在jsp页面中显示jfreechart

Question

我想jfreechart在jsp页面中显示一个图表.我写的代码如下 -

...
<%
ChartCreator chart = new ChartCreator();
chart.createCategoryChart();
%>
<img src = "chart.jpg"/>

其中createCategoryChart()方法创建所需的JPG.它存储在eclipse文件夹中(我没有在我的文件名中放置任何路径).

我无法在jsp页面中查看图表,但是创建了该文件.

我究竟做错了什么？

Answer 1

我建议使用Servlet来创建Chart.

JSP主要用于表示(View).

创建一个servlet,创建图表并将其作为响应发回.

import javax.imageio.ImageIO;


protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        OutputStream out = response.getOutputStream(); /* Get the output stream from the response object */
        response.setContentType("image/png"); /* Set the HTTP Response Type */
        ChartCreator chart = new ChartCreator(); // Create chart
        chart.createCategoryChart(); 
        ChartUtilities.writeChartAsPNG(out, chart, 400, 300);/* Write the data to the output stream */
    }

从JSP调用Servlet.

<img src="/drawChartServlet?type=myDesiredChart&width=..and other processed parameters" ..>