Application Research Of Design Patterns In Virtual Trade Platform

Coal is an important basis of resources. Coal logistics occupies an important position in the domain of Chinese circulation. Shanxi Coal Transportation and Marketing Group Limited have abundant coal and infrastructure network resources, maturity the highway system of coal transportation. The construction of virtual trade platform can share resources, accelerate the circulation speed of resources, reduce business costs, and improve business efficiency. This paper finds out a new method to build the system, which via the use of Design Pattern on different level, and combinates patterns and the resultes of software requirement analysis to specific the software design, to build a flexible architecture for software system and improve the reuse and maintenance of software.This paper firstly introduces the basic theories of design pattern and analyses its method of choice and using. The paper applies design pattern to system development process in order to guide the design and development of system. The paper describes 23 kinds of mature design patterns and their application environments, and deeply studies how to choose and reuse right design pattern on the basis of actual situation to improve development efficiency. It introduces .NET platform's (an emerging development platform) development and major features, and focuses on the combination of .NET platform's advantage and design patterns, such as factory, faced and proxy pattern. We have successfully applied the results that we have researched into developing a virtual trade platform.Through the analyzing the characteristics of the coal logistics enterprises and traditional models, this paper constructs a virtual trade platform model based on design pattern. This model includes three layers: data layer, business logical layer and presentation layer. This paper designs general data layer component upon the combination of abstract factory and Data Access Object (DAO) pattern to solve the problem of different types of data sources; in order to realize low-coupling and high-aggregation function between layers, we design business logical component model with facade pattern; in presentation layer we focuse on the implementation of common components with observer pattern and MVC (Model-View-Controller).In this paper, the traditional MVC pattern is introduced. The emphasis of the paper includes design principle and key technique of controller, model and view. Based on 23 kinds of design patterns, a virtual trade platform using ASP.NET is developed according to the Object-Orient software engineering thinking.In the virtual trade platform, the users may demand requirement, query the coal resources and the transportation of enterprises, sign contracts, purchase and transport coal resources. Under this pattern, the system functions can be clearly divided and the system flow can be flexibly configured. The system also has the advantage of strong scalability and maintainability, easy to develop and support multiple types of user interface.