如何在jfreechart柱状图中的每个柱子上显示数值的问题
小弟刚接触jfreechart,在网上找了个柱状图的列子,我用的是jfreechart1.05的。网上的列子太旧,小弟做了点修改,图出来了,就是每跟柱子上无法显示数值,不知道何缘故。代码如下:   
  <%@   page   contentType= "text/html;charset=GBK "%>  
  <%@   page   import= "java.awt.Color "%>  
  <%@   page   import= "org.jfree.chart.ChartFactory "%>  
  <%@   page   import= "org.jfree.chart.JFreeChart "%>  
  <%@   page   import= "org.jfree.chart.plot.PlotOrientation "%>  
  <%@   page   import= "org.jfree.chart.servlet.ServletUtilities "%>  
  <%@   page   import= "org.jfree.data.category.CategoryDataset "%>  
  <%@   page   import= "org.jfree.data.general.DatasetUtilities "%>  
  <%@   page   import= "org.jfree.chart.plot.CategoryPlot "%>  
  <%@   page   import= "org.jfree.chart.axis.CategoryAxis "%>  
  <%@   page   import= "org.jfree.chart.axis.ValueAxis "%>  
  <%@   page   import= "org.jfree.chart.renderer.category.BarRenderer3D "%>  
  <%@   page   import= "org.jfree.chart.axis.AxisLocation "%>    
  <% 
 double[][]   data   =   new   double[][]   {{672,   766,   223,   540,   126},{325,   521,   210,   340,   106},{332,   256,   523,   240,   526}}; 
 String[]   rowKeys   =   { "苹果 ", "梨子 ", "葡萄 "}; 
 String[]   columnKeys   =   { "北京 ", "上海 ", "广州 ", "成都 ", "深圳 "}; 
 CategoryDataset   dataset   =   DatasetUtilities.createCategoryDataset(rowKeys,   columnKeys,   data);   
 JFreeChart   chart   =   ChartFactory.createBarChart3D( "水果销量图统计 ", 
                                                          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); 
 renderer.setWallPaint(Color.gray);//设置   Wall   的颜色 
 //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,