有关JFreeChart生成的图形如何在jsp页面中显示问题！

public String genLineChartHWL(BarChartInfo barChartInfo, List staticsResult,
                                   HttpSession session, java.io.PrintWriter pw) {
            //要返回的文件名，如果异常则返回null
            String filename = null;
            List forList = new ArrayList();
            try {
                //Throw a custom NoDataException if there is no data
                if (staticsResult == null || staticsResult.size() == 0) {
                    logger.error("No data has been found");
                    return filename;
                }
                //Create and populate a CategoryDataset
                DefaultCategoryDataset dataset = new DefaultCategoryDataset();
                int currentSize = staticsResult.size();
                for (int i = 0; i < currentSize; i++) {
                    ComDisplay info = (ComDisplay) staticsResult.get(i);
                    String curValue = null;
                    if (barChartInfo.getColString().equals("话务量")) {
                        curValue = info.getPhoneCapacityData();
                    }
                    String cityName = info.getCityName();
                    String dataDate = info.getDataDate().substring(5);
                    //添加实际数值
                    dataset.addValue( (curValue == null) ? 0 : Float.parseFloat(curValue), cityName, dataDate);
                }
                // create the chart...
                JFreeChart chart = ChartFactory.createLineChart(
                      "", // chart title
                      barChartInfo.getRowName(), // Domain axis label
                      barChartInfo.getColName(), // range axis label
                      dataset, // data
                      PlotOrientation.VERTICAL, // orientation
                      true, // include legend
                      true, // tooltips
                      false // urls
                      );                chart.setBackgroundPaint(Color.white);
                CategoryPlot plot = chart.getCategoryPlot();
                CategoryAxis categoryAxis = plot.getDomainAxis();
                categoryAxis.setMaxCategoryLabelWidthRatio(10);
                //判断 Labels 是横 or 纵
                categoryAxis.setVerticalCategoryLabels(true);
                categoryAxis.setCategoryLabelPositionOffset(0);                LineAndShapeRenderer renderer = (LineAndShapeRenderer)plot.getRenderer();
                renderer.setDrawShapes(false);
                renderer.setItemLabelGenerator(new StandardCategoryItemLabelGenerator());
                //xiugai 8/20 begin
                renderer.setItemLabelsVisible(false);
                //xiugai 8/20
                //OPTIONAL CUSTOMISATION COMPLETED.
                plot.setRenderer(renderer);
                plot.setBackgroundPaint(new Color(0xEE, 0xEE, 0xFF));
                //Write the chart image to the temporary directory
                ChartRenderingInfo info = new ChartRenderingInfo(new StandardEntityCollection());
                //生成图片600*400大小
                filename = ServletUtilities.saveChartAsPNG(chart, 550, 350, info,session);
                //Write the image map to the PrintWriter
                ChartUtilities.writeImageMap(pw, filename, info);
                pw.flush();            }
            catch (Exception e) {
                logger.error("Exception - " + e.toString());
                e.printStackTrace(System.out);
                filename = null;
            }
            return filename;
        }以上是java 代码，
jsp : String graphURL = request.getContextPath() + "/servlet/DisplayChart?filename=" + filename;
    if ( null != filename )
    {
%>
     <tr>
<td class="b2" bgcolor="#FFFFFF" nowrap >
<div align="center">
<table width="100%" border="0" cellspacing="1" cellpadding="1" gcolor="#E7F5FF">
<tr>
<td width="100%" class="pt10" align="center" nowrap >
 <img src="<%= graphURL %>" width=600 height=400 border=0 usemap="#<%= filename %>">
 </td>
     </tr>
    </table>
</div>
</td>
     </tr>
<%
    }

解决方案 »

  1.   

    <html>
    <head>
    <title>Chart</title>
    </head>
    <body bgcolor="#FFFFFF">
    <img src="/路径/ChartDemoServlet"><br>
    </body>
    </html>就可以调用你上面的Servlet了
      

  2.   

    web.xml <servlet>
        <servlet-name>ChartDemoServlet</servlet-name>
        <servlet-class>com...ChartDemoServlet</servlet-class>
      </servlet>
      <servlet-mapping>
        <servlet-name>ChartDemoServlet</servlet-name>
        <url-pattern>/路径/ChartDemoServlet</url-pattern>
      </servlet-mapping>
      

  3.   

    jsp
    <img src="/路径/ChartDemoServlet">
    web.xml
    web.xml <servlet>
        <servlet-name>ChartDemoServlet</servlet-name>
        <servlet-class>com...ChartDemoServlet</servlet-class>
      </servlet>
      <servlet-mapping>
        <servlet-name>ChartDemoServlet</servlet-name>
        <url-pattern>/路径/ChartDemoServlet</url-pattern>
      </servlet-mapping>