保存到文件后，已编辑的XML内容不会更改

Question

I am parsing an XML file to modify possibly all values and save. But after save, there are no changes. What am i doing wrong or what can i do better ?

My goal is to parse all contents in an XML file, check for all strings containing special characters and replace them with escape characters. Please don't ask why, the parser that receives the XML document doesn't treat these characters so i am left with no choice but to escape them.

String xmlfile = FileUtils.readFileToString(new File(filepath));


       DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
       DocumentBuilder docBuilder = docFactory.newDocumentBuilder();
       Document doc = docBuilder.parse(new InputSource(new StringReader(xmlfile)));

       NodeList nodeList = doc.getElementsByTagName("*");

       for (int i = 0; i < nodeList.getLength(); i++)
       {        
           Node currentNode = nodeList.item(i);

           if (currentNode.getNodeType() == Node.ELEMENT_NODE)
           {               
             if (currentNode.getFirstChild()==null)
                  {}
              else {currentNode.setNodeValue(StringEscapeUtils.escapeXml(currentNode.getFirstChild().getNodeValue())); }
           } 
       }


         TransformerFactory transformerFactory = TransformerFactory.newInstance();
         javax.xml.transform.Transformer transformer = transformerFactory.newTransformer();
         DOMSource source = new DOMSource(doc);

         StringWriter writer = new StringWriter();
         StreamResult result = new StreamResult(writer);
         transformer.transform(source, result);


       FileOutputStream fop = null;
       File file;

       file = File.createTempFile("escapedXML"+UUID.randomUUID(), ".xml");

       fop = new FileOutputStream(file);

       String xmlString = writer.toString();
       byte[] contentInBytes = xmlString.getBytes();

       fop.write(contentInBytes);
       fop.flush();
       fop.close();

Answer 1

You are updating the Element node, and that operation has no effect. Besides, I think the following is more robust, since it wll iterate over all text nodes, and not just the first.

for (int i = 0; i < nodeList.getLength(); i++) {
    Node currentNode = nodeList.item(i);
    if (currentNode.getNodeType() == Node.ELEMENT_NODE) {
        Node child = currentNode.getFirstChild();
        while(child != null) {
            if (child.getNodeType() == Node.TEXT_NODE) {
                child.setTextContent(StringEscapeUtils.escapeXml(child.getNodeValue()));
            }
            child = child.getNextSibling();
        }
    }
}