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How to parse an XML file in Java ME with kXML

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Created: jappit (14 May 2008)
Last edited: hamishwillee (27 Jun 2013)

We'll see how to parse a generic XML file using kXML library.

Source code: XmlNode class

First, we'll define an XmlNode class to represent a generic XmlNode. We'll define 2 node types:

  • Text nodes: nodes without a name, containing only a textual value
  • Element nodes: nodes with a tag name, containing children nodes

Each node will have also a list of attributes.

public class XmlNode
{
public static final int TEXT_NODE = 0;
public static final int ELEMENT_NODE = 1;
 
public int nodeType = 0;
public String nodeName = null;
public String nodeValue = null;
public Vector children = null;
public Hashtable attributes = null;
 
public XmlNode(int nodeType)
{
this.nodeType = nodeType;
this.children = new Vector();
this.attributes = new Hashtable();
}
public String[] getAttributeNames()
{
String[] names = new String[attributes.size()];
 
Enumeration e = attributes.keys();
 
int i = 0;
 
while(e.hasMoreElements())
{
names[i] = (String)e.nextElement();
 
i++;
}
return names;
}
public void setAttribute(String key, String value)
{
attributes.put(key, value);
}
public String getAttribute(String key)
{
return (String)attributes.get(key);
}
 
public void addChild(XmlNode child)
{
this.children.addElement(child);
}
}

Source code: GenericXmlParser class

GenericXmlParser is the class with which we'll able to parse XML files. It has only one public method, parseXML(), that will accept as arguments:

  • a KXmlParser instance to do parsing
  • a boolean that defines if whitespaces-only children must be ignored
import org.kxml2.io.KXmlParser;
import org.xmlpull.v1.XmlPullParser;
 
public class GenericXmlParser
{
public XmlNode parseXML(KXmlParser parser,
boolean ignoreWhitespaces) throws Exception
{
parser.next();
 
return _parse(parser, ignoreWhitespaces);
}
XmlNode _parse(KXmlParser parser,
boolean ignoreWhitespaces) throws Exception
{
XmlNode node = new XmlNode(XmlNode.ELEMENT_NODE);
 
if(parser.getEventType() != XmlPullParser.START_TAG)
{
throw new Exception("Illegal XML state: " +
parser.getName() + ", " + parser.getEventType());
}
else
{
node.nodeName = parser.getName();
 
for(int i = 0; i < parser.getAttributeCount(); i++)
{
node.setAttribute(parser.getAttributeName(i), parser.getAttributeValue(i));
}
 
parser.next();
 
while(parser.getEventType() != XmlPullParser.END_TAG)
{
if(parser.getEventType() == XmlPullParser.START_TAG)
{
node.addChild(_parse(parser, ignoreWhitespaces));
}
else if(parser.getEventType() == XmlPullParser.TEXT)
{
if(!ignoreWhitespaces || !parser.isWhitespace())
{
XmlNode child = new XmlNode(XmlNode.TEXT_NODE);
 
child.nodeValue = parser.getText();
 
node.addChild(child);
}
}
parser.next();
}
}
return node;
}
}

Source code: sample usage

To use the classes defined above, you can simply do as follows:

InputStreamReader reader = new InputStreamReader(getClass().getResourceAsStream("/test3.xml"));
 
KXmlParser parser = new KXmlParser();
 
parser.setInput(reader);
 
GenericXmlParser gParser = new GenericXmlParser();
 
XmlNode xml = gParser.parseXML(parser, true);

And, if you want to dump out the parsed XML data, you can use the following method:

void dumpXML(XmlNode node, int deep)
{
for(int i = 0; i < deep; i++)
{
System.out.print(" ");
}
System.out.print(node.nodeName + " - ");
 
if(node.nodeValue != null)
{
System.out.print("(" + node.nodeValue + ") - ");
}
String[] attributes = node.getAttributeNames();
 
for(int i = 0; i < attributes.length; i++)
{
System.out.print(attributes[i] + ": " + node.getAttribute(attributes[i]) + ", ");
}
 
System.out.println();
 
for(int i = 0; i < node.children.size(); i++)
{
dumpXML((XmlNode)node.children.elementAt(i), deep + 1);
}
}
This page was last modified on 27 June 2013, at 06:53.
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