By using JSP forward attriputes within the html tag we can 
just forward our page to servlet.or by using 
response.sendRedirect()method we can call servlet page.
for example
-----------
<jsp:forward page="/relativepath/YourServlet" /> or 
response.sendRedirect("http://path/YourServlet"). 

We can also pass the parameters in the same way to the 
servlet
for example
-----------
<jsp:forward page=/relativepath/YourServlet>
<jsp:param name="name1" value="value1" />
<jsp:param name="name2" value="value2" />
</jsp:forward>
You may also pass parameters to your servlet by specifying 
response.sendRedirect("http://path/YourServlet?
param1=val1").