使用JFreeChart显示您的Oracle数据库数据(12)

   /**
* Create 3D pie chart displaying the number of employees at each
* commission level.This method demonstrates use of DatasetReader to
* translate data from XML format to JFreeChart data format.
    * 
* @return 3D Pie Chart showing number of employees at each commission
*         level.
    */
public JFreeChart createCommissionsPercentagePerLevelPieChart()
   {
PieDataset pieData = null;

final String xmlData =
databaseAccess.getCommissionPercentageBreakdownAsXml();

final DatasetReader reader = new DatasetReader();
try
      {
pieData = reader.readPieDatasetFromXML(
new ByteArrayInputStream(xmlData.getBytes()) );
      }
catch (IOException ioEx)
      {
ioEx.printStackTrace();
      }

JFreeChart chart =
ChartFactory.createPieChart3D(
"Commissioned Employees at Each Commission Level",
pieData,
false, true, false );

// Chart specifically provides getCategoryPlot() and getXYPlot() methods,
// but not a getPiePlot() or getPiePlot3D() method.
final PiePlot3D plot = (PiePlot3D) chart.getPlot();
plot.setDepthFactor(0.35);       // pie depth 35% of plot height
plot.setForegroundAlpha(0.5f);   // Declare explicitly as float (50%)
plot.setLabelGenerator(new HrCommissionsPieGenerator());

return chart;
   }

public class HrCommissionsPieGenerator implements PieSectionLabelGenerator
{       
   /**
* Generates a customized label for a pie section of pie chart depicting
* commissions levels.
    * 
* @param aDataset Dataset destined for pie chart.
* @param aKey The identifying key for each section of the pie chart.
    * 
* @return Customized label for section of pie chart identified by aKey.
    */
public String generateSectionLabel(final PieDataset aDataset,
final Comparable aKey)
   {
String labelResult = null;
if (aDataset != null)
      {
labelResult = (int)(Double.parseDouble(aKey.toString())*100) +
"% sales (" + aDataset.getValue(aKey).intValue() +
" employees)";
      }
      
return labelResult;
   }
}