jfreechart例子

+------+-------------+
| id   | client_name |
+------+-------------+
|    1 | 一级经销商  |
|    2 | 二级经销商  |
|    3 | 三级经销商  |
+------+-------------+
3 rows in set (0.00 sec)

package com;

import java.io.IOException;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.Iterator;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServlet;

import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartUtilities;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.labels.StandardPieSectionLabelGenerator;
import org.jfree.chart.plot.PiePlot3D;
import org.jfree.data.general.DefaultPieDataset;

public class ChartDemoServlet extends HttpServlet {

	private static final long serialVersionUID = 1L;

	public void service(ServletRequest req, ServletResponse res)
			throws ServletException, IOException {
		res.setContentType("image/jpeg");
		DefaultPieDataset data = getDataSet();
		req.setCharacterEncoding("UTF-8");
		res.setCharacterEncoding("UTF-8");
		JFreeChart chart = ChartFactory.createPieChart3D("I LOVE YOU", data,true, false, false);

		PiePlot3D plot = (PiePlot3D) chart.getPlot();

		// 图片中显示百分比:默认方式

		// plot.setLabelGenerator(new
		// StandardPieSectionLabelGenerator(StandardPieToolTipGenerator.DEFAULT_TOOLTIP_FORMAT));

		// 图片中显示百分比:自定义方式，{0} 表示选项， {1} 表示数值， {2} 表示所占比例 ,小数点后两位

		plot.setLabelGenerator(new StandardPieSectionLabelGenerator("{0}={1}({2})", NumberFormat.getNumberInstance(),new DecimalFormat("0.00%")));
		// 图例显示百分比:自定义方式， {0} 表示选项， {1} 表示数值， {2} 表示所占比例
		plot.setLegendLabelGenerator(new StandardPieSectionLabelGenerator("{0}={1}({2})"));
		ChartUtilities.writeChartAsJPEG(res.getOutputStream(),1.0f, chart, 400, 300, null);
	}

	/**
	 * 
	 * 获取一个演示用的简单数据集对象
	 * 
	 * @return
	 */

	private static DefaultPieDataset getDataSet() {
		DefaultPieDataset dataset = new DefaultPieDataset();
		Map map = StateReportManger.getIntense().getClientLevelCount(); // 调用getClientLevelCount()得到所有的数据
		for (Iterator iter = map.entrySet().iterator(); iter.hasNext();) {// 遍历，用到Map的.
																			// entrySet()方法
			Map.Entry entry = (Map.Entry) iter.next();
			dataset.setValue((String) entry.getKey(),Double.parseDouble(String.valueOf(entry.getValue())));// 设置数据
		}
		return dataset;
	}
}

在浏览器上输入，http://localhost:8080/JFreeChartTest/ChartDemoServlet