Servlet Example 3
The Servlet
is setup here to read both the configuration data and the
graph data from server side processes, in this case 2 Java
Servlets VbarConfigServlet
and VbarDataServlet.
Please Note: In order for the Graphing Servlet to
produce the image below, a Servlet Runner must be running
on your local machine - see beginning
of this section.
and here
is the HTML code,
<img src="http://localhost:8080/servlet/VbarchartServlet?
config=http://localhost:8080/servlet/VbarConfigServlet&
data=http://localhost:8080/servlet/VbarDataServlet"
width="450" height="440">
The
VbarDataServlet ( click here
to view code ) is a simple servlet designed to demonstrate
how a servlet can be used to return data to either the graphing
applet or servlet. As you will see the main routine ( doGet()
) uses the method GraphData() to construct the return data.
Although in this example the GraphData() routine simply
builds the return data from 'hard coded' values, in practice
this routine would be expanded to first gather data from
any number of datasources. eg. databases, files other server
processes.
The
VbarConfigServlet ( click
here to view code ) again is just a simple servlet to
demonstrate the method. The routine ConfigData() is used
to construct the return data from 'hard coded' values. Again,
in practice this method would be expanded to derive data
from a number of datasources.
There
are various methods by which the graphing servlet can be
set to acquire data from databases including:-
Direct
Database Binding
Database Script Interface
For a full dicussion on the varius methods and example
scripts please see the
Tutorial section - click here.
Note:
If you are using the evaluation version then in the applet
a pop-up window will appear upon the startup and an evaluation
message will be incorporated by the servlet. Both these features
have been removed from the licensed version. Licensing information
can be found at http://www.jpowered.com/graph_chart_collection/index.htm
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