Directory Structure | Servlets Tutorial pdf

Directory Structure

A Web application exists as a structured hierarchy of directories. The root of this hierarchy serves as the document root for files that are part of the application. For example, for a Web application with the context path /catalog in a Web container, the index.html file at the base of the Web application hierarchy can be served to satisfy a request from /catalog/index.html. The rules for matching URLs to context path are laid out in Chapter SRV.11, “Mapping Requests to Servlets”. Since the context path of an application determines the URL namespace of the contents of the Web application, Web containers must reject Web applications defining a context path could cause potential conflicts in this URL namespace. This may occur, for example, by attempting to deploy a second Web application with the same context path. Since requests are matched to resources in a case-sensitive manner, this determination of potential conflict must be performed in a case-sensitive manner as well.
A special directory exists within the application hierarchy named “WEB-INF”.
This directory contains all things related to the application that aren’t in the document root of the application. The WEB-INF node is not part of the public document tree of the application. No file contained in the  WEB-INF directory may be served directly to a client by the container. However, the contents of the WEBINF directory are visible to servlet code using the getResource and getResource- AsStream method calls on the ServletContext, and may be exposed using the RequestDispatcher calls. Hence, if the Application Developer needs access, from servlet code, to application specific configuration information that he does not wish to be exposed directly to theWeb client, he may place it under this directory.
Since requests are matched to resource mappings in a case-sensitive manner, client requests for ‘/WEB-INF/foo’, ‘/WEb-iNf/foo’, for example, should not result in contents of the Web application located under /WEB-INF being returned, nor any form of directory listing thereof.
The contents of the WEB-INF directory are:
=> The /WEB-INF/web.xml deployment descriptor.
=> The /WEB-INF/classes/ directory for servlet and utility classes. The classes in this directory must be available to the application class loader.
=> The /WEB-INF/lib/*.jar area for Java ARchive files. These files contain servlets, beans, and other utility classes useful to the Web application. The Web application class loader must be able to load classes from any of these archive files.
TheWeb application class loader must load classes from the WEB-INF/ classes directory first, and then from library JARs in the WEB-INF/lib directory. Also, any requests from the client to access the resources in WEB-INF/ directory must be returned with a SC_NOT_FOUND(404) response.

 Example of Application Directory Structure

The following is a listing of all the files in a sample Web application:
/index.html
/howto.jsp
/feedback.jsp
/images/banner.gif
/images/jumping.gif
/WEB-INF/web.xml
/WEB-INF/lib/jspbean.jar
/WEB-INF/classes/com/mycorp/servlets/MyServlet.class
/WEB-INF/classes/com/mycorp/util/MyUtils.class