关于JFreeChart 生成图片

Question

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>
<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>

  <servlet>
    <servlet-name>JFreeChart</servlet-name>
    <servlet-class>test.JFreeChartServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>JFreeChart</servlet-name>
    <url-pattern>/JFreeChart</url-pattern>
  </servlet-mapping>
</web-app>
------------------------------------------------
JFreeChartServlet

public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
DefaultPieDataset dataset = new DefaultPieDataset();
dataset.setValue("初级程序员", 10000);
dataset.setValue("中级程序员", 23000);
dataset.setValue("高级程序员", 10000);
dataset.setValue("项目经理", 6000);
dataset.setValue("系统分析师", 6000);
dataset.setValue("软件架构师", 3000);
dataset.setValue("其他", 10000);
JFreeChart chart = ChartFactory.createPieChart3D("IT行业职业分布图",dataset, true, false, false);
PiePlot3D plot = (PiePlot3D) chart.getPlot();
plot.setStartAngle(150D);
plot.setDirection(Rotation.CLOCKWISE);
plot.setForegroundAlpha(0.5F);
plot.setNoDataMessage("无数据显示");
plot.setCircular(true);
plot.setLabelGenerator(new StandardPieSectionLabelGenerator("{0}:{1}={2}"));

//第一种 session方式
//String fileName = ServletUtilities.saveChartAsPNG(chart, 700, 400,
// null, request.getSession());
//String graphURL = request.getContextPath() + "/DisplayChart?filename=" + fileName;
//request.setAttribute("url", graphURL);
//request.getRequestDispatcher("index.jsp").forward(request, response);

//第二种 流输出方式
ChartUtilities.writeChartAsJPEG(response.getOutputStream(),chart,500,300);
}

-----------------------------------------------------------
jsp

//第一种 session方式
<%@ page contentType="text/html;"%>
<img src="<%=request.getAttribute("url")%>">

/第二种 流输出方式
<%@ page contentType="image/jpeg;"%>
<img src="<%=request.getContextPath()%>/JFreeChart">





流输出方式怎么不显示？
大家来看看

Answer 1

那就是：
[code="java"]response.setContentType("image/jpeg"); [/code]