Question

Here is my code:

// get the factory
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

try {

    // Using factory get an instance of document builder
DocumentBuilder db = dbf.newDocumentBuilder();

// parse using builder to get DOM representation of the XML file
    dom = db.parse(file);

} catch (ParserConfigurationException pce) {
    pce.printStackTrace();
} catch (SAXException se) {
    se.printStackTrace();
} catch (IOException ioe) {
    ioe.printStackTrace();
}

NodeList n1 = dom.getChildNodes();
Element e1 = (Element) n1.item(0);

System.out.println(n1.getLength());
System.out.println(e1.getNodeName());

NodeList n2 = n1.item(0).getChildNodes();
Element e2 = (Element) n2.item(0);   //Line 61

System.out.println(n2.getLength());
System.out.println(e2.getNodeName());

Here is my XML file:

<?xml version="1.0" encoding="utf-8"?>

<test-fw:test
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:test-fw="http://simitar/test-fw"> 

<rule-tree>
<rule class="matchlines">
<property name="contiguous"> true</property>
<property name="inOrder">false</property>
<property name="exact">false</property>
<property name="lines">modelInstantiated</property>
</rule>
<rule class="matchlines">
<property name="contiguous"> true</property>
<property name="inOrder">true</property>
<property name="exact">false</property>
<property name="lines">InitEvent</property>
</rule>
</rule-tree>

</test-fw:test>

Here is my output:

1
test-fw:test
Exception in thread "main" java.lang.ClassCastException: com.sun.org.apache.xerces.internal.dom.DeferredTextImpl cannot be cast to org.w3c.dom.Element
    at testpack.Main.run(Main.java:61)
    at testpack.Main.main(Main.java:86)

I keep getting this error. I am completely lost. I have no idea what to do. I want to able to have one node, and be able to grab all it’s children and put them into an array or list, so I can iterate through them.

Here are all my imports:

import java.io.File;
import java.io.IOException;
import java.util.List;
import java.util.Stack;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

I’ve had the hardest time trying to get this Java to parse this XML file.

Answer 1

NodeList n1 = dom.getChildNodes();
Element e1 = (Element) n1.item(0);

The node is not an Element, but a Node.

Try this:

Node no1 = (Node) n1.item(0);

Nodes can be text nodes or elements, for example. In particular,

<root>
<element/>
</root>

is 4 nodes. A root element, a text node containing \n, the element element and another text node containing \n.