JAXB hello world example

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.

 
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.

 
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("teachtoJava");
   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

 version="1.0" encoding="UTF-8" standalone="yes"?>
 id="100">
    >29

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.

 
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=teachtoJava, age=29, id=100]

TeachToJava

Wednesday, August 29, 2012

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