B/S方式下使用jfreechart生成统计图表

package gov.gwssi.tax.nspg.datadisposal; 

import java.awt.Insets; 
import java.awt.Image; 
import java.io.PrintWriter; 
import java.text.SimpleDateFormat; 
import java.util.Date; 
import java.util.ArrayList; 
import java.util.Iterator; 
import java.util.Locale; 
import java.text.NumberFormat; 
import javax.servlet.http.HttpSession; 
import org.jfree.data.*; 
import org.jfree.chart.*; 
import org.jfree.chart.axis.*; 
import org.jfree.chart.renderer.VerticalBarRenderer; 
import org.jfree.chart.renderer.StandardXYItemRenderer; 
import org.jfree.chart.plot.*; 
import org.jfree.chart.entity.*; 
import org.jfree.chart.tooltips.*; 
import org.jfree.chart.urls.*; 
import org.jfree.chart.servlet.*; 
import java.awt.Font; 

/** 
 * <p>Title: </p> 
 * <p>Description: </p> 
 * <p>Copyright: Copyright (c) 2003</p> 
 * <p>Company: </p> 
 * @author jagie 
 * @version 1.0 
 */ 

public class GSPieChart { 
  public static void main(String[] args) { 
    Long[] testData = { 
        new Long(10), new Long(20), new Long(30), new Long(40)}; 
    generatePieChart(testData, "", null, new PrintWriter(System.out), 580, 250); 
  } 

  /** 
   * 生成图像文件 
   * @param datas Long[]数组 
   * @param targetUrl 点饼形图上的扇形，定向到的url 
   * @param session httpsession 
   * @param pw PrintWriter 
   * @param w 生成的图的宽度 
   * @param h 生成的图的高度 
   * @return 生成的图像文件的路径 
   */ 

  public static String generatePieChart(Long[] datas, String targetUrl, 
                                        HttpSession session, PrintWriter pw, 
                                        int w, int h) { 
    String filename = null; 
    try { 

      DefaultPieDataset data = new DefaultPieDataset(); 
      data.setValue("正常纳税人", datas[0]); 
      data.setValue("异常纳税人", datas[1]); 
      data.setValue("数据不全纳税人", datas[2]); 
      data.setValue("未处理纳税人", datas[3]); 

      //  Create the chart object 
      Pie3DPlot plot = new Pie3DPlot(data); 
      plot.setInsets(new Insets(0, 5, 5, 5)); 
      plot.setForegroundAlpha(0.6f); 
      plot.setSectionLabelType(plot.NO_LABELS); 

      plot.setURLGenerator(new StandardPieURLGenerator(targetUrl, "type")); 
      plot.setToolTipGenerator(new StandardPieToolTipGenerator()); 
      JFreeChart chart = new JFreeChart(
"数据处理结果统计图", JFreeChart.DEFAULT_TITLE_FONT, plot, true); 
      chart.setTitle(new TextTitle(
"数据处理结果统计图", new Font("黑体", Font.BOLD, 15))); 
      StandardLegend sl = (StandardLegend) chart.getLegend(); 
      sl.setItemFont(new Font("黑体", Font.TRUETYPE_FONT, 12)); 

      chart.setBackgroundPaint(new java.awt.Color(254, 254, 141)); 

      //因为jfreechart把生成的png文件保存在系统的临时文件夹中，你需要在适当的  
      //时候调用session.removeAttribute("JFreeChart_Deleter")，这样可以保证png文 
      //件被删除掉 

      ChartRenderingInfo info = new ChartRenderingInfo(new 
          StandardEntityCollection()); 
      filename = ServletUtilities.saveChartAsPNG(chart, w, h, info, session); 

      //  Write the image map to the PrintWriter 
      ChartUtilities.writeImageMap(pw, filename, info); 
      pw.flush(); 

    } 
    catch (Exception e) { 
      System.out.println("Exception - " + e.toString()); 
      e.printStackTrace(System.out); 
      filename = "public_error_500x300.png"; 
    } 
    return filename; 
  } 
}
.........java代码.................

<% 

//以下部分为图象输出 
String targetUrl="../servlet/gov.gwssi.tax.nspg.
controlservlet.GSMainControlServlet?id="+sid; 
Long[] datas={normals,new Long(totalAbnormal),
dataLacks,notProcesses}; 
String filename=GSPieChart.generatePieChart
(datas,targetUrl,session,new PrintWriter(out),580,250); 
String graphURL = request.getContextPath() + 
"/servlet/DisplayChart?filename=" + filename; 

%>

<!-- pie chart --> 
<table  width="580" border="0" cellspacing="0" cellpadding="0"> 
  <tr> 
    <td>  
      <ccid_file values="<%=" graphURL % />" width=580 height=250 border=0  
         usemap="#<%=filename %>"> 
    </td> 
  </tr> 
</table>

[pre]<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>/servlet/DisplayChart</url-pattern>
</servlet-mapping>[/pre]