不同版本Servlet的web.xml头信息配备

?

Servlet 2.3
<?xml version="1.0" encoding="UTF-8"?>
<!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>
??...
</web-app>


Servlet 2.4
<?xml version="1.0" encoding="UTF-8"?>
<web-app 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>

Servlet 2.5
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 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 ">
??...
</web-app>