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Take an XML document like the following, but imagine it more complex with additional Nodes and Children for each Node.

<Vehicles>
    <FourWheels>
      <Truck>
        <HeavyDuty>
          <Engine></Engine>
          <BedSize length="6.5"/>
          <Exterior>
            <Doors>
              <Door> FrontLeft
                <DoorDetails>
                  <InsidePanel>
                    <Locktype type="A"/>
                  </InsidePanel>
                </DoorDetails>
              </Door>
              <Door> FrontRight             ///<------Door #2
                <DoorDetails>
                  <InsidePanel>
                    <Locktype type="A"/>
                  </InsidePanel>
                </DoorDetails>
              </Door>
              <Door> BackLeft
                <DoorDetails>
                  <InsidePanel>
                    <Locktype type="A"/>
                  </InsidePanel>
                </DoorDetails>
              </Door>
              <Door> BackRight
                <DoorDetails>
                  <InsidePanel>
                    <Locktype type="A"/>
                  </InsidePanel>
                </DoorDetails>
              </Door>
            </Doors>
          </Exterior>
        </HeavyDuty>
        
        <LightDuty>
          <Engine></Engine>
          <BedSize length="5.5"/>
          <Exterior>
            <Doors>
              <Door> FrontLeft
                <DoorDetails>
                  <InsidePanel>
                    <Locktype type="A"/>
                  </InsidePanel>
                </DoorDetails>
              </Door>
              <Door> FrontRight     ///<------Door #2
                <DoorDetails>
                  <InsidePanel>
                    <Locktype type="B"/>   ////<-----Check if type B
                  </InsidePanel>
                </DoorDetails>
              </Door>
              <Door> BackLeft
                <DoorDetails>
                  <InsidePanel>
                    <Locktype type="A"/>
                  </InsidePanel>
                </DoorDetails>
              </Door>
              <Door> BackRight
                <DoorDetails>
                  <InsidePanel>
                    <Locktype type="A"/>
                  </InsidePanel>
                </DoorDetails>
              </Door>
            </Doors>
          </Exterior>
        <LightDuty>
    </Truck>

    <Car>
        :
        :Same as above.
        :
    </Car>

    </FourWheels>
                
</Vehicles>

Keep in mind there could be numerous other Nodes and Children involved.

If the objective is to check the LockType on the 2nd Door only, is it possible to jump right down to that particular Door and LockType to see if the attribute is "A" or "B"?

Or will you have to traverse through each parent/child/child/child.... relationship to get down to the particular Node and check the attribute?

EDITED TO ADD CODE BASED ON RECOMMENDED REFERENCE.

import java.io.IOException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;


public class VehicleTest {

public static void main (String[] args)
{
    VehicleTest test = new VehicleTest();
    test.readXML();
}

private void readXML()
{
    Document doc = null;
    try 
    {
        doc = parseXML("c:\\Downloads\\VehicleTest.xml");
    } 
    catch (ParserConfigurationException e) 
    {
        e.printStackTrace();
    } 
    catch (SAXException e) 
    {
        e.printStackTrace();
    } 
    catch (IOException e) 
    {
        e.printStackTrace();
    }

    if(doc != null)
    {
        NodeList nList = doc.getElementsByTagName("Truck");
        for (int i = 0; i < nList.getLength(); i++) 
        {
            Node nNode = nList.item(i);
            System.out.println("nNode : " + nNode);
            
            Element eElement = (Element) nNode;
            System.out.println("eElement : " + eElement);
            
            Element cElement =  (Element) eElement.getElementsByTagName("HeavyDuty").item(0);
            System.out.println("cElement : " + cElement);   
            
            Element E2  =  (Element) cElement.getElementsByTagName("Exterior").item(0);
            System.out.println("E2 : " + E2);   

            Element E3  =  (Element) E2.getElementsByTagName("Doors").item(0);
            System.out.println("E3 : " + E3);   
            
            Element E4  =  (Element) E3.getElementsByTagName("Door").item(1); 
            System.out.println("E4 : " + E4);   
            
            Element E5  =  (Element) E4.getElementsByTagName("Locktype").item(0);
            System.out.println("E5 : " + E5);   

            System.out.println("LockType : " + E5.getAttribute("type"));
        }
    }
}

private Document parseXML(String filePath) throws ParserConfigurationException, SAXException, IOException
{
    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    DocumentBuilder db = dbf.newDocumentBuilder();
    Document doc = db.parse(filePath);
    doc.getDocumentElement().normalize();
    return doc;
}
}

Output :

enter image description here

I will have to play around with this. Although it works, it only processed one of the Truck items and need to process both.

In the code I provided, using "HeavyDuty" would case an exception for the 2nd iteration as its only LightDuty.

Unhandled Exception
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  • Can you refer this ? it might be of some help. For example : you can directly do `doc.select("Doors")` to get all Doors objects and if there are multiple you can select elements like you do in an array. It uses jsoup as library https://stackoverflow.com/questions/67693039/retrieving-attribute-values-from-a-xml-string-in-java/67694231#67694231 – Chandan Jun 09 '21 at 17:55
  • @Chandan, it a little more involved than this example because in my example, I would only want the Doors related to Trucks and not Cars. Using the above would bring back all references. – Unhandled Exception Jun 09 '21 at 18:27
  • 1
    actually not very different. you have to do first select Truck and then Doors thats it like `doc.select("Truck").select("Doors")` – Chandan Jun 09 '21 at 18:39
  • I just noticed you are referencing JSoup which I don't have and would not be able to install on the required machines. – Unhandled Exception Jun 09 '21 at 19:06
  • I did take the code above in the Sample and applied it to my actual XML file and it worked nicely. – Unhandled Exception Jun 09 '21 at 19:07

0 Answers0