Weblogic - WEB SERVICES
Web services is a blanket term used for defining the infrastructure required to link
applications in a business-to-business (B2B) world. Web services go beyond those
things traditionally provided by Web applications and provide a standard mechanism
for linking disparate systems in a uniform and well-defined manner. Web services
provide a common protocol that Web applications can use to connect to each other
over the Internet.
Web services will change the way the industry and companies view their
applications. Applications that previously were difficult or impossible to combine
can be exposed and connected quickly and easily using Web services.
A Web service is made up of a number of the following parts and services:
- Web Services Description Language, or WSDL, is used to define the external
view of a service. Applications use WSDL to understand how to talk to existing
Web services and how to expose functionality as a Web service. WSDL works
much like a Remote Procedure Call (RPC) mechanism and is written completely
in XML.
- UDDI and Electronic Business XML Initiative (ebXML) provide a mechanism
that both registers and searches for a given service. Using WSDL, a Web service
makes itself known in the global “marketplace” via the UDDI publish service
(by publishing your XML Web service to the UDDI registry). Other Web services
can then find an existing service by using the UDDI Inquiry API. UDDI represents
simple, typically point-to-point Web services. ebXML provides a mechanism
similar to UDDI but with a much broader list of query APIs. It is typically
found in more complex applications that require multiple services to interact
at one time.
- SOAP provides the final portion of a Web service, using a mechanism to invoke
a Web service that we have found using UDDI and understand via WSDL.
Web services are an interesting new area that focuses on exposing enterprise services
through the Web. A point to note is that Web services are a number of interconnected
protocols, defined using the Java community process (JCP), but technically not J2EE
services.
