jFreeChart初探

//****************************************** //*             author:rautinee                         * //*         Email:rautinee@21cn.com        * //*         http://www.tryitsoft.com                * //****************************************** jFreeChart也许对大家来说很陌生，她是一款免费的、功能强大的统计图生成工具，可以直接生成PNG,JPG等各式的文件 为我们java项目的开发增加了一部利器。她的英文简介 JFreeChart is a free Java class library for generating charts, including: pie charts; line charts and horizontal/vertical bar charts (regular and stacked, with optional 3D-effect); XY plots and scatter plots; time series, high/low/open/close charts and candle stick charts; combination charts; Pareto charts; Gantt charts; bubble charts; wind plots, meter charts and symbol charts; 正好我最近的一个项目用到她，于是就很粗略的看了一下，现在把它拿出来和大家分享，希望对大家的工作有所 帮助。 本文主要是讲解她在jsp上面的应用。例子采用jsp+javaBean结构实现 准备工作：首先我们需要什么？当然是jFreeChart的package了，可以在她的官方网站上面找到下载链接 http://www.jfree.org/jfreechart/，把包下下来，配置到tomcat当中，然后可以开始我们的Jfreechart之旅 了。 下面我要做的是一个饼状统计图，首先建立javaBean文件 文件名：Tryitshow.java package com.tryit; import java.io.*; import java.awt.Insets; import java.awt.Font; import java.io.PrintWriter; import java.text.SimpleDateFormat; import java.util.Iterator; import java.util.Locale; import java.text.NumberFormat; import javax.servlet.http.HttpSession; import org.jfree.data.*; import org.jfree.chart.*; import org.jfree.chart.axis.*; import org.jfree.chart.renderer.VerticalBarRenderer; import org.jfree.chart.renderer.StandardXYItemRenderer; import org.jfree.chart.plot.*; import org.jfree.chart.entity.*; import org.jfree.chart.tooltips.*; import org.jfree.chart.urls.*; import org.jfree.chart.servlet.*; import org.jfree.chart.TextTitle; import java.net.URL; public class Tryitshow {     public static String generatePieChart(String infoStr, String titles,HttpSession session, PrintWriter pw)         {             String filename = null;             Font font;                          try {                     //  建立PieDataSet             DefaultPieDataset data = new DefaultPieDataset();             String ss[]=infoStr.split(",");             for (int n=0;n<ss.length;n++)             {                 String ssPart[]=ss[n].split("#");                 int tt=Integer.parseInt(ssPart[1]);                 String mm=ssPart[0];                 data.setValue(mm,tt);             }                          //  生成chart物件             PiePlot plot = new PiePlot(data);             plot.setInsets(new Insets(0, 5, 5, 5));                      plot.setToolTipGenerator(new StandardPieToolTipGenerator());                          font=new Font("黑体",Font.CENTER_BASELINE,20);//这个地方是设置统计图标题的字体和大小                          JFreeChart chart = new JFreeChart("",JFreeChart.DEFAULT_TITLE_FONT, plot, true);                          TextTitle tt=new TextTitle(titles);             tt.setFont(font);             chart.setBackgroundPaint(java.awt.Color.white);//统计图片的底色             chart.setTitle(tt);             //  把生成的文件写入到临时的目录中             ChartRenderingInfo info = new ChartRenderingInfo(new StandardEntityCollection());             filename = ServletUtilities.saveChartAsPNG(chart, 500, 300, info, session); //选择存储成png格式的文件，当然你也可以使用saveChartAsJPEG的方法生成jpg图片             //  把image map 写入到 PrintWriter             ChartUtilities.writeImageMap(pw, filename, info);             pw.flush();             }             catch (Exception ex) {             System.out.println("error:"+ex.getMessage());             }             return filename;             }     } 接着是jsp文件 <%@ page contentType="text/html;charset=gb2312"%> <%@ page import = "com.tryit.Tryitshow" %> <%@ page import = "java.io.PrintWriter" %> <%@ page import = "java.text.SimpleDateFormat" %> <%@ page import = "java.text.ParseException" %> <%@ page import = "java.util.ArrayList" %> <%@ page import = "java.util.Date" %> <%@ page import = "java.util.Iterator" %> <%@ page import = "java.util.Locale" %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML> <HEAD> <TITLE> New Document </TITLE> <META NAME="Generator" CONTENT="EditPlus"> <META NAME="Author" CONTENT=""> <META NAME="Keywords" CONTENT=""> <META NAME="Description" CONTENT=""> </HEAD> <% String filename = Tryitshow.generatePieChart("本科#100,专科#200","人才学历信息统计",session, new PrintWriter(out));     String graphURL = request.getContextPath() + "/servlet/DisplayChart?filename=" + filename;     %> <BODY> <img src="<%= graphURL %>" width=500 height=300 border=0 usemap="#<%= filename %>"> </BODY> </HTML> ok,大功告成，当然，你可以采用其他方式，比如你可以把DataSet的数据设置在xml文件中，从xml文件读取 统计数据中添加百分比等等，还可以选择生成柱状图、折线图等。 jFreeChart还有很多其他的用法，希望大家可以多多交流。 web.xml文件的配置 <web-app>   <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> </web-app>