web.xml file

The web.xml file provides configuration and deployment information for the Web components that comprise a Web application. Examples of Web components are servlet parameters, servlet and JavaServer Pages (JSP) definitions, and Uniform Resource Locators (URL) mappings.

The Java Servlet 2.4 specification defines the web.xml deployment descriptor file in terms of an XML schema document. For backwards compatibility of applications written to the Java Servlet 2.2 Specification, Web containers are also required to support the Java Servlet 2.2 specification. For backwards compatibility of applications written to the Java Servlet 2.3 specification, Web containers are also required to support the Java Servlet 2.3 specification. If you use Rational Application Developer version 6 (RAD) 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 Application Server Toolkit.
If so, what triggers its update?
The Application Server Toolkit 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?
WebSphere Application Server functions use information in this file during the configuration and deployment phases of Web application development.

Sample file entry

<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_9" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
 <display-name>Servlet 2.4 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-patter>/DoFilterTest</url-pattern>
  <dispatcher>REQUEST</dispatcher>
 </filter-mapping>
 <filter-mapping>
  <filter-name>ServletMappedDoFilter_Filter</filter-name>
  <url-patter>/IncludedServlet</url-pattern>
  <dispatcher>INCLUDE</dispatcher>
 </filter-mapping>
 <filter-mapping>
  <filter-name>ServletMappedDoFilter_Filter</filter-name>
  <url-patter>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>
</web-app>

Related concepts
Assembly tools

Related reference
Web applications: Resources for learning