JSP下用JfreeChart生成柱状图
1，首先是在web.xml当中配置一下DisplayChar
2.JSP页面代码：
< 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>
2.JSP页面代码：
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ page import="org.jfree.data.category.DefaultCategoryDataset" %>
<%@ page import="org.jfree.chart.JFreeChart" %>
<%@ page import="java.awt.Color" %>
<%@ page import="org.jfree.chart.ChartFactory" %>
<%@ page import="org.jfree.chart.plot.PlotOrientation" %>
<%@ page import="org.jfree.chart.plot.CategoryPlot" %>
<%@ page import="org.jfree.chart.axis.CategoryAxis" %>
<%@ page import="org.jfree.chart.axis.ValueAxis" %>
<%@ page import="org.jfree.chart.renderer.category.BarRenderer3D" %>
<%@ page import="org.jfree.chart.axis.AxisLocation" %>
<%@ page import="org.jfree.chart.servlet.ServletUtilities" %>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'barChart.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<%
//测试数据
DefaultCategoryDataset dataset=new DefaultCategoryDataset();
dataset.addValue(100,"January","China");
dataset.addValue(200,"February","China");
dataset.addValue(200,"March","China");
dataset.addValue(125,"January","USA");
dataset.addValue(111,"February","USA");
dataset.addValue(99,"March","USA");
dataset.addValue(99,"January","Japan");
dataset.addValue(80,"February","Japan");
dataset.addValue(70,"March","Japan");
//得到Chart对象
JFreeChart chart=ChartFactory.createBarChart3D("第一个Web下的柱状图","Country","amount",dataset,
PlotOrientation.VERTICAL,false,false,false);
chart.setBackgroundPaint(Color.WHITE);
CategoryPlot plot=chart.getCategoryPlot();
plot.setBackgroundPaint(Color.GRAY);
//设置横轴
CategoryAxis categoryAxis=plot.getDomainAxis();
//设置标签之间的距离是20%
categoryAxis.setCategoryMargin(0.2);
categoryAxis.setLowerMargin(0.1);
categoryAxis.setUpperMargin(0.1);
//设置纵轴
ValueAxis valueAxis=plot.getRangeAxis();
valueAxis.setLowerMargin(0.1);
valueAxis.setUpperMargin(0.1);
BarRenderer3D render=new BarRenderer3D();
render.setSeriesPaint(0,Color.RED);
render.setSeriesPaint(1,Color.GREEN);
plot.setRenderer(render);
plot.setDomainAxisLocation(AxisLocation.BOTTOM_OR_LEFT);
plot.setRangeAxisLocation(AxisLocation.BOTTOM_OR_LEFT);
String filename=ServletUtilities.saveChartAsPNG(chart,500,500,null,session);
String getURL=request.getContextPath()+"/servlet/DisplayChart?filename="+filename;
%>
<div id='bar' align="center">
<img src='<%=getURL %>' usemap="#<%=filename %>" width="500" height="500">
</div>
</body>
</html>