Web Service Overview

Websites without Web services are like isolated islands. Web Service Reduces the communication gap between web applications and enhances interaction.

Web service?
• Is it a revolution in the software industry?
• Will it restructure the entire software industry?
• Is it a form of future software?
• What is the "third revolution" of the Internet "?
• A large "gold mine "?
• Great business opportunities?
• Fundamentally changing the business model of enterprises?

Web Service Overview
1. Web Service Evolution
-PC: the first computer revolution
-The advent of Web: entered the global network and information age. The network is only a platform that provides information, exchange information, and use information. Not a computing platform.
• Host/terminal-Client/Server-middleware-Distributed Components
• The emergence of Java technology: cross-platform
• XML: data exchange between different systems
-Web Service: provides a technical and standard for the production and circulation of software components. "Software is the true implementation of services.

3. three cornerstones of Web Services
• Simple Object Access Protocol-soap. Is an XML-based communication protocol. It consists of three parts:
-Soap encapsulation structure: defines the XML format of a message, including the overall framework, message content, and who processes the content.
-Soap programming rules: defines how to express program data as XML.
-Soap RPC: defines how to use soap for Remote Procedure Calls. In addition, the SOAP specification defines HTTP message styles that contain soap messages.

 

• Web Service Description Language-WSDL
-It is an XML document that describes a group of soap messages and how to exchange them.
-The location of the service and the communication protocol used by the Service are also defined.
-Provides high-level messages, such as the business type and associated Keywords of Web Services.

 

• Unified description, discovery, and integration-UDDI
-Yellow Pages of Web Services
-Its core component is UDDI commercial registration. It uses an XML document to describe Web Services. Including three parts
• White Pages: Describes the companies that provide services, including names, addresses, and contact information.
• Yellow Pages: including industry categories classified by standard
• Green page: Detailed descriptions, access service interfaces, and other technical information
-Microsoft Windows Server 2003 provides the UDDI service.

 

UDDI
• UDDI allows enterprises to publish their own services and services publicly
Call method.
• UDDI provides a set of standard-based specifications such as eXtensible Markup Language
(XML) and Simple Object Access Protocol (SOAP), used to describe
And discovery services also provide a set of Internet-based implementations.
UDDI supports a highly adaptive service description, which can make
Use any interface.
• With UDDI, programs can discover and publish Web
Service Interaction
• Both IBM WebSphere and Microsoft's Windows2003 Server
Provides the UDDI service. You can set up your own UDDI.

 

How UDDI works
• Step 2: publish useful information to the Registration Center. This information complies
It complies with certain standards and is called a technical model ).
• Step 4: The company registers a description of its business and the services it provides
.
• Step 1, the UDDI registration center will specify
The unique identifier in the program, called the unique universal identifier (
Unique universal identifier, UUID) Key
Understand the situation of all these entities.
• Step 2: Use the UDDI registration center to discover their interests
.
• Step 2, other enterprises can call these services, which is simple
For dynamic integration.