一、Servlet 2.3

<!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>

二、Servlet 2.4

<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">  
<web-app>  
  <display-name>Servlet 2.4 Web Application</display-name>  
</web-app>  

三、Servlet 2.5

<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>  
  <display-name>Servlet 2.5 Web Application</display-name>  
</web-app>  

四、Servlet 3.0

<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>  
  <display-name>Servlet 3.0 Web Application</display-name>  
</web-app>  

五、Servlet 3.1

<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>  
  <display-name>Servlet 3.1 Web Application</display-name>  
</web-app>