The requirement of mapping from one servlet to another is common issue...So below is the code how to map from servlet 1 to Servlet 2.
The XML shows mapping of HTML through FILTER file to SERVLET... If we have more than 1 servlet then we proceed through same procedure again and again....

<xmp>
<servlet>
<servlet-name>servlet _1</servlet-name> 
<servlet-class>HelloServlet</servlet-class> 
</servlet> 

<servlet-mapping> 
<servlet-name>servlet 1</servlet-name> 
<url-pattern>/servlet1</url-pattern> 
</servlet-mapping> 

<filter>
<filter-name>f1</filter-name> 
<filter-class>Myfilter</filter-class>
</filter>

<filter-mapping> 
<filter-name>f1</filter-name> 
<url-pattern>/servlet1</url-pattern> 
</filter-mapping>
</xmp>

Hope this will help in solving common problem we usually face.....