Understanding Web Service

first, what is Web Service?

Web Service is a programmable Web -based application that is used to develop distributed, interoperable applications.

WEB Service technology enables different applications running on different machines to exchange data with each other without the use of additional, specialized third-party software or hardware . Applications that are implemented according to the Web Service specification can exchange data with each other, regardless of the language, platform, or internal protocol they are using.

Web service is also easy to deploy because they are based on some common industry standards and some of the technologies that are available, such as subset XML, HTTP, in standard generic markup language.

Web Service reduces the cost of application interfaces .

WEB Service provides a common mechanism for integration of business processes across the enterprise and even across multiple organizations.

Web Service is a new branch of Web application that can perform any function from simple requests to complex business processing. once deployed, other Web Service the application can discover and invoke the services it deploys. as a result, Web service is the latest technology and development trend for building distributed, modular applications, and service-oriented application integration.

Second, Web Service the problem solved

More and more Web applications in the network environment have been built up, using HTML, CGI and other web technology can easily in the Internet environment to achieve e-commerce, e-government and other applications. However, these applications may be distributed in different geographic locations, using different data organization forms and operating system platforms, and inconsistent data resulting from the application , making it possible to centralize these highly distributed data and make full use of them as a problem to be solved urgently.

Web Service is the new technology that is proposed to solve this problem.

Third, Web Service the basis

L TCP/IP: Universal network protocol, used by various devices

L HTML (an application under standard Universal Markup Language): Common user interface, can display data using HTML tags

L. NET: Sharing data and data exchange among different applications

L Java: Write a common programming language that can run on any system, because Java has cross-platform features

L XML (a subset of standard common markup languages): a common data expression language, an easy way to transfer structured data over the web

They are characterized by their openness and cross-platform nature . This is the foundation of Web Service.

Four, Web Service the important technology

The data representation method differs from the type system for different platforms . To achieve interoperability, the WEB service platform must provide a standard set of type systems for communicating different types of systems in different platforms, programming languages, and component models .

4.1XML and XSD

The Xml:web service platform represents the basic format of the data .

L easy to build and easy to analyze

L is not only platform-independent, but also vendor-independent.

Xsd:web the data type System in the service platform.

XML solves the problem of data representation, but it does not define a set of standard data types, much less how to extend this set of data types. The XML Schema (XSD) developed by the consortium is a set of standards specifically designed to address this problem. It defines a standard set of data types and gives a language to extend this set of data types.

In order to conform to the Web service standard, all data types that you use must be converted to XSD types . If you want it to be passed between different organizations on different platforms and different software , you need to wrap it up with something. This kind of thing is a protocol, like SOAP.

4.2SOAP

Soap is a Simple Object Access Protocol (PROTOCOL), which is used to interchange XML(a subset of the standard Common Markup Language) encoded information ( data) The lightweight protocol .

4.3WSDL

How will you introduce your Web service to others? what are the functions and parameters of each function call?

provide a formal description document in a way that the machine can read. The Web Service Description Language (WSDL) is a language based on XML (a subset of standard generic markup languages) that describes Web service and its functions, parameters, and return values. WSDL is both machine readable and human readable, which is a great benefit. Some of the latest development tools can generate WSDL documents based on your Web service, import WSDL documents, and generate code that invokes the corresponding Web service.

4.4UDDI

Register the Web Service provided by the enterprise itself to enable other enterprises to discover access to use .

is a directory service that an enterprise can use for Web services for registration and search.

Understanding Web Service