Design,Realization And Application Of A SOA Framework

With the development of Information Technology, enterprises built a lot of applications for the business require during their constructions of Enterprise Information Systems(EIS), like ERP, CRM, OA and so on. These applications are isolated, and developed by different technologies, and running in different environments. So it will be difficult and expensive to try to build good communication between them. This is"Information Isolated Island"problem, which causes that the enterprise information systems are running isolated, and can't work together.Nowadays, enterprises need to change their business logic rapidly because of the changes of market, but the need could not get better assistances from their Enterprise Information Systems, because the way is to develop new applications and extend the old applications. It's impossible to adapt the rapidly changing environment using this way.If use SOA to build the EIS,"Information Isolated Island"problem can be avoided, and enterprises will adapt the rapidly changing market.Service-Oriented Architecture (SOA) is an IT architectural style that supports the transformation of your business into a set of linked services, or repeatable business tasks, that can be accessed when needed over a network. This may be a local network, it may be the Internet, or it may be geographically and technologically diverse, combining services in New York, London, and Hong Kong as though they were all installed on your local desktop. These services can coalesce to accomplish a specific business task, enabling your business to quickly adapt to changing conditions and requirements.A SOA architecture must include the following three points:1. Services in the architecture must be loosely coupling.2. Services are identified from the view of actual business.3. The realization, location and transport protocols of services are Transparent for the service-invokers.SOA is the ideal architecture for constructing the EIS. Compared with the traditional architecture for constructing the EIS, SOA has some advantages:It reflects the business model of enterprise, and makes enterprises escape from the limit of technology.It makes enterprises quickly adapt to changing conditions and requirements.It makes enterprises fully use the old assets.Web Service is the truthly technology for realizing the SOA. A Web service is an interface that describes a collection of operations that are network-accessible through standardized XML messaging. A Web service is described using a standard, formal XML notion, called service description. It covers all details necessary to interact with the service, including message formats, transport protocols and location. The interface hides the implementation details of the services, allowing it to be used independently of the hardware or software platform on which it is implemented and also independently of the programming language in which it is written.Web service is consisted of three parts: WSDL, SOAP and UDDI.WSDL's full name is Web Service Description Language, which is a description language of Web service and based on XML.SOAP(Simple Object Access Protocol) is a light and simple protocol based on XML. It was designed to exchange structural information on the website.UDDI is the abbreviation of Universal, Description, Discovery and Integration. It is a specification of creating a registration service, in order to register and find it by service users.At present, there are few guidance literatures about SOA development. This paper brought forward a SOA framework named JEBS, which is based on J2EE and Enterprise Service Bus(ESB).JEBS framework has a character that services are transparent.The traditional service-invoke way is to send a direct request from clients to service providers. The applications of clients must handle the location andtransport protocol of a service provider.Another character of JEBS is loosely-coupling. An EIS maybe has many sub systems. When constructing these sub systems, they will be consisted of services. A sub system invokes another by services, and the services are loosely coupling, so all the sub systems become loosely coupling.A good framework must be practicable and reusable. In this paper, combining an actual example, it told us the application of JEBS.This paper first described the general situation of this example: A cosmetic sale company decided to rebuild its EIS because of the new need of business.After analyzing the business logic, three steps would be taken to construct an EIS, which was based on SOA. These three steps were:1. Create loosely coupling services. Make all the sub systems loosely coupling.2. Identify the interface method of service. Make sure that the interfaces are coarse-gained and close to actual business.3. Integrate the separate services by ESB, realize SOA architecture.This paper also enumerated the important part of the database design of the example project, and analyzed the relating relationship between database tables. Then taking a sequence diagram of creating a new order as example, it showed the applications of all parts of JEBS. At last, this paper discussed the problem of transaction process.The design of JEBS follows the concept of SOA, and it will be a good reference and guidance for developers to understand and realize SOA. It is also based on J2EE, so it has the advantages of J2EE n- layers architecture: interfaces are clear between the layers, and layers are comparatively independent. Furthermore, if use some middleware of ESB, ORM and so on, JEBS will be much better. But this paper didn't pay much attention to the transaction process and service security of JEBS, which will be researched in the future work .