JFreeChart饼图作图手顺

JFreeChart饼图绘制手顺

1 将jfreechart配置到web容器中。即在web.xml中配置

    <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 绘图，并保存至内存

//方法各块的分布及显示信息,需要将饼图切成几块就执行几次

DefaultPieDataset.setValue(string message,double value)

//穿件3D饼图对象

JFreeChart chart = ChartFactory.createPieChart3D(String title, DefaultPieDataset dataset,boolean legend,boolean tooltips, boolean urls);

//获取饼图中块对象，通过该快对象可以对饼图中的块进行描述

PiePlot3D plot = (PiePlot3D) chart.getPlot();

//生成图小标准渲染信息

ChartRenderingInfo info = new ChartRenderingInfo(new StandardEntityCollection());

//根据以后信息绘制图片，并保存到Session中

String fileName = ServletUtilities.saveChartAsPNG( JFreeChart chart,int width,int height,ChartRenderingInfo info,HttpSession session);

3 页面获取图片

filePath为request.getContextPath() + "/servlet/DisplayChart?filename=" + fileName

JFreeChart饼图作图手顺

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