JFreeChart製作簡單的餅狀圖

 

下載jfreechart框架包，百度上可以查到，開源的。這個是csdn上的

http://download.csdn.net/source/3108268

 

<!--[if !supportLists]-->二．<!--[endif]-->配置web.xml

加上以下信息：

    <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>

 

<!--[if !supportLists]-->三．<!--[endif]-->編寫類

  代碼如下：

package com.qm;

import java.awt.Color;

import java.awt.Font;

import java.io.PrintWriter;

import javax.servlet.http.HttpSession;

import org.jfree.chart.ChartFactory;

import org.jfree.chart.ChartRenderingInfo;

import org.jfree.chart.ChartUtilities;

import org.jfree.chart.JFreeChart;

import org.jfree.chart.entity.StandardEntityCollection;

import org.jfree.chart.plot.PiePlot;

import org.jfree.chart.servlet.ServletUtilities;

import org.jfree.data.general.DefaultPieDataset;

import org.jfree.data.general.PieDataset;

 

public class AA {

    //在此方法內填入數據，key-value.value爲數字。

    private static PieDataset createDataset()

    {

       DefaultPieDataset dpd=new DefaultPieDataset();

       dpd.setValue("A", 1);

       dpd.setValue("B", 2);

       dpd.setValue("C", 3);

       dpd.setValue("d", 4);

       dpd.setValue("E", 5);

       return dpd;

    }

   

    private static JFreeChart createChart(PieDataset dpd)

    {

       JFreeChart jfc=ChartFactory.createPieChart3D("",dpd,true,true,false);  //這個有3D效果

       //JFreeChart jfc=ChartFactory.createPieChart("",dpd,true,true,false);    //這個沒有有3D效果

       jfc.setBackgroundPaint(Color.white);  //背景色

       jfc.getTitle().setFont(new Font("宋體",Font.BOLD,20));//設置標題字體

        PiePlot plot= (PiePlot) jfc.getPlot();//獲取圖表區域對象

        plot.setLabelFont(new Font("宋體",Font.BOLD,10));

        jfc.getLegend().setItemFont(new Font("宋體",Font.BOLD,10));

       return jfc;

    }

   

    public static String generateBarChart(HttpSession session, PrintWriter pw)

    {

       String filename=null;

       PieDataset cd=createDataset();

       JFreeChart chart=createChart(cd);

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

       try {

           filename=ServletUtilities.saveChartAsPNG(chart, 800, 400, info,session);//設置生成的圖片的大小

           ChartUtilities.writeImageMap(pw, filename, info, false);

       } catch (Exception e) {

           e.printStackTrace();

       }

       pw.flush();

       return filename;

    }

}

 

<!--[if !supportLists]-->四． <!--[endif]-->在jsp中使用圖表

  代碼如下：

<%@page import="com.qm.AA"%>

<%@page import="java.io.PrintWriter"%>

<%

    String filename=AA.generateBarChart(request.getSession(),new PrintWriter(out));

    String graphURl = request.getContextPath() + "/servlet/DisplayChart?filename=" + filename;

 

<img alt="分析圖" src="<%=graphURl %>" width="800" height="400">

%>