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This tutorial examines the deployment descriptor files that define the resources and operating attributes of the MedRec Web applications.
Like most WebLogic Server Web Applications, each MedRec Web application uses two deployment descriptor files, web.xml
and weblogic.xml
. These files reside in the WEB-INF
folders that are part of the directory structure of WebLogic Server Web Applications.
A web.xml
deployment descriptor file is a J2EE standard XML document that sets properties for a Web Application. These properties are defined by the
Servlet 2.4 Deployment Descriptor XML Schema.
A weblogic.xml
deployment descriptor file is an XML document that defines WebLogic Server-specific properties for Web applications. These properties are defined by the XML Schema at
http://www.bea.com/ns/weblogic/90/weblogic-web-app.xsd.
MedRec's Web Applications are developed using Struts, which is an open source Web framework developed by the
Apache Struts. The Struts framework has its own configuration file, called struts-config.xml
, located in the same directory as the Web application deployment descriptor (WEB-INF
). This configuration file is defined by the
Struts 1.2 DTD. These tutorials do not describe the Struts framework; for more information, see the
Apache Struts site.
The tutorial includes the following sections:
Before starting this tutorial:
The following procedure walks you through the contents of the web.xml
and weblogic.xml
files.
In this section, examine how the web.xml
file from mainWebApp
Web Application (of the medrecEar
Enterprise application) containes the configuration of mainWebApp
's resources. mainWebApp
responds to HTTP requests in MedRec, either creating HTTP responses or forwarding requests to other Web components.
web.xml
can define the following attributes for a Web Application:
web.xml
file that configures mainWebApp
:prompt> notepad c:\medrec_tutorial\src\medrecEar\mainWebApp\WEB-INF\web.xml
<?xml version="1.0" encoding="UTF-8"?>
web-app
element that they modify. <web-app xmlns:j2ee="http://java.sun.com/xml/ns/j2ee">
....
</web-app>
web.xml
. The servlet
element and its servlet-class
attributes set the name of the servlet and the location of the compiled class that executes the servlet.
The following listing names a servlet called action
and associates it with a class:
<servlet>
<servlet-name>action</servlet-name>
<servlet-class>
org.apache.struts.action.ActionServlet
</servlet-class>
The init-param
attribute is part of the servlet
element; in this case, of the servlet defined in the previous step. The servlet reads its init-param
values when it is invoked. <init-param>
<param-name>config</param-name>
<param-value>/WEB-INF/struts-config.xml</param-value>
</init-param>
servlet-mapping
element determines how the MedRec application invokes a servlet. <servlet-mapping>
<servlet-name>action</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
welcome-file-list
element defines the Web application's welcome files. <welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
taglib
child element of the jsp-config
element defines the tag libraries that are available to the application:<taglib>
<taglib-uri>/WEB-INF/struts-bean.tld</taglib-uri>
<taglib-location>/WEB-INF/struts-bean.tld</taglib-location>
</taglib>
See
web.xml Deployment Descriptor Elements in Developing Web Applications for WebLogic Server for a description of the other elements in the web.xml file, such as filter
and filter-mapping
.
In this section, examine the contents of the weblogic.xml
file that configures the physicianWebApp
of the physicianEar
application. Physicians and nurses log in to the physician Web Application to search and access patient profiles, create and review patient medical records, and prescribe medicine to patients.
A WebLogic Server Web Application's weblogic.xml
file can set, among other things, the following major properties:
weblogic.xml
file that configures physicianWebApp
:prompt> notepad c:\medrec_tutorial\src\physicianEar\physicianWebApp\WEB-INF\weblogic.xml
<?xml version="1.0" encoding="UTF-8"?>
<weblogic-web-app xmlns="http://www.bea.com/ns/weblogic/90">
This URL is the directory that contains the current WebLogic Server 9.2 XML Schema for Web Applications.
weblogic.xml
file are members of the weblogic-web-app
element that opens and closes every instance of weblogic.xml
: <weblogic-web-app>
....
</weblogic-web-app>
session-descriptor
element contains session parameters for the Web Application's servlet sessions. The names of the child elements are defined in weblogic-web-app.xsd
, whose values can be set within the same session-descriptor
element:<session-descriptor>
<timeout-secs>600</timeout-secs>
<invalidation-interval-secs>60</invalidation-interval-secs>
<persistent-store-type>
replicated_if_clustered
</persistent-store-type>
</session-descriptor>
The timeout-secs
child element sets the number of seconds the server waits before timing out a session.
The second child element, invalidation-interval-secs
, is a performance-related setting that specifies the number of seconds the server waits before checking to determine if a session is invalid or has timed out.
The value assigned to the third child element, persistent-store-type
, determines the persistent store method for servlet sessions. The current value, replicated_if_clustered
, means that sessions on this server are stored in accordance with the value set for the cluster of servers to which this server belongs—if the Web Application is deployed to a cluster. Absent a clustered server configuration, servlet sessions default to the memory
PersistentStoreType
, in which sessions are not stored persistently.
virtual-directory-mapping
element sets the location that the servlet checks first when fulfilling HTTP image requests. Its child elements, local-path
and url-pattern
, map the URL pattern of an incoming request to a physical location. <virtual-directory-mapping>
<local-path>c:/medrec_tutorial/src/common/web</local-path>
<url-pattern>images/*</url-pattern>
</virtual-directory-mapping>
context-root
element in a weblogic.xml
file sets the context root directory for a Web Application. The context root is the base path of a Web application relative to the server's base URL. For example, MedRecServer's base URL is http://
host
:7101
and the Web application's context root is physician
. Users access components of the physician
Web application relative to http://
host
:7101/physician
.
The setting physician
means that users access the physicianWebApp when they specifically request it.
<context-root>physician</context-root>
See
weblogic.xml Deployment Descriptor Elements in Developing Web Applications for WebLogic Server for descriptions of all possible elements of the weblogic.xml
file.
The MedRec application contains five Web Applications:
The resources and attributes of these Web Applications are defined by deployment descriptor files. This tutorial describes the function of these deployment descriptors, specifically web.xml
, the standard J2EE Web application deployment descriptor file, and weblogic.xml
, the WebLogic Server-specific Web application deployment descriptor file.
Deployment descriptor files configure properties for MedRec's applications, EJBs, and Web Services, as well as its Web applications.
For example, physicianEar
, the application to which physicianWebApp
belongs, also contains a session EJB component, physSessionEJBs
. physSessionEJBs
's deployment descriptor files, generated into the C:\medrec_tutorial\build\physicianEar\physSessionEjbs\META-INF
directory, are the standard J2EE EJB deployment descriptor file ejb-jar.xml
, and the WebLogic Server-specific EJB deployment descriptor file, weblogic-ejb-jar.xml
.
Similarly, the physicianEar
also contains a Web Service called PhysicianWebServices
, whose deployment descriptor files are generated into the C:\medrec_tutorial\build\physicianEar\PhysicianWebServices\WEB-INF
directory. The Web Service deployment descriptors include the J2EE standard webservices.xml
, as well as the WebLogic-specific weblogic-webservices.xml
. Because the PhysicianWebServices
service is implemented with an EJB, the META-INF directory also contains EJB-related deployment descriptor files.
medrecEar
, the main MedRec application, is configured by a standard J2EE application deployment descriptor file, application.xml
, located at C:\medrec_tutorial\src\medrecEar\META-INF
.
You are encouraged to examine the EJB, Web Service, and application deployment descriptor files and the XML Schema files that they reference.
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