How to parse this XML file and what parser to use?

Question

I am very new to XMLParsing. It sat at work today without managing to parse a file and get it into an arrayList.

My file looks kinda like this

<type>
 <OBJECT_TYPE>horse</OBJECT_TYPE>
   <prop>blabla</prop>
   <param>black</param>
  <OBJECT_TYPE>cat</OBJECT_TYPE>
   <prop>blabla</prop>
   <param>black</param>
  <OBJECT_TYPE>car</OBJECT_TYPE>
   <prop>blabla</prop>
   <param>black</param>
</type>

But alot longer and not that content. I tried to use SaxParser but no success. And I have read pretty much every SaxParser turials around but all parse xml that has attibutes and my XML doesnt have any attributes.

So for this kind of XML what parser should I use to be able to save it into an ArrayList? And I only wanna list my OBJECT_TYPES nothing else. No prop and no params.

If all you want is to get the OBJECT_TYPE element text, SAX is overkill. use XPath: see my answer http://stackoverflow.com/a/19407505/217324 — Nathan Hughes, Jan 17 '14 at 18:20

score 1 · Answer 1 · answered Jan 17 '14 at 17:05

The standard pattern for SAX parsing this kind of format would be

startElement
- if tag name is OBJECT_TYPE then create a new buffer (e.g. StringBuilder) to gather character data.
characters
- if there is an active buffer, append the current chunk of characters to that buffer
endElement
- if the tag name is OBJECT_TYPE turn the buffer into a string and do whatever you need to do with it.

The parser will deliver the text content of elements to the characters method of your handler, but it is not guaranteed to give you the whole block of contiguous text in one single chunk, which is why you need to accumulate it in a buffer and do the processing at endElement.

score 1 · Accepted Answer · answered Jan 17 '14 at 17:12

This is the way

import java.util.ArrayList;

import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

public class ReadXMLFile {

   public static void main(String argv[]) {
       final ArrayList<String> al=new ArrayList<String>();

    try {

    SAXParserFactory factory = SAXParserFactory.newInstance();
    SAXParser saxParser = factory.newSAXParser();

    DefaultHandler handler = new DefaultHandler() {

    boolean bfname = false;
    boolean blname = false;
    boolean bnname = false;
    boolean bsalary = false;

    public void startElement(String uri, String localName,String qName, 
                Attributes attributes) throws SAXException {

        System.out.println("Start Element :" + qName);

        if (qName.equalsIgnoreCase("OBJECT_TYPE")) {
            bfname = true;
        }



    }

    public void endElement(String uri, String localName,
        String qName) throws SAXException {

        System.out.println("End Element :" + qName);

    }

    public void characters(char ch[], int start, int length) throws SAXException {

        if (bfname) {

            al.add(new String(ch, start, length));
            bfname = false;
        }



    }

     };

       saxParser.parse("C:\\Users\\Naren\\workspace\\Regex\\src\\test.xml", handler);
       System.out.println(al);

     } catch (Exception e) {
       e.printStackTrace();
     }

   }

}

output

[horse, cat, car]

Are you sure that one works?. Cuz I am pretty sure I did like that and it only wrote out something like this: example.com@49030, example.com@930490 — Sembrano, Jan 17 '14 at 17:16
Check it i have written and tested now only.. and i have posted output also... IT WILL WORK.. — Naren, Jan 17 '14 at 17:17
@Sembrano: the characters method here is not good (read Ian's answer). so if that is what you have then you are reading the wrong tutorials. see Oracle's: http://docs.oracle.com/javase/tutorial/jaxp/sax/parsing.html — Nathan Hughes, Jan 17 '14 at 18:06
Yes Naren it works for this solution atleast but the problem wil lbe when I get all the data from the params and prop depending on what object type you have. Then the other issues is if the user edit the xml and wanna save it SAX parsing wont work at all I guess. — Sembrano, Jan 20 '14 at 07:18
working fine with XPath I did : String expression = "//OBJECT_TYPE"; Then it got the things out that I wanted. But If I want to list all properties and params in the Object_type how do I do then? — Sembrano, Jan 20 '14 at 12:03

score 0 · Answer 3 · answered Jan 20 '14 at 12:49

This is how I solved it :

public void ParserForObjectTypes() throws SAXException, IOException,
            ParserConfigurationException {

        try {
            FileInputStream file = new FileInputStream(new File(
                    "xmlFiles/CoreDatamodel.xml"));

            DocumentBuilderFactory builderFactory = DocumentBuilderFactory
                    .newInstance();

            DocumentBuilder builder = builderFactory.newDocumentBuilder();

            Document xmlDocument = builder.parse(file);

            XPath xPath = XPathFactory.newInstance().newXPath();

            String expression = "//OBJECT_TYPE";
            NodeList nodeList = (NodeList) xPath.compile(expression).evaluate(
                    xmlDocument, XPathConstants.NODESET);
            for (int i = 0; i < nodeList.getLength(); i++) {


                model.addElement(nodeList.item(i).getFirstChild()
                        .getNodeValue());

            }

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (SAXException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (ParserConfigurationException e) {
            e.printStackTrace();
        } catch (XPathExpressionException e) {
            e.printStackTrace();
        }
    }

How to parse this XML file and what parser to use?

3 Answers3