javax.xml.bind.JAXB.unmarshal() Method

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Description

The Javax.xml.bind.JAXB.unmarshal(File xml, Class<T> type) method reads in a Java object tree from the given XML input.

Declaration

Following is the declaration for javax.xml.bind.JAXB.unmarshal(File xml, Class<T> type) method

public static <T> T unmarshal(File xml, Class<T> type)

Parameters

• xml − Reads the entire file as XML.

• type − This is the type of the class to be unmarshaled.

Return Value

The method retutns object of type Class<T>

Exception

NA

Example

The following example shows the usage of javax.xml.bind.JAXB.unmarshal(File xml, Class<T> type) method. To proceed, consider the following Student class which will be used to have objects for marshalling purpose −

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 unmarshal ie. convert Student.xml file to JAXB object.

package com.tutorialspoint;

import java.io.File;
import javax.xml.bind.JAXB;

public class JAXBDemo {
   public static void main(String[] args) {

      try {         
         // create file writer object
         File f = new File("Student.xml");
         
         // marshal object to file writer
         Student st = JAXB.unmarshal(f, Student.class);
         
         System.out.println("Age : "+st.getAge());
         System.out.println("Name : "+st.getName());
         
      }catch(Exception ex) {
         ex.printStackTrace();
      }
   }
}

To create document, an XML file is needed as input. The XML file is named as Student.xml−

<?xml version = "1.0" encoding = "UTF-8" standalone = "no"?>
<student id = "10">
   <age>14</age>
   <name>Soniya</name>
</student>

Before we proceed for compilation, we need to make sure that that we download JAXB2.xxx.jar and put it in our CLASSPATH. Once setup is ready, let us compile and run the above program, this will produce the following result −

Age : 14
Name : Soniya