Java HTML / XML How to - Insert a xml node as first child in another xml document

Question

We would like to know how to insert a xml node as first child in another xml document.
Answer

// w w w.ja  v  a 2  s . co  m
import java.io.ByteArrayInputStream;
import java.io.StringWriter;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.OutputKeys;
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;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.Text;

public class Main {
  public static void main(String[] args) throws Exception {
    String initial = "<root><param value=\"abc\"/><param value=\"bc\"/></root>";
    ByteArrayInputStream is = new ByteArrayInputStream(initial.getBytes());
    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    DocumentBuilder db = dbf.newDocumentBuilder();
    Document doc = db.parse(is);

    // Create the new xml fragment
    Text a = doc.createTextNode("asdf");
    Node p = doc.createElement("parameterDesc");
    p.appendChild(a);
    Node i = doc.createElement("insert");
    i.appendChild(p);
    Element r = doc.getDocumentElement();
    r.insertBefore(i, r.getFirstChild());
    r.normalize();

    // Format the xml for output
    Transformer transformer = TransformerFactory.newInstance().newTransformer();
    transformer.setOutputProperty(OutputKeys.INDENT, "yes");

    // initialize StreamResult with File object to save to file
    StreamResult result = new StreamResult(new StringWriter());
    DOMSource source = new DOMSource(doc);
    transformer.transform(source, result);

    System.out.println(result.getWriter().toString());

  }
}