Parsing xml with dom4j or jdom or anyhow

Question

I wanna read feed entries and I'm just stuck now. Take this for example : https://stackoverflow.com/feeds/question/2084883 lets say I wanna read all the summary node value inside each entry node in document. How do I do that? I've changed many variations of code this one is closest to what I want to achieve I think :

Element entryPoint = document.getRootElement();
  Element elem;
  for(Iterator iter = entryPoint.elements().iterator(); iter.hasNext();){
   elem = (Element)iter.next();
                    System.out.println(elem.getName());
  }

It goes trough all nodes in xml file and writes their name. Now what I wanted to do next is

if(elem.getName().equals("entry"))

to get only the entry nodes, how do I get elements of the entry nodes, and how to get let say summary and its value? tnx

Question: how to get values of summary nodes from this link

@vtd-xml-author no I didn't I don't even know what that is – ant Aug 11 '10 at 07:52 — ant, Aug 11 '10 at 07:52

score 2 · Answer 1 · answered May 13 '10 at 15:03

Have you tried jdom? I find it simpler and convenient.

http://www.jdom.org/

To get all children of an xml element, you can just do

SAXBuilder sb = new SAXBuilder();
            StringReader sr = new StringReader(xmlDocAsString);
            Document doc = sb.build(sr);
            Element root = doc.getRootElement();
            List l = root.getChildren("entry");
            for (Iterator iter = l.iterator(); iter.hasNext();) {
...//do whatever...
}

I'm using dom4j, its not an option sorry – ant May 13 '10 at 15:04 — ant, May 13 '10 at 15:04

score 1 · Answer 2 · answered May 13 '10 at 15:32

1

if(elem.getName() == "entry")

I have no idea whether this is your problem (you don't really state what your problem is), but never test string equality with --. Instead, use equals():

if(elem.getName().equals("entry"))

answered May 13 '10 at 15:32

Anon

91
1

Michael · Accepted Answer · 2010-05-19T17:37:39.133

Here's how you'd do it using vanilla Java:

//read the XML into a DOM
StreamSource source = new StreamSource(new StringReader("<theXml></theXml>"));
DOMResult result = new DOMResult();
Transformer transformer = TransformerFactory.newInstance().newTransformer();
transformer.transform(source, result);
Node root = result.getNode();

//make XPath object aware of namespaces
XPath xpath = XPathFactory.newInstance().newXPath();
xpath.setNamespaceContext(new NamespaceContext(){
    @Override
    public String getNamespaceURI(String prefix) {
        if ("atom".equals(prefix)){
            return "http://www.w3.org/2005/Atom";
        }
        return null;
    }

    @Override
    public String getPrefix(String namespaceURI) {
        return null;
    }

    @Override
    public Iterator getPrefixes(String namespaceURI) {
        return null;
    }
});

//get all summaries
NodeList summaries = (NodeList) xpath.evaluate("/atom:feed/atom:entry/atom:summary", root, XPathConstants.NODESET);
for (int i = 0; i < summaries.getLength(); ++i) {
    Node summary = summaries.item(i);

    //print out all the attributes
    for (int j = 0; j < summary.getAttributes().getLength(); ++j) {
        Node attr = summary.getAttributes().item(j);
        System.out.println(attr.getNodeName() + "=" + attr.getNodeValue());
    }

    //print text content
    System.out.println(summaries.item(i).getTextContent());
}

this code works if you remove atom:summary part, it loops trough every entry and prints out values of child nodes. Question: How to do this. If there are any child nodes loop and get their value, if there are no more children or children values collect their attribute value else get child node attribute value — ant, May 18 '10 at 08:08

score 0 · Answer 4 · answered Jul 13 '11 at 22:29

A bit late but it might be useful for people googling...

There is a specialized API for dealing with RSS and Atom feeds in Java. It's called Rome, can be found here :

http://java.net/projects/rome/

It is really quite useful, it makes easy to read feed whatever the RSS or Atom version. You can also build feeds and generate the XML with it though I have no experience with this feature.

Here is a simple example that reads a feed and prints out the description nodes of all the entries in the feed :

URL feedSource = new URL("http://....");
feed = new SyndFeedInput().build(new XmlReader(feedSource));
List<SyndEntryImpl> entries = (List<SyndEntryImpl>)feed.getEntries();

for(SyndEntryImpl entry : entries){
    System.out.println(entry.getDescription().getValue());
}

Simple enough.

Parsing xml with dom4j or jdom or anyhow

4 Answers4