Beginning Java EE 6 with GlassFish 3, Second Edition

CHAPTER 14 ■ SOAP WEB SERVICESListing 14-6. A Main Class Marshalling a CreditCard Objectpublic class Main {public static void main(String[] args) {CreditCard creditCard = new CreditCard("1234", "12/09", 6398, "Visa");StringWriter writer = new StringWriter();JAXBContext context = JAXBContext.newInstance(CreditCard.class);Marshaller m = context.createMarshaller();m.marshal(creditCard, writer);}}System.out.println(writer.toString());Metro, the JAXB reference implementation, has other tools, specifically the schema compiler (xjc)and the schema generator (schemaGen); while marshalling/unmarshalling deals with objects and XMLdocuments, the schema compiler and the schema generator deal with classes and XML Schemas. Thesetools can be used in the command line (they are bundled with Java SE 6) or as Maven goals.With JAXB, you have two possible scenarios from which bindings arise:• Start from Java classes: The Java classes exist and are used to generate an XMLSchema.• Start from an XML Schema: In this scenario, the schema exists, and the Javaclasses are created using a schema compiler.These two scenarios are very important for web services. A SOAP web service can generate its WSDLfiles, and, based on that WSDL, a consumer can generate a set of Java classes, all in a transparent andportable way.AnnotationsJAXB is similar to JPA in many ways. However, instead of mapping objects to a database, JAXB does themapping to an XML document. Also, like JPA, JAXB defines a set of annotations (in thejavax.xml.bind.annotation package) to customize this mapping, and relies on configuration byexception to minimize the work of the developer. If persistent objects have to be annotated with @Entity,the correspondent in JAXB is @XmlRootElement (see Listing 14-7).Listing 14-7. A Customized CreditCard Class@XmlRootElement@XmlAccessorType(XmlAccessType.FIELD)public class CreditCard {425