JAVA EE: How to convert an object into XML and XML into object using JAXB? - Employee Example

Saturday, 14 September 2019

How to convert an object into XML and XML into object using JAXB? - Employee Example | JAXB Tutorial

💡 Level Up Your Java Skills with Ram N Java!

Subscribe now for clear explanations, practical coding demos, and end-to-end tutorials.

Introduction to JAXB

JAXB (Java Architecture for XML Binding) provides a simple and clean API to convert Java objects into XML documents and vice versa. It removes the need for tedious manual parsing with DOM or SAX.

Core Operations in JAXB

Marshalling: Converting a Java object representation into an XML file or stream.
Unmarshalling: Reading an XML file or stream and converting it back into a Java object.

Annotations Used in Employee Example

@XmlRootElement: Specifies that the Employee class represents the root element in the generated XML.
@XmlAttribute: Configures a property (like id) to appear as an attribute of the XML root tag.
@XmlElement: Maps class fields (like name and salary) to child elements within the XML.

Step-by-Step Code Walkthrough

1. Annotated Employee Class

@XmlRootElement(name = "employee")
public class Employee {
    private int id;
    private String name;
    private double salary;

    public Employee() {}

    public Employee(int id, String name, double salary) {
        this.id = id;
        this.name = name;
        this.salary = salary;
    }

    @XmlAttribute(name = "id")
    public int getId() { return id; }
    public void setId(int id) { this.id = id; }

    @XmlElement(name = "name")
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }

    @XmlElement(name = "salary")
    public double getSalary() { return salary; }
    public void setSalary(double salary) { this.salary = salary; }
}

2. Marshalling: Java Object to XML

JAXBContext context = JAXBContext.newInstance(Employee.class);
Marshaller marshaller = context.createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);

Employee emp = new Employee(1, "Peter", 50000);
FileOutputStream fos = new FileOutputStream("employee.xml");
marshaller.marshal(emp, fos);
fos.close();

3. Unmarshalling: XML to Java Object

JAXBContext context = JAXBContext.newInstance(Employee.class);
Unmarshaller unmarshaller = context.createUnmarshaller();

File xmlFile = new File("employee.xml");
Employee emp = (Employee) unmarshaller.unmarshal(xmlFile);
System.out.println(emp);