web.xml不同的头文件

《转自：http://blog.csdn.net/qq_16313365/article/details/53783288》

1. Servlet 3.1

Java EE 7 XML schema，命名空间是 http://xmlns.jcp.org/xml/ns/javaee/

<?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_3_1.xsd"
        version="3.1">

</web-app>

2. Servlet 3.0

Java EE 6 XML schema，命名空间是 http://Java.sun.com/xml/ns/javaee

<?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">

</web-app>

3. Servlet 2.5

Java EE 5 XML schema，命名空间是 http://java.sun.com/xml/ns/javaee

<?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>

4. Servlet 2.4

Java EE 1.4 XML schema, 命名空间是 http://java.sun.com/xml/ns/j2ee

<?xml version="1.0" encoding="UTF-8"?>
<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>

5. Servlet 2.3

Java EE 1.3 DTDs schema，这个版本的web.xml文件太老了，强烈建议升级

<!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>
  <display-name>Servlet 2.3 Web Application</display-name>
</web-app>