Servlet spec - web.xml
Status
Released on (mm/dd/yyyy) : 02/06/2012
Description
JEE web specification provides a way to configure, declaratively in the web deployment descriptor ("web.xml" file), the web app. behavior when an exception occur in a web component.
Behavior can be configured to react on elements below to display a resource:
- Java exception
- HTTP response code
Possible configurations
Configuration below redirect user to page "/errorManagement.jsp" when an error occur.
Configuration to react on Java exception
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0"> ... <!-- Define error page to react on Java exception --> <error-page> <exception-type>java.lang.Throwable</exception-type> <location>/errorManagement.jsp</location> </error-page> ... </web-app>
Configuration to react on HTTP response code
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0"> ... <!-- Define error page to react on HTTP response code --> <error-page> <error-code>500</error-code> <location>/errorManagement.jsp</location> </error-page> ... </web-app>
Content of the error management page
<?xml version="1.0" encoding="ISO-8859-1" ?>
<%@ page language="java"
contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"
isErrorPage="true"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" />
<title>Page to manage error</title>
</head>
<body>
<%-- Log error on server side --%>
<%
//When the page attribute "isErrorPage" is set to "true" the exception object is available
System.err.println("Error : " + exception.getMessage());
%>
<%-- Display generic error to client --%>
<b>An error occur !</b>
</body>
</html>
1. Servlet 3.1 deployment descriptor
Java EE 7 XML schema, namespace is http://xmlns.jcp.org/xml/ns/javaee/
web.xml
Markup
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
version="3.1">
</web-app>2. Servlet 3.0 deployment descriptor
Java EE 6 XML schema, namespace is http://java.sun.com/xml/ns/javaee
web.xml
Markup
<web-app 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"
version="3.0">
</web-app>3. Servlet 2.5 deployment descriptor
Java EE 5 XML schema, namespace is http://java.sun.com/xml/ns/javaee
web.xml
Markup
<web-app 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_2_5.xsd"
version="2.5">
</web-app>4. Servlet 2.4 deployment descriptor
J2EE 1.4 XML schema, namespace is http://java.sun.com/xml/ns/j2ee
web.xml
Markup
<web-app 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"
version="2.4">
<display-name>Servlet 2.4 Web Application</display-name>
</web-app>5. Servlet 2.3 deployment descriptor
J2EE 1.3 DTDs schema. This
web.xml file is too old, highly recommend you to upgrade it.
web.xml
Markup
<!DOCTYPE web-app PUBLIC
"-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd" >
<web-app>
<display-name>Servlet 2.3 Web Application</display-name>
</web-app>
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