Chapter 20. EJB 3.1: Web Services Standards
Web services have taken the enterprise computing industry by storm in the past couple of years, and for good reason. They present the opportunity for real interoperability across hardware, operating systems, programming languages, and applications. Based on the XML, SOAP, and WSDL standards, web services have enjoyed widespread adoption by nearly all of the major enterprise players, including Microsoft, IBM, BEA, JBoss, Oracle, Hewlett-Packard, and others. Sun Microsystems has integrated web services into the Java EE platform; specifically, Sun and the Java Community Process have introduced several web services APIs, including the Java API for XML Web Services (JAX-WS), the Java API for XML-based RPC (JAX-RPC), the SOAP with Attachments API for Java (SAAJ), and the Java API for XML Registries (JAXR). These web services APIs were integrated into J2EE 1.4 and have been expanded upon in subsequent releases, including Java EE 6 and EJB 3.1.
This chapter provides an overview of the technologies that are the foundation of web services: XML Schema and XML Namespaces, SOAP, and WSDL. Chapter 21 provides an overview of JAX-WS and JAX-RPC, the most important web services APIs.
Web Services Overview
The term web services means different things to different people, but thankfully, the definition is straightforward for EJB developers because the Java EE platform has adopted a rather narrow view of them. Specifically, a web service is a remote application ...