[转]jfreechart 应用_例题_生成饼状图（展示，生成文件，WEB项目）_可以直接运行
jsp页面中
<%@ page contentType="text/html;charset=GBK"%>
<%@ page import="org.jfree.data.general.DefaultPieDataset"%>
<%@ page import="org.jfree.chart.JFreeChart"%>
<%@ page import="org.jfree.chart.plot.PiePlot"%>
<%@ page import="org.jfree.chart.ChartRenderingInfo"%>
<%@ page import="org.jfree.chart.servlet.ServletUtilities"%>
<%@ page import="org.jfree.chart.urls.StandardPieURLGenerator"%>
<%@ page import="org.jfree.chart.entity.StandardEntityCollection"%>
<%@ page import="org.jfree.chart.encoders.SunPNGEncoderAdapter"%>
<%
DefaultPieDataset data = new DefaultPieDataset();
data.setValue("六月", 500);
data.setValue("七月", 580);
data.setValue("八月", 828);
PiePlot plot = new PiePlot(data);
JFreeChart chart = new JFreeChart("",
JFreeChart.DEFAULT_TITLE_FONT, plot, true);
chart.setBackgroundPaint(java.awt.Color.white); //可选，设置图片背景色
chart.setTitle("Welcome to Jfreechart !"); //可选，设置图片标题
ChartRenderingInfo info = new ChartRenderingInfo(
new StandardEntityCollection());
//500是图片长度，300是图片高度
String filename = ServletUtilities.saveChartAsPNG(chart, 500, 300,
info, session);
String graphURL = request.getContextPath()
+ "/servlet/DisplayChart?filename=" + filename;
%>
<HTML>
<HEAD>
<TITLE>Welcome to Jfreechart !</TITLE>
</HEAD>
<BODY>
<P ALIGN="CENTER">
<img src="<%=graphURL%>" width=500 height=300 border=0
usemap="#<%= filename %>">
</P>
</BODY>
</HTML>
web.xml中
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<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>
<servlet>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
转自：http://www.blogjava.net/liudecai/archive/2009/01/11/250847.html