parse xml using dom java

Question

I have the bellow xml:

    
        
            wish
             


        

Answer 1

I like to use XMLBeam for such tasks:

public class Answer {

    @XBDocURL("resource://data.xml")
    public interface DataProjection {

        public interface Topic {
            @XBRead("./@id")
            int getID();

            @XBRead("./@percentage")
            String getPercentage();
        }

        @XBRead("/modelingOutput/listOfDocs//document/topic")
        List<Topic> getTopics();
    }

    public static void main(final String[] args) throws IOException {
        final DataProjection dataProjection = new XBProjector().io().fromURLAnnotation(DataProjection.class);
        for (Topic topic : dataProjection.getTopics()) {
            System.out.println(topic.getID() + ": " + topic.getPercentage());
        }
    }
}

There is even a convenient way to convert the percentage to float or double. Tell me if you like to have an example.

Answer 2

If you do not want to use the if statement you can use XPath to get the element you need directly.

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse("source.xml");
XPathFactory xPathfactory = XPathFactory.newInstance();
XPath xpath = xPathfactory.newXPath();
XPathExpression expr = xpath.compile("/*/listOfDocs/documents/document/topic");
NodeList nodes = (NodeList) expr.evaluate(doc, XPathConstants.NODESET);

for (int i = 0; i < nodes.getLength(); i++) {
    System.out.println(nodes.item(i).getAttributes().getNamedItem("id"));
    System.out.println(nodes.item(i).getAttributes().getNamedItem("percentage"));
}

Please check GitHub project here.

Hope this helps.

Answer 3

First, when checking the node name you shouldn't compare Strings using ==. Always use the equals method instead.

You can use XPath to evaluate only the document topic elements under listOfDocs:

XPathFactory xPathFactory = XPathFactory.newInstance();
XPath xPath = xPathFactory.newXPath();
XPathExpression xPathExpression = xPath.compile("//listOfDocs//document/topic");

NodeList topicnl = (NodeList) xPathExpression.evaluate(dom, XPathConstants.NODESET);
for(int i = 0; i < topicnl.getLength(); i++) {
   ...