's toString:
org.apache.crimson.tree.XmlDocument@18a992fPlease does anyone know which implementation of Document overrides the toString() method to produce xml?
... I'm stuck on java 1.4.2_11 ...
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import java.io.ByteArrayInputStream;
class NodeToDocumentConverter
  public static void main(String[] args) {     
    try {
      DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
      DocumentBuilder db = dbf.newDocumentBuilder();
      ByteArrayInputStream bais = new ByteArrayInputStream("<test><one>hello world</one></test>".getBytes());
      Document doc1 = db.parse(bais);
      Node node = doc1.getElementsByTagName("one").item(0);
      Document doc2 = db.newDocument();
      doc2.appendChild(doc2.importNode(node, true));
      System.out.println(doc2.toString());
    } catch (Exception e) {
      e.printStackTrace();
}Thanking you, Keith.

Answer 1

Here's the final version... the fun part was using reflections to print the stack-trace of the root cause exception (if any).
forums/DomSerializer3.java
// http://java.sun.com/j2ee/1.4/docs/tutorial/doc/JAXPXSLT4.html
package forums;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import org.xml.sax.SAXException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import java.io.ByteArrayInputStream;
import java.lang.reflect.Method;
import krc.utilz.ExceptionHandler;
class DOMSerializerException extends java.lang.RuntimeException {
  private static final long serialVersionUID = 546980432534L;
  DOMSerializerException() {
    super();
  DOMSerializerException(String message) {
    super(message);
  DOMSerializerException(String message, Throwable cause) {
    super(message, cause);
  DOMSerializerException(Throwable cause) {
    super(cause);
class DOMSerializer
  // get a transformer from the factory
  private final TransformerFactory transformerFactory;
  private final Transformer transformer;
  public DOMSerializer() {
    try {
      transformerFactory = TransformerFactory.newInstance();
      transformer = transformerFactory.newTransformer();
    } catch (TransformerConfigurationException e) { //from newInstance
      e.printStackTrace();
      throw new DOMSerializerException("TransformerFactory.newInstance failed: "+e, e);
  public void serialize(org.w3c.dom.Document document, java.io.OutputStream outputStream) {
    try {
      DOMSource source = new DOMSource(document);
      StreamResult result = new StreamResult(outputStream);
      transformer.transform(source, result);
    } catch (TransformerException e) { //from newInstance
      e.printStackTrace();
      throw new DOMSerializerException("Transformer.transform failed: "+e, e);
public class DomSerializer3
  public static void main(String[] args){
    try {
      DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
      DocumentBuilder builder = factory.newDocumentBuilder();
      ByteArrayInputStream input = new ByteArrayInputStream("<test><one>hello world</one></test>".getBytes());
      Document originalDocument = builder.parse(input);
      Node node = originalDocument.getElementsByTagName("one").item(0);
      Document newDocument = builder.newDocument();
      newDocument.appendChild(newDocument.importNode(node, true));
      DOMSerializer serializer = new DOMSerializer();
      serializer.serialize(newDocument, System.out);
    } catch (DOMSerializerException e) {
      System.err.println(e.toString());
      ExceptionHandler.printLowestStackTrace(e);
    } catch (Exception e) {
      e.printStackTrace();
krc/utilz/ExceptionHandler.java
// http://java.sun.com/j2ee/1.4/docs/tutorial/doc/JAXPXSLT4.html
package krc.utilz;
import java.lang.reflect.Method;
public abstract class ExceptionHandler
  public static void print(org.xml.sax.SAXParseException e) {
    System.err.println(
      "org.xml.sax.SAXParseException: "+e.getMessage()
      + ", line "+e.getLineNumber()
      + ", uri "+e.getSystemId()
    printLowestStackTrace(e);
  public static void print(java.lang.Exception e) {
    System.err.println(e.toString());
    printLowestStackTrace(e);
   * Prints the stackTrace of the lowest level exception.
   * </p>
   * if possible invokes e.getException().printStackTrace()
   * else if possible invokes e.getCause().printStackTrace()
   * otherwise invokes e.printStackTrace()
  public static void printLowestStackTrace(Exception e) {
    Throwable x = null;
    // try getException
    try {
      Method method = e.getClass().getDeclaredMethod("getException");
      method.setAccessible(true);
      x = (Throwable) method.invoke(e);
    } catch (Exception eaten) { //NoSuchMethodException, IllegalAccessException
      // do nothing
    // else getCause
    if (x==null) {
      try {
        Method method = e.getClass().getDeclaredMethod("getCause");
        method.setAccessible(true);
        x = (Throwable) method.invoke(e);
      } catch (Exception eaten) { //NoSuchMethodException, IllegalAccessException
        // do nothing
    // otherwise default to e itself
    if (x==null) {
      x = e;
    x.printStackTrace();
}In a "real" application DOMSerializerException and DOMSerializer would be public classes under krc.utilz.domz... and DomSerializer3 would become krc.utilz.domz.test.DomSerializerTest. All in one file will do for a quick prototype.
Thanx ejp. I really appreciate your thoughtful comments. Yeah reply 3 was the result of a minor brain explosion, but it's all right, I got better!
On exception handling... I prefer to throw unchecked exceptions for everything except the expected use-cases like FileNotFoundException or NoRowsException or InsufficientFundsException... everything else percolates automagically (with NO intervening exception handling code) up to the fault barrier at the top of the component (or layer)... after all what-the-frag am I (or the user) expected to do with a javax.xml.transform.TransformerConfigurationException error except spit, quit, and call those-wankas-in-IT-support-to-sort-it-out? O hang on, that's me... and I would expect to have to deal with this manually... The root cause is probably a installation or configuration issue after all... not something the program can deal with on the fly.
Cheers, and thanx again. Keith. It's beer o'clock :-)
Edited by: corlettk on Nov 10, 2007 7:15 AM