= XML File Routines =

== Read XML Files ==

Sample XML file:
<code xml>
<?xml version="1.0"?>
<company>
	<staff id="1001">
		<firstname>yong</firstname>
		<lastname>mook kim</lastname>
		<nickname>mkyong</nickname>
		<salary>100000</salary>
	</staff>
	<staff id="2001">
		<firstname>low</firstname>
		<lastname>yin fong</lastname>
		<nickname>fong fong</nickname>
		<salary>200000</salary>
	</staff>
</company>
</code>

Read the list of items found in XML file:
<code java>
package com.acme.myproj;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.w3c.dom.Node;
import org.w3c.dom.Element;
import java.io.File;

public class XmlFileUtils {

  public static void ReadXmlFile(String aFileName) {

    try {

	File fXmlFile = new File(aFileName); // Eg: "/Users/mkyong/staff.xml"
	DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
	DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
	Document doc = dBuilder.parse(fXmlFile);

	// Optional, but recommended
	// Read this - http://stackoverflow.com/questions/13786607/normalization-in-dom-parsing-with-java-how-does-it-work
	doc.getDocumentElement().normalize();

	System.out.println("Root element :" + doc.getDocumentElement().getNodeName());

	NodeList nList = doc.getElementsByTagName("staff");

	System.out.println("----------------------------");

	for (int temp = 0; temp < nList.getLength(); temp++) {

		Node nNode = nList.item(temp);

		System.out.println("\nCurrent Element :" + nNode.getNodeName());

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

			Element eElement = (Element) nNode;

			System.out.println("Staff id : " + eElement.getAttribute("id"));
			System.out.println("First Name : " + eElement.getElementsByTagName("firstname").item(0).getTextContent());
			System.out.println("Last Name : " + eElement.getElementsByTagName("lastname").item(0).getTextContent());
			System.out.println("Nick Name : " + eElement.getElementsByTagName("nickname").item(0).getTextContent());
			System.out.println("Salary : " + eElement.getElementsByTagName("salary").item(0).getTextContent());

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

}
</code>

To read the list of items and their children in XML file, loop through the nodes:
<code java>
package com.acme.myproj;

import java.io.File;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

public class XmlFileUtils 
{

  public static void ReadAllNodes(String aFileName)
  {

    try {

	File file = new File(aFileName);  // Eg. "/Users/mkyong/staff.xml"

	DocumentBuilder dBuilder = DocumentBuilderFactory.newInstance()
                             .newDocumentBuilder();

	Document doc = dBuilder.parse(file);

	System.out.println("Root element :" + doc.getDocumentElement().getNodeName());

	if (doc.hasChildNodes()) {

		printNote(doc.getChildNodes());

	}

    } catch (Exception e) {
	System.out.println(e.getMessage());
    }

  }

  private static void printNote(NodeList nodeList) 
  {

    for (int count = 0; count < nodeList.getLength(); count++) {

	Node tempNode = nodeList.item(count);

	// make sure it's element node.
	if (tempNode.getNodeType() == Node.ELEMENT_NODE) {

		// get node name and value
		System.out.println("\nNode Name =" + tempNode.getNodeName() + " [OPEN]");
		System.out.println("Node Value =" + tempNode.getTextContent());

		if (tempNode.hasAttributes()) {
			// get attributes names and values
			NamedNodeMap nodeMap = tempNode.getAttributes();

			for (int i = 0; i < nodeMap.getLength(); i++) {

				Node node = nodeMap.item(i);
				System.out.println("attr name : " + node.getNodeName());
				System.out.println("attr value : " + node.getNodeValue());
			}
		}

		if (tempNode.hasChildNodes()) {
			// loop again if has child nodes
			printNote(tempNode.getChildNodes());

		}

		System.out.println("Node Name =" + tempNode.getNodeName() + " [CLOSE]");

	}

    }

  }

}
</code>

From other code, call routines as follows:
<code java>
private void OpenXmlDataFile() 
{
    Path pth = Paths.get(System.getProperty("user.dir") + "/src/com/acme/myproj/data/", "staff.xml");
    XmlFileUtils.ReadAllNodes(pth.toString());
}
</code>    

References:  [[https://www.mkyong.com/java/how-to-read-xml-file-in-java-dom-parser/]]