不同版本（2.3/2.4/2.5/3.0/3.1）web.xml头信息

1 <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
2          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
3          xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
4          http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
5          version="3.1">
6 
7   ...
8 </web-app>   

1 <?xml version="1.0" encoding="UTF-8"?>  
2 <web-app  xmlns="http://java.sun.com/xml/ns/javaee" 
3 　　　　　　xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
4 　　　　　　xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
5           http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" 
6 　　　　　　version="3.0">
7 
8   ...
9 </web-app>

1 <?xml version="1.0" encoding="UTF-8"?>
2 <web-app xmlns="http://java.sun.com/xml/ns/javaee"
3         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
5         http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
6         version="2.5">
7 
8   ...
9 </web-app>

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 3         xmlns="http://java.sun.com/xml/ns/j2ee"
 4         xmlns:web="http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
 5         xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
 6         http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
 7         version="2.4">
 8 
 9   ...
10 </web-app>

1 <?xml version="1.0" encoding="UTF-8"?>
2 <!DOCTYPE web-app
3     PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
4     "http://java.sun.com/dtd/web-app_2_3.dtd">
5 <web-app>
6 
7   ...
8 </web-app>