AJAX Architecture Dojo Chapter_dojo

作者：hopesoft
出处：http://www.51ajax.com

一、前言
自去年开始，AJAX一下成了关注的技术热点，各种AJAX框架迅速的发展了起来，其中又分为客户端AJAX架构，服务器端AJAX架构等，其中DojoToolkit做为一个优秀的客户端AJAX架构，被越来越多的人所关注，学习。自去年开始，AJAX一下成了关注的技术热点，各种AJAX框架迅速的发展了起来，其中又分为客户端AJAX架构，服务器端AJAX架构等，其中DojoToolkit做为一个优秀的客户端AJAX架构，被越来越多的人所关注，学习。

二、Dojo简介

作为早期的开源AJAX架构之一，Dojo开始于2004年9月，网址是 http://www.dojotoolkit.org，由JotSpot的Alex Russell所领导。

Dojo是一个开源的JavaScript工具包，本身预置了很多模块，可以实现完整的轻量级窗口组件及很多功能。Dojo的包加载机制(Package System)可以实现动态加载所需模块，而且用户可以编写自己的Dojo扩展模块，有很好的灵活性。

三、技术特点

1.文件结构

Dojo目前最高版本号是0.3.1，它的文件主要由一个包含主要功能的核心代码文件(Dojo.js)和众多的Javascript文件组成。使用时可以根据包机制，动态载入所需模块。

根据核心代码包含模块的不同，又细分为以下多个版本：
·AJAX版本：可以创建带有AJAX应用程序，集成复杂的可视效果，并使用事件模块。
·Widget版本：包括与小器件实现松散耦合的 HTML 和CSS 模板能力，提供明确分离的样式、内容和逻辑。
·Event and I/O版本：包括事件模块及I/O模块
·Event版本：包括事件模块
·Kitchen Sink版本：该版本包括整个工具集合

以上版本分别适用于不同的场合。用户也可以根据自己的需求重新构建自己的核心代码文件，只包含自己常用的模块，以避免频繁动态加载常用的模块。

2.程序结构

Dojo官方的定义中，将Dojo称之为Toolkit(工具包)，不是Framework（只是Framework的一部分），也不是Library（在Library之上又加了一层封包系统）。Dojo包括了Javascript本身的语言扩展，以及各个方面的工具类库，和比较完善的UI组件库。

如下图：(原地址http://manual.dojotoolkit.org/WikiHome/DojoDotBook/Book16)

As can also be seen from the picture, Dojo has a very reasonable design structure and is very scalable. It can continuously add new functions and ensure the efficient operation of the program.

4. Official resources

Dojo’s official website has the following resources, which can help us quickly become familiar with the structure of Dojo. Of course, because Dojo has rich functions, to fully master them, we need to gradually master them in actual development.

1. Dojo Manual (The Dojo Manual)
Website: http://manual.dojotoolkit.org/
Systematically introduces the mechanism of Dojo and uses Methods, sample code, etc.

2． The Dojo Mailing Lists (The Dojo Mailing Lists)
You can discuss and exchange problems encountered in using Dojo, or suggestions for improvements
Application address for joining: http://dojotoolkit.org/ mailman/listinfo/dojo-interest
View archive:http://news.gmane.org/gmane.comp.web.dojo.user

3． Dojo Bug Tracking System (Bug Tracking)
Website: http://trac.dojotoolkit.org/
Can be submitted to effectively discover bugs and submit bugs so that they can be eliminated in a timely manner Bug in Dojo

4． Code repository (The Dojo Subversion Repository)
Website: http://trac.dojotoolkit.org/browser
You can easily obtain the latest version of the Dojo package

5． The Dojo Wiki
Website: http://dojo.jot.com/
The content categories of Dojo Wiki are relatively rich, involving all aspects of Dojo.

6． IRC
Chat room address: irc.freenode.net

7． The Demo program
included in the Dojo package provides nearly 30 Demo programs in 8 categories, which can help you master the usage of Dojo faster in practice.

Tip: It is recommended to join the Dojo mailing list and study the sample code carefully, so that you can master the use of Dojo faster.

5. Development Prospects

1． Technical level
Compared with other AJAX frameworks, the package loading mechanism (Package System) and modular (Libraries) structure designed by Dojo can maintain better scalability, improve execution performance, and ease user development workload and maintain a certain degree of flexibility (users can write their own extensions).

2． Market level
Dojo is now developing rapidly and has received widespread support, and the Dojo Foundation has been established. Big companies such as IBM, AOL, and SUN, as well as open source teams such as WebWork, Tapestry, and Open Laszlo, are all members of the Dojo Foundation. , strong backing ensures that Dojo can continue to develop.

3． Development Team
Under the leadership of Alex Russell, Dojo’s development team has strong development capabilities, which can be seen from the functions, quality and update speed of the current version. In addition, Dojo will release 0.4.0 in the near future.

4． User Group
Due to Dojo's excellent design, more and more AJAX experts and novices have joined Dojo developers, and these developers will also drive the development of Dojo accordingly.

5． Learning Resources
Dojo official website has rich learning resources (see the "Official Resources" section), which can help people master Dojo faster and reduce learning costs.

6. Conclusion

Dojo can help developers develop large-scale AJAX projects and help build robust code and save development time. The strong support behind Dojo can also ensure the continuous addition of new features, helping us to break away from low-level repetitive work and focus on development on this basis.