What libraries are there for processing XML on Google App Engine/Java Servlet

Question

I'm writing a Java servlet in Eclipse (to be hosted on Google App Engine) and need to process an XML document. What libraries are available that are easy to add to an Eclipse project and have good example code?

Answer 1

I ended up using JAXP with the SAX API.

Adding something like the following to my servlet:

import org.xml.sax.*;
import org.xml.sax.helpers.*;
import javax.xml.parsers.*;

....

InputStream in = connection.getInputStream();

InputSource responseXML = new InputSource(in);
final StringBuilder response = new StringBuilder();
DefaultHandler myHandler = new DefaultHandler() {

    public void startElement(String uri, String localName, String qName, 
            Attributes attributes) throws SAXException {
        if (localName.equals("elementname")) {
            response.append(attributes.getValue("attributename"));
            inElement = true;
        }
    }
    public void characters(char [] buf, int offset, int len) {
        if (inElement) {
            inElement = false;
            String s = new String(buf, offset, len);
            response.append(s);
            response.append("\n");
        }
    }
};

SAXParserFactory factory = SAXParserFactory.newInstance();
try {
    SAXParser parser = factory.newSAXParser();
    parser.parse(responseXML, myHandler);
} catch (ParserConfigurationException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
} catch (SAXException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}

in.close();
connection.disconnect();

....