| SOA (Service-Oriented Architecture) has brought profound impact on thedeveloping module of modern software, as it provides services for other applicationprograms through mechanisms such as the publishing, finding and the binding etc ofservice. SOA possesses the advantages such as being loosened coupling, roughgrain-size and retro-operative etc. Through the means of the design scheme adopting theSOA framework, the coupling among systems can be reduced to the maximum extentand the software reusing can be improved, therefore the remaining system can achieve abetter integration to upgrade its flexibility and expandability.With the popularity of the new software architecture, SOA improves the increase ofthe enterprise application which also enlarges the number of Web Services available onthe Internet. Thus, how to reuse these services becomes a hot issue of current research.The technique of services composition can compose the available services based oncertain business logic which makes the composed one achieve more powerful and morecomplete business functions. In other word, such composition realizes the reuse of Webservice. And based on such composing technique, one can also construct a newenterprise application quickly.This paper briefly introduces the basic conception and theory of SOA, analysis theprinciple should be abided in the design atomic service under the guidance of SOA,studies the way in which the services coordinate and cooperate with each other, anddesigns a method of layered service. On the basis of this method, this paper presents ageneral technology of service composition: using ontology model to express service,generating composition program, giving an algorithm which can converse thecomposition program to BPEL4WS (Business Process Execution Language for WebService). This paper also dose research on BPEL4WS which implement servicecomposition. Finally, we achieved a Travel Reservation Service to test the researchresults,the practice indicate that the use of layered service and general technology ofservice composition is good for services composition based on SOA. |
