Jfreechart的节点上放上鼠标显示数据

项目需求：移动鼠标，在jfreechart生成的时间曲线图的节点上，显示数据。

 

 

具体过程：

资料1中，列出了用applet实现该功能的例子，

package gg;

import java.awt.Color;
import java.awt.Dimension;
import java.text.SimpleDateFormat;
import javax.swing.JPanel;
import org.jfree.chart.*;
import org.jfree.chart.axis.DateAxis;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.XYLineAndShapeRenderer;
import org.jfree.data.time.*;
import org.jfree.data.xy.XYDataset;
import org.jfree.ui.*;

public class TimeSeriesDemo1 extends ApplicationFrame
{

    public TimeSeriesDemo1(String s)
    {
        super(s);
        XYDataset xydataset = createDataset();
        JFreeChart jfreechart = createChart(xydataset);
        ChartPanel chartpanel = new ChartPanel(jfreechart, false);
        chartpanel.setPreferredSize(new Dimension(500, 270));
        chartpanel.setMouseZoomable(true, false);
        setContentPane(chartpanel);
    }

    private static JFreeChart createChart(XYDataset xydataset)
    {
        JFreeChart jfreechart = ChartFactory.createTimeSeriesChart("Legal & General Unit Trust Prices", "Date", "Price Per Unit", xydataset, true, true, true);
        jfreechart.setBackgroundPaint(Color.white);
        XYPlot xyplot = (XYPlot)jfreechart.getPlot();
        xyplot.setBackgroundPaint(Color.lightGray);
        xyplot.setDomainGridlinePaint(Color.white);
        xyplot.setRangeGridlinePaint(Color.white);
        xyplot.setAxisOffset(new RectangleInsets(5D, 5D, 5D, 5D));
        xyplot.setDomainCrosshairVisible(true);
        xyplot.setRangeCrosshairVisible(true);
        org.jfree.chart.renderer.xy.XYItemRenderer xyitemrenderer = xyplot.getRenderer();
        if(xyitemrenderer instanceof XYLineAndShapeRenderer)
        {
            XYLineAndShapeRenderer xylineandshaperenderer = (XYLineAndShapeRenderer)xyitemrenderer;
            xylineandshaperenderer.setBaseShapesVisible(true);
            xylineandshaperenderer.setBaseShapesFilled(true);
        }
        DateAxis dateaxis = (DateAxis)xyplot.getDomainAxis();
        dateaxis.setDateFormatOverride(new SimpleDateFormat("MMM-yyyy"));
        return jfreechart;
    }

    private static XYDataset createDataset()
    {
        TimeSeries timeseries = new TimeSeries("L&G European Index Trust", org.jfree.data.time.Month.class);
        timeseries.add(new Month(2, 2001), 181.80000000000001D);
        timeseries.add(new Month(3, 2001), 167.30000000000001D);
        timeseries.add(new Month(4, 2001), 153.80000000000001D);
        timeseries.add(new Month(5, 2001), 167.59999999999999D);
        timeseries.add(new Month(6, 2001), 158.80000000000001D);
        timeseries.add(new Month(7, 2001), 148.30000000000001D);
        timeseries.add(new Month(8, 2001), 153.90000000000001D);
        timeseries.add(new Month(9, 2001), 142.69999999999999D);
        timeseries.add(new Month(10, 2001), 123.2D);
        timeseries.add(new Month(11, 2001), 131.80000000000001D);
        timeseries.add(new Month(12, 2001), 139.59999999999999D);
        timeseries.add(new Month(1, 2002), 142.90000000000001D);
        timeseries.add(new Month(2, 2002), 138.69999999999999D);
        timeseries.add(new Month(3, 2002), 137.30000000000001D);
        timeseries.add(new Month(4, 2002), 143.90000000000001D);
        timeseries.add(new Month(5, 2002), 139.80000000000001D);
        timeseries.add(new Month(6, 2002), 137D);
        timeseries.add(new Month(7, 2002), 132.80000000000001D);
        TimeSeries timeseries1 = new TimeSeries("L&G UK Index Trust", org.jfree.data.time.Month.class);
        timeseries1.add(new Month(2, 2001), 129.59999999999999D);
        timeseries1.add(new Month(3, 2001), 123.2D);
        timeseries1.add(new Month(4, 2001), 117.2D);
        timeseries1.add(new Month(5, 2001), 124.09999999999999D);
        timeseries1.add(new Month(6, 2001), 122.59999999999999D);
        timeseries1.add(new Month(7, 2001), 119.2D);
        timeseries1.add(new Month(8, 2001), 116.5D);
        timeseries1.add(new Month(9, 2001), 112.7D);
        timeseries1.add(new Month(10, 2001), 101.5D);
        timeseries1.add(new Month(11, 2001), 106.09999999999999D);
        timeseries1.add(new Month(12, 2001), 110.3D);
        timeseries1.add(new Month(1, 2002), 111.7D);
        timeseries1.add(new Month(2, 2002), 111D);
        timeseries1.add(new Month(3, 2002), 109.59999999999999D);
        timeseries1.add(new Month(4, 2002), 113.2D);
        timeseries1.add(new Month(5, 2002), 111.59999999999999D);
        timeseries1.add(new Month(6, 2002), 108.8D);
        timeseries1.add(new Month(7, 2002), 101.59999999999999D);
        TimeSeriesCollection timeseriescollection = new TimeSeriesCollection();
        timeseriescollection.addSeries(timeseries);
        timeseriescollection.addSeries(timeseries1);
        return timeseriescollection;
    }

    public static JPanel createDemoPanel()
    {
        JFreeChart jfreechart = createChart(createDataset());
        return new ChartPanel(jfreechart);
    }

    public static void main(String args[])
    {
        TimeSeriesDemo1 timeseriesdemo1 = new TimeSeriesDemo1("Time Series Demo 1");
        timeseriesdemo1.pack();
        RefineryUtilities.centerFrameOnScreen(timeseriesdemo1);
        timeseriesdemo1.setVisible(true);
    }
}

运行结果如下图，鼠标放到一数据点，显示出数值。

 

 

 需求是在html页面上显示，怎样将applet转换到html上呢？

 

又找到资料2，关键是这句话：“JFreeChart所产生的原表如何得知滑鼠位置與這個區域的ToolTip、超連結的對應是什麼。事實上，我們還必須替這張圖表在網頁中建立區域對應表”。区域对应表（也称热区）怎么生成呢？在她给出了例子中，step5中，提到了生成的方法。

 //Step 1 建立 Dataset 資料結構物件
 HashMap datas = new HashMap();
 datas.put("Java",new Long(721));
 datas.put(".Net",new Long(543));
 datas.put("PHP",new Long(374));
 datas.put("C++",new Long(438));
 datas.put("Others",new Long(424)); 
  
 DefaultPieDataset dataSet = new DefaultPieDataset();
 for(Iterator it = datas.keySet().iterator();it.hasNext();){
  String technology = (String)it.next();    
  dataSet.setValue(technology, (Long)datas.get(technology));
 } 
 
 //Step 3 建立 Plot 物件
        PiePlot plot = new PiePlot(dataSet);
        plot.setInsets(new RectangleInsets(5, 5, 5, 5));
        plot.setURLGenerator(new StandardPieURLGenerator("DetailBarChart.jsp","section"));       
        plot.setToolTipGenerator(new StandardPieItemLabelGenerator());
 plot.setExplodePercent(0, 0.2);        
       
        //Step 4 產生 JFreeChart 物件,並設定圖表底色                 
 JFreeChart chart = new JFreeChart("My First Pie Chart",
        JFreeChart.DEFAULT_TITLE_FONT,
        plot,
        true);                
        chart.setBackgroundPaint(Color.LIGHT_GRAY);        
       
 //Step 5 輸出圖表,使用 ServletUtilities 將圖表輸出後由 DisplayChart Servlet 讀取
 ChartRenderingInfo info = new ChartRenderingInfo(new StandardEntityCollection());
 String filename = ServletUtilities.saveChartAsPNG(chart, 500, 300, info, session);   
 PrintWriter writer = new PrintWriter(out); 
 ChartUtilities.writeImageMap(writer, filename, info,false);
 writer.flush();          
 String graphURL = request.getContextPath() + "/servlet/DisplayChart?filename=" + filename;       
%>
<html>
 <body>
  <img src="<%= graphURL %>" width=500 height=300 border=0 usemap="#<%= filename %>">
 </body>
</html>

 

step1-step4，生成一个图表信息chart，只差将其显示出来。step5中，

 

 

1、首先调用ServletUtilities.saveChartAsPNG方法，将chart保存为一张png图的同时，把图表的绘制信息保存到info变量中。

2、将图片路径和图片的绘制信息输出

 ChartUtilities.writeImageMap(writer, filename, info,false);

3、结束

问题：她这里是将生成的图片保存到某一路径下，