Applet Example 6
This example
demonstrates how to implement the applet so that the graph
data is acquired from a database. Here we set up the applet
to acquire the configuration data from a text file and the
graph data from a server side process which in turn acquires
the data from a database.
The Graphing
Software provides several methods by which data can be acquired
from databases. For a full discussion on the various methods
and Template Scripts please see the
Tutorial Section.
The configuration
data is acquired from the text file barprops.txt
(click here to view)
and here
is the HTML code,
<applet code="SHbarchartApplet.class"
archive="SHbarchart.jar" width="450" height="440"
mayscript>
<!-- Start Up
Parameters -->
<PARAM name="LOADINGMESSAGE" value="Creating
Chart - Please Wait.">
<PARAM name="STEXTCOLOR" value="0,0,100">
<PARAM name="STARTUPCOLOR" value="255,255,255">
<!-- Data files
-->
<PARAM name="chartproperties" value="barprops.txt">
<PARAM name="chartdata" value="http://www.jpowered.com/siriusjava/servlet/DatabaseServletSHbar">
</applet>
The DatabaseServletSHbar
is designed to retrieve product sales data from a MySQL database,
from a table with the following structure,
Table
Name : SalesBar |
|
|
ProductName |
Character |
Year |
Integer |
Month |
Integer |
Value |
double |
Our servlet
will pick out the sales figures for three products ( ProductX,
ProductY and ProductZ) and return the data in the correct
format for the graph.
The method
is as follows,
- Set
the output characteristics for the return data
- Establish
the database connection
- Build
the query statement and retrieve the database records
- Process
the database records and return the Data
- All
finished so close the database connection
The full
servlet code is contained in the DatabaseServletSHbar
file.
(Click
here to view the code).
As you
will see from the code the servlet connects to the database
via JDBC and as such it is essential to have the correct JDBC
drivers for your database. ( For further information on JDBC
drivers please see http://industry.java.sun.com/products/JDBC/drivers
)
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/index.htm
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