一个jfreechar的问题 郁闷啊

Question

//创建曲线图
        public String linePic(DT_KpiData kpi_data,String fileName,int width,int height,int img_type)
        {
                try
                {
                        if(kpi_data == null || kpi_data.vec_val.size() == 0) return("");
                        double max_val = 0;//最大值
                        double min_val = 0;//最小值
                        boolean flag = false;
                        DefaultCategoryDataset data = new DefaultCategoryDataset();//设定数据源
                        for (int j = 0; j < kpi_data.vec_val.size() - 1; j++)
                        {
                                DT_KpiValue data_bt = (DT_KpiValue)kpi_data.vec_val.elementAt(j);
                                if(data_bt.vec_val == null)
                                {
                                        if (j == 0 && kpi_data.vec_val.size() > 2)
                                        {
                                                max_val = data_bt.col_val;
                                                min_val = data_bt.col_val;
                                        }
                                        else
                                        {
                                                if (data_bt.col_val > max_val) max_val = data_bt.col_val;
                                                if (data_bt.col_val < min_val) min_val = data_bt.col_val;
                                        }
                                        data.addValue(data_bt.col_val, null, data_bt.col_name);
        }
        else
        {
                flag = true;
                if(j == 0 && data_bt.vec_val.size() > 2) min_val = data_bt.col_val;
                else min_val = 0;
                for(int k = 0;k < data_bt.vec_val.size() - 1;k++)
                {
                        DT_KpiValue dt_kpivalue2 = (DT_KpiValue)data_bt.vec_val.elementAt(k);
                        if(dt_kpivalue2.col_val > max_val) max_val = dt_kpivalue2.col_val;
            if(dt_kpivalue2.col_val < min_val) min_val = dt_kpivalue2.col_val;
            data.addValue(dt_kpivalue2.col_val, dt_kpivalue2.col_name, data_bt.col_name);
                }
        }
                        }
                        //创建曲线图
                        JFreeChart chart = null;
                        CategoryItemRenderer renderer2 = new LineAndShapeRenderer();
                        //CategoryLabelGenerator generator = new StandardCategoryLabelGenerator();
                        DT_KpiValue dt_kpivalue = (DT_KpiValue)kpi_data.vec_val.elementAt(kpi_data.vec_val.size() - 1);
                        if(flag) {
                            chart=ChartFactory.createLineChart(kpi_data.name,dt_kpivalue.col_name,kpi_data.unit,data,PlotOrientation.VERTICAL, true, true, false);
                            //chart = ChartFactory.createLineChart(kpi_data.name,
                                    //dt_kpivalue.col_name, kpi_data.unit, data, true, true, false);
                        }
                        else chart = ChartFactory.createLineChart(kpi_data.name,dt_kpivalue.col_name,kpi_data.unit,data,PlotOrientation.VERTICAL, false, true, false);                        // 设置背景色
                        chart.setBackgroundPaint(new GradientPaint(0, 0, Color.white, 1000, 0, Color.lightGray));
                        //设置标题
                        // chart.setTitle(new TextTitle(kpi_data.name, new Font("隶书", Font.ITALIC, 15)));
                        CategoryPlot plot = (CategoryPlot)chart.getPlot();
                        //设置描点
                        LineAndShapeRenderer lineandshaperenderer = (LineAndShapeRenderer)plot.getRenderer();
                        //lineandshaperenderer.setDrawLines(true);                        //设定前景透明度（0-1.0之间）
                        plot.setForegroundAlpha(0.9f);
                        //plot.setValueLabelFont(new Font("黑体", Font.TRUETYPE_FONT, 12));
                        //plot.setSectionLabelFont(new Font("黑体", Font.TRUETYPE_FONT, 12));                        //注意以下代码
                        NumberAxis verticalAxis = (NumberAxis)plot.getRangeAxis();
                        //设定Y轴的最大值和最小值
                        if (max_val - min_val < min_val * 0.15)
                        {
                                min_val = min_val * 1.25 - max_val * 0.25;
                                max_val = max_val * 1.25 - min_val * 0.25;
                        }
                        else
                        {
                                min_val = min_val * 0.85;
                                max_val = max_val * 1.05;
                        }
                        verticalAxis.setMinimumAxisValue(min_val);
                        verticalAxis.setMaximumAxisValue(max_val);
                        verticalAxis.setStandardTickUnits(NumberAxis.createIntegerTickUnits());
                        //verticalAxis.setItemLabelsVisible(true);
                        //verticalAxis.setShapesVisible(true);
                        lineandshaperenderer.setDrawShapes(true);
                        lineandshaperenderer.setItemLabelsVisible(true);
                        lineandshaperenderer.setItemLabelFont(new Font("黑体",Font.PLAIN,12));
                        ItemLabelPosition itemlabelposition = new ItemLabelPosition();
                        lineandshaperenderer.setPositiveItemLabelPosition(itemlabelposition);                        String img_name = String.valueOf(Math.random());
                        if(img_type == 0) img_name += ".jpeg";
                        else img_name += ".png";
                        fileName += img_name;
                        int chart_width = 0;
                        if (kpi_data.vec_val.size() > 10) chart_width = (kpi_data.vec_val.size() - 1) * 50 + 200;
                        else chart_width = width;
                        if(img_type == 0) ChartUtilities.saveChartAsJPEG(new File(fileName),100,chart,chart_width, height);
                        else ChartUtilities.saveChartAsPNG(new File(fileName),chart,chart_width, height);
                        return(img_name);
                }
                catch(Exception e){System.out.println(e.getMessage());return "";}
        }
为什么鼠标移动到曲线点上的时候没办法显示y轴的值呢郁闷啊  星期一就要上线了  同志们帮帮忙看看

Answer 1

鼠标移上要有效果 是因为在页面上创建了热点 map 
你需要一个info 才能生成热点
ChartRenderingInfo info = new ChartRenderingInfo(new StandardEntityCollection());

try{
response.setContentType("text/html;charset=UTF-8");
PrintWriter pw = response.getWriter();
filename = ServletUtilities.saveChartAsPNG(chart,600,360,null,request.getSession());
ChartUtilities.writeImageMap(pw, filename,info,true);
pw.flush();


}catch(Exception e){
System.out.print(e.getMessage());
}