Hello Programmers,

A number of times, we need to cast our Java object into an XML or vice-versa. The turms are technically know as marshalling and un-marshalling. There are many different Java libraries to do the same in which Castor and JAXB are commonly used.

I am going to use JAXB as this comes with our JDK 1.6+ package.

Let understand with an example. Suppose we have a company with a number of its employees. So, we all might have similar class hierarchy in our mind to represent it. 

package com.evontech.blog;

import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement
public class Company {
	
	private EmployeeList employeeList;

	public EmployeeList getEmployeeList() {
		return employeeList;
	}

	@XmlElement
	public void setEmployeeList(EmployeeList employeeList) {
		this.employeeList = employeeList;
	}
	
}

In the code snippet above, Annotation @XmlRootElement describe as this class will be the root of the XML. @XmlElement is an element for that root.

That's it. Let's test it.

package com.evontech.blog;

import java.io.File;
import java.util.ArrayList;
import java.util.List;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.Marshaller;

import org.junit.Test;

public class BlogTest {

	@Test
	public void testJaxb() {

		List<Employee> empoyees = new ArrayList<Employee>();

		Employee emp1 = new Employee();
		emp1.setId(1);
		emp1.setName("Dinesh");
		empoyees.add(emp1);

		Employee em2 = new Employee();
		em2.setId(2);
		em2.setName("Babita");
		empoyees.add(em2);
		
		EmployeeList empList = new EmployeeList();
		empList.setEmployees(empoyees);

		Company company = new Company();
		company.setEmployeeList(empList);

		try {

			File file = new File("D:\\file.xml");
			if(!file.exists()) {
				file.createNewFile();
			}
			JAXBContext jaxbContext = JAXBContext.newInstance(Company.class);
			Marshaller jaxbMarshaller = jaxbContext.createMarshaller();

			// output pretty printed
			jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);

			jaxbMarshaller.marshal(company,file);
		} catch(Exception e) {
			e.printStackTrace();
		}
	}

}

Just run this test case. If you will check the file in your D drive.

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<company>
    <employeeList>
        <employees>
            <id>1</id>
            <name>Dinesh</name>
        </employees>
        <employees>
            <id>2</id>
            <name>Babita</name>
        </employees>
    </employeeList>
</company>

Thanks :)

Happy programming.