XML Web Service

 

What Is An XML Web Service?

通过标准的 Web 协议（HTTP）可编程访问的WEB组件，或者说提供函数调用的WEB 站点。

优势: 真正的与平台无关; 采用W3C 标准； 没有防火墙的限制问题

更多的Web service slides

A programmable application component accessible via standard Web protocols  that provides a universal language for applications to talk to each other - XML Web services allow applications to communicate regardless of operating system or programming language via the Internet. They can be implemented on any platform and are defined through public standards organizations such as the W3C. And with XML Web services, not only can applications share data, but they can also invoke capabilities from other applications without regard to how other applications were built. Sharing data through XML allows them to be independent of each other while simultaneously giving them the ability to loosely link themselves into a collaborating group that performs a particular task.

What is the difference between a Web site and an XML Web Service - Web sites are about presenting information to a user: they are the communication vehicle for servers to talk to users. XML Web services, on the other hand, offer a direct means for applications to interact with other applications. Applications hosted internally, as well as on remote systems, can communicate via the Internet by using XML and SOAP messages.

XML Web services are built on standard Web protocols; HTTP and XML.

The technology innovations for XML Web services:

DISCO (Discovery) and UDDI (Universal Description, discovery, and Integration) - Standards for locating XML Web services

SOAP (Simple Object Access Protocol) - Explicit serialization (HTTP + XML description) protocol used in service exchanges

WSDL (XML Web services Description Language) - XML document describing the location and interfaces a particular service supports – the client's contract