//下面用来让柱图更加好看
BarRenderer barrenderer = (BarRenderer) categoryplot.getRenderer();
barrenderer.setDrawBarOutline(true);
barrenderer.setOutlinePaint(Color.black);//加了个黑边，
barrenderer.setMaximumBarWidth(0.05);
barrenderer.setSeriesFillPaint(0, Color.blue);
return jfreechart;
}
public static String generateBarChart(HttpSession session, PrintWriter pw) {
String filename = "";
CategoryDataset categorydataset = createDataset();//在类里可以调用私有的成员啊
JFreeChart jfreechart = createChart(categorydataset);
ChartRenderingInfo info = new ChartRenderingInfo(
new StandardEntityCollection());
try {
filename = ServletUtilities.saveChartAsPNG(jfreechart, 500, 300,
info, session);
} catch (IOException e) {
e.printStackTrace();
}<