在b/s方式下使用jfreechart来生成统计图表

package gov.gwssi.tax.nspg.datadisposal;
import java.awt.Insets;
import java.awt.Image;
import java.io.PrintWriter;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.Locale;
import java.text.NumberFormat;
import javax.servlet.http.HttpSession;
import org.jfree.data.*;
import org.jfree.chart.*;
import org.jfree.chart.axis.*;
import org.jfree.chart.renderer.VerticalBarRenderer;
import org.jfree.chart.renderer.StandardXYItemRenderer;
import org.jfree.chart.plot.*;
import org.jfree.chart.entity.*;
import org.jfree.chart.tooltips.*;
import org.jfree.chart.urls.*;
import org.jfree.chart.servlet.*;
import java.awt.Font;
/**
* Title:
* Description:
* Copyright: Copyright (c) 2003
* Company:
* @author jagie
* @version 1.0
*/
public class GSPieChart {
public static void main(String[] args) {
Long[] testData = {
new Long(10), new Long(20), new Long(30), new Long(40)};
generatePieChart(testData, "", null, new PrintWriter(System.out), 580, 250);
}
/**
* 生成图像文件
* @param datas Long[]数组
* @param targetUrl 点饼形图上的扇形，定向到的url
* @param session httpsession
* @param pw PrintWriter
* @param w 生成的图的宽度
* @param h 生成的图的高度
* @return 生成的图像文件的路径
*/
public static String generatePieChart(Long[] datas, String targetUrl,
HttpSession session, PrintWriter pw,
int w, int h) {
String filename = null;
try {
DefaultPieDataset data = new DefaultPieDataset();
data.setValue("正常纳税人", datas[0]);
data.setValue("异常纳税人", datas[1]);
data.setValue("数据不全纳税人", datas[2]);
data.setValue("未处理纳税人", datas[3]);
// Create the chart object
Pie3DPlot plot = new Pie3DPlot(data);
plot.setInsets(new Insets(0, 5, 5, 5));
plot.setForegroundAlpha(0.6f);
plot.setSectionLabelType(plot.NO_LABELS);
plot.setURLGenerator(new StandardPieURLGenerator(targetUrl, "type"));
plot.setToolTipGenerator(new StandardPieToolTipGenerator());
JFreeChart chart = new JFreeChart("数据处理结果统计图",
JFreeChart.DEFAULT_TITLE_FONT, plot, true);
chart.setTitle(new TextTitle("数据处理结果统计图", new Font("黑体", Font.BOLD, 15)));
StandardLegend sl = (StandardLegend) chart.getLegend();
sl.setItemFont(new Font("黑体", Font.TRUETYPE_FONT, 12));
chart.setBackgroundPaint(new java.awt.Color(254, 254, 141));
// 因为jfreechart把生成的png文件保存在系统的临时文件夹中，你需要在适当的
//时候调用session.removeAttribute("JFreeChart_Deleter")，这样可以保证png文
//件被删除掉
ChartRenderingInfo info = new ChartRenderingInfo(new
StandardEntityCollection());
filename = ServletUtilities.saveChartAsPNG(chart, w, h, info, session);
// Write the image map to the PrintWriter
ChartUtilities.writeImageMap(pw, filename, info);
pw.flush();
}
catch (Exception e) {
System.out.println("Exception - " + e.toString());
e.printStackTrace(System.out);
filename = "public_error_500x300.png";
}
return filename;
}
}