How can I get childnode's attribute from xml in java dom4j?

Question

I'm trying to get the childnode's attribute from my xml file.For example,the file's name is bb.xml, The xml is just like this:

<?xml version="1.0" encoding="utf-8"?>
<aaa>
 <bbb name="MainMenu">
  <ccc name="abc" Classes="1"
           A="2"
           B="3"/>
 </bbb>
 <bbb name="Mainwindow">
  <ccc name="abc" Classes="4"
           A="3"
           B="2"/>
 </bbb>
</aaa>

and main java file is this:

    public static void main(String[] args) throws Exception {   

    Document doc = new SAXReader().read(new File("D:/bb.xml"));
    List itemList = doc.selectNodes("/aaa");
    for (Iterator iter=itemList.iterator(); iter.hasNext();) {
    Element el = (Element)iter.next();

    String name = el.attributeValue("name");
    System.out.println("name:"+name);
    String b = el.attributeValue("B");
    System.out.println("b:"+b); 
    }

I get the result in my console:

name:null
b:null

But I want the result is:

name:MainMenu
b:3
name:Mainwindow
b:2

How can figure it out?

Answer 1

Quick and dirty:

public static void main(String[] args) throws Exception {    
    Document doc = new SAXReader().read(new File("D:/bb.xml"));
    Element root = doc.getRootElement();
    Iterator bbbIt = root.elementIterator();
    while (bbbIt.hasNext()) {
        Element bbb = ((Element) bbbIt.next());
        System.out.println("name:" + bbb.attributeValue("name"));
        Iterator cccIt = bbb.elementIterator();
        while (cccIt.hasNext()) {
            System.out.println("b:"
                    + ((Element) cccIt.next()).attributeValue("B"));
        }
    }

}

A better solution (because of flexibility) is to use Java native org.w3c.dom package. That way the solution would look like this:

DocumentBuilder db = DocumentBuilderFactory.newInstance().newDocumentBuilder();
        org.w3c.dom.Document myDoc = db.parse(new File("D:/bb.xml"));
        org.w3c.dom.NodeList bbbNodes = myDoc.getElementsByTagName("bbb");
        for (int i=0; i < bbbNodes.getLength(); i++) {
            if (bbbNodes.item(i).hasAttributes())
                System.out.println(bbbNodes.item(i).getAttributes().getNamedItem("name"));
            org.w3c.dom.NodeList cccNodes = bbbNodes.item(i).getChildNodes();
            for (int j=0; j < cccNodes.getLength(); j++) {
                if (cccNodes.item(j).hasAttributes())
                    System.out.println(cccNodes.item(j).getAttributes().getNamedItem("B"));
            }
        }

In any case: don't forget the closing </aaa> in your xml.