jfreechart，到http://www.jfree.org/下载最新的。
一、在web.xml文件中添加：
<servlet>
<servlet-name>DisplayChart</servlet-name>
<servlet-class>org.jfree.chart.servlet.DisplayChart</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>DisplayChart</servlet-name>
<url-pattern>/servlet/DisplayChart</url-pattern>
</servlet-mapping>
二、解压下载的jfreechar工具包，将解压后的jfreechar下lib目录中的五个文件复制到你的项目的WEB-INF\lib下。
如下载 jfreechart-1.0.0-rc1.zip
三、创建数据库中的表 test
四、JSP源程序：
<%@ page contentType="text/html;charset=GBK"%>
<%@ page import="java.sql.*" %>
<%@ page import="java.io.*" %>
<%@ page import="java.awt.*" %>
<%@ page import="org.jfree.chart.*" %>
<%@ page import="org.jfree.chart.plot.*" %>
<%@ page import="org.jfree.chart.servlet.ServletUtilities" %>
<%@ page import="org.jfree.chart.entity.StandardEntityCollection" %>
<%@ page import="org.jfree.chart.renderer.category.BarRenderer3D" %>
<%@ page import="org.jfree.data.category.DefaultCategoryDataset" %>
<%@ page import="org.jfree.data.general.DefaultPieDataset" %>
<%@ page import="org.jfree.chart.renderer.category.BarRenderer3D" %>
<html>
<head><title>Jfree图表</title>
<meta http-equiv="Content-Type" content="text/html;charset=gb2312">
</head>
<body>
<div align="cente"><P><font size="4" face="楷体_GB2312"><strong><font color="#0099ff">招生统计信息</font></strong></font>< /p>
</div>
<%
//设置生成饼状图
int i=0;
String[] area={"南京市","镇江市","常州市","无锡市","苏州市","南通市"};
try{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection con=DriverManager.getConnection("jdbc:odbc:aaa");
Statement sql=con.createStatement();
ResultSet rs=sql.executeQuery("select * from test");
//按地区进行统计
PrintWriter pw=null;
DefaultPieDataset dataset=new DefaultPieDataset();
//设置数据源
while(rs.next()){
String dq=rs.getString("dq");
dataset.setValue(area[i],Integer.parseInt(dq));
//添加数据，参数包括名称和数值
i++;
}
rs.close();
sql.close();
con.close();
JFreeChart chart=ChartFactory.createPieChart("饼型图",dataset,true,true,true);
chart.setTitle("统计图");//设置图片标题
ChartRenderingInfo info=new ChartRenderingInfo(new StandardEntityCollection());
String filename=ServletUtilities.saveChartAsJPEG(chart,300,200,info,session);
//设置生成图片，包括图片的大小，长度是300，宽是200
//out.println(filename);
session.setAttribute("file_name1",filename);
String URL= request.getContextPath() + "/servlet/DisplayChart?filename=" + filename;
session.setAttribute("file_url1",URL);
}
catch(SQLException e){
out.println(e);
}
%>
<%
