XML Parsing in Java

Estimated study time: 16 minutes.

Java's standard library ships with built-in support for all three major XML parsing approaches — DOM, SAX, and StAX — so you don't need any external dependency to get started.

DOM Parsing in Java

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse(new File("course.xml"));

NodeList titles = doc.getElementsByTagName("title");
System.out.println(titles.item(0).getTextContent());

SAX Parsing in Java

SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser parser = factory.newSAXParser();

parser.parse("course.xml", new DefaultHandler() {
    public void startElement(String uri, String localName,
                              String qName, Attributes attrs) {
        System.out.println("Start: " + qName);
    }
});

StAX Parsing in Java

XMLInputFactory factory = XMLInputFactory.newInstance();
XMLStreamReader reader = factory.createXMLStreamReader(new FileReader("course.xml"));

while (reader.hasNext()) {
    reader.next();
}

Choosing an Approach in Java

• DOM — small configuration files, or when you need to edit and rewrite the XML.
• SAX — very large files where you only need to extract specific data in a single pass.
• StAX — large files where you also want cleaner, more controllable code than SAX offers.