用JfreeChart创建热点图片

<% ... @ page language="java" pageEncoding="UTF-8" %>
<% ... @ include file="/WEB-INF/jsp/include.jsp" %>
<% ... @ page import="org.jfree.data.general.DefaultPieDataset" %>  
<% ... @ page import="org.jfree.chart.*" %>  
<% ... @ page import="org.jfree.chart.plot.*" %>  
<% ... @ page import="org.jfree.chart.servlet.ServletUtilities" %>  
<% ... @ page import="org.jfree.chart.urls.StandardPieURLGenerator" %>  
<% ... @ page import="org.jfree.chart.entity.StandardEntityCollection" %>  
<% ... @ page import="java.io.*" %>  
< HTML >  
< HEAD >  
< META  http-equiv =Content-Type  content ="text/html; charset=utf-8" >  
< TITLE > JfreeChart </ TITLE >  
</ HEAD >  
< BODY >  
<% ...  
DefaultPieDataset data = new DefaultPieDataset(); 
data.setValue("高中以下",370); 
data.setValue("高中",1530); 
data.setValue("大专",5700); 
data.setValue("本科",8280); 
data.setValue("硕士",4420); 
data.setValue("博士",80); 

PiePlot3D plot = new PiePlot3D(data);//3D饼图 
plot.setURLGenerator(new StandardPieURLGenerator("barview.jsp","lion"));//设定链接 
JFreeChart chart = new JFreeChart("",JFreeChart.DEFAULT_TITLE_FONT, plot, true); 
chart.setBackgroundPaint(java.awt.Color.white);//可选，设置图片背景色 
chart.setTitle("程序员学历情况调查表");//可选，设置图片标题 

StandardEntityCollection sec = new StandardEntityCollection(); 
ChartRenderingInfo info = new ChartRenderingInfo(sec); 
PrintWriter w = new PrintWriter(out);//输出MAP信息 
//500是图片长度，300是图片高度 
String filename = ServletUtilities.saveChartAsPNG(chart, 500, 300, info, session); 
ChartUtilities.writeImageMap(w, "map0", info, false); 
String graphURL = request.getContextPath() + "/servletDisplayChart?filename=" + filename; 
%>  
< P  ALIGN ="CENTER" >  
< img  src ="<%= graphURL %>"  width =500  height =300  border =0  usemap ="#map0" >  
</ P >  
</ BODY >  
</ HTML >  

   < servlet >  
     < servlet-name > DisplayChart </ servlet-name >  
     < servlet-class > org.jfree.chart.servlet.DisplayChart </ servlet-class >  
   </ servlet >  
   < servlet-mapping >  
   < servlet-name > DisplayChart </ servlet-name >  
     < url-pattern > /servletDisplayChart </ url-pattern >  
   </ servlet-mapping >   

public   class  ImageAction  extends  Action  ... {

    public ActionForward execute(ActionMapping mapping, ActionForm form,
            HttpServletRequest request, HttpServletResponse response) ...{
    ImageForm image = (ImageForm)form;
        int width=0, height=0;

        JFreeChart chart = null;
    width = 248;
    height = 240;
    
    chart = createEventShareImage();
    try ...{
                StandardEntityCollection sec = new StandardEntityCollection(); 
                ChartRenderingInfo info = new ChartRenderingInfo(sec); 
                
                String filename = ServletUtilities.saveChartAsJPEG(chart, width, 240, info, request.getSession());
                String mapMessage = ChartUtilities.getImageMap("map0", info);
                String src = request.getContextPath()+"/servletDisplayChart?filename=" + filename ;
                String useMap = "#" + filename ;

    } catch (IOException e) ...{
                e.printStackTrace();
    }

     image.setMap(mapMessage);
     image.setSrc(src) ;
     image.setUseMap(useMap) ;

         return mapping.getInputForward();
    }

    private JFreeChart createEventShareImage() ...{

        Object[] share = eventCommonService.getEventShare();

        DefaultPieDataset pieDataset = new DefaultPieDataset();

        pieDataset.setValue("严重", new Long("100"));
        pieDataset.setValue("高级", new Long("200"));
        pieDataset.setValue("中级", new Long("150"));
        pieDataset.setValue("低级", new Long("300"));
        pieDataset.setValue("轻微", new Long("288"));
        
        PiePlot plot = new PiePlot(pieDataset);
        
        plot.setNoDataMessage("No data available");

        plot.setSectionPaint("严重", Constant.TERRIBLE_COLOR);
        plot.setSectionPaint("高级", Constant.HIGH_COLOR);
        plot.setSectionPaint("中级", Constant.MIDDLE_COLOR);
        plot.setSectionPaint("低级", Constant.LOW_COLOR);
    plot.setSectionPaint("轻微", Constant.INFO_COLOR);

    plot.setLabelGenerator(new StandardPieSectionLabelGenerator("{0} ({2})"));
    plot.setURLGenerator(new StandardPieURLGenerator("eventImage.do","type","id"));        

        JFreeChart chart = new JFreeChart("",JFreeChart.DEFAULT_TITLE_FONT, plot, true); 

        return chart;
    }

< bean:write  name ="imageForm"  property ="mapMessage"  filter ="false" />

< img  src ="<bean:write name=" imageForm" property ="src"   /> " usemap=" < bean:write  name ="imageForm"  property ="useMap"   /> "/>