Javax.xml.bind.JAXBElement Class

Introduction

The javax.xml.bind.JAXBElement class is the JAXB representation of an Xml Element.This class represents information about an Xml Element from both the element declaration within a schema and the element instance value within an xml document with the following properties −

• element's xml tag name

• value represents the element instance's atttribute(s) and content model

• element declaration's declaredType (xs:element @type attribute)

• scope of element declaration

• boolean nil property. (element instance's xsi:nil attribute)

Class declaration

Following is the declaration for javax.xml.bind.JAXBElement class −

public class JAXBElement<T>
   extends Object
      implements Serializable

Field

Following are the fields for javax.xml.bind.JAXBElement class −

• protected Class<T> declaredType − This is the Java datatype binding for xml element declaration's type

• protected QName name − This is the xml element tag name.

• protected boolean nil − This is true if the xml element instance has xsi:nil="true".

• protected Class scope − This is the scope of xml element declaration representing this xml element instance.

• protected T value − This is the xml element value.

Class constructors

Class methods

Methods inherited

This class inherits methods from the following classes −

javax.xml.Object

Example

The following example shows the usage of java.xml.bind.JAXBElement class. To proceed, consider the following Student class which will be used to have objects for marshalling and unmarshalling purposes −

package com.tutorialspoint;

import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
 
@XmlRootElement
public class Student{
 
   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;
   }
}

Now let us create main class which will be used to marshal ie. convert Student object to XML. Here we will create a JAXBElement of a Student object and then update StringWriter object using JAXBContext. This example marshals the Student object and prints the XML.

package com.tutorialspoint;

import java.io.StringWriter;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBElement;
import javax.xml.bind.JAXBException;
import javax.xml.namespace.QName;

public class JAXBElementDemo {
   public static void main(String[] args) {
      //Create a student object
      Student student = new Student();

      //fill details of the student
      student.setName("Robert");
      student.setId(1);
      student.setAge(12);

      try {
         //create JAXBElement of type Student
         //Pass it the student object
         JAXBElement<Student> jaxbElement =  new JAXBElement( 
            new QName(Student.class.getSimpleName()), Student.class, student);

         //Create a String writer object which will be 
         //used to write jaxbElment XML to string
         StringWriter writer = new StringWriter();

         // create JAXBContext which will be used to update writer 		
         JAXBContext context = JAXBContext.newInstance(Student.class);

         // marshall or convert jaxbElement containing student to xml format
         context.createMarshaller().marshal(jaxbElement, writer);
      
         //print XML string representation of Student object			
         System.out.println( writer.toString() ); 

      } catch (JAXBException e) {			
         e.printStackTrace();
      }
   }
}

Let us compile and run the above program, this will produce the following result −

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Student id="1">
   <age>12</age>
   <name>Robert</name>
</Student>