web.xml各版本头文件及与JDK、Tomcat版本对应关系

web.xml——version2.2——JDK1.1——Tomcat3.3

web.xml——version2.3——JDK1.3——Tomcat4.1

<?xml version="1.0" encoding="ISO-8859-1"?>  
<!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>

web.xml——version2.4——JDK1.4——Tomcat5.5

<?xml version="1.0" encoding="UTF-8"?>  
<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——version2.5——JDK5.0——Tomcat6.0

<?xml version="1.0" encoding="UTF-8"?>  
<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——version3.0——JDK6.0——Tomcat7.0

<?xml version="1.0" encoding="UTF-8"?>  
<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">
        <display-name>Archetype Created Web Application</display-name>
</web-app>

web.xml——version3.1——JDK7.0——Tomcat8.0,Tomcat8.5

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
	<display-name>Archetype Created Web Application</display-name>
</web-app>

web.xml——version4.0——JDK8.0——Tomcat9.0

<?xml version="1.0" encoding="UTF-8"?>
<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_4_0.xsd" version="4.0">
    <display-name>Archetype Created Web Application</display-name>
</web-app>