graph chart

Vertical Bar Graph Examples

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Servlet Example 3 - Configuration and Data from Server Processes

If you do not see the graph image below then click here»

and here is the HTML code,

<img src="http://localhost:8080/servlet/VbarchartServlet?
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 data sources. 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 data sources.

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 discussion on the various methods and example scripts please see the
Tutorial section - click here.


For a full explanation of and range of values for the above parameters please see the Documentation - Configuration Options».

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The servlet examples are designed to run on the local machine and require that Servletrunner ( part of the JSDK environment ) has already been installed. If you haven't already done so then you should implement the JSDK environment first, see

(The graph servlet will of course work with all servlet engines. If you wish to view the examples with another servlet engine then you will need to adjust the example pages to point to your servlet engine ).

Once you have installed the JSDK environment please copy all the files in the ./Servlet/ directory to the JSDK servlet directory ( usually c:\JSDK2.0\examples\ ). Now start the ServletRunner and then click on the examples below.

Getting Started




Common Problems
This section describes and provides solutions to common problems.