What did the web service bring?
Chai Xiaowei
2002-3-8
E-commerce application challenge
With the rise of the Internet, the application deployed on the web With the intention of the Internet, it continues to develop. When web applications have entered people's daily work and life, people found that there is a connection between web applications and traditional desktop applications (such as enterprise internal management systems, office automation systems, etc.), people have to repeat Data migrate from web applications to traditional desktop applications, or transfer data from traditional desktop applications to web applications, where the migration operations are basically completed by human operation, which has become a huge way to hinder web applications into mainstream workflows. obstacle. The computer's application is to pursue information automation, however, current application conditions make people have to adopt several artificial steps between automated processes, which will reduce the enthusiasm of people using computer systems varying degrees.
For example, a company provides an online product order system through the web. A customer of this company found this online product order system, entered an order in the web form, and gains an order confirmation in the browser. . Since the company's company's internal use of the enterprise management system should be managed internal management, he has to confirm this order from the browser, and then fill in the corresponding interface of the internal management system in the ground to make The transactions in the internal system can be turned normally. At this time, this user truly entered the information twice, and the user is a bored things, from the perspective of the computer system, this is completely avoided.
Currently, most e-commerce applications are different from the connection between the buyer, the supplier, MarketPlace, and the service provider. How to easily connect these applications low-cost, thereby achieving a wide range of applications system levels of business application systems across corporate entities, which is a big problem in front of developers. Different applications (especially different enterprises) have different languages, deployment platforms, the communication protocol may also be different, and the data format for external exchange may have a huge difference. How to face the complicated system integration of language differences, platform differences, differences in agreement, and data structures are the key to solving this problem.
XML & Web services, the continuous efforts of eliminating differences
The XML technology and its related techniques that have begun to develop in 1998 are attempts to solve the preliminary attempts of these differences. The proposal of XML technology has the original intention to improve the structure of the global web information caused by the non-structured conditions of HTML. In order to make the global web information to make the global web information, the XML 1.0 is developed based on the powerful SGML language. Initially, XML applications are indeed focusing on the field of information release, and a large number of websites using XML / XSLT technology have appeared to prove that XML is superior in the field of information. Later, as the XSL specification continues to mature, XML technology extends from the information release area to traditional electronic publishing fields, while Web-based information publishing is also officially made in the form of electronic publishing: Network media publishing.
On the other hand, since the XML processor (Parser, it is generally DOM get or SAX) to interactively develop personnel, and everyone is discovered, and it is found that using XML exchange data between different heterogeneous systems. It is such a convenient thing: First, the XML format has the ability to describe various types of data; secondly, use DOM / SAX to process XML, developers can save modules that typically needed file format processing, DOM / SAX is XML processing has enabled a effective method; So, very fast, XML has become a tool for data exchange for application scope. As the idea of using XML data exchange is constantly inseparable, the other two XML-related specifications are slowly introduced into the field of data exchange using XML, and developers use XSLT to implement different XML data exchange formats. Transition, At the same time, XML Schema is used to model the XML data exchange format. Since they are all XML-based, the platform tools continue to be updated to support these new specifications, so that the application of data layer integration (data exchange) is strongly rear shield. Under support, continuous promotion. Data exchange using XML has become a standard technology model in the field of computer software, especially in the field of e-commerce applications. XML solves the difference in data structures / modes between different platforms / systems, so that the data layer is unified with the support of XML technology.
The integration of light data layers is not enough for extensive e-commerce applications and integration proposed by global e-commerce. The integration capabilities of the data layer make the two sides of the interaction to understand the data sent by each other, but which application should be by the data, what kind of method, what context is used to implement processing, the processing, how to return, etc. Processing semantics cannot be completed through the integration of data layers. Everyone may think that I contain the specified application in the data, the specified processing semantics, and then pass this data package to the equivalent, peer-to-peer system, analyze the application and processing semantics of the sender's expectations. Then implement real data processing, and return processing results according to the request of the sender. This is the application mode of the prototype of the web service.
However, at this time, how to specify an application in the data, how to map the application assignment to the real deployment on the platform, how to pack the return result requires the developer to specify it, this is something similar to the original unused standard data. An occasion of the data exchange in the format.
The web service series technology is an open technology architecture that the architecture is based on XML technology to solve the problem of unavoidable problems in which these application layers integration is resolved in the platform layer.
The web service architecture is similar to the N-layer architecture of the web application, and the difference is that the top-oriented browser-oriented web server is replaced by the web service client. The program that uses the web service can be a desktop application, and it can also be another web service. Figure 1 shows a simple and simple architecture mode of the web service.
Figure 1 System architecture for web services
The main members of the Web Services Technical Family in Building Web Services include XML Schema, SOAP, WSDL and UDDI, which are all based on the new Internet seed technology XML. XML Schema provides a core cross-platform data modeling tool for exchange data between different systems (Web services). SOAP defines a set of basic meta-rules and cross-platform messaging mechanisms that are unrelated to implement platforms between different systems, and SOAP is an infrastructure for service interaction in the web service system. WSDL is a cross-platform description tool for the web service interface interface, relying on the interactive interface of WSDL and web services to be automatically processed by the system. UDDI is the first attempt in a dynamic service integration solution. This group of technologies makes the underlying platform to transparent application interaction, and the interoperability of the application has been improved unprecedented. They form the first generation of web service technology. Use web service technology
Since Web Service Technology is a cross-platform technology framework for application layer intersection, we will see what application models originally can't achieve or difficult, and it will become realized or easy to implement after using Web service technology.
In this article, I will mainly examine three areas:
§ EAI, enterprise application integration
§ B2BI and online service integration
§ Desktop app for the entire background service
EAI, enterprise application integration
In many large enterprises, with the growth of enterprise business, ERP, CRM, SCM and other enterprise applications are deployed one by one. For most companies, in the field of investment, technology and application, generally different applications may use different applications. The products provided by the manufacturer. At this point, each application has its own unique infrastructure, which is extremely high in deployment, change, and maintenance. Companies have to configure unique professional technicians for each set of applications, and maintain close contact with different technical suppliers or solutions. At the same time, these applications can not be easily inherited, and the scale expansion of the application cannot be easily implemented as the scale of business commerce.
We clearly realize that even if there is only one e-commerce application, its cost, maintenance and customization is so amazing. What's more, it is conceivable that the cost of the cost is imagined.
Let us examine the situation when enterprises deploy several such e-commerce applications:
The first application, the total cost of the company's payment should be the development and deployment cost of the application, as well as maintenance and update costs of operational timeliness. The second application, the development and deployment cost of the application is the same, but the company needs to spend additional integration costs, while the entire enterprise application environment becomes more complicated, the maintenance and update cost of its operation timeline may be exponentially increase. Similarly, when the third, the fourth application is deployed, the cost of the company may be highly amazing.
The actual operation status of such e-commerce applications is not possible, but it is impossible to grow rapidly, and even causing the opposite effect, because at this time, IT departments have to hire more employees and spend more funds to manage these complicated. Various applications and maintained a variety of infrastructure of various load applications.
We know that in traditional EAI technology, apply A to be integrated with application B, then apply A to write an integrated adapter for application B, which also apply B to apply A integrated adapter. When the situation is more complex, there are three applications exist, then each application needs to write an integrated adapter for the other two applications. This is simply a nightmare for the interior of the company's application integration. Of course, in these areas, there are also some universal integration means, such as IBM's MQ Series solutions, for each application, as long as you write an integrated adapter, you can apply the technology framework to complete integration, however, this type of technology Means often can only be used in a company's products, or in situations using the same type of platform, do not have versatility.
Using a web service, through loose application integration, a company can achieve only one subset of EAI, which can achieve effectiveness. In contrast, EAI wants to achieve a full-scale program to closely integrate and contact all systems and applications for company services. In the company's internal different business systems and technical monomers, you may need to spend ongoing sustained efforts, high investment, and enriched resources equipped. Web services, in such a loose service bundle collection (also a special solution), can develop, publish, discovery, and dynamically binding applications quickly, low cost. The existing EAI solution that is mainly focused on the application is therefore changed. In the future, packaging applications will display their functions or methods as the interface of Web services as XML, SOAP, WSDL, and UDDI technology. Therefore, EAI solutions will have to provide a wide range of support for service integration, not just application integration.
B2BI and online service integration
As a broad integrated basis, B2BI (B2B Integration) can make a schedule, EAI is the foundation of B2BI. In general, only its own internal management system truly realizes each other, and companies and enterprises. The integration is meaningful, otherwise business data is more likely to flow directly, and cross-enterprises cannot be truly implemented.
From the perspective of technology, the first EAI is also the development route suitable for enterprise information systems. It is relatively, and the application within the company is more familiar with the company's technicians. The difficulty of technology is low, by implementing Web service integration within the enterprise, which will enable IT technicians within the enterprise to implement IT technicians that Web services to familiarize themselves with Web service technology. When companies use web services to carry out B2BI projects, there will be Help the project effective. Control, management, search, execution, and maintenance of Web services are relatively easy to use web services over enterprise firewalls over enterprise firewalls. Further, it will help companies compare and identify, use standardized and relatively cheap web service solutions that are more helpful to expensive traditional EAI solutions.
B2BI is an item implemented in order to strengthen the competitiveness of the company, so it has the following objectives:
§ Reduce expenditures of business activities
§ Reduce the cost of entering e-commerce
§ Provide more convenient user operating tools
§ Improve data integrity and accessibility
§ Appropriate security and control
§ Provide scalable and controllable technology
§ Integrate with existing application systems
§ Using open standards
§ Global deployment and maintenance
XML Web services are a powerful tool that meets these goals. On the commercial web, different companies use different applications, deployment platforms. For a company, their business partners will be a lot, and if they are integrated with each business partner, using traditional technologies must pass and each A business partner is agreed, and the communication protocol, message format, and data model respectively, and the efficiency is obviously low. And if you use web service technology, developers will pack their own applications into web services, using WSDL to describe these packaging web services, and put these Web services and their descriptions to the web service registration center For inquiry, all of these tasks can be done using tools that support specifications. At this time, the integration between enterprises is transformed into a docking of Web services. Developers can query the Web service registry through the UDDI API or communicate with the technical personnel of business partners, get the WSDL description document for the other party's web service, then The WSDL description document is automatically loaded into its own development platform, and the developer can quickly understand the data structure that needs to be used using XML Schema's tools, and then introducing just in its own application. Using the call interface and data structure generated by the platform tool, use SOAP technology to interact with the other party's Web service to complete the B2B application integration. The concept of B2B integration can extend into all online services, such as enterprise own systems, can be connected with public financial services, customs services, third-party logistics services, online stores, etc., will rely on paper. Converting into electronically, and its system's implementation can still make companies maintain a technical team: "Web Services Enabling" technology team.
Desktop application with Internet as a whole background service
In the field of enterprise applications, personal applications are also a very large application area, while the influence of its formation is too uncomfortable. In the past, desktop applications for Web have been quite apps, such as:
§ Very frequent instant messaging software, including MSN Messenger, Yahoo! Messenger, ICQ, OICQ, etc., to deploy messages between different terminals to deploy messages on the web, complete the messages between different terminals.
§ Stock Market Software Client, Representative Securities Star, etc. They rely on the continuous download of market data from the online quote server to provide services.
§ Financial software, such as Microsoft's Money 2002, and basic access to all US banks online services.
For these applications, the entity for providing services and services is either a company (former two), or one-on-one sign agreement, build a pair of connection protocols (latter), although from mode, This is already the "Web Service" application mode, however, those "Web services" are not open, except for client applications that have their clients, or private reach an agreement, other desktop applications are unable to use these services. .
Even, the developers of some desktop applications have acquired certain services in the reverse engineering. Since those services are not open, once the interfaces have changed (mostly non-malicious), then the code for desktop applications should not Do not conduct a corresponding upgrade.
However, if those online services are re-encapsulated using web service technology, the development model is as mentioned in the EAI integration, as we mentioned in EAI integration, as we mentioned in EAI integration. WSDL The document is loaded into the development environment and then generates a call interface and integrates into the code. At runtime, the interface of the web service is possible to change. When the interface changes, the web service call failed, at this time, the desktop application should have the ability to re-generate the WSDL document again, re-generate the calling interface, and bind the code. That is, the Web service technology gives the ability to apply dynamic binding, not the ability to only have static bindings before. In addition, desktop applications can also choose to query the registry of the web service (such as UDDI Business Registry), get the web service they need, and then dynamically bind one by one, and implement calls. When these technical features are applied to several applications we have previously discussed, we will find: § You can use a single instant messaging software, which can be connected to MSN Messenger Service, Yahoo! Messenger Service, ICQ Service, etc. Users only need to use a client to communicate with any instant messaging terminal.
§ Many stock market analysis software can use the data update service of the stock market service online, download the data to the local implementation analysis, and the user's choice has increased a lot, and the software developer's division of labor is also more clear.
§ Financial software can dynamically search for the UDDI Registry, get online online checking services, providing users with more immediate services.
Our opportunities
We know that Web service technology is still an emerging technology, but countless signs show that Web services will be an extremely important model for future application architectures. The first inventory has the advantage, how to optimize this direction, there is no reason to let it be idle, and the arched hand will slowly enter the foreign market and easily capture China's market. For the current situation of China, there is such an opportunity to wait for us:
1. Web service developer, web service technology provider. With the deep people of Web services, there will be more and more applications that use web service architectures. The development of web services will continue to increase. The application of China's background needs to be involved in local companies, completely relying on foreign companies that cannot meet the local Demand of the chemical.
2. WEB services practices in large enterprises EAI / B2BI. For large companies, the maintenance and benign development of business relationship with overseas suppliers, the business relationship of business relationships is an unavoidable problem. Although the B2B will succeed to be adopted in the international business environment, it is not carried out in the international field. The B2B integration can not facely compete, and can even say that you don't join the B2B integrated environment, there is no permit for international business activities.
3. Web service transformation of public web application. For many web applications with a wide range of usage but limited usage, we can consider the WEB service packaging, and are open to software developers, deliver to users via desktop software. You can consider that users buy software to desktop software providers, desktop software providers to pay the service provider by service usage.
Of course, in addition to these, there are many other opportunities. When I think that PC just appears, I think about the Internet, the new mode is in silently pregnant.
Current effort
