JFreeChar_03
将生成的图表移到浏览器上
为了将生成的图表直接传给客户端浏览器，只需要将前面两个例子中的文件流换成是通过HttpServletResponse对象获取到的,这里就是用简单的sevlet,
输出流，详细代码清单如下：
/**
* 柱状图
*/
package com.ll.JFreeChat.Demo1;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartUtilities;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.data.category.CategoryDataset;
import org.jfree.data.category.DefaultCategoryDataset;
/**
* 该类用于演示最简单的柱状图生成
* @author Mr liu
*/
public class ZhuZhuang extends HttpServlet{
private static final long serialVersionUID = 1L;
public void doGet(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException{
res.setContentType("image/jpeg");
CategoryDataset dataset=getDataSet();
JFreeChart chart=ChartFactory.createBarChart3D(
"水果产量图",//图标标题
"水果",//目录轴的显示标签
"产量",//数值轴的显示标签
dataset,//数据集
PlotOrientation.VERTICAL,//图表的方向：水平、垂直
true,//是否显示图例（对于简单的柱状图必须是false）
false,//是否生成工具
false//是否生成URL链接
);
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
*/
public CategoryDataset getDataSet(){
DefaultCategoryDataset dataset=new DefaultCategoryDataset();
dataset.addValue(100, "", "苹果");
dataset.addValue(200, "", "梨子");
dataset.addValue(300, "", "葡萄");
dataset.addValue(400, "", "香蕉");
dataset.addValue(500, "", "栗子");
return dataset;
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doGet(request, response);
}
}
web.xml中
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.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>ZhuZhuang</servlet-name>
<servlet-class>com.ll.JFreeChat.Demo1.ZhuZhuang</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ZhuZhuang</servlet-name>
<url-pattern>/ZhuZhuang</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
index.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<a href="ZhuZhuang">获取图片</a>
</body>
</html>
然后图片就会立刻出现，没大问题