A web service is software that is identified by a URI and whose interfaces and bindings are specified through XML. The web service can then be discovered by other distributed software systems and communicated with via XML-based messages. In its simplest form, a web service can be viewed as a client/server architecture that allows varying systems to interact with one another through the use of industry standards protocols. Web services is an interface or wrapper around disparate system implementations.
Because web services can operate over the Internet, they are accessible from anywhere Internet service is available. This enables applications as well as people to consume these web services in order to achieve business goals. Because web services can run over existing transport infrastructures and web standards, you don't need to install any new infrastructure to use them.
This chapter will cover the server aspect of web services. The next chapter will cover the client aspect. Specifically, this chapter covers the following:
The concepts behind web services
Why you want to use web services
An analysis of the PIX services that need to be exposed
XFire, an open-source web service container
Integrating Spring with XFire
Exposing POJOs as web services
Intercepting web service messages
Creating web service clients and invoking web services
In this chapter, you add new Spring configurations and code to the PIX application to expose PIX functionality as web ...