Web.xml parsing error

Question

Hello,
I am a newbie to servlet programming. I am using Tomcat4.1.24. When I
am trying out some examples, I got a bunch of parsing errors. After double-checking my web.xml, I still do not see why it caused so many parsing errors. I am using NotePad to edit web.xml, does that affect this? These errors are always about the last line and the last column.
Very weird. Please help.
web.xml
<?xml version="1.0" encoding="ISO-8859-1"?>
<!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>Welcome to Tomcat</display-name>
<description>
Welcome to Tomcat
</description>
<servlet>
     <servlet-name>HelloWorld</servlet-name>
     <servlet-class>HelloWorld</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>HelloWorld</servlet-name>
<url-pattern>*.myservlet</url-pattern>
</servlet-mapping>
<servlet>
     <servlet-name>Primes</servlet-name>
     <servlet-class>coreservlets.Primes</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Primes</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
</web-app>
[ERROR] Digester - -Parse Error at line 29 column 11: The content of element typ
e "web-app" must match "(icon?,display-name?,description?,distributable?,context
-param*,filter*,filter-mapping*,listener*,servlet*,servlet-mapping*,session-conf
ig?,mime-mapping*,welcome-file-list?,error-page*,taglib*,resource-env-ref*,resou
rce-ref*,security-constraint*,login-config?,security-role*,env-entry*,ejb-ref*,e
jb-local-ref*)". <org.xml.sax.SAXParseException: The content of element type "we
b-app" must match "(icon?,display-name?,description?,distributable?,context-para
m*,filter*,filter-mapping*,listener*,servlet*,servlet-mapping*,session-config?,m
ime-mapping*,welcome-file-list?,error-page*,taglib*,resource-env-ref*,resource-r
ef*,security-constraint*,login-config?,security-role*,env-entry*,ejb-ref*,ejb-lo
cal-ref*)".>

Answer 1

Hi.
The answer is rather simple. The file is not valid against the XML v.1.0 standard. That's because all <servlet> elements must come first before all <servlet-mapping> elements. If you change the order of the Primes <servlet> element, the file is valid and Tomcat should not throw an exception.
This is the correct web deployment descriptor:
<?xml version="1.0" encoding="ISO-8859-1"?>
<!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>Welcome to Tomcat</display-name>
<description>
Welcome to Tomcat
</description>
<servlet>
<servlet-name>HelloWorld</servlet-name>
<servlet-class>HelloWorld</servlet-class>
</servlet>
<servlet>
<servlet-name>Primes</servlet-name>
<servlet-class>coreservlets.Primes</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>HelloWorld</servlet-name>
<url-pattern>*.myservlet</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>Primes</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
</web-app>