area2.jsp

JFreeChart开发全攻略,JFreeChart开发全攻略

<%@ page contentType="text/html;charset=GBK"%>
<%@ page import="org.jfree.chart.ChartFactory,
                 org.jfree.chart.JFreeChart,
                 org.jfree.chart.servlet.ServletUtilities,
                 org.jfree.chart.axis.DateAxis,
                 org.jfree.chart.plot.PlotOrientation,
                 org.jfree.chart.plot.XYPlot,
                 org.jfree.data.time.*"%>
                 
<%
//构造时序序列
TimeSeries timeseries = new TimeSeries("随机数时序序列");
double d = 0.0D;
Day day = new Day();
for (int i = 0; i < 200; i++) {
	d = (d + Math.random()) - 0.5D;
	timeseries.add(day, d);
	day = (Day)day.next();
}

//构造XYDataset数据集(说明：TimeSeriesCollection实现了XYDataset类)
TimeSeriesCollection xydataset = new TimeSeriesCollection(timeseries);

JFreeChart jfreechart = ChartFactory.createXYAreaChart(
				"XY区域图",
				"时间",
				"数值",
				xydataset,
				PlotOrientation.VERTICAL,
				true,
				true,
				false);
				
XYPlot xyplot = (XYPlot)jfreechart.getPlot();
//设置X轴参数
DateAxis dateaxis = new DateAxis("时间");
dateaxis.setLowerMargin(0.0D);
dateaxis.setUpperMargin(0.0D);
xyplot.setDomainAxis(dateaxis);
//设置为半透明
xyplot.setForegroundAlpha(0.5F);

String filename = ServletUtilities.saveChartAsPNG(jfreechart, 600, 400, null, session);
String graphURL = request.getContextPath() + "/DisplayChart?filename=" + filename;
%>
<img src="<%= graphURL %>" width="600" height="400" border="0" usemap="#<%= filename %>">