Default Servlet

The Default servlet (or DefaultServlet) is a special servlet provided with Tomcat, which is called when no other suitable page is found in a particular folder.

For example, it will be called if the following folders are empty:

http://yoursite.com/
http://yoursite.com/images

It's purpose is to display a directory listing, which may be enabled or disabled by modifying the "listings" parameter.

The definition for the Default Servlet is in the server-wide default web.xml file (<jakarta>/conf/web.xml). It looks like this (for Tomcat 5.5):

<servlet>
    <servlet-name>default</servlet-name>
    <servlet-class>
      org.apache.catalina.servlets.DefaultServlet
    </servlet-class>
    <init-param>
        <param-name>debug</param-name>
        <param-value>0</param-value>
    </init-param>
    <init-param>
        <param-name>listings</param-name>
        <param-value>false</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>

As you can see from the above, the servlet is built into one of the Apache libraries.
There is also a <servlet-mapping> tag which maps the servlet to the "/" url-mapping:

<!-- The mapping for the default servlet -->
<servlet-mapping>
    <servlet-name>default</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>

When is the Default Servlet called?

• The Default Servlet is called when no suitable <welcome-file> page is found in the folder. See the <welcome-file-list> tag for information on the exact sequence of events.

What can I do with the Default Servlet?

• You can override it, to provide your own handler
• You can use it to enable or disable the Directory Listings Feature of Tomcat

See Also

• Enabling or disabling directory listings using web.xml article, describing how to override the normal settings for the Default Servlet, or even provide your own.
• web.xml Reference Guide