Design And Implementation On Online Marking System Based On Middleware Platform

With the help of computer and network, online marking system can support teachers for their marking work, it can resolve problems in traditional manual marking work, such as inefficient, prone to error and difficult to control quality control, thus ensure the efficient, accurate, fair and impartial in the marking work. Online marking is the trend of test paper marking. However, there are still many problems in application systems currently. So it is necessary to improve the architecture of adaptability, performance and stability of the system.Considering the development trends of applications based on Internet, the online marking system designed here used J2EE(Java 2 Platform,Enterprise Edition) architecture and EJB(Enterprise Java Beans) standard. In order to improve the performance and stability, on the basis of analysis of data structure and proceeding, four kinds of technologies are well used here, that is, cache mechanism, concurrent technology, sharing of resources in the database, and optimization the middleware which visited the database.In order to reduce the speed gap between the application server and the database, and to improve the data access efficiency influenced by network transmission and database access, the cache mechanism set up image data in the memory of application server for data in the database, and the policy of data access and elimination of the cache is well designed according to the data access rule of the online marking. Multithreading Bean is not allowed in EJB standard, and RMI-IIOP(Remote Method Invoke-Internet Inter- Object Request Broker Protocol) can only use blocked transfer mode, so some concurrent work can hardly be completed, in order to solve this problem, concurrency is implemented by the combination of JMS(Java Message Service) and MDB(Message-Driven Bean), it not only ensured the response time, but also improved the stability. Database access efficiency is sometimes influenced by frequent connection and disconnection with the database, In order to make database access more effective, and to make the connection resources share efficiently and safely, connection pool is used here, it initialed by some connections, a timer will monitor and manage connections all the time, a new connection will be build when needed, and idle connections will be closed. In order to optimize data access efficiency of middleware based on EJB, on the basis of analysis of the key factor which influent the data access efficiency mostly, the interface of Entity Bean is encapsulated by Session Bean, and the updating time of Entity Bean for database is changed.It is proved that the efficiency of the system designed here is improved greatly, and the stability is advanced. It is worthy to practice.