JAVA JFreeChart畫圖

1.導入JFreeChart  JAR包

2.String shebeino=request.getParameter("shebeino");
  Ianalysis ian=new AnalysisImpl();
  Analysis a=ian.getAnalysisByUserAnaly(shebeino);
  if(a!=null){
  response.setContentType("image/jpeg");
  HttpSession session=request.getSession();
  
   DefaultPieDataset dataset = new DefaultPieDataset();
   if(a.getNewCar()!=0){
   dataset.setValue("A",a.getNewCar());
   }
   if(a.getShoppingGuide()!=0){
   dataset.setValue("B",a.getShoppingGuide());
   }
   if(a.getCartest()!=0){
   dataset.setValue("C",a.getCartest());
   }
   if(a.getInformation()!=0){
   dataset.setValue("D",a.getInformation());
   }
   if(a.getMarket()!=0){
   dataset.setValue("E",a.getMarket());
   }
   if(a.getKutu()!=0){
   dataset.setValue("F",a.getKutu());
   }
   if(a.getVedio()!=0){
   dataset.setValue("G",a.getVedio());
   }
  
   DefaultPieDataset data = dataset;
   //DefaultPieDataset data = getDataSet();
   JFreeChart chart = ChartFactory.createPieChart3D(a.getUserAnaly(),  // 圖表標題
   data,
   true, // 是否顯示圖例
   false,
   false
   );
  
   PiePlot pieplot = (PiePlot) chart.getPlot();
   pieplot.setNoDataMessage("無數據可供顯示！"); // 沒有數據的時候顯示的內容
   pieplot.setLabelGenerator(new StandardPieSectionLabelGenerator(
   ("{0}: ({2})"), NumberFormat.getNumberInstance(),
   new DecimalFormat("0.00%")));
  
   // 寫圖表對象到文件，參照柱狀圖生成源碼
//   ChartUtilities.writeChartAsJPEG(response.getOutputStream(),
//     100,chart,400,300,null);
   String filename=ServletUtilities.saveChartAsPNG(chart,300,300,session);
   String url=request.getContextPath()+"/DisplayChart?filename="+filename;
   //System.out.println(url);
   request.setAttribute("url",url);
  }
    request.getRequestDispatcher("userbehavior.jsp").forward(request, response);