Research And Application Of Pool Resource And Cache In Data Access Middleware

With the development of information technology and Internet, B/S structure has been applied. The core thinking of it is put data access and business logic in the middle layer. Present database access middleware of water domain is designed on J2EE platform; it can resolve the problems of C/S structure. There are some problems. The control of user access is not so efficient; on the aspect of data access efficiency, the hit-rate of cache is on the low side.This article firstly analyses the character of water information system and the problems of data access middleware. Base on the analysis, the article put forward an improved scheme to the design of data access middleware. The whole model uses the light container. The light container doesn't support EJB, so we must design the persistent layer. The main works of this paper are: 1. the technology of multi-thread and thread pool are used to optimize the run of task thread, it can control the cocurrent access and reduce the waste of resource and fall of performance due to the repeat creation of thread. The system can adapt to great cocurrent access and control the load efficiency. 2. The entity bean cache in application server can not be used in light framework. The middleware adds a layer of matching and parser of query sentence; it can implement dynamic filtration of cache and reduce the range of cache. Using correlative query cache to replace tradition cache, the article designs and implements the cache structure, query matching, strategy of consistency and strategy of replacement. The application of water domain accesses database mainly for data query and the queries have high correlation, so it may raise the efficiency of data access. 3. At the part of database connection, the article designs a database connection pool. The client uses data resource to access database, gets the connection from connection pool. When the client completes the access, the client returns the connection to the pool. This method reduces the time of connecting to database and raises the efficiency of access. Finally, the article designs the application project in Jiangsu water database system and tests these technologies. Through testing under different conditions, the result show that thread pool reduce time spending of multi-thread; the design of correlative query cache have higher hit-rate and reduce the data transfers from database to middleware under the condition of huge correlative access.