Gullele's Corner

Get XML values as key value pair in Java

This simple java class would help to get values of the xml format as key and value map in java.

It has some limitation on the xml that you would be using, yet it would be a ground step for building other.

package helpers;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

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;
import org.xml.sax.SAXParseException;

/**
 *
 * Simple XML Class -
 * This XML Class is a simple helper only for specific case. Originally developed to get
 * key and value of flat xml.
 * Feel free to use this piece of code as you like with/out permission - if possible mention this site.
 * I am not responsible for any consequences that would result after using this piece of code.
 *
 * @author http://gullele.com
 */
public class XMLHelper {
	private DocumentBuilderFactory documentBuilderFactory;
	private DocumentBuilder documentBuilder;

	public XMLHelper(){
		try{
			this.documentBuilderFactory = DocumentBuilderFactory.newInstance();
			this.documentBuilder = this.documentBuilderFactory.newDocumentBuilder();
		}
		catch(ParserConfigurationException pce){
			//log error
		}
	}

	//Simple test
	public static void main(String argv[]) {
		XMLHelper xmlHelper = new XMLHelper();
		  try {
			  String xmlDoc = "<?xml version="1.0"?><flatFields><java>6.0</java><xml>yes</xml><tags>given tags</tags><doc /><multipleRow /></flatFields>";
			  Document doc = xmlHelper.getDocumentBuilder().parse(
					  xmlHelper.getInputStream(xmlDoc)
			  );
			  doc.getDocumentElement().normalize();
			  NodeList nodeLst = doc.getDocumentElement().getChildNodes();
			  Map elemen = xmlHelper.getElementKeyValue(nodeLst);
			  Iterator it = elemen.entrySet().iterator();
			  while (it.hasNext()) {
				  Map.Entry pairs = (Map.Entry)it.next();
				  	System.out.println(pairs.getKey() + " = " + pairs.getValue());
			  }
			} catch (SAXParseException e) {
			   //log error
			} catch (SAXException e) {
				   //log error
			} catch (IOException e) {
				   //log error
			}
	}

	/**
	 * Provides NodeList from the given Document object by the tagName
	 * @param Document - doc
	 * @param tagname
	 * @return NodeList
	 */
	public NodeList getNodeListByTag(Document doc, String tagname){
		NodeList nodeList = null;
		if (doc !=null && !tagname.isEmpty()){
			nodeList = doc.getElementsByTagName(tagname);
		}
		return nodeList;
	}

	/**
	 *
	 * @param nodeList
	 * @return Map
	 */
	public Map getElementKeyValue(NodeList nodeList){
		Map elements = new HashMap();
		if (nodeList!=null && nodeList.getLength()>0 ){
			for(int i=0 ; i < nodeList.getLength() ; i++){
				Node node = nodeList.item(i); //Take the node from the list
				NodeList valueNode = node.getChildNodes(); // get the children of the node
		        String value = (valueNode.item(0)!=null) ? valueNode.item(0).getNodeValue() : "";
		        elements.put(node.getNodeName(), value);
			}
		}
		return elements;
	}

	/**
	 * Returns InputString given string
	 * @param string
	 * @return InputStream
	 */
	public InputStream getInputStream(String string){
		InputStream inputStream = null;
		if (!string.isEmpty()){
			try{
				inputStream = new ByteArrayInputStream(string.getBytes("UTF-8"));
			}
			catch(UnsupportedEncodingException uee){
			}
		}
		return inputStream;
	}

	/**
	 * Setters and getters
	 * @return
	 */
	public DocumentBuilderFactory getDocumentBuilderFactory() {
		return documentBuilderFactory;
	}
	public void setDocumentBuilderFactory(
			DocumentBuilderFactory documentBuilderFactory) {
		this.documentBuilderFactory = documentBuilderFactory;
	}
	public DocumentBuilder getDocumentBuilder() {
		return documentBuilder;
	}
	public void setDocumentBuilder(DocumentBuilder documentBuilder) {
		this.documentBuilder = documentBuilder;
	}
}

An output for the test main method would be:
tags = given tags
doc =
multipleRow =
xml = yes
java = 6.0

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