获取节点内节点的值

Question

I've been trying to find a clear solution for my problem since every explanation I've found until now its confusing (for me at least).

I've tried DOM readers but I can't complement it with this file since its a more complex XML file.

My XML file:

<Order>
  <OrderID>
    <OrderConfirmationDate>
      <Date>
       <Year>2000</Year>
       <Month>10</Month>
       <Day>06</Day>
      </Date>
    </OrderConfirmationDate>
  <Adress>
    <Name>Papel do Porto</Name>
      <Address1>Rua da Alegria</Address1>
      <Address2>nº1</Address2>
      <City>Porto</City>
      <PostalCode>4000-032</PostalCode>
      <Country ISOCountryCode="PT">Portugal</Country>
    </NameAddress>

This is the code I've understood until now

dBuilder = dbFactory.newDocumentBuilder();
            Document doc = dBuilder.parse(xmlFile);
            doc.getDocumentElement().normalize();
            
            System.out.println("Root element :" + doc.getDocumentElement().getNodeName());

So, I can easily get the root of document with getDocumentElement() . And I can easily get a node of the root with getNodeName() .

But how do I get the "node.getNodeName(). (in this case I mean to get the <OrderConfirmationDate> out of <OrderID> ) Also, I've read that tags like <Year> and <Month> are Ids of the node <Date> .

Answer 1

To select a particular node, you can use a XPath expression.

XPath xpath = XPathFactory.newDefaultInstance().newXPath();
XPathExpression expr = xpath.compile("//OrderConfirmationDate/Date");
Element orderConfirmationDateElement = (Element) expr.evaluate(doc, XPathConstants.NODE);
        

Then to go through the node's children:

NodeList dateChildren = orderConfirmationDateElement.getChildNodes();
for(int i = 0; i < dateChildren.getLength(); i++) {
    if (dateChildren.item(i).getNodeType() == Node.ELEMENT_NODE) {
        System.out.println(dateChildren.item(i).getNodeName() + ": " + dateChildren.item(i).getTextContent());
    }
}

Output:

Year: 2000
Month: 10
Day: 06