WebLogic: The Definitive Guide

Chapter 19. Web Services

Web services can be characterized by three properties. First, web services are accessed over the Web through standard Internet protocols, such as HTTP or HTTPS. Second, web services describe themselves using XML and typically rely on registries to aid the lookup and invocation of the services. Finally, web services talk to their clients (and other web services) using an XML-based protocol — i.e., remote procedure calls to a web service operation are transmitted in the form of XML messages.

The combination of these properties is quite powerful — distributed applications that span heterogeneous hardware and software platforms can now interoperate using a cross-platform language (XML) over standard Internet protocols. Web services provide an environment for building loosely coupled, decentralized applications where the diverse services can collaborate in a platform-independent and language-agnostic way. Application interoperability is the primary motivation for adopting web services. Given an environment in which a number of applications written in different programming languages running on diverse platforms need to communicate with each other, web services can help bridge language barriers and overcome these platform differences. As long as the participating applications adhere to the published standards that determine the formats of the XML messages, processing rules, and more, it is possible to expose the different application services in the form of web ...