How to modify a huge XML file by StAX?

Question

I have a huge XML (~2GB) and I need to add new Elements and modify the old ones. For example, I have:

    ....
    ...         


        

Answer 1

Try this

    XMLInputFactory inFactory = XMLInputFactory.newInstance();
    XMLEventReader eventReader = inFactory.createXMLEventReader(new FileInputStream("1.xml"));
    XMLOutputFactory factory = XMLOutputFactory.newInstance();
    XMLEventWriter writer = factory.createXMLEventWriter(new FileWriter(file));
    XMLEventFactory eventFactory = XMLEventFactory.newInstance();
    while (eventReader.hasNext()) {
        XMLEvent event = eventReader.nextEvent();
        writer.add(event);
        if (event.getEventType() == XMLEvent.START_ELEMENT) {
            if (event.asStartElement().getName().toString().equalsIgnoreCase("book")) {
                writer.add(eventFactory.createStartElement("", null, "index"));
                writer.add(eventFactory.createEndElement("", null, "index"));
            }
        }
    }
    writer.close();

Notes

new FileWriter(file, true) is appending to the end of the file, you hardly really need it

equalsIgnoreCase("book") is bad idea because XML is case-sensitive