jfreechart简单示例

以下信息来源于网络
下载Jfreechart，引入jar包


PieChartServlet.java

public class PieChartServlet extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		response.setContentType("image/png; charset=utf-8");
		//获取数据集对象
		PieDataset dataset = createPieDataset();
		String language = "The 13 years programming language list";
		//创建图形对象
		JFreeChart jfreechart = ChartFactory
                           .createPieChart3D(language, dataset, true, true, false);
		//获得图表区域对象
		PiePlot pieplot = (PiePlot)jfreechart.getPlot();
		//设置图标区域的标签字体
		pieplot.setLabelFont(new Font("宋体", 0, 12));
		//设置图标区域无数据时默认显示的文字
		pieplot.setNoDataMessage("没有排行数据");
		pieplot.setCircular(false);
		pieplot.setLabelGap(0.02D);
		//将图表以数据流的方式返回给客户端
		ChartUtilities.writeChartAsPNG(response.getOutputStream(), 
                               jfreechart, 500, 270);
	}

	/**
	 * 返回数据集
	 * @return
	 */
	public PieDataset createPieDataset() {
		//创建饼形图数据对象
		DefaultPieDataset defaultpiedataset = new DefaultPieDataset();
		defaultpiedataset.setValue("JAVA", DataUtils.getRandomData());
		defaultpiedataset.setValue("JavaScript", DataUtils.getRandomData());
		defaultpiedataset.setValue("Perl", DataUtils.getRandomData());
		defaultpiedataset.setValue("Python", DataUtils.getRandomData());
		defaultpiedataset.setValue("C/C++", DataUtils.getRandomData());
		
		return defaultpiedataset;
	}
}

DataUtils.java

public class DataUtils {
	private static Random random = new Random();
	private static final int MAX_NUMBER = 100;
	
	/**
	 * 取0~100之间的数
	 */
	public static int getRandomData() {
		return random.nextInt(MAX_NUMBER);
	}
}

页面：


Jfreechart还提供了对多种图形的支持。