文档介绍：Some Web Service definitions
• W3C definition
A web service is a software system designed to support
interoperable machine-to-machine interaction over work.
It has an interface described in a machine-processable format
(WSDL). Other systems interact with the Web Service in a
manner prescribed by its description using SOAP messages,
conveyed using HTTP with an XML serialization in conjunction
with other Web-related standards
•“Computer”- Magazine of the puter Society
Web services are Web-based posed of
coarse-grained business functions accessed through the
• IBM
Web services are self-contained, modular applications that can
be described, published, located and invoked over work;
generally, the Web
What is a Web Service
• Function
– A collection of operations
– Machine-to-machine interaction via XML-based messages
• Access
– Well defined, Web-based interface
• Networked (via HTTP protocol)
–
– Web
• Loosely coupled
– The service requester has no knowledge of the technical details of
the provider’s implementation
W3C Web Service Architecture
Figure : Service Oriented Model (from /ws-arch/ )
Rationale of WS
• WS evolve object-oriented techniques for sw design
to puting, e-science, and e-business
• Promote interoperability by minimizing the
requirements for shared programming models
– Normal program-to-munication model
– Web Services are platform and language independent
• Enabling just-in-time integration
– Services are bound dynamically at runtime
– Systems are self-configuring, adaptive, and robust
• Reducing plexity by encapsulation
– ponents of an application are services
• Enabling interoperability of legacy applications
Interoperability
Web Services are an evolutionary step towards
software interoperability
• Before Web Services:
– Common Object Request Broker Architecture (CORBA)
– ponent Object Model (DCOM)
• These were reasonable protocols for server-to-server
communications, but:
– weak in client-municati