web.xml deployment descriptor exampless

java web 项目  各servlet 版本的 web.xml  文件格式

来源: http://www.mkyong.com/web-development/the-web-xml-deployment-descriptor-examples/

The web.xml is a configuration file to describe how a web application should be deployed. Here’re 5 web.xml examples, just for self-reference.

1. Servlet 3.1 deployment descriptor

Java EE 7 XML schema, namespace is http://xmlns.jcp.org/xml/ns/javaee/

web.xml

Markup

<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 deployment descriptor

Java EE 6 XML schema, namespace is http://java.sun.com/xml/ns/javaee

web.xml

Markup

<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 deployment descriptor

Java EE 5 XML schema, namespace is http://java.sun.com/xml/ns/javaee

web.xml

Markup

<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 deployment descriptor

J2EE 1.4 XML schema, namespace is http://java.sun.com/xml/ns/j2ee

web.xml

Markup

<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">

  <display-name>Servlet 2.4 Web Applicationdisplay-name>
web-app>

5. Servlet 2.3 deployment descriptor

J2EE 1.3 DTDs schema. This web.xml file is too old, highly recommend you to upgrade it.

web.xml

Markup

<web-app>
  <display-name>Servlet 2.3 Web Applicationdisplay-name>
web-app>

Java Servlet important changes 
Visit this  Servlet wiki for the summary of important changes from Servlet 2.3 to 3.0

References

1. Wikipedia – Deployment Descriptor
2. Wikipedia – Java Servlet Wiki
3. Oracle – web.xml documentation
4. Oracle – XML Schemas for Java EE Deployment Descriptors
5. Google App Engine web.xml for Java
6. JSR-000315 JavaTM Servlet 3.0