JAXB 在内部使用 SAX 或 DOM 吗

JAXB（Java Architecture for XML Binding）是Java平台上一个用于将XML数据与Java对象相互转换的技术。它提供了一种简单的方式来映射XML文档的元素和属性到Java对象的属性，从而方便开发人员处理XML数据。在JAXB内部，既可以使用SAX（Simple API for XML）解析器，也可以使用DOM（Document Object Model）解析器。

java
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.XMLReaderFactory;
public class JAXBExample {
  public static void main(String[] args) {
    try {
      // 创建JAXBContext对象
      JAXBContext jaxbContext = JAXBContext.newInstance(Employee.class);
      
      // 创建SAX解析器
      XMLReader xmlReader = XMLReaderFactory.createXMLReader();
      
      // 创建Unmarshaller对象
      Unmarshaller unmarshaller = jaxbContext.createUnmarshaller();
      
      // 设置Unmarshaller的SAX解析器
      unmarshaller.setUnmarshallerHandler(xmlReader.getContentHandler());
      
      // 解析XML数据并转换为Java对象
      Employee employee = (Employee) unmarshaller.unmarshal(new InputSource("employee.xml"));
      
      // 打印Java对象的属性
      System.out.println("Employee ID: " + employee.getId());
      System.out.println("Employee Name: " + employee.getName());
      System.out.println("Employee Age: " + employee.getAge());
    } catch (JAXBException | SAXException e) {
      e.printStackTrace();
    }
  }
}

java
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;
import org.w3c.dom.Document;
import org.xml.sax.InputSource;
public class JAXBExample {
  public static void main(String[] args) {
    try {
      // 创建JAXBContext对象
      JAXBContext jaxbContext = JAXBContext.newInstance(Employee.class);
      
      // 创建DOM解析器
      DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
      DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
      
      // 解析XML数据并转换为Document对象
      Document document = dBuilder.parse(new InputSource("employee.xml"));
      
      // 创建Unmarshaller对象
      Unmarshaller unmarshaller = jaxbContext.createUnmarshaller();
      
      // 解析Document对象并转换为Java对象
      Employee employee = (Employee) unmarshaller.unmarshal(document);
      
      // 打印Java对象的属性
      System.out.println("Employee ID: " + employee.getId());
      System.out.println("Employee Name: " + employee.getName());
      System.out.println("Employee Age: " + employee.getAge());
    } catch (JAXBException | ParserConfigurationException | SAXException | IOException e) {
      e.printStackTrace();
    }
  }
}