基于BlazeDS消息推送的WebGIS系统设计与实现

DESIGN AND IMPLEMENTATION OF WEBGIS SYSTEM BASED ON BLAZEDS MESSAGE PUSH TECHNOLOGY

为满足一些WebGIS应用对实时性的要求,在分析传统WebGIS采用请求/响应工作方式的不足的基础上,提出利用开源框架BlazeDS的基于HTTP协议的消息推送技术,实现WebGIS系统服务端地理信息数据的实时推送。通过服务器向客户端主动推送数据以获得更好的实时性,并使用Flex作为客户端更好的表达地理信息数据。在分析BlazeDS服务器推送技术的原理和基本过程的基础上,给出WebGIS系统体系结构,讨论其核心设计与系统实现,最后通过实例说明系统应用的可行性。

To meet the demand for real-time requirements of some WebGIS applications, according to the analyses of traditional WebGIS on its deficiency of adopting the work mode of request/response, this paper proposes to achieve the real-time push of geographic information data on server side of WebGIS system using HTrP protocol-based information push technology of open source framework BlazeDS, the active data push through server to clients provides a better real-time performance, and the use of Flex as the clients can better express the geographic information data. By analysing the principles and basic processes of push technology on BlazeDS server, the architecture of the WebGIS system is presented. Then the core design and the implementation of the WebGIS system are discussed, and finally an example is given to illustrate the feasibility of the system application.