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用JfreeChart创建热点图片

2007-08-17 10:46 309 查看

在实际项目开发中，尤其是报表开发经常要用来热点图片

JAVA的开源项目JfreeChart提供了热点生成图片的方法

这里介绍几种方法

第一在JSP页面中：

<%...@ page language="java" pageEncoding="UTF-8"%>

<%...@ include file="/WEB-INF/jsp/include.jsp"%>

<%...@ page import="org.jfree.data.general.DefaultPieDataset"%>

<%...@ page import="org.jfree.chart.*"%>

<%...@ page import="org.jfree.chart.plot.*"%>

<%...@ page import="org.jfree.chart.servlet.ServletUtilities"%>

<%...@ page import="org.jfree.chart.urls.StandardPieURLGenerator"%>

<%...@ page import="org.jfree.chart.entity.StandardEntityCollection"%>

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

<HTML>

<HEAD>

<TITLE>JfreeChart</TITLE>

</HEAD>

<BODY>

<%...

DefaultPieDataset data = new DefaultPieDataset();

data.setValue("高中以下",370);

data.setValue("高中",1530);

data.setValue("大专",5700);

data.setValue("本科",8280);

data.setValue("硕士",4420);

data.setValue("博士",80);

PiePlot3D plot = new PiePlot3D(data);//3D饼图

plot.setURLGenerator(new StandardPieURLGenerator("barview.jsp","lion"));//设定链接

JFreeChart chart = new JFreeChart("",JFreeChart.DEFAULT_TITLE_FONT, plot, true);

chart.setBackgroundPaint(java.awt.Color.white);//可选，设置图片背景色

chart.setTitle("程序员学历情况调查表");//可选，设置图片标题

StandardEntityCollection sec = new StandardEntityCollection();

ChartRenderingInfo info = new ChartRenderingInfo(sec);

PrintWriter w = new PrintWriter(out);//输出MAP信息

//500是图片长度，300是图片高度

String filename = ServletUtilities.saveChartAsPNG(chart, 500, 300, info, session);

ChartUtilities.writeImageMap(w, "map0", info, false);

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

<img src="<%= graphURL %>" width=500 height=300 border=0 usemap="#map0">

</P>

</BODY>

</HTML>
相应的web.xml加入如下配置

<servlet-name>DisplayChart</servlet-name>

<servlet-class>org.jfree.chart.servlet.DisplayChart</servlet-class>

</servlet>

<servlet-mapping>

<servlet-name>DisplayChart</servlet-name>

<url-pattern>/servletDisplayChart</url-pattern>

</servlet-mapping>
生成的图片如下

该方法引用网站：http://dev.yesky.com/307/2036307.shtml

第二种方法

把java代码写在jsp页面中在大的工程维护起来极不方便，我所用的项目采用Struts框架做表现层

这里我就介绍我所用的方法

java文件：

public class ImageAction extends Action ...{

public ActionForward execute(ActionMapping mapping, ActionForm form,

HttpServletRequest request, HttpServletResponse response) ...{

ImageForm image = (ImageForm)form;

int width=0, height=0;

JFreeChart chart = null;

width = 248;

height = 240;

chart = createEventShareImage();

try ...{

StandardEntityCollection sec = new StandardEntityCollection();

ChartRenderingInfo info = new ChartRenderingInfo(sec);

String filename = ServletUtilities.saveChartAsJPEG(chart, width, 240, info, request.getSession());

String mapMessage = ChartUtilities.getImageMap("map0", info);

String src = request.getContextPath()+"/servletDisplayChart?filename=" + filename ;

String useMap = "#" + filename ;

} catch (IOException e) ...{

e.printStackTrace();

}

image.setMap(mapMessage);

image.setSrc(src) ;

image.setUseMap(useMap) ;

return mapping.getInputForward();

}

private JFreeChart createEventShareImage() ...{

Object[] share = eventCommonService.getEventShare();

DefaultPieDataset pieDataset = new DefaultPieDataset();

pieDataset.setValue("严重", new Long("100"));

pieDataset.setValue("高级", new Long("200"));

pieDataset.setValue("中级", new Long("150"));

pieDataset.setValue("低级", new Long("300"));

pieDataset.setValue("轻微", new Long("288"));

PiePlot plot = new PiePlot(pieDataset);

plot.setNoDataMessage("No data available");

plot.setSectionPaint("严重", Constant.TERRIBLE_COLOR);

plot.setSectionPaint("高级", Constant.HIGH_COLOR);

plot.setSectionPaint("中级", Constant.MIDDLE_COLOR);

plot.setSectionPaint("低级", Constant.LOW_COLOR);

plot.setSectionPaint("轻微", Constant.INFO_COLOR);

plot.setLabelGenerator(new StandardPieSectionLabelGenerator("{0} ({2})"));

plot.setURLGenerator(new StandardPieURLGenerator("eventImage.do","type","id"));

JFreeChart chart = new JFreeChart("",JFreeChart.DEFAULT_TITLE_FONT, plot, true);

return chart;

}
jsp页面：

<bean:write name="imageForm" property="mapMessage" filter="false"/>

<img src="<bean:write name="imageForm" property="src" />" usemap="<bean:write name="imageForm" property="useMap" />"/>
xml的配置和上面一样

生成图片：

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