外文翻译---基于J2EE在分布式环境下的底层结构自动动态部署应用.docx

附录1 翻译原文Infrastructure for Automatic Dynamic Deploymentof J2EE Application in Distributed EnvironmentsAnatoly Akkerman, Alexander Totok, and Vijay KaramchetiAbstract: in order to achieve such dynamic adaptation, we need an infrastructure for automating J2EE application deployment in such an environment. This need is quite evident to anyone who has ever tried deploying a J2EE application even on a single application server, which is a task that involves a great deal of configuration of both the system services and application components.Key words: j2ee; component; Distributed; Dynamic Deployment; 1 IntroductionIn recent years, we have seen a significant growth in component-based enterprise application development. These applications are typically deployed on company Intranets or on the Internet and are characterized by high transaction volume, large numbers of users and wide area access. Traditionally they are deployed in a central location, using server clustering with load balancing (horizontal partitioning) to sustain user load. However, horizontal partitioning has been shown very efficient only in reducing application-related overheads of user-perceived response times, without having much effect on network-induced latencies. Vertical partitioning (e.g., running web tier and business tier in separate VMs) has been used for fault isolation and load balancing but it is sometimes impractical due to significant run-time overheads (even if one would keep the tiers on a fast local-area network) related to heavy use of remote invocations. Recent work [14] in the context of J2EE component based applications has shown viability of vertical partitioning in wide-area networks without incurring the aforementioned overheads. The key conclusions from that study can be summarized as follows:? Using properly designed applications, vertical distribution across wide-area networks improves user-perceived latencies.? Wide-area vertical layering requires replication of application com