xml parsing with dom

[John Gregory]

Here's an xml question. Suppose I have an xml structure called
defined as follows:

<orders>
<order>
<partNum>12345778A</partNum>
<description>widget controller</description>
<quantity>2</quantity
</order>
<order>
<partNum>67789A2C</partNum>
<description>widget adapter</description>
<quantity>3</quantity
</order>
. another order
. another order
</orders>

In my xml file, I have several orders. Suppose I'd like to
iterate through and see all the nodes in each order. By doing

NodeList orders = root.getElementsByTagName(�order�);
I�m able to iterate through and print each node name, but when I
try to print the node value, I get null.
Should I cast to an Element instead of node? As you can see, there
no attributes, and I did this intentionally to learn how to pull data
out of a Node.

Thanks,

John

[Paul Clapham]

Well, no. Check the API documentation for the Node interface and you'll see what the "node value" is for each type of Node. For an Element node, the value is indeed null.

Most likely you were looking for the value of the Element's child, which is a Text node.

[John Gregory]

Ok, then what code can I use to get something like

partNum === 1234577A
description === "blah, blah"
quantity === 2

Iterating I can print out partNum, description, and quantity
by using node.getNodeName() method, however, when I do
node.getNodeValue(), I get null back and clearly, there is
SOMETHING there.

John

[Freddy Wong]

You can either use getTextContent() to get the element value or iterate the element node and then use getNodeValue().

Below is an example to print the element and its corresponding value. Take a note that this is only an example. You can do a much better approach, such as using recursion, etc.

    
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(new File("/home/freddy/test.xml"));
NodeList nl = doc.getElementsByTagName("order");
for (int i = 0; i < nl.getLength(); i++)
{
    Node n = nl.item(i);
    NodeList nl1 = n.getChildNodes();
    for (int j = 0; j < nl1.getLength(); j++)
    {
        Node n1 = nl1.item(j);
        if (n1.getNodeType() == Node.ELEMENT_NODE)
        {
            System.out.print(n1.getNodeName() + "=");
            // System.out.println(n1.getTextContent()); 
            NodeList nl2 = n1.getChildNodes();
            for (int k = 0; k < nl2.getLength(); k++)
            {
                Node n2 = nl2.item(k);
                System.out.println(n2.getNodeValue());
            }    
         }
    }
}

[John Gregory]

Freddy,

Thanks, I totally passed by the getTextContent() method when
I was looking at the api...I was more focused on the getNodeValue()
call that I missed it.

Again, thanks.

John

[Paul Clapham]

That will work well for your particular question. But note that getTextContent() does exactly what it says, and that might not be what you expect in the case of mixed content elements. Try it on the <orders> element of your original post, for example, and see what it produces.