Appending data to existing XML file

[Booma Devi]

Hi,

Can any one tell how to append the new element to existing xml file? I have the following code..


import org.w3c.dom.*;

import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.stream.*;
import java.io.*;

import javax.xml.transform.dom.DOMSource;

class processXML
{
public void process(String name) throws Exception, DOMException,ParserConfigurationException
{

DocumentBuilderFactory dbf=DocumentBuilderFactory.newInstance();
DocumentBuilder db =dbf.newDocumentBuilder();

// Read books.xml file
Document dct=db.parse("C:\\Data\\books.xml");

Element child1 = dct.createElement("Name");
// Get the root node so we can explore its children

Element root = dct.getDocumentElement();
root.appendChild(child1);
// Get the element from the user..
Text text1 = dct.createTextNode(name);
// Append the element to existing XML file
root.getLastChild().appendChild(text1);


// Create blank document
Document mainDoc = db.newDocument();
Element root1 = mainDoc.createElement("Root1");
mainDoc.appendChild(root1);

// Copy the existing XML file with newly created element
root1.appendChild(mainDoc.importNode(root, true));

// Save the created DOM tree to XML file...

Transformer transformer = TransformerFactory.newInstance().newTransformer();
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
StreamResult result = new StreamResult(new FileWriter("C:\\Data\\LBN.xml"));
DOMSource source = new DOMSource(mainDoc);
transformer.transform(source, result);
System.out.println("File saved!");

}
}


public class XMLTest
{
public static void main(String args[])throws Exception,DOMException

{


BufferedReader in= new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter element");

String name = null;
processXML p=new processXML();

while((name=in.readLine())!=null)
{
p.process(name);
}

}


}

books.xml:
***********

<?xml version="1.0" encoding="UTF-8" standalone="no" ?>
- <Root>
<Name>rev</Name>
</Root>


When I add the element "Hello" to the books.xml file for the first time, system appended the element Hello in books.xml file.. but for the second time , it overwrite the hello .. How can i append the element to existing file.. ?

[John Jai]

Hi Rt,

The issue is that every a new DOM document gets created and written into the file. Check before you add whether the existing file (BN.xml) has already nodes or not.

Next time please UseCodeTags - I have added and updated the code below. See how good it looks.

import java.io.*;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.*;

class processXML 
{ 
	public void process(String name) throws Exception, DOMException,ParserConfigurationException { 
		DocumentBuilderFactory dbf= DocumentBuilderFactory.newInstance(); 
		DocumentBuilder db = dbf.newDocumentBuilder(); 

		Document dct=db.parse(new File("C:\\books.xml")); 

		Element child1 = dct.createElement("Name"); 

		Element root = dct.getDocumentElement(); 
		root.appendChild(child1); 

		Text text1 = dct.createTextNode(name); 
		root.getLastChild().appendChild(text1); 

		//Document mainDoc = db.newDocument();
		Document mainDoc = db.parse(new File("C:\\BN.xml"));
		if (mainDoc.getDocumentElement() == null){
			Element root1 = mainDoc.createElement("Root1"); 
			mainDoc.appendChild(root1);
		}		
		mainDoc.getDocumentElement().appendChild(mainDoc.importNode(root, true)); 		

		Transformer transformer = TransformerFactory.newInstance().newTransformer(); 
		transformer.setOutputProperty(OutputKeys.INDENT, "yes"); 
		StreamResult result = new StreamResult(new FileWriter("C:\\BN.xml")); 
		DOMSource source = new DOMSource(mainDoc); 
		transformer.transform(source, result); 
		System.out.println("File saved!"); 
	} 
} 

public class XMLTest { 
	public static void main(String args[])throws Exception,DOMException 	{ 
		BufferedReader in= new BufferedReader(new InputStreamReader(System.in)); 
		System.out.println("Enter element"); 
		String name = null; 
		processXML p=new processXML();
		while((name=in.readLine())!=null) 
		{ 
			p.process(name); 
		} 
	} 
} 

[Booma Devi]

Thank you so much John for spending time to read my code and gave suggestion..

[Ashish Agre]

import java.io.*;
import org.w3c.dom.*;
import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.*;
import javax.xml.transform.stream.*;

public class CreateMessageXMLFile {
	public static void main(String...args) {
		String[] data = {"FROM", "SUBJECT", "CONTENTTYPE", "DATE", "MESSAGEID", "ISMULTIPART"};
		String [] data1 = {"[e-mail]", "hi", "text/html", "21 March'12", "1735299191", "true"};
		String [] data2 = {"[e-mail]", "hello", "text/plain", "1'st March'12", "17892892299191", "true"};

		String language = "Language";
		try{
			DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
			DocumentBuilder db = dbf.newDocumentBuilder();
			Document document = db.newDocument();

			//create and attach root element to the XML File
			Element rootElement = document.createElement("Inbox");
			document.appendChild(rootElement);

			for(int i=0;i<2;i++) {
				Element element = document.createElement("Message");
				for(int j=0;j<data.length;j++) {
				Element elementInside = document.createElement(data[j]);
				Text text = document.createTextNode(data1[j]);
				elementInside.appendChild(text);
				element.appendChild(elementInside);
				rootElement.appendChild(element);
				}
			}
			TransformerFactory tf = TransformerFactory.newInstance();
			Transformer t = tf.newTransformer();
			t.setOutputProperty(OutputKeys.INDENT, "yes");
			t.setOutputProperty(OutputKeys.INDENT, "yes");
			File f = new File("Message.xml");
			StreamResult sr = new StreamResult(f);
			Node node = document.getDocumentElement();
			DOMSource src = new DOMSource(node);
			t.transform(src, sr);
			//String str = sw.toString();
			//System.out.println(str);
			/*BufferedWriter bw = new BufferedWriter(new FileWriter("ProgrammingLanguages.xml"));
			bw.write(str);
			bw.flush();
			bw.close();*/

			document = db.parse("Message.xml");
			rootElement = document.getDocumentElement();
			for(int i=0;i<2;i++) {
				Element element = document.createElement("Message");
				for(int j=0;j<data.length;j++) {
				Element elementInside = document.createElement(data[j]);
				Text text = document.createTextNode(data2[j]);
				elementInside.appendChild(text);
				element.appendChild(elementInside);
				rootElement.appendChild(element);
				}
			}
			File ff = new File("Message.xml");
						StreamResult srf = new StreamResult(ff);
						Node nodef = document.getDocumentElement();
						DOMSource srcf = new DOMSource(nodef);
			t.transform(srcf, srf);
		}catch(Exception e) {
			e.printStackTrace();
		}
	}
}

May be you are done with this, but i used this code to modify my XML File