web.xml不同版本之间头信息的区别

一、Servlet 2.3 

 "-//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 Applicationdisplay-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 Applicationdisplay-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 Applicationdisplay-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 Applicationdisplay-name>
web-app>

三、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 Applicationdisplay-name>
web-app>