CICS Transaction Gateway V5 The WebSphere ... - IBM Redbooks

Since there is no definition of our Web application (CTGTesterCCIWeb) in the
WebSphere plugin configuration file (was.conf), then the HTTP request is
automatically sent to the Web container in the J2EE Server, rather than
executing in the WebSphere plugin within the HTTP Server address space.
Once the request is mapped over to the J2EE Server, the Web container will
search through all the virtual-host/context-root pairs in its configuration file
(webcontainer.conf) to see if the request matches. If the URL received matches a
virtual-host/context-root pair, then the Web container knows to proceed. If no
match is found, then WebSphere will reject the URL. We had the following
definitions in our webcontainer.conf:
host.default_host.alias=wtsc66oe.itso.ibm.com:80,SC66:80,
wtsc66oe.itso.ibm.com:99
host.default_host.contextroots=/
This then is how our Web application functions:
1. The first request to our Web application using the URL
http://wtsc66oe.itso.ibm.com:99/CTGTesterECIWeb/ is passed to the Web
container in the J2EE Server.
2. The URI CTGTesterECIWeb causes the default welcome page to be loaded,
which is defined in the Web deployment descriptor (web.xml) to be the Java
Server Page (JSP) index.jsp.
3. This index.jsp contains an HTML form that is then used to invoke the servlet
CTGTesterECIServlet.
4. WebSphere next goes looking for an application whose defined
servletmapping value matches that implied on the received URL. In this
example, the servletmapping string on the URL is CTGTesterECIServlet, and
it knows this because the servletmapping value is whatever comes after the
context root value on the URL. WebSphere looks through the web.xml files
contained in each Web application's WAR file looking for a tag
that matches the servletmapping string on the URL. When it finds one, it
takes the value and goes to the point in the web.xml file
where is defined. This is the class file that is executed. In our
web.xml (Example 10-4), the following servlet mapping was defined.
Example 10-4 web.xml
CTGTesterECIWeb
CTGTesterECIServlet
CTGTesterECIServlet
Chapter 10. CICS TG and WebSphere Application Server for z/OS 267