How to use JAXB for Unmarshalling

Hello everyone,

Today, I would like to show you how to read and XML using JAXB library.

0-Make sure your project has the library
1- We need to create the object for JAXBContext.
2- We need also to create Unmarshaller objects that will be used to unmarshal method loading the content of the file.




package thiagolguimaraes;

/**
 * @author Thiago leoncio
 *
 *This is JAXB Unmarshalling Example: Converting XML into Object
 *
 *The steps to convert XML document in the java object are:
 *
 *Create POJO or bind the schema and generate the classes
 *Create the JAXBContext object
 *Create the Unmarshaller objects
 *Call the unmarshal method
 *Use getter methods of POJO to access the data
 *
 */
import java.io.File;
import java.util.List;
 
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;
 
public class XmlToObject {
    public static void main(String[] args) {
 
     try {
 
        File file = new File("src\\thiagolguimaraes\\question.xml");
       
       
        //Create the JAXBContext object
        JAXBContext jaxbContext = JAXBContext.newInstance(Retrieve.class);
        //Create the Unmarshaller objects
        Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
        //Use getter methods of POJO to access the data
        Retrieve que= (Retrieve) jaxbUnmarshaller.unmarshal(file);
         
        System.out.println(que.getId()+" "+que.getRetrievename());
        System.out.println("Responses:");
        List<Response> list=que.getResponses();
        for(Response ans:list)
          System.out.println(ans.getId()+" "+ans.getResponsename()+"  "+ans.getPostedby());
 
      } catch (JAXBException e) {
        e.printStackTrace();
      }
 
    }
}

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/**
 *
 */
package thiagolguimaraes;

/**
 * @author Thiago Leoncio
 *
 */
import java.util.List;

import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
 
@XmlRootElement
public class Retrieve {
private int id;
private String questionname;
private List<Response> answers;
public Retrieve() {}
public Retrieve(int id, String questionname, List<Response> answers) {
    super();
    this.id = id;
    this.questionname = questionname;
    this.answers = answers;
}
@XmlAttribute
public int getId() {
    return id;
}
public void setId(int id) {
    this.id = id;
}
@XmlElement
public String getRetrievename() {
    return questionname;
}
public void setRetrievename(String questionname) {
    this.questionname = questionname;
}
@XmlElement
public List<Response> getResponses() {
    return answers;
}
public void setResponses(List<Response> answers) {
    this.answers = answers;
}
}

---------------------------------------------------------------------------------------------------

/**
 *
 */
package thiagolguimaraes;

/**
 * @author Thiago Leoncio
 *
 */
public class Response {
private int id;
private String answername;
private String postedby;
public Response() {}
public Response(int id, String answername, String postedby) {
    super();
    this.id = id;
    this.answername = answername;
    this.postedby = postedby;
}
public int getId() {
    return id;
}
public void setId(int id) {
    this.id = id;
}
public String getResponsename() {
    return answername;
}
public void setResponsename(String answername) {
    this.answername = answername;
}
public String getPostedby() {
    return postedby;
}
public void setPostedby(String postedby) {
    this.postedby = postedby;
}
 
}



Happy coding,
Thiago Leoncio.