NonStop Servlets for JSP System Administrator's Guide

Configuring NSJSP

NonStop Servlets for JavaServer Pages (NSJSP) System Administrator’s Guide—525644-001

3-15

Map Requests to Applications and Servlets

Mapping requests to servlets is closely linked to the concepts of a context path.

The application name and the context path gets you to the application subdirectory. No

further path is necessary to find a servlet or JSP within that application. The

deployment descriptor XML (web.xml) file defines the rest of the path.

The location of the application directory (and therefore the servlet or JSP) is

determined in the docBase attribute inside iTP_server.xml.

The servlet or JSP could be any name (given the <servlet-name> and <servlet-

class> XML elements of the web.xml file) not just the class name. Using these

elements allows separation between the web pages (using a servlet name) and the

underlying Java code (using the class name) and so makes maintenance easier.

The servlet or JSP does not even need a name, given the <servlet-mapping> XML

element of the web.xml file. You can set the mapping so that one servlet or JSP is

always the start of the application and, accordingly, does not need to be named in the

URL. Mapping is certainly convenient, and it might also be more secure.

URL Mapping to the Application

In a web container, each application is associated with a context and all resources

exist relative to that context. The context path starts at the root level of the application

directory. In our Configuring Web Applications on page 3-10, the context is /myapp1,

the name of the application.

Consider the URL that locates that context:

http://www.hostname.com/myapp1

The http://www.hostname.com is a URL for the HTTP scheme located at

www.hostname.com. The URI path is /myapp1. Together they form the URL.

As well as the www.hostname.com notation shown above, URLs can take the form

http://hostname:portnumber/myapp1

Each web application must be mapped to a unique URL path prefix, for instance,

/myapp1. The web container uses this prefix to map requests to resources within the

web application. The path name therefore serves as the document root for serving

resources within the application.

URL Mapping to the Servlet

The mapping process has two parts. The first part is to provide servlet name and,

optionally, an alias for the full servlet class name. Thus we could have a servlet name

such as start that refers to the servlet class startCartRequest.

The second part, again optional, is to use the <servlet-mapping> elements of the

deployment descriptor. This would be used to provide a more complex mapping than

the usual inclusion of servlet name (or class name) in the URL.