JAXB - Code Sample

JAXB uses annotations to indicate the central elements.

Table 1.

Annotation	Description
@XmlRootElement(namespace = "namespace")	Define the root element for a XML tree
@XmlType(propOrder = { "field2", "field1",.. })	Allows to define the order in which the fields are written in the XML file
@XmlElement(name = "neuName")	Define the XML element which will be used. Only need to be used if the neuNeu is different then the JavaBeans Name

2.2. Usage

Create a new Java project called "de.vogella.xml.jaxb".
Create the following domain model with the JAXB annotations.

package de.vogella.xml.jaxb.model;

import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlType;

@XmlRootElement(name = "book")
// If you want you can define the order in which the fields are written
// Optional
@XmlType(propOrder = { "author", "name", "publisher", "isbn" })
public class Book {

 private String name;
 private String author;
 private String publisher;
 private String isbn;

 // If you like the variable name, e.g. "name", you can easily change this
 // name for your XML-Output:
 @XmlElement(name = "bookName")
 public String getName() {
  return name;
 }

 public void setName(String name) {
  this.name = name;
 }

 public String getAuthor() {
  return author;
 }

 public void setAuthor(String author) {
  this.author = author;
 }

 public String getPublisher() {
  return publisher;
 }

 public void setPublisher(String publisher) {
  this.publisher = publisher;
 }

 public String getIsbn() {
  return isbn;
 }

 public void setIsbn(String isbn) {
  this.isbn = isbn;
 }

}

   

package de.vogella.xml.jaxb.model;

import java.util.ArrayList;

import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlElementWrapper;
import javax.xml.bind.annotation.XmlRootElement;

//This statement means that class "Bookstore.java" is the root-element of our example
@XmlRootElement(namespace = "de.vogella.xml.jaxb.model")
public class Bookstore {

 // XmLElementWrapper generates a wrapper element around XML representation
 @XmlElementWrapper(name = "bookList")
 // XmlElement sets the name of the entities
 @XmlElement(name = "book")
 private ArrayList<Book> bookList;
 private String name;
 private String location;

 public void setBookList(ArrayList<Book> bookList) {
  this.bookList = bookList;
 }

 public ArrayList<Book> getBooksList() {
  return bookList;
 }

 public String getName() {
  return name;
 }

 public void setName(String name) {
  this.name = name;
 }

 public String getLocation() {
  return location;
 }

 public void setLocation(String location) {
  this.location = location;
 }
}

   

Create the following test program for writing and reading the XML file.

package test;

import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.Writer;
import java.util.ArrayList;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;

import de.vogella.xml.jaxb.model.Book;
import de.vogella.xml.jaxb.model.Bookstore;

public class BookMain {

 private static final String BOOKSTORE_XML = "./bookstore-jaxb.xml";

 public static void main(String[] args) throws JAXBException, IOException {

  ArrayList<Book> bookList = new ArrayList<Book>();

  // create books
  Book book1 = new Book();
  book1.setIsbn("978-0060554736");
  book1.setName("The Game");
  book1.setAuthor("Neil Strauss");
  book1.setPublisher("Harpercollins");
  bookList.add(book1);

  Book book2 = new Book();
  book2.setIsbn("978-3832180577");
  book2.setName("Feuchtgebiete");
  book2.setAuthor("Charlotte Roche");
  book2.setPublisher("Dumont Buchverlag");
  bookList.add(book2);

  // create bookstore, assigning book
  Bookstore bookstore = new Bookstore();
  bookstore.setName("Fraport Bookstore");
  bookstore.setLocation("Frankfurt Airport");
  bookstore.setBookList(bookList);

  // create JAXB context and instantiate marshaller
  JAXBContext context = JAXBContext.newInstance(Bookstore.class);
  Marshaller m = context.createMarshaller();
  m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
  m.marshal(bookstore, System.out);

  Writer w = null;
  try {
   w = new FileWriter(BOOKSTORE_XML);
   m.marshal(bookstore, w);
  } finally {
   try {
    w.close();
   } catch (Exception e) {
   }
  }

  // get variables from our xml file, created before
  System.out.println();
  System.out.println("Output from our XML File: ");
  Unmarshaller um = context.createUnmarshaller();
  Bookstore bookstore2 = (Bookstore) um.unmarshal(new FileReader(
    BOOKSTORE_XML));

  for (int i = 0; i < bookstore2.getBooksList().toArray().length; i++) {
   System.out.println("Book " + (i + 1) + ": "
     + bookstore2.getBooksList().get(i).getName() + " from "
     + bookstore2.getBooksList().get(i).getAuthor());
  }

 }
}

   

If you run the BookMain a XML file will be created from the object. Afterwards the file is read again and the object are created again.