Introduction:

Handling XML data in Java applications often requires converting it into Java objects for easy manipulation and processing. In this blog, we will explore three powerful techniques for XML to object conversion: JAXB, DOM Parser, and Jackson XML. Through practical examples and step-by-step explanations, you will learn how to efficiently convert XML data into Java objects. So let's dive in and master the art of XML to object conversion in Java.

Method 1: Using JAXB (Java Architecture for XML Binding)

JAXB provides a convenient way to map XML elements and attributes to Java classes. To illustrate this technique, consider the following example:

import javax.xml.bind.annotation.*;

@XmlRootElement(name = "book")
public class Book {
    @XmlElement
    private String title;
    @XmlElement
    private String author;
    // Getters and setters
}

// Perform XML to object conversion using JAXB
import javax.xml.bind.*;

public class JAXBExample {
    public static void main(String[] args) throws JAXBException {
        JAXBContext jaxbContext = JAXBContext.newInstance(Book.class);
        Unmarshaller unmarshaller = jaxbContext.createUnmarshaller();
        Book book = (Book) unmarshaller.unmarshal(new File("book.xml"));

        System.out.println("Title: " + book.getTitle());
        System.out.println("Author: " + book.getAuthor());
    }
}

Output:

Title: The Great Gatsby
Author: F. Scott Fitzgerald

Method 2: Using DOM Parser

The DOM Parser allows manual parsing and mapping of XML elements to Java objects. Let's see an example that demonstrates this approach:

import org.w3c.dom.*;
import javax.xml.parsers.*;
import java.io.*;

public class DOMParserExample {
    public static void main(String[] args) throws Exception {
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder = factory.newDocumentBuilder();
        Document document = builder.parse(new File("book.xml"));

        NodeList bookNodes = document.getElementsByTagName("book");
        for (int i = 0; i < bookNodes.getLength(); i++) {
            Element bookElement = (Element) bookNodes.item(i);
            String title = bookElement.getElementsByTagName("title").item(0).getTextContent();
            String author = bookElement.getElementsByTagName("author").item(0).getTextContent();

            System.out.println("Title: " + title);
            System.out.println("Author: " + author);
        }
    }
}

Output:

Title: The Great Gatsby
Author: F. Scott Fitzgerald

Method 3: Using Jackson XML

Jackson XML provides powerful data-binding capabilities for XML in Java. Consider the following example:

import com.fasterxml.jackson.dataformat.xml.*;

public class JacksonXMLExample {
    public static void main(String[] args) throws Exception {
        XmlMapper xmlMapper = new XmlMapper();
        Book book = xmlMapper.readValue(new File("book.xml"), Book.class);

        System.out.println("Title: " + book.getTitle());
        System.out.println("Author: " + book.getAuthor());
    }
}

Output:

Title: The Great Gatsby
Author: F. Scott Fitzgerald

Conclusion:

In this blog, we explored three popular techniques for XML to object conversion in Java. We learned about JAXB, which provides a declarative approach for mapping XML elements to Java classes. Additionally, we explored the DOM Parser technique for manual parsing and object creation. Lastly, we discovered the power of Jackson XML for XML data-binding in Java.