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A practical guide to JAXB 2.0
Take a peek at its new features
Create an ArticleType
object, which represents an article element. Set the edition
, title
and author
values. Obtain a List
object of parameter type ArticleType
and add the ArticleType
object to the List
. Similarly, add another ArticleType
object to the Java object representation. Next, obtain a JAXBElement
object of parameter type CatalogType
using a factory object. A JAXBElement
object is a JAXB representation of an XML element.
JAXBElement<CatalogType> catalogElement=factory.createCatalog(catalog);
Marshal the Java object using the marshal()
method.
marshaller.marshal(catalogElement, new FileOutputStream(xmlDocument));
To run the JAXBMarshaller.java
application in Eclipse, right-click on the application node and select Run As>Run. File catalog.xml gets generated. Refresh the JAXB2 project with File>Refresh. The XML file catalog.xml gets added to the JAXB2 project.
Mapping Java to XML Using Annotations
JAXB 2.0 has added the provision to marshal a Java object to an XML document using annotations. The annotations are defined in the javax.xml.bind.annotation
package. In this section we shall generate an example XML document, catalog2.xml (resources zip file), from a Java object using JAXB 2.0 annotations. The corresponding schema representation is listed in catalog2.xsd (resources zip file).
To create the XML document, create an annotated class, Catalog.java
(resources zip file). Create root element of the XML document with @XmlRootElement
annotation. Create a complexType
using @XmlType
annotation.
@XmlRootElement @XmlType(name="", propOrder={"publisher", "edition", "title", "author"})
The annotation element name
is specified as an empty string, because the complexType
is defined within an element. The element order is specified using propOrder
annotation element. In the Catalog
class define constructors for the class, the different JavaBean properties (edition, title, author). Root element catalog
has an attribute journal
. Define the journal
attribute using @XmlAttribute
annotation.
@XmlAttribute public String journal;
Define getter and setter methods for the different properties and the journal
attribute. Add a Java class, Catalog.java
, to the JAXB2 project in Eclipse. The directory structure of the JAXB2 project with the Catalog.java
class is shown in Figure 8.
In the marshalling class JavaToXML.java
create a JAXBContext
using newInstance()
method with Catalog.class
as argument to the method. Create a Catalog
class object and set the values of elements and attributes. Marshal the Catalog
object with a Marshaller
object. Run the JavaToXML.java
class in Eclipse. The XML document gets created. Java classes may also be mapped to XML Schemas.®
Click here for the resources file (zip)