import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.DateAxis;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.XYItemRenderer;
import org.jfree.chart.renderer.xy.XYLineAndShapeRenderer;
import org.jfree.data.time.*;
import org.jfree.ui.RectangleInsets;
public class MemoryUsageDemo extends JPanel
{
class DataGenerator extends Timer
implements ActionListener
{
public void actionPerformed(ActionEvent actionevent)
{
long l = Runtime.getRuntime().freeMemory();
long l1 = Runtime.getRuntime().totalMemory();
addTotalObservation(l1);
addFreeObservation(l);
}
DataGenerator(int i)
{
super(i, null);
addActionListener(this);
}
}
public MemoryUsageDemo(int i)
{
super(new BorderLayout());
total = new TimeSeries("Total Memory", org.jfree.data.time.Millisecond.class);
total.setMaximumItemAge(i);
free = new TimeSeries("Free Memory", org.jfree.data.time.Millisecond.class);
free.setMaximumItemAge(i);
TimeSeriesCollection timeseriescollection = new TimeSeriesCollection();
timeseriescollection.addSeries(total);
timeseriescollection.addSeries(free);
DateAxis dateaxis = new DateAxis("Time");
NumberAxis numberaxis = new NumberAxis("Memory");
dateaxis.setTickLabelFont(new Font("SansSerif", 0, 12));
numberaxis.setTickLabelFont(new Font("SansSerif", 0, 12));
dateaxis.setLabelFont(new Font("SansSerif", 0, 14));
numberaxis.setLabelFont(new Font("SansSerif", 0, 14));
XYLineAndShapeRenderer xylineandshaperenderer = new XYLineAndShapeRenderer(true, false);
xylineandshaperenderer.setSeriesPaint(0, Color.red);
xylineandshaperenderer.setSeriesPaint(1, Color.green);
xylineandshaperenderer.setSeriesStroke(0, new BasicStroke(3F, 0, 2));
xylineandshaperenderer.setSeriesStroke(1, new BasicStroke(3F, 0, 2));
XYPlot xyplot = new XYPlot(timeseriescollection, dateaxis, numberaxis, xylineandshaperenderer);
xyplot.setBackgroundPaint(Color.lightGray);
xyplot.setDomainGridlinePaint(Color.white);
xyplot.setRangeGridlinePaint(Color.white);
xyplot.setAxisOffset(new RectangleInsets(5D, 5D, 5D, 5D));
dateaxis.setAutoRange(true);
dateaxis.setLowerMargin(0.0D);
dateaxis.setUpperMargin(0.0D);
dateaxis.setTickLabelsVisible(true);
numberaxis.setStandardTickUnits(NumberAxis.createIntegerTickUnits());
JFreeChart jfreechart = new JFreeChart("JVM Memory Usage", new Font("SansSerif", 1, 24), xyplot, true);
jfreechart.setBackgroundPaint(Color.white);
ChartPanel chartpanel = new ChartPanel(jfreechart, true);
chartpanel.setBorder(BorderFactory.createCompoundBorder(BorderFactory.createEmptyBorder(4, 4, 4, 4), BorderFactory.createLineBorder(Color.black)));
add(chartpanel);
}
private void addTotalObservation(double d)
{
total.add(new Millisecond(), d);
}
private void addFreeObservation(double d)
{
free.add(new Millisecond(), d);
}
public static void main(String args[])
{
JFrame jframe = new JFrame("Memory Usage Demo");
MemoryUsageDemo memoryusagedemo = new MemoryUsageDemo(30000);
jframe.getContentPane().add(memoryusagedemo, "Center");
jframe.setBounds(200, 120, 600, 280);
jframe.setVisible(true);
(memoryusagedemo. new DataGenerator(100)).start();
jframe.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent windowevent)
{
System.exit(0);
}
}
);
}
private TimeSeries total;
private TimeSeries free;
}
以上的代码如果运行的话就成为一个很好的时序图了。青年人网站提示可以动态显示出来电脑内存的变化情况。好好研究一下其代码。
责任编辑：小草
