Question

I am using following code to remove some specific nodes from xml file..It show correct output on console
but somehow xml file is not getting updated..the contents remains as it is..
please help..
Thanks…

package com.sumit.xml.client;

import java.io.*;

import org.apache.xml.serialize.OutputFormat;
import org.apache.xml.serialize.XMLSerializer;
import org.w3c.dom.*;
import org.xml.sax.*;
import javax.xml.parsers.*;
import javax.xml.transform.*; 
import javax.xml.transform.dom.DOMSource; 
import javax.xml.transform.stream.StreamResult;

public class ReadCDATA {
  static public void main(String[] arg) {
  try{
  BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
  System.out.print("Enter a XML file name: ");
  String xmlFile = bf.readLine();
  File file = new File(xmlFile);
  System.out.print("Enter an element which have to delete: ");
  String remElement = bf.readLine();
  if (file.exists()){
  DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
  DocumentBuilder builder = factory.newDocumentBuilder();
  Document doc = builder.parse(xmlFile);
  TransformerFactory tFactory = TransformerFactory.newInstance();
  Transformer tFormer = tFactory.newTransformer();
  Element element = (Element)doc.getElementsByTagName(remElement).item(0);
//  Remove the node
  element.getParentNode().removeChild(element);
//  Normalize the DOM tree to combine all adjacent nodes
  doc.normalize();
  Source source = new DOMSource(doc);
  Result dest = new StreamResult(System.out);
  tFormer.transform(source, dest);
  System.out.println();

  }
  else{
  System.out.println("File not found!");
  }
  }
  catch (Exception e){
  System.err.println(e);
  System.exit(0);
  }
  }
} 

Answer 1

DOM is changed in process memory only. There’s nothing in code you shown which would write data to the underlying XML file transparently.

You need to add something like

createOutputFile("output.xml", transformToString(document));

private static String transformToString(Document document) {
    try {
        TransformerFactory transFactory = TransformerFactory.newInstance();
        Transformer transformer = transFactory.newTransformer();
        StringWriter buffer = new StringWriter();
        transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
        transformer.setOutputProperty(OutputKeys.INDENT, "yes");
        transformer.transform(new DOMSource(document), new StreamResult(buffer));
        return buffer.toString();
    } catch (TransformerException e) {
        throw new RuntimeException(e);
    }
}


private static void createOutputFile(String filePath, String content) {
    FileWriter writer = null;
    try {
        try {
            writer = new FileWriter(filePath);
            writer.write(content);
        } finally {
            if (writer != null) {
                writer.flush();
                writer.close(); 
            }
        }
    } catch (IOException e) {
        throw new RuntimeException(e);
    }
}