XML处理与解析：Java代码示例，包括DOM、SAX和JAXB

原创今天药忘吃喽~ 2024-10-21 04:03 80阅读 0赞

XML处理和解析在Java中可以使用DOM（Document Object Model）、SAX（Simple API for XML）和JAXB（Java Architecture for XML Binding）等技术。

以下是这几种方法的Java代码示例：

1. DOM：
```java
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

public class DOMExample {
    public static void main(String[] args) {
        try {
            // Create a Document
            DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
            Document doc = docFactory.newDocument();

// Set the root element
            Element rootElement = doc.createElement("root");
            doc.appendChild(rootElement);

// Create child elements and add to document
            for (int i = 1; i <= 5; i++) {
                Element childElement = doc.createElement("child");
                childElement.setTextContent(Integer.toString(i));
                rootElement.appendChild(childElement);
            }

// Print the whole XML Document
            System.out.println(doc);

} catch (Exception e) {
            e.printStackTrace();
        }
    }
}
```

2. SAX：
```java
import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;

public class SAXExample {
    public static void main(String[] args) throws Exception {
        XMLReader reader = XMLReaderFactory.newXMLReader();
        MySAXHandler handler = new MySAXHandler();
        reader.setContentHandler(handler);
        reader.parse(new InputSource(new File("example.xml")))));

// Print the whole XML Document
        System.out.println(handler.getXml());
    }
}

class MySAXHandler extends DefaultHandler {
    private StringBuilder xmlBuilder = new StringBuilder();

@Override
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
        xmlBuilder.append("<").append(localName).append(">");

if (attributes != null) {
            for (Object pair : attributes.entrySet())) {
                Attribute attribute = (Attribute) pair;
                xmlBuilder.append(" ").append(attribute.getName()).append("=\"").append(attribute.getValue()).append("\"");
            }
        }
    }

@Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
        xmlBuilder.append("</").append(localName).append(">");
    }

public String getXml() {
        return xmlBuilder.toString();
    }
}
```

3. JAXB（Java API for XML Binding）：
```java
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBElement;
import java.io.File;

public class JAXBExample {
    public static void main(String[] args) throws Exception {
        // Create a JAXB Context for the desired XML Schema
        JAXBContext context = JAXBContext.newInstance("com.example.schema", new Class[]{File.class}));

// Unmarshal the XML file into a Java object
        File xmlFile = new File("example.xml");
        JAXBElement<YourObject> element = context.createUnmarshaller().unmarshal(xmlFile, YourObject.class);

// Access the object's data and print it
        YourObject yourObject = element.getValue();
        System.out.println(yourObject.getProperty1() + " " + yourObject.getProperty2()));

// Also, you can marshall this Java object back into XML.
        JAXBElement<YourObject> marshalledElement = new JAXBElement<YourObject>(new QName("yourElementName"), YourObject.class), null, yourObject);
        String marshalledXml = context.createMarshaller().marshal(marshalledElement));
        System.out.println("Marshalled XML: " + marshalledXml);
    }
}

// Create a Java class to represent the XML structure
class YourObject {
    String property1;
    String property2;

// Constructor, getters and setters (omitted for brevity)
}
```
注意：以上示例中，你需要将`YourObject`, `YourElementName`等替换为你的实际XML结构和Java类名。