利用JFreechart绘制复杂柱状图(三)

web.xml

<?xml version="1.0"?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.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>/DisplayChart</url-pattern>
	</servlet-mapping>
</web-app>

demo.jsp

<%@ page contentType="text/html;charset=GBK"%>

<%@ page
	import="org.jfree.chart.ChartFactory,org.jfree.chart.JFreeChart,org.jfree.chart.plot.PlotOrientation,org.jfree.chart.servlet.ServletUtilities,org.jfree.data.category.CategoryDataset,org.jfree.data.general.DatasetUtilities,org.jfree.chart.plot.*,org.jfree.chart.labels.*,org.jfree.chart.renderer.category.BarRenderer3D,java.awt.*,org.jfree.ui.*,org.jfree.chart.axis.AxisLocation"%>

<%
	double[][] data = new double[][] { { 1310, 1220, 1110, 1000 },
			{ 720, 700, 680, 640 }, { 1130, 1020, 980, 800 },
			{ 440, 400, 360, 300 } };
	String[] rowKeys = { "pig", "beef", "chicken", "fish" };
	String[] columnKeys = { "Guangzhou", "Shenzhen", "Dongguan",
			"Foshan" };
	CategoryDataset dataset = DatasetUtilities.createCategoryDataset(
			rowKeys, columnKeys, data);
	JFreeChart chart = ChartFactory.createBarChart3D("JFreeChart Demo", "type",
			"amount", dataset, PlotOrientation.VERTICAL, true, true,
			false);
	CategoryPlot plot = chart.getCategoryPlot();
	//设置网格背景颜色
	plot.setBackgroundPaint(Color.white);
	//设置网格竖线颜色
	plot.setDomainGridlinePaint(Color.pink);
	//设置网格横线颜色
	plot.setRangeGridlinePaint(Color.pink);
	//显示每个柱的数值，并修改该数值的字体属性
	BarRenderer3D renderer = new BarRenderer3D();
	renderer.setBaseItemLabelGenerator(new StandardCategoryItemLabelGenerator());
	renderer.setBaseItemLabelsVisible(true);
	//默认的数字显示在柱子中，通过如下两句可调整数字的显示
	//注意：此句很关键，若无此句，那数字的显示会被覆盖，给人数字没有显示出来的问题
	renderer.setBasePositiveItemLabelPosition(new ItemLabelPosition(
			ItemLabelAnchor.OUTSIDE12, TextAnchor.BASELINE_LEFT));
	renderer.setItemLabelAnchorOffset(10D);
	//设置每个地区所包含的平行柱的之间距离
	//renderer.setItemMargin(0.3);
	plot.setRenderer(renderer);
	//设置地区、销量的显示位置
	//将下方的“肉类”放到上方
	plot.setDomainAxisLocation(AxisLocation.TOP_OR_RIGHT);
	//将默认放在左边的“销量”放到右方
	plot.setRangeAxisLocation(AxisLocation.BOTTOM_OR_RIGHT);
	String filename = ServletUtilities.saveChartAsPNG(chart, 700, 400,
			null, session);
	String graphURL = request.getContextPath()
			+ "/DisplayChart?filename=" + filename;
%>
<img src="<%=graphURL%>" width=700 height=400 border=0
	usemap="#<%= filename %>">