| Since China’s reform and opening-up, a large number of information systems have beenexisting in enterprises and different ranks of government organization such as online production,office automation, information management and internet portals had been put into practicalapplications through30years’construction of computer informatization, which plays positive andeffective roles in promoting productivity, improving work efficiency, improving quality ofservices and aiding decision-making. As computer application systems which are in practicalapplication were constructed in different ages and applied to different objects and purposes, evenin the same company, the same government organization or the same industry, cooperation withwork, interaction, sharing and using data of legacy systems are facing great challenges, many ofthese legacy systems formed isolated islands of information. SOA (Service-oriented Architecture)can solve the technical problems about cooperation with work, interaction, sharing and using datain heterogeneous systems perfectly.Ahydrological monitoring system which involves cooperation with work, interaction, sharingand using data across multiple departments such as water conservancy planning design, waterresources utilization, water resources protection, water resources monitoring and etc had beendesigned and implemented in this paper, based on SOA. Effective practices had been done byapplying of the SOA technology.The major research work and innovations in this paper are summarized as the followings:1) According to the technical characteristics of SOA architecture and Web services, asoftware system model of hydrological monitoring system based on SOA had been designed andimplemented. The model adopted the design method of system hierarchical structure so that eachlayer of software system exchanges data through the data interface protocol and has thecharacteristic of loosely coupled, making it convenient for parallel development, testing andexpansion of systems. 2) Basic services were constructed. Guided by thought of service-oriented, combined with thepractical application scenarios and requirements of hydrological monitoring system, the basicservices were divided into appropriate granularity. The user management module in existingsystem was exposed as user management services using CXF (Apache CeltiXfire) engine. Otherbasic services were developed using EJB3technology.3) A framework that can automatically generate BPEL (Business Process ExecutionLanguage) document was proposed. Use workflow model based on DAG (Directed Acyclic Graph)and Practice indicated that the framework is simple and easy to apply, the cumbersome processamong service compositions can be hid as well as aspect on professional knowledge of BusinessProcess Execution Language is not be required. By using DAG to create a service compositionworkflow modeling and using dependent algorithm to analyze modeling, the framework cangenerate a various of document required for service composition. Practice indicated that theframework is simple and easy to apply, the process among service compositions can be clearlyreflected as well as aspect on professional knowledge of Business Process Execution Language isnot be required and the work quantity for service composition can be reduced.4) A JBoss AS7cluster was realized. The JBoss AS7cluster was realized based on analysis ofthe principle of JBoss AS7clusters and reference of JBoss official documents, solving the problemof load balancing.The hydrological monitoring system in this paper had been designed and implemented basedon B/S architecture pattern, Web Services and Java EE software framework. The actual runningresults indicate that this system had achieved the desired goal. The system not only reuses theexisting functional modules, but also provides some shared basic services, paving the way forreusing function module and cross-system integration. |
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