web.xml

Servlet Deployment Descriptor Files

It is an xml file which acts as a mediator between a web application developer and a web container. It is also called Deployment Descriptor Files.

In web.xml file, we configure the following

• Servlet
• JSP
• Filter
• Listeness
• Welcome files
• Security
• etc....

To configure a servlet file we need the following two xml tag.

• <Servlet>
• <Serlet-mapping>

<servlet>: tag are used for configure the servlet, Within this tag we write Servlet name and class name.

<Serlet-mapping>: tag are used for map the servlet to a URL .

The structure of web.xml files is already defined by sun MicroSystem. So as a developer we should follows the structure to develop the configuration of web resources.

While configuring a servlet in web.xml, three names are added for it.

• Alias name or register name
• Fully qualified class name
• url-pattern

<web-app>
<servlet>
<servlet-name>alias name</servlet-name>
<servlet-class>fully qualified class name</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>alias name</servlet-name>
<url-pattern>/url pattern</url-pattern>
</servlet-mapping>
</web-app>