Struts中的图形报表

我在只实现了柱状图，其它的图形可以参看我的JavaWeb部门的中图形报表说明！

 

步骤说明:
1,导入log4j.jar,jfreechart-0.9.18.jar,jcommon-0.9.3.jar三个jar包

2,在某个包中写入BarChart.java类
 private DefaultCategoryDataset dataset = new DefaultCategoryDataset();

 public void setValue(int value, String rowKey, String columnKey) {
  dataset.setValue(value, rowKey, columnKey);
 }

 public String generateBarChart(String title, HttpSession session,PrintWriter pw,int width,int heigth) {
  String filename = null;
  try {
   JFreeChart chart = ChartFactory
     .createBarChart3D(title, null, null, dataset,
       PlotOrientation.VERTICAL, true, false, false);
   chart.setBackgroundPaint(Color.WHITE);
   CategoryPlot plot = chart.getCategoryPlot();

   CategoryAxis domainAxis = plot.getDomainAxis();
   //domainAxis.setVerticalCategoryLabels(false);
   
   plot.setDomainAxis(domainAxis);

   ValueAxis rangeAxis = plot.getRangeAxis();
   // 设置最高的一个 Item 与图片顶端的距离
   rangeAxis.setUpperMargin(0.15);
   // 设置最低的一个 Item 与图片底端的距离
   rangeAxis.setLowerMargin(0.15);
   plot.setRangeAxis(rangeAxis);

   BarRenderer3D renderer = new BarRenderer3D();
   renderer.setBaseOutlinePaint(Color.BLACK);
   // 设置 Wall 的颜色
   renderer.setWallPaint(Color.gray);
   // 设置每种水果代表的柱的颜色
   renderer.setSeriesPaint(0, new Color(0, 0, 255));
   renderer.setSeriesPaint(1, new Color(0, 100, 255));
   renderer.setSeriesPaint(2, Color.GREEN);
   // 设置每个地区所包含的平行柱的之间距离
   renderer.setItemMargin(0.1);
   // 显示每个柱的数值，并修改该数值的字体属性
   //renderer.setItemLabelGenerator(new StandardCategoryItemLabelGenerator());
   
   renderer.setItemLabelsVisible(true);
   plot.setRenderer(renderer);

   // 设置柱的透明度
   plot.setForegroundAlpha(0.6f);
   // 设置地区、销量的显示位置
   plot.setDomainAxisLocation(AxisLocation.TOP_OR_RIGHT);
   plot.setRangeAxisLocation(AxisLocation.BOTTOM_OR_RIGHT);
   
   ChartRenderingInfo info = new ChartRenderingInfo(
     new StandardEntityCollection());
   filename = ServletUtilities.saveChartAsPNG(chart, width, heigth,
     info, session);
   ChartUtilities.writeImageMap(pw, filename, info);
   
   //pw.flush();
   //若你的访问数据库的代码和显示图片同在一个jsp中，就里就不能去掉**********
   //否则你就在这要注释掉
  } catch (Exception e) {
   e.printStackTrace();
  }
  return filename;
 }

3,配置web.xml,在web.xml中添加如下内空:
 <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>/DisplayChart</url-pattern>
 </servlet-mapping>

4,在要显示图片的jsp中添加内容:
  在action中去访问数据库，我这就不访问了
  public ActionForward execute(ActionMapping mapping, ActionForm form,
   HttpServletRequest request, HttpServletResponse response) {
  
  BarChart bch = new BarChart();
  
  //第一组
  bch.setValue(200,"苹果","武汉");
  bch.setValue(400,"香蕉","武汉");
  bch.setValue(500,"橘子","武汉");
  bch.setValue(300,"梨子","武汉");
  
  //第二组
  bch.setValue(400,"苹果","黄冈");
  bch.setValue(300,"香蕉","黄冈");
  bch.setValue(100,"橘子","黄冈");
  bch.setValue(300,"梨子","黄冈");
  
  //第三组
  bch.setValue(600,"苹果","A");
  bch.setValue(300,"香蕉","A");
  bch.setValue(400,"橘子","A");
  bch.setValue(200,"梨子","A");
  HttpSession session=request.getSession();
  
  //System.out.println("默认的格式："+response.getCharacterEncoding());
  //这里在改成gbk格式，否则在显示图片的jsp中不能显示中文
  response.setCharacterEncoding("gbk");
  
  String filename=null;
  try {
   filename = bch.generateBarChart("水果比图", session,
     new PrintWriter(response.getWriter()),700,500);
   
  } catch (IOException e) {
   e.printStackTrace();
  }
  String url = request.getContextPath() + "/DisplayChart?filename="
    + filename;
  
  request.setAttribute("filename", filename);
  request.setAttribute("url", url);
  
  try {
   request.setCharacterEncoding("gbk");
  } catch (UnsupportedEncodingException e) {
   e.printStackTrace();
  }
  return mapping.findForward("show");
 }
5,有两点要注意：
 ***************第一：在工具类BarChart.java：把pw.flush();去掉或注释掉
 ***************第二：在filename = bch.generateBarChart("水果比图", session,
       new PrintWriter(response.getWriter()),700,500);
        之前一定要//System.out.println("默认的格式："+response.getCharacterEncoding());
          //这里在改成gbk格式，否则在显示图片的jsp中不能显示中文
         response.setCharacterEncoding("gbk");
   
6，在jsp中：  
  <table align="center" border="0">
   <tr>
    <td>
     <P ALIGN="CENTER">
      <img src=${url } width=700 height=500 border=1 usemap=${filename }>
     </p>
    </td>
   </tr>
  </table>