J2EE deployment files(web.xml)

<web-app>
This file contains the configuration for a web-application.
<icon>
The icon element contains a small-icon and a large-icon element which specify the location within the web application for a small and large image used to represent the web application in a GUI tool.
<small-icon>path/to/icon.gif</small-icon>
The small-icon element contains the location within the web application of a file containing a small (16x16 pixel) icon image. The image must be either GIF or JPEG format and the filename must end with the extension of ".gif" or ".jpg".
<large-icon>path/to/icon.gif</large-icon>
The large-icon element contains the location within the web application of a file containing a large (32x32 pixel) icon image. The image must be either GIF or JPEG format and the filename must end with the extension of ".gif" or ".jpg".

<display-name>A friendly name</display-name>
A friendly name that describes this unit.
<description>The description</description>
A short description, use etc.
<distributable />
The distributable element, by its presence in a web application deployment descriptor, indicates that this web application is programmed appropriately to be deployed into a distributed servlet container.
<context-param>
The context-param element contains the declaration of a web application's servlet context initialization parameters. There are two special kinds of initialization parameters for the optional cases where the parameter is used to obtain the JNDI name of an EJB or a data source for a subsequent look up. These are indicated by an context-param element together with an accompanying ejb-ref or resource-ref element with matching name.
<param-name>theName</param-name>
The name of the configuration parameter.

补充：Jsp教程,J2EE/EJB/服务器