JAXB Hello World Example

jaxb-sample.md

JAXB, stands for Java Architecture for XML Binding, using JAXB annotation to convert Java object to / from XML file. In this tutorial, we show you how to use JAXB to do following stuffs :

• Marshalling – Convert a Java object into a XML file.
• Unmarshalling – Convert XML content into a Java Object.

Technologies used in this article

• JDK 1.6
• JAXB 2.0

Working with JAXB is easy, just annotate object with JAXB annotation, later use jaxbMarshaller.marshal() or jaxbMarshaller.unmarshal() to do the object / XML conversion.

1. JAXB Dependency =================

No extra jaxb libraries are required if you are using JDK1.6 or above, because JAXB is bundled in JDK 1.6.

Note: For JDK < 1.6, download JAXB from here, and puts “jaxb-api.jar” and “jaxb-impl.jar” on your project classpath.

2. JAXB Annotation ===================

For object that need to convert to / from XML file, it have to annotate with JAXB annotation. The annotation are pretty self-explanatory, you can refer to this JAXB guide for detail explanation.

package com.mkyong.core;
 
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
 
@XmlRootElement
public class Customer {
	String name;
	int age;
	int id;
 
	public String getName() {
		return name;
	}
 
	@XmlElement
	public void setName(String name) {
		this.name = name;
	}
 
	public int getAge() {
		return age;
	}
 
	@XmlElement
	public void setAge(int age) {
		this.age = age;
	}
 
	public int getId() {
		return id;
	}
 
	@XmlAttribute
	public void setId(int id) {
		this.id = id;
	}
}

3. Convert Object to XML ============================

JAXB marshalling example, convert customer object into a XML file. The jaxbMarshaller.marshal() contains a lot of overloaded methods, find one that suit your output.

package com.mkyong.core;
 
import java.io.File;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
 
public class JAXBExample {
    public static void main(String[] args) {
        Customer customer = new Customer();
        customer.setId(100);
        customer.setName("mkyong");
        customer.setAge(29);
    
        try {
            File file = new File("C:\\file.xml");
            JAXBContext jaxbContext = JAXBContext.newInstance(Customer.class);
            Marshaller jaxbMarshaller = jaxbContext.createMarshaller();
            
            // output pretty printed
            jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
            
            jaxbMarshaller.marshal(customer, file);
            jaxbMarshaller.marshal(customer, System.out);
        } catch (JAXBException e) {
            e.printStackTrace();
        }
    }
}

Output

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<customer id="100">
    <age>29</age>
    <name>mkyong</name>
</customer>

4. Convert XML to Object ====================================

JAXB unmarshalling example, convert a XML file content into a customer object. The jaxbMarshaller.unmarshal() contains a lot of overloaded methods, find one that suit yours.

package com.mkyong.core;
 
import java.io.File;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;
 
public class JAXBExample {
    public static void main(String[] args) {
        try {
            File file = new File("C:\\file.xml");
            JAXBContext jaxbContext = JAXBContext.newInstance(Customer.class);
            
            Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
            Customer customer = (Customer) jaxbUnmarshaller.unmarshal(file);
            System.out.println(customer);
        } catch (JAXBException e) {
            e.printStackTrace();
        }
    }
}

Output

Customer [name=mkyong, age=29, id=100]

References

• JAXB Official Website
• J2EE 5 JAXB tutorial