摘要： 性能和伸缩性是Web 工程中的两个重要概念，从不同方面反映了Web 应用系统提供响应时间的能力，但一直没有一个有效的评价方法。该文明确了性能和伸缩性的定义，提出了一个基于统计的性能和伸缩性评价模型，并给出了其在J2EE 平台上的应用。该模型易于实现，可为Web 应用系统的建设、维护以及升级改造提供可靠的决策依据。

关键词: 性能；伸缩性；评价；Web 应用系统

Abstract: Performance and scalability are two important concepts in Web engineering, they show the capability of response time of Web application system from two aspects, but have no efficacious evaluation. This paper defines the two concepts, and gives a performance and scalability evaluation modeling based on statistics, and shows its application on J2EE platform. This modeling is apt to be realized, and it can offer reliable decision-making for making, maintaining and upgrading.

Key words: Performance; Scalability; Evaluation; Web application system