web.xml 不同版本的dtd配置

web.xml v2.3

  
  

<web-app>  

web-app> 

web.xml v2.4

  
<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">  

web-app>  

web.xml v2.5

  

<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>  

web.xml v3.0

  

<web-app  
        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">  

web-app>  

web-fragment.xml

<web-fragment 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-fragment_3_0.xsd" version="3.0">  

web-fragment>