XML child node attribute value

Question

I\'m trying to read xml file, ex :

    
    5467sdad98787ad3149878sasda
    

        

Answer 1

As pointed out, <contento> doesn't have any child so instead of:

(contento.item(0)).getFirstChild().getAttributes()

You should treat the Node as Element and use getAttribute(String), something like this:

((Element)contento.item(0)).getAttribute("madeIn")

Here is a modified version of your code (it's not the most robust code I've written):

InputStream inputStream = new ByteArrayInputStream(xml.getBytes());
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(inputStream);
doc.getDocumentElement().normalize();
System.out.println("Root element " + doc.getDocumentElement().getNodeName());
NodeList nodeLst = doc.getElementsByTagName("entry");
System.out.println("Information of all entries");

for (int s = 0; s < nodeLst.getLength(); s++) {

    Node fstNode = nodeLst.item(s);

    if (fstNode.getNodeType() == Node.ELEMENT_NODE) {

        Element fstElmnt = (Element) fstNode;

        NodeList title = fstElmnt.getElementsByTagName("title").item(0).getChildNodes();
        System.out.println("Title : " + (title.item(0)).getNodeValue());

        NodeList id = fstElmnt.getElementsByTagName("id").item(0).getChildNodes();
        System.out.println("Id: " + (id.item(0)).getNodeValue());

        Node tempiNode = fstElmnt.getElementsByTagName("tempi").item(0);
        System.out.println("Type : " + ((Element) tempiNode).getAttribute("type"));

        Node contento = tempiNode.getChildNodes().item(0);
        System.out.println("Made in : " + ((Element) contento).getAttribute("madeIn"));
    }
}

Running it on your XML snippet produces the following output:

Root element entry
Information of all entries
Title : FEED TITLE
Id: 5467sdad98787ad3149878sasda
Type : application/xml
Made in : USA

By the way, did you consider using something like Rome instead?

Answer 2

The best solution for this is to use XPath. Your pastebin is expired, but here's what I gathered. Let's say we have the following feed.xml file:

<?xml version="1.0" encoding="UTF-8" ?>
<entries>
<entry>
    <title>FEED TITLE 1</title>
    <id>id1</id>
    <tempi type="type1">
      <conento xmlns="dontcare?" madeIn="MadeIn1" />
    </tempi>
</entry>
<entry>
    <title>FEED TITLE 2</title>
    <id>id2</id>
    <tempi type="type2">
      <conento xmlns="dontcare?" madeIn="MadeIn2" />
    </tempi>
</entry>
<entry>
    <id>id3</id>
</entry>
</entries>

Here's a short but compile-and-runnable proof-of-concept (with feed.xml file in the same directory).

import javax.xml.xpath.*;
import javax.xml.parsers.*;
import org.w3c.dom.*;
import java.io.*;
import java.util.*;

public class XPathTest {
    static class Entry {
        final String title, id, origin, type;
        Entry(String title, String id, String origin, String type) {
            this.title = title;
            this.id = id;
            this.origin = origin;
            this.type = type;
        }
        @Override public String toString() {
            return String.format("%s:%s(%s)[%s]", id, title, origin, type);
        }
    }

    final static XPath xpath = XPathFactory.newInstance().newXPath();
    static String evalString(Node context, String path) throws XPathExpressionException {
        return (String) xpath.evaluate(path, context, XPathConstants.STRING);
    }

    public static void main(String[] args) throws Exception {
        File file = new File("feed.xml");
        Document document = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(file);
        NodeList entriesNodeList = (NodeList) xpath.evaluate("//entry", document, XPathConstants.NODESET);

        List<Entry> entries = new ArrayList<Entry>();
        for (int i = 0; i < entriesNodeList.getLength(); i++) {
            Node entryNode = entriesNodeList.item(i);
            entries.add(new Entry(
                evalString(entryNode, "title"),
                evalString(entryNode, "id"),
                evalString(entryNode, "tempi/conento/@madeIn"),
                evalString(entryNode, "tempi/@type")
            ));
        }
        for (Entry entry : entries) {
            System.out.println(entry);
        }
    }
}

This produces the following output:

id1:FEED TITLE 1(MadeIn1)[type1]
id2:FEED TITLE 2(MadeIn2)[type2]
id3:()[]

Note how using XPath makes the value retrieval very simple, intuitive, readable, and straightforward, and "missing" values are also gracefully handled.

API links

• package javax.xml.xpath
• http://www.w3.org/TR/xpath
• Wikipedia/XPath

Answer 3

Use Element.getAttribute and Element.setAttribute

In your example, ((Node) content.item(0)).getFirstChild().getAttributes(). Assuming that content is a typo, and you mean contento, getFirstChild is correctly returning NULL as contento has no children. Try: ((Node) contento.item(0)).getAttributes() instead.

Another issue is that by using getFirstChild and getChildNodes()[0] without checking the return value, you are running the risk of picking up child text nodes, instead of the element you want.