Question

I am using SAX to parse an XML file I’m pulling from the web. I’ve extended DefaultHandler with code similar to:

public class ArrivalHandler extends DefaultHandler {    
    @Override
    public void startElement(String namespaceUri, String localName, String qualifiedName, Attributes attributes) throws SAXException {
        if (qualifiedName.equalsIgnoreCase("resultSet")) {
            System.out.println("got a resultset");
        } else if (qualifiedName.equalsIgnoreCase("location")) {
            System.out.println("got a location");
        } else if (qualifiedName.equalsIgnoreCase("arrival")) {
            System.out.println("got an arrival");
        } else {
            System.out.println("There was an unknown XML element encountered: '" + qualifiedName + "'");
        }        
    }

    @Override
    public void endElement(String namespaceUri, String localName, String qualifiedName) throws SAXException {
        // we'll just ignore this for now
    }

    @Override
    public void characters(char[] chars, int startIndex, int length) throws SAXException {
        // ignore this too
    }
}

The problem I’m having is that I’m just getting a series of empty elements. The log reads:

There was an unknown XML element encountered: ''
There was an unknown XML element encountered: ''
There was an unknown XML element encountered: ''
etc

This worked fine when I was just passing parser.parse a local file, but now I’m pulling it from the web with:

HttpClient httpClient = new DefaultHttpClient();
resp = httpClient.execute("http://example.com/whatever");

SAXParserFactory saxFactory = SAXParserFactory.newInstance();
ArrivalHandler handler = new ArrivalHandler();
SAXParser parser = saxFactory.newSAXParser();
parser.parse(resp.getEntity().getContent(), handler);

and I get the (apparently) empty results described above.

What I’ve looked into so far:

1. I converted the InputStream from resp.getEntity().getContent() to a string and dumped it out and it looks like I’m getting the XML from the server correctly.
2. There are no exceptions thrown but there is a warning that reads “W/ExpatReader(232): DTD handlers aren't supported.“.

Any other ideas for what I’m doing incorrectly or how to debug this?

Answer 1

From the docs for ContentHandler.startElement:

the qualified name is required when
the namespace-prefixes property is
true, and is optional when the
namespace-prefixes property is false
(the default).

So, do you have the namespace-prefixes property set to true?

Can you just cope with the uri and localName instead?