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，
