Network Deployment (Distributed operating systems), v8.0 > Reference > Configuration file descriptions

web.xml file

The web.xml file provides configuration and deployment information for the web components that comprise a web application.

The Java Servlet specification defines the web.xml deployment descriptor file in terms of an XML schema file. For backwards compatibility, any web.xml file that is written to Servlet 2.2 or above that worked in previous versions of WAS are supported by the web container.

If you use Rational Application Developer v6 to create your portlets, remove the following reference to the std-portlet.tld from the web.xml file:

<taglib id="PortletTLD">
<taglib-uri>http://java.sun.com/portlet
</taglib-uri>
<taglib-location>/WEB-INF/tld/std-portlet.tld
</taglib-location>
</taglib> 

Location

The web.xml file must reside in the WEB-INF directory under the context of the hierarchy of directories that exist for a web application.

For example, if the application is client.war, then the web.xml file is placed in the install_root/client war/WEB-INF directory.

Usage notes

• Is this file read-only?

  No

• Is this file updated by a product component?

  This file is updated by the assembly tool.

• If so, what triggers its update?

  The assembly tool updates the web.xml file when you assemble web components into a web module, or when you modify the properties of the web components or the web module.

• How and when are the contents of this file used?

  WAS functions use information in this file during the configuration and deployment phases of web application development.

Sample file entry

The web.xml file does not represent the entire configuration that is available for the web application. There are other servlets filters, and listeners that can be defined using programmatic configurations, annotations, and web fragments. Marking the web application metadata complete will prevent annotations and web fragments from being able to configure components.

<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_9" version="3.0" xmlns="http://java.sun.com/xml/ns/javaee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
  http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
<display-name>Servlet 3.0 application </display-name>
<filter>
<filter-name>ServletMappedDoFilter_Filter
</filter-name>
<filter-class>tests.Filter.DoFilter_Filter
</filter-class>
<init-param>
<param-name>attribute
</param-name>
<param-value>tests.Filter.DoFilter_Filter.SERVLET_MAPPED
</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>ServletMappedDoFilter_Filter
</filter-name>
<url-pattern>/DoFilterTest
</url-pattern>
<dispatcher>REQUEST
</dispatcher>
</filter-mapping>
<filter-mapping>
<filter-name>ServletMappedDoFilter_Filter
</filter-name>
<url-pattern>/IncludedServlet
</url-pattern>
<dispatcher>INCLUDE
</dispatcher>
</filter-mapping>
<filter-mapping>
<filter-name>ServletMappedDoFilter_Filter
</filter-name>
<url-pattern>ForwardedServlet
</url-pattern>
<dispatcher>FORWARD
</dispatcher>
</filter-mapping>
<listener>
<listener-class>tests.ContextListener
</listener-class>
</listener>
<listener>
<listener-class>tests.ServletRequestListener.RequestListener
</listener-class>
</listener>
<servlet>
<servlet-name>welcome
</servlet-name>
<servlet-class>WelcomeServlet
</servlet-class>
</servlet>
<servlet>
<servlet-name>ServletErrorPage
</servlet-name>
<servlet-class>tests.Error.ServletErrorPage
</servlet-class>
</servlet>
<servlet>
<servlet-name>IncludedServlet
</servlet-name>
<servlet-class>tests.Filter.IncludedServlet
</servlet-class>
</servlet>
<servlet>
<servlet-name>ForwardedServlet
</servlet-name>
<servlet-class>tests.Filter.ForwardedServlet
</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>welcome
</servlet-name>
<url-pattern>/hello.welcome
</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>ServletErrorPage
</servlet-name>
<url-pattern>/ServletErrorPage
</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>IncludedServlet
</servlet-name>
<url-pattern>/IncludedServlet
</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>ForwardedServlet
</servlet-name>
<url-pattern>/ForwardedServlet
</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>hello.welcome
</welcome-file>
</welcome-file-list>
<error-page>
<exception-type>java.lang.ArrayIndexOutOfBoundsException
</exception-type>
<location>/ServletErrorPage
</location>
</error-page>
<error-page>
<error-code>404
</error-code>
<location>/error404.html
</location>
<error-page>
</web-app>

For each <error-page> declaration, select either <exception-type> or <error-code>, but not both. The <location> tag is required.
Web applications
Web modules
Assembly tools
View web services deployment descriptors in the administrative console
View deployment descriptors

Related

Web applications: Resources for learning
Servlets

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