Research Of Legacy System Integration Based On Web Services

With the development of computer and internet technology, computer systems and internet resources were used more and more widely. These systems were called Legacy System once they were put into practice. How to integrate isolated legacy systems and make them interact and cooperate became a hot research topic. Currently, researchers and engineers mainly focus on developing new integration architecture. They treat legacy systems as the objects of integration and integrate these resources by re-engineering or re-constructing. However, resources in such integration method could only be applied to a single platform. It lacked flexibility in resource reusing and combination. In addition, it is difficult and costly to re-build the some legacy systems to support the new integration architecture.In order to solve these problems in tradition integration method, this thesis proposed an assistant integration method SOSIM based on SOA and Web Services. It integrated heterogeneous resources by referring to a descriptive model and a dynamic mapping method without changing the architecture of legacy system. The main research contents were as follow: Proposing a system integration descriptive model IDM, describing the system hierarchy via tasks, which could provide guidance to system integration and decision support from different domains and dimensions to managers; designing a dynamic parameter mapping method based on XML and a collaborative method among computer resources, which improved the flexibility of system integration and expanded the range of integration; presenting Semantics-Based resource descriptive method based on OWL-S and WSDL-S, improved the efficiency of resources locating and reusing; a visual modeling editor and integration services were developed in Java, which was well-known for its across- platform feature. And the method was implemented in a real SBA system which proved its feasibility.This integration method is especially useful in the system whose tasks and processes could not be predicted in the system develop phrase. The combination of the dynamic mapping method of resources and the task based description model provided a more flexible integration platform for legacy system,reduced the time and cost of integration and improved the efficiency.