文档介绍：摘要
随着计算机网络通信技术的飞速发展,教育界越来越重视通过网络方便和丰富
教学方式,发展网上虚拟教室成为计算机辅助教育的热点,是现代教育发展的一个
方向。目前的实时异地交流系统有 C/S 和 B/S 两种结构模式。前者通过双方安装某
一指定软件,能实现功能齐全的交流平台;后者为基于 Browser 容器(如 IE 浏览器)
的交流平台,对客户端要求较低,但易造成“瘦客户,胖服务器”的局面,因此只
适合开发小型系统。开发一个既能适合学术交流的交流需求又不会造成服务器太
“胖”的系统平台是本文的目标。
本文首先介绍了在
本系统需要具备的背景知识,接着详细描述了设计实现本系统的架构、细节、关键
技术,最后总结了该系统的功能和一些新的探索,指出了部分不足之处。本系统采
用 Java 语言开发,用 Java Applet(Java 小程序控件)实现了功能较完善的实时交
流模块,包括电子白板、文本聊天、存储及读取历史记录,用 JMF(Java 媒体框架)
提供的一套通用 Java API 访问底层的媒体框架,通过 RTP(实时传输协议)协议实
现对时基媒体数据捕获、传输的管理,用 JSP 网页技术实现前台界面设计及数据库
操作。借由 Java 平台的优越性,做到“编写一次,处处运行”。
本文采用 B/S(浏览器/服务器)的结构方式进行设计,系统中的客户端程序都
扩展为 Applet 的子类,能在浏览器内良好运行,实现了客户端“零安装”,服务器
端的交互程序在 DOS 环境运行,作用是对客户端消息判别、转发与存储。该系统已
经在本机子网内通过测试,能实现多对多的交流。
关键词:Java 小程序; Java 媒体框架; 电子白板; 音频传输; 数字签名
IV
Abstract
With the rapid development work and munication technology,
the education sector are paying more and more attention to facilitate and enrich teaching
through work methods, the development of on-line virtual classroom has e a
hot pot int puter-aided education, which is also a direction of the modern
education path. The current real-time munication systems are this twos: C / S
and B / S structure model. The former can be installed by the two sides to support
large-scale developed software, and fully functional platform for munication; the
latter is based on the Browser containers (such as IE browser), lower requirements for the
client, but easy to create a "thin clients, fat server" problem, so this one is only suitable for
small applications. To develop a platform for academic exchanges which can not only
satisfys munication needs but also would not cause the server too "fat" problem
is the goal.
This paper firstly introduces work education system developed on the
basis of the , and then introduced the needed the background knowledge,
and then described the design of the structure of this article’s system, realization details,
the key technologies and the used methods, finally