How to parse xml using DocumentBuilder ?

Question

I am trying to parse this xml snippet:
<root>
<data a="0.0" b="1.0"/>
<data a="0.1" b="2.0"/>
<data a="0.2" b="3.0"/>
<data a="0.3" b="4.0"/>
<data a="0.4" b="5.0"/>
<data a="0.5" b="6.0"/>
</root>
using the following:
    String test = getDummyXmlSnippet()
    StringReader sr = new StringReader(test);
    input = new InputSource(sr);
    Document document = null;
    try {
      DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
      DocumentBuilder builder = factory.newDocumentBuilder();
      document = builder.parse(input);
      NodeList nodes = document.getChildNodes();
      // this only prints 1
      System.out.println(nodes.getLength());
      Node nn = nodes.item(0);
      // this prints this first root node name (root)
      System.out.println(nn.getNodeName());
      // Cannot get the remaning nodes....!
      NodeList nnt = nn.getChildNodes();
      Node n0 = nnt.item(0);
      System.out.println(n0.getNodeValue());  // just prints #text
      System.out.println(n0.getNodeName()); // just prints #text
      // THis prints 13
      System.out.println(nn.getChildNodes().getLength());
      // this will only iterate once!
      NodeList children = document.getChildNodes();
      for (int i=0;i<children.getLength();i++) {
        Node node = children.item(i);
        if (node.getNodeType()==Node.ELEMENT_NODE) {
          System.out.println("bob = " + node.getNodeName());
    } catch(Exception e){
      e.printStackTrace();
    }I can only get the first root node printed. How do I get the child (data nodes) elements out?

Answer 1

What do you mean by the "first" root node? An XML document only has one root node, and your XML document is no exception.
As for the 13 child nodes of the root, you could have written a program which iterated over them and displayed them. That would have clarified your understanding of the document. But instead you wrote a program which just displayed the first of them, then iterated over the children of the document (which has the root as its only child) instead of iterating over the children of the root element.
You wouldn't be the first person to not realize that whitespace text nodes are nodes just like all the others. Or that the document and the root node are different things.