Java中常见的XML解析方法与应用详解

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

SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser parser = factory.newSAXParser();
XMLHandler handler = new XMLHandler();
parser.parse(new File("example.xml"), handler);

// Sample Java class
@XmlRootElement
public class Person {
    private String name;
    private int age;

    // Getters and setters
}

// Usage of JAXB
JAXBContext context = JAXBContext.newInstance(Person.class);
Unmarshaller unmarshaller = context.createUnmarshaller();
Person person = (Person) unmarshaller.unmarshal(new File("example.xml"));

// Using XPath
XPathFactory xPathFactory = XPathFactory.newInstance();
XPath xPath = xPathFactory.newXPath();
String value = xPath.evaluate("/root/element", document);

// Using DOM
Element element = (Element) document.getElementsByTagName("element").item(0);
String value = element.getTextContent();

Element element = (Element) document.getElementsByTagName("element").item(0);
element.setTextContent("New Value");

// Save changes
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
transformer.transform(new DOMSource(document), new StreamResult(new File("example.xml")));

Element newElement = document.createElement("newElement");
newElement.setTextContent("Value");

Element parentElement = (Element) document.getElementsByTagName("parent").item(0);
parentElement.appendChild(newElement);

// Example using HttpURLConnection
URL url = new URL("https://api.example.com/data");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
InputStream inputStream = connection.getInputStream();

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse(inputStream);

// Example using DOM parser
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse(new File("config.xml"));

// Extract configuration values
String value = document.getElementsByTagName("param").item(0).getTextContent();

// Example using JAXB
JAXBContext context = JAXBContext.newInstance(Person.class);
Marshaller marshaller = context.createMarshaller();
Person person = new Person("John", 25);
marshaller.marshal(person, new File("person.xml"));