我看着书写了个jFreeChart小例子,不晓得哪儿做的不对,网页上总出不了图(实际上图已经出来了,我在tomcat/temp文件夹中找到了) 我将jcommon-1.0.10.jar\jfreechart-1.0.6.jar放到了WEB-INF的lib文件夹里。下面的是源文件内容: jsp:(在工程的根目录下,即webroot下) <%@ page contentType="text/html;charset=GB2312"%>
<%@ page import="org.jfree.chart.ChartFactory,org.jfree.chart.JFreeChart,
org.jfree.chart.plot.PlotOrientation,org.jfree.chart.servlet.ServletUtilities,
org.jfree.data.category.DefaultCategoryDataset,org.jfree.chart.ChartUtilities"
%>
<%
DefaultCategoryDataset dataset=new DefaultCategoryDataset();
dataset.addValue(300,"北京","苹果");
dataset.addValue(200,"北京","西瓜");
dataset.addValue(500,"北京","葡萄");
dataset.addValue(340,"北京","芒果");
dataset.addValue(280,"北京","香蕉");
JFreeChart chart=ChartFactory.createBarChart3D("水果销量统计图","水果","销量",dataset,PlotOrientation.VERTICAL,false,false,false);
String fileName=ServletUtilities.saveChartAsJPEG(chart,400,300,null,null);
String url=request.getContextPath()+"/servelt/DisplayChart?filename="+fileName;
%>
<html>
<head>
<title>JFreeChart Example</title>
</head>
<body>
<center>
<img src="<%=url%>" border=1>
</center>
</body> web.xml: <?xml version="1.0" encoding="UTF-8"?>
<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>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<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> </web-app>
</html>
<%@ page import="org.jfree.chart.ChartFactory,org.jfree.chart.JFreeChart,
org.jfree.chart.plot.PlotOrientation,org.jfree.chart.servlet.ServletUtilities,
org.jfree.data.category.DefaultCategoryDataset,org.jfree.chart.ChartUtilities"
%>
<%
DefaultCategoryDataset dataset=new DefaultCategoryDataset();
dataset.addValue(300,"北京","苹果");
dataset.addValue(200,"北京","西瓜");
dataset.addValue(500,"北京","葡萄");
dataset.addValue(340,"北京","芒果");
dataset.addValue(280,"北京","香蕉");
JFreeChart chart=ChartFactory.createBarChart3D("水果销量统计图","水果","销量",dataset,PlotOrientation.VERTICAL,false,false,false);
String fileName=ServletUtilities.saveChartAsJPEG(chart,400,300,null,null);
String url=request.getContextPath()+"/servelt/DisplayChart?filename="+fileName;
%>
<html>
<head>
<title>JFreeChart Example</title>
</head>
<body>
<center>
<img src="<%=url%>" border=1>
</center>
</body> web.xml: <?xml version="1.0" encoding="UTF-8"?>
<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>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<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> </web-app>
</html>
另:图的位置应该是没错的,这个是一个临时文件。
中的"servelt"是错的。不好意思啦 !