摘要
面向服务的体系结构(Service Oriented Architecture,SOA)是一种新型的软件体系结构,它具有可重用性、松散耦合、粗粒度、互操作性等优点。SOA已经成为企业应用系统架构设计的主要方法,得到了广泛应用。目前服务建模主要采用三种建模规则:面向对象的分析与设计、企业体系结构框架和业务流程建模。但是早期的SOA项目经验表明,上述三种建模方法各自单独使用时均达不到SOA的要求。有必要研究服务建模的新方法,使得容易、成功地进行SOA开发。
本文首先阐述了SOA的概念、基本框架和原则,分析了SOA中的服务及SOA架构所带来的优点。研究了SOA架构当前最好的实现方式—Web服务技术。
接着,描述了面向服务的开发流程,明确了服务建模和设计在SOA交付周期中所处的位置,分析了面向服务的设计和分析过程。重点研究服务建模与设计的原理与方法。通过研究已有的服务建模方法的不足,论文提出了一个基于SOA交付周期的、自顶向下发现服务的建模方法,用于指导系统的建模。
在服务设计的研究中,分析了服务设计的过程,研究了服务粒度的划分对SOA质量的影响。重点从服务层次和操作层次对设计合适粒度的服务做了研究,总结出了服务设计的原则。
采用Web服务技术开发和实现了一个基于SOA的在线医药销售系统应用实例。实践表明,本文提出的服务建模与设计的方法是先进的,可行的。
Service Oriented Architecture (SOA) is a new software architecture with many advantages, such as reusability, loose coupling, course granularity, interoperability and so on. Adoption of the SOA design ideas can get the greatest extent to reduce the coupling between systems, enhanced reusability, and better integration of legacy systems, enhancing the system's flexibility and interoperability. SOA has a wide range of applications and has become the main method of enterprise application system architecture design.
By introducing the concepts of the SOA, basic framework and principles, the advantages of SOA are discussed in detail in this paper, and the important concept "service" is explained in detail. Web Services as the best implementation of SOA is studied in-depth as well.
Service-oriented application development process is presented. This helps us to fully understand the location of modeling and design service in the SOA life cycle. Principles and methods of service modeling and design have been studied in-depth. By analysising the shortcomings of existing modeling methods, a new method of service modeling is described, which is based on Service-oriented application development process and service discovery from top to down. Since service design is one important process of service-oriented design, service-oriented design process is presented in detail. Aiming to find methods used to design appropriate services granularity, those issues from service level to operational level definitions and principles of service design are studied in detail.
As a demo, an on-line medicine sales system based on SOA is analyzed and designed by using principles and methods of services decomposition and design. The practical project shows that the methods described in this paper are good and useful.
引文
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