WebService reference: What is Web Services? (AMT Research Institute yuan lei)

  This article was very early. I was on my Sina site. I recorded it before and moved it if I didn't want to discard it. Don't worry about me!

CurrentApplication Development is slowly shifting from the C/S structure to the B/S structure, and people are beginning to prefer browser-based thin client applications. This is because it avoids the high cost of publishing desktop applications. The cost for publishing desktop applications is high, half because of application installation, configuration, and maintenance, and the other half because of communication between the customer and the server. For the B/S structure, the browser is the standard configuration of almost every client. A perfect solution for communication between the client and the server is to use HTTP protocol. This is because any machine running a Web browser is using the HTTP protocol. At the same time, many firewalls are configured to only allow HTTP connections. Many commercial applications face another problem: interoperability with other programs. These programs are developed and run on different platforms in different languages. 

  At the same time, we often find this term in major technical forums or enterprise information system forums: Web Services. At the same time, we will find that most of the technology vendors that come along with this term are major technical suppliers, and all major technical suppliers are not concerned about the development of this field. From Microsoft's. NET architecture to sun one and IBM's IBM Web Services, these heavyweight technology providers respect and pay attention to Web Services.

  These provide opportunities for Web Services, and the development of e-commerce has promoted this development. Web services allow companies to reduce their e-commerce costs, deploy solutions faster, and open up new opportunities. Web services make Application Integration faster, easier, and cheaper than before. Integration occurs at a higher level in the protocol stack. It implements loose integration of business functions based on messages that focus more on service semantics than network protocol semantics. These features are ideal for connecting businesses between enterprises and enterprises through web. They provide a consistent programming model that allows both inside and outside the enterprise to utilize common infrastructure and integrate applications in a common way. 

  What is Web Services? From a technical perspective, Web Services is a new technical architecture and a new software application environment. Its system architecture and implementation technology completely inherit the existing technology. It can be considered that Web Services is an extension of the Internet and an extension of the existing Internet for better interoperability. 

 Web Services

Web Services, literally, are Services provided through the Web. We can understand that Web Services are self-contained, modular applications that can be described, published, searched, and called on the Network (usually the Web; it can also be understood that Web Senices is a network-based, distributed modular component that executes specific tasks and complies with specific technical specifications, these specifications Enable Web Sevices to interoperate with other compatible components. You can also understand that Web services are online application services released by enterprises to fulfill their special business needs, other companies or applications can access and use this application service over the Internet.

 For Web Services, many people will be confused with Web Services and think that the two refer to the same thing. Otherwise, the former refers to the technical framework used to construct the Web Service, and the latter refers to the Application Instances created using the Web Services technology. Web Services is an interface describing some operations. These operations can be accessed over the network through the standardized XML message transmission mechanism. Web Services are described using the standard and standard XML-based WSDL language, which is called the service description of Web Services. This description includes all the details required for interaction with the service, including the Message format (detailed description of the Input and Output Message format of the operation), transmission protocol, and location. This interface hides the details of service implementation and allows you to use this service by means of independent service implementation, independent software and hardware platform, and independent programming language used for service writing. This makes Web Services-based applications loosely coupled, component-oriented, and cross-technology implementation. All Web Services perform certain specific Services or tasks and can be used together with other Web Services to implement complex business transactions. 

 Web Services features 

  From the perspective of external users, Web Services is an object and component deployed on the Web. It has the following features:

· Sound encapsulation:

  Since Web services are an object deployed on wbb, they are naturally well encapsulated. for users, they can only see the list of functions provided by this object. 

· Loose coupling

  This feature is also derived from the object/component technology. When the implementation of a Web service changes, the caller will not feel this. For the caller, as long as the Web service call interface remains unchanged, any changes to the implementation of Web services are transparent to them, even when the implementation platform of Web Services is migrated from J2EE. NET or the opposite migration process, users can have no idea about this. For a loose pot, especially for Web Services in the Internet environment, a message exchange protocol suitable for the Internet environment is required. XML/SOAP is currently the most suitable message exchange protocol.

· Normative use of protocols

  This feature comes from objects, but its interface specifications are more standardized and easier to understand than general objects. First, as a Web service, the functions provided by the object interface should be described in a standard descriptive language (such as WSDL). Second, the service interface described by the standard descriptive language should be discoverable. Therefore, this descriptive document must be stored in a private or public registry. At the same time, the Use Agreement described in standard descriptive languages will not only be a service interface, but will be extended to Web Service aggregation, cross-Web service transactions, workflows, etc, all of these require QoS Assurance. Secondly, we know the importance of security mechanisms for loosely coupled object environments. Therefore, we need to perform authorization authentication and data integrity (such as signature mechanisms) use standard methods to describe, transfer, and exchange the source authentication and the non-repudiation of transactions. Finally, the processing at all levels should be manageable, so the same mechanism should be applied to the management agreement. 

· High Integration Capability

   Because Web services adopt simple and easy-to-understand standards, the Web protocol, as a Component Interface Description and collaborative description specification, completely shields the differences between different software platforms, whether it is CORBA, DCOM or EJB, all can be operated through this standard protocol, achieving the highest possible integration in the current environment.