java中使用jfree饼图的实现

工作需要涉及到饼图的实现，这是一个实现饼图的类，通过传入HashMap中键存放的是需要显示的项目，值为对应项的数值，用来计算并显示比例，该类的代码如下：

packagecom.sjth.zdsygl.chart;

importjava.awt.Font;
importjava.io.PrintWriter;
importjava.util.HashMap;
importjava.util.Iterator;

importjavax.servlet.http.HttpSession;

importorg.jfree.chart.ChartRenderingInfo;
importorg.jfree.chart.ChartUtilities;
importorg.jfree.chart.JFreeChart;
importorg.jfree.chart.entity.StandardEntityCollection;
importorg.jfree.chart.labels.StandardPieItemLabelGenerator;
importorg.jfree.chart.plot.PiePlot3D;
importorg.jfree.chart.servlet.ServletUtilities;
importorg.jfree.chart.title.TextTitle;
importorg.jfree.data.DefaultPieDataset;


publicclassPieChart
...{
//这个方法用来计算显示项数据所占比例
privatedoublegetRatio(HashMapmap,Objectvalue)
...{
doubleresult=0.00;
doubletotal=0.00;
StringstrTemp="";
Iteratoriter=map.keySet().iterator();
while(iter.hasNext())
...{
Objectkey=iter.next();
strTemp=(String)map.get(key);
total+=(Double.parseDouble(strTemp));
}
strTemp=(String)map.get(value);
result=Double.parseDouble(strTemp)/total;
//result=(double)Math.round(result);
returnresult;
}

publicStringJCreate(HashMapmap,Stringtitle,HttpSessionsession,intw,
inth)
...{
DefaultPieDatasetpiedata=newDefaultPieDataset();
/**//*piedata.setValue("Google",130);//如果没有数据可以通过这一块来测试
piedata.setValue("Baidu",40.3);
piedata.setValue("sohu",19.6);
piedata.setValue("msn",29.6);*/

Iteratoriter=map.keySet().iterator();

while(iter.hasNext())
...{
Objectkey=iter.next();
piedata.setValue(key.toString(),getRatio(map,key));
}

//3D饼图
PiePlot3Dplot=newPiePlot3D(piedata);
//饼图
//PiePlotplot=newPiePlot(piedata);

//设定链接("link.jsp","section"));//section为参数，不填写则默认为category
//plot.setURLGenerator(newStandardPieURLGenerator("link.jsp","section"));

//指定图片的透明度
plot.setForegroundAlpha(1.0f);
plot.setDepthFactor(0.08);

//指定显示的饼图上圆形(false)还椭圆形(true)
plot.setCircular(false);

//显示百分比
//plot.setLabelGenerator(new
//StandardPieItemLabelGenerator(StandardPieItemLabelGenerator.DEFAULT_TOOLTIP_FORMAT));
//plot.setLegendLabelGenerator(newStandardPieItemLabelGenerator("{0}:
//({1}M,{2})"));

JFreeChartchart=newJFreeChart("",JFreeChart.DEFAULT_TITLE_FONT,plot,
true);
//设置图片背景色
chart.setBackgroundPaint(java.awt.Color.white);

//设置图片标题属性
Fontfont=newFont("黑体",Font.CENTER_BASELINE,20);
TextTitle_title=newTextTitle(title);
_title.setFont(font);
chart.setTitle(_title);

plot.setToolTipGenerator(newStandardPieItemLabelGenerator());
//把生成的图片放到临时目录
StandardEntityCollectionsec=newStandardEntityCollection();
ChartRenderingInfoinfo=newChartRenderingInfo(sec);

Stringfilename=null;
try
...{
filename=ServletUtilities.saveChartAsPNG(chart,w,h,info,session);
}
catch(Exceptione)
...{
System.out.println("Exception-"+e.toString());
filename="public_error_500x300.png";
}
returnfilename;
}
}