Jfreechart DialPlot(一)仪表盘



Jfreechart仪表盘DialPlot图形例子

最近公司让用jfreechart做一个仪表盘，到网上找资料看了下，jreechart dialplot资料不多，最后也能在页面上显示，觉得还算简单。我主要看的例子地址是：http://blog.sina.com.cn/u/1766082610觉的这位大哥的例子还是比较全的。以后要向这位大哥多学学

用jfreechart生成DialPlot图形只需三步即可完成.

1.下载jfreechart_1.0.6.zip的类库，这里使用的是jfreechart_1.0.6，也可以到我的资源库里下免费的。

2.新建一个web项目

3.需要在web项目的web.xml中添加以下配置：

<?xmlversion="1.0"encoding="UTF-8"?>

<web-appversion="2.5"xmlns="http://java.sun.com/xml/ns/javaee"

   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

   xsi:schemaLocation="http://java.sun.com/xml/ns/javaee

   http://java.sun.com/xml/ns/javaee/web-app_2_5.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>/servlet/DisplayChart</url-pattern>   

    </servlet-mapping>

</web-app>

下面是在JSP页面实现代码，如下例子所示:

<%@pagelanguage="java"import="java.util.*"pageEncoding="UTF-8"%>

<%@pagecontentType="text/html; charset=GBK"%>

<%@pageimport="org.jfree.chart.JFreeChart,

   org.jfree.chart.*,

   org.jfree.chart.servlet.ServletUtilities,

   org.jfree.data.general.DefaultValueDataset,

   org.jfree.experimental.chart.plot.dial.*,

   java.awt.*,

   org.jfree.ui.StandardGradientPaintTransformer,

   org.jfree.chart.ChartUtilities,java.io.*,

   org.jfree.ui.GradientPaintTransformType"

%>

<%

   //数据集合对象此处为DefaultValueDataset

   DefaultValueDataset dataset =new DefaultValueDataset();

   //当前指针指向的位置，即：我们需要显示的数据

   dataset =newDefaultValueDataset(40D);

   //实例化DialPlot 

   DialPlot dialplot =new DialPlot();

   dialplot.setView(0.0D, 0.0D, 1.0D, 1.0D);

  //设置数据集合

   dialplot.setDataset(dataset);

   //开始设置显示框架结构(仪表盘属性外框)

   SimpleDialFrame simpledialframe =new SimpleDialFrame();

   //外框背景色

   simpledialframe.setBackgroundPaint(Color.lightGray);

   //外框前景色

   simpledialframe.setForegroundPaint(Color.darkGray);

   dialplot.setDialFrame(simpledialframe);

   //结束设置显示框架结构(仪表盘颜色)

   GradientPaint gradientpaint =new GradientPaint(new Point(),

   new Color(255, 255, 220), new Point(),new Color(170, 100,220));

    DialBackground dialbackground =new DialBackground(gradientpaint);

    dialbackground.setGradientPaintTransformer(new StandardGradientPaintTransformer(

                 GradientPaintTransformType.VERTICAL));

   dialplot.setBackground(dialbackground);

   //设置显示在表盘中央位置的信息

   DialTextAnnotation dialtextannotation =new DialTextAnnotation("人数");

   dialtextannotation.setFont(new Font("Dialog", 1, 14));

   dialtextannotation.setRadius(0.69999999999999996D);

   dialplot.addLayer(dialtextannotation);

   DialValueIndicator dialvalueindicator =new DialValueIndicator(0,"");

   dialplot.addLayer(dialvalueindicator);

   //根据表盘的直径大小（0.80），设置总刻度范围

   StandardDialScale standarddialscale =new StandardDialScale(10D,100D, -120D, -300D);

   standarddialscale.setTickRadius(0.80D);

   standarddialscale.setTickLabelOffset(0.14999999999999999D);

   standarddialscale.setTickLabelFont(new Font("Dialog", 0, 14));

   //主意是dialplot.addScale（）不是dialplot.addLayer（）

   dialplot.addScale(0, standarddialscale);

   //设置刻度范围（红色）

   StandardDialRange standarddialrange =new StandardDialRange(10D,100D, Color.red);

   standarddialrange.setInnerRadius(0.52000000000000002D);

   standarddialrange.setOuterRadius(0.55000000000000004D);

   dialplot.addLayer(standarddialrange);

   //设置刻度范围（橘黄色）

   StandardDialRange standarddialrange1 =new StandardDialRange(10D, 40D, Color.orange);

   standarddialrange1.setInnerRadius(0.52000000000000002D);

   standarddialrange1.setOuterRadius(0.55000000000000004D);

   dialplot.addLayer(standarddialrange1);

   //设置刻度范围（绿色）

   StandardDialRange standarddialrange2 =new StandardDialRange(-40D,10D, Color.green)

   standarddialrange2.setInnerRadius(0.52000000000000002D);

   standarddialrange2.setOuterRadius(0.55000000000000004D);

   dialplot.addLayer(standarddialrange2);

   //设置指针

   DialPointer.Pointer pointer =new DialPointer.Pointer();

   dialplot.addLayer(pointer);

   //实例化DialCap 

   DialCap dialcap =new DialCap();

   dialcap.setRadius(0.10000000000000001D);

   dialplot.setCap(dialcap);//生成chart对象

   JFreeChart jfreecharts =new JFreeChart(dialplot);

   //设置标题

   jfreecharts.setTitle("商务部人数统计");

    //显示方法一

    String filename =ServletUtilities.saveChartAsPNG(jfreecharts,400,400, session);

    //调用DisplayChart（配置在web.xml中），生成图形

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

/** //显示方法二这种方法用输出流输出，不用调用后面的img两种方法都可实现图片输出

   OutputStreamouts = response.getOutputStream();

   response.setContentType("image/png");

   response.reset();

   ChartUtilities.writeChartAsPNG(outs,jfreechart, 400, 300);

   outs.flush();

   outs.close();

   */

%>

<!DOCTYPEHTMLPUBLIC"-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

   <head>

      <title>生成仪表盘</title>

   </head>

   <body>

      <tablewidth="100%">

          <tr>

             <tdalign="center">

                 <h1>生成仪表盘</h1>

                   <!—方法一调用<img>，方法二不用 -->

                 <imgsrc="<%=graphURL%>"width=500height=400border=0usemap="<%=filename%>">

             </td>

          </tr>

      </table>

   </body>

</html>

效果图如下：