Research And Application On Re-engineering Of Legacy System Based On SOA-SSH

With the further development of information construction, the current information management systems become increasingly unable to meet the requirements of modern information management system, which is high agility and business requirements with the need to change. In order to fit for the need of modern information construction, we need to modernize the legacy systems. SOA (Service Oriented Architecture) is concerned by IT sector and the business community by its advantages, such as loosely coupled, flexibility to change business and so on. SOA is linked together with system integration, legacy systems re-engineering and so on, and became the best solutions of them. Web Services technology with its superior interoperability, loose coupling characteristic is considered as the best practices of SOA, and was widely used in IT application system which based on SOA. With the problems of modernizing the legacy systems, this paper study on the legacy systems re-engineering program under the platform of SOA.For solving the problem of legacy systems re-engineering under the platform of SOA, firstly this paper researched on the basic theory and system structure of using Web Services for integration based on SOA, gave an introduction on the design idea of service-oriented, compared SOA with Web Services and elaborated the relationship and difference between them; then, according to study on the status re-engineering of legacy systems, the author proposed a program to realize legacy re-engineering based on a new frame, which is named SOA-SSH. The program is a complete re-engineering program with three steps to implement specific process of re-engineering includes reverse-engineering, reconstruction, forward-engineering and so on. It will packaged data layer, business layer and application layer of the legacy system to web service, then combine the web services and SSH(Struts+Spring+Hibernate) framework to set up a new web application system. SOA-SSH framework is the combination of SSH framework and the Web Services technology, it gather the hierarchical structure, loosely coupled, flexible business changes together, can build a new application system which is scalable, flexible and easy to maintain. SOA-SSH framework realizes the real landing of SOA theory, and is a fundamental solution of difficulties such as information silos and integration of the legacy system and can achieve the modernization of the legacy systems.At last, we'll re-engineer the teaching evaluation system of Taiyuan University of Technology based on this program. We will show how to make reverse-engineering for legacy systems. We'll also show the process of forward-engineering such as how to implement the package of data layer, business layer, application layer on the legacy system under the SOA-SSH framework of Web services, how to achieve the combination of web services through BPEL to create "coarse-grained" services which meet the business, and integrate the web service with Struts to a whole web application system. This will verify the feasibility of the program further.