[SOLVED] Update an XML file

[Eranga]

Hi all,

Here is my XML file format.

 <?xml version="1.0"?>

<data>
<key>467</key>
<name>Paul</name>
<id>123</id>
</data>

Using DOM, read the xml file and get the value of id. Then I want to do some modification on that value and write back/or update the existing value into new one.

I tried this.

        try{
            DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance();
            DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder();
            
            Document doc = docBuilder.parse (new File("records.xml"));
            
            NodeList ints = doc.getElementsByTagName("option");
            if(ints.getLength() != 0) {
                Element firstKeyElement = (Element)ints.item(0);
                NodeList firstKey = firstKeyElement.getChildNodes();
                
                String value = ((Node)firstKey.item(0)).getNodeValue().trim();
                System.out.println(value);
                
            // change the value and write it to the same location
                setValue((Node)firstKey.item(0), "ssss");
             }
        }

Here is the setValue() method.

    private static void setValue(Node node, String value){
            if(node.getNodeType()!=Node.TEXT_NODE){
                    NodeList l=node.getChildNodes();
                    for(int i=0;i<l.getLength();i++){
                            if(l.item(i).getNodeType()==Node.TEXT_NODE){
                                    l.item(i).setNodeValue(value);
                                    return;
                            }
                            
                    }
            }
            else{
                try{
                    node.setTextContent(value);
                }
                catch(DOMException e) {
                    System.out.println(e.getMessage() + " " + e.getLocalizedMessage());
                }
            }
    }

But it not update the value. At the time I just try to write a string, without doing any modifications on the existing value.

Anyone of you can figure, where I'm going wrong. Debug and try but no any exceptions at all.

Eranga.

[pankaj_salwan]

i did that... use SetTextCOntent anf then write dom to a file
as follows:--
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
DOMSource source = new DOMSource(doc);
//StreamResult result = new StreamResult(System.out);
StreamResult result = new StreamResult("out.txt");
transformer.transform(source, result);

[Eranga]

That's a different approach. I feel it's not easy to me, still not able to fix it. So that why I suggested a different way to you.

[Amrutha]

Eranga,
I think what pankaj posted is correct. In ur code ur modified the value but ur not writing the modified content back into file. Thats what "Transformer" will do for u.
U can check "java.sun.com/j2se/1.4.2/docs/api/javax/xml/transform/Transformer.html" for more info. :o

[Eranga]

Yes, as I said it's another approach pal. I've already solved this. Thanks for the comment.