这种方法是怎么实现的 ？

在准备使用一个标签库ditchnet-tabs-taglib时，它的安装文档这样写的：

Install

Thanks to the JSP and Servlet APIs, Installation of the Tabs Taglib is simple:

1. Download the Ditchnet JSP Tabs Taglib JAR file.
2. Drop the JAR file into the WEB-INF/lib directory of your web application.
3. Make sure that the root directory of your web app is writable.
4. Reload your web web app.

The Tabs Taglib is now installed. Yup, that's it.

You can now begin authoring web pages with Tabs as described next...

You may be wondering why the root directory of your web app must be writable... The Tabs Taglib includes a ServletContextListener that will automatically be registered for your web app -- you don't need to add anything to your web.xml deployment descriptor to register this listener -- the configuration for this listener is included in the taglib tld file in the JAR, and will be registered without additional effort.

This ServletContextListener's first job is to create a directory in the root of your web app named org.ditchnet.taglib. Next, the listener will copy the necessary CSS, JavaScript, and image resources from the JAR to this new directory. After dropping the JAR into your WEB-INF/lib directory, and reloading your web app, you will see these directories and files appear.

If you do not see these directories and files appear upon web app reload, there may be a permission issue in writing to your web app's root directory. Try to change this, and re-reload the web app.

 

按照这个文档，配置后发现该标签库不能满足要求，就把它生产的目录和lib，tld删除了，问题就来了，一启动Tomcat就报错，说这个标签库里面的一个类找不到，标签库都被删了，他还加载这个类，被他配置在什么地方了？在WTP里删除掉Server也没有用，然后使用另一个Tomcat重新建Server就能用，然后再使用原来的Tomcat创建服务器，又可以跑了？这个标签库到底修改了什么文件？Tomcat？还是我的WebApp配置文件？web.xml里面内容没被修改， 等待ing

主要想问问这种方法是怎么实现的，因为对Servlet编程不是很熟悉 ^_^ 居然被评为新手帖了 ……

如果还不会用ditchnet jsp tab我有很详细的攻略，可以看看。

http://blog.sina.com.cn/s/blog_508a31520100a35v.html

我的个人网站使用了ditchnet jsp tab， 你可以看看效果
http://www.seaofchina.com/Forum/subforum.jsp?subid=1