使用JFreeChart显示 Java 虚拟机中的空闲内存量

因为需要使用JFreeChart动态显示出采集的数据，就看了这方面的资料！根据给出的例子，改了下啊，实时显示出内存大小！

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.Ellipse2D;
import java.sql.Timestamp;
import java.text.DecimalFormat;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;

import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.DateAxis;
import org.jfree.chart.axis.DateTickUnit;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.axis.NumberTickUnit;
import org.jfree.chart.labels.StandardXYToolTipGenerator;
import org.jfree.chart.plot.Marker;
import org.jfree.chart.plot.ValueMarker;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.XYLineAndShapeRenderer;
import org.jfree.data.time.Day;
import org.jfree.data.time.Hour;
import org.jfree.data.time.Minute;
import org.jfree.data.time.Second;
import org.jfree.data.time.TimeSeries;
import org.jfree.data.time.TimeSeriesCollection;
import org.jfree.ui.RectangleAnchor;
import org.jfree.ui.TextAnchor;

public class MyMemoryChart extends JPanel {
	private static final long serialVersionUID = 1L;
	private TimeSeriesCollection dataCollection = null;
	private TimeSeries series = null;
	private JFreeChart chart = null;
	private XYPlot plot = null;
	private ChartPanel chartPanel = null;


	private int seconds_interval_of_X_axis = 30;
	private int tickUnit_second_Count = 1;
	private Marker vMarker = null;
	private Marker hMarker = null;

	public MyMemoryChart() {
		series = new TimeSeries("");
		series.setMaximumItemCount(100);
		dataCollection = new TimeSeriesCollection(series);
		createChart(dataCollection);
		chartPanel = new ChartPanel(chart);
		this.setLayout(new BorderLayout());
		this.add(chartPanel, BorderLayout.CENTER);
	}

	private void createChart(TimeSeriesCollection dataCollection) {
		chart = ChartFactory.createTimeSeriesChart("", "", "", dataCollection,
				false, // 是否显示图例(对于简单的柱状图必须是false)
				true, // 是否生成工具
				false // 是否生成URL链接
				);
		chart.getTitle().setFont(new Font("Dialog", Font.PLAIN, 10));
		chart.setTitle("No Data");
		plot = chart.getXYPlot();

		// 设置X轴特性
		DateAxis domainAxis = new DateAxis();
		GregorianCalendar gc = new GregorianCalendar();
		GregorianCalendar gc1 = gc;

		int year = gc.get(Calendar.YEAR);
		int month = gc.get(Calendar.MONTH);
		int day = gc.get(Calendar.DATE);
		int hour = gc.get(Calendar.HOUR_OF_DAY);
		int miniute = gc.get(Calendar.MINUTE);
		int second = gc.get(Calendar.SECOND);

		gc = new java.util.GregorianCalendar(year, month, day, hour, miniute,
				second + 10);
		second = second - seconds_interval_of_X_axis;
		gc1 = new java.util.GregorianCalendar(year, month, day, hour, miniute,
				second);
		domainAxis.setTickLabelFont(new Font("Dialog", Font.PLAIN, 10));

		domainAxis.setRange(gc1.getTime(), gc.getTime());
		domainAxis.setAutoRange(false);
		domainAxis.setTickUnit(new DateTickUnit(DateTickUnit.SECOND,
				tickUnit_second_Count, new SimpleDateFormat("mm:ss")));
		plot.setDomainAxis(domainAxis);

		// 1. 设置Y轴特性
		NumberAxis vValueAxis = (NumberAxis) plot.getRangeAxis();
		vValueAxis.setTickLabelFont(new Font("Dialog", Font.PLAIN, 10));
		vValueAxis.setAutoTickUnitSelection(false);

		NumberTickUnit nt = new NumberTickUnit(0.2d); // 设置刻度
		vValueAxis.setTickUnit(nt);
		vValueAxis.setUpperBound(1); // 设置Y轴最大值
		vValueAxis.setLowerBound(0); // 设置Y轴最小值

	}

	// 初始化图表的相关配置
	public void setGraphNameAndInit(String name) {
		chart.setTitle(name);

		// 1. 设置Y轴特性
		NumberAxis vValueAxis = (NumberAxis) plot.getRangeAxis();
		vValueAxis.setTickLabelFont(new Font("Dialog", Font.PLAIN, 10));
		vValueAxis.setAutoTickUnitSelection(false);

		double maxValue = Runtime.getRuntime().totalMemory();
		double minValue = 32;
		NumberTickUnit nt = new NumberTickUnit((maxValue - minValue) / 10.0); // 设置刻度
		vValueAxis.setTickUnit(nt);

		// 1. 设置Y轴特性

		vValueAxis = (NumberAxis) plot.getRangeAxis();
		vValueAxis.setTickLabelFont(new Font("Dialog", Font.PLAIN, 10));
		vValueAxis.setAutoTickUnitSelection(false);
		vValueAxis.setUpperBound(maxValue); // 设置Y轴最大值
		// vValueAxis.setLowerBound(minValue); // 设置Y轴最小值

		// 2. 设置曲线颜色
		XYLineAndShapeRenderer renderer = new XYLineAndShapeRenderer();
		renderer.setSeriesShapesVisible(0, true);
		renderer.setSeriesPaint(0, Color.BLUE);
		renderer.setSeriesShape(0,
				new Ellipse2D.Float(-3.0f, -3.0f, 6.0f, 6.0f)); // circle
		plot.setRenderer(renderer);

		// 3. 设置点击出现数据点值的提示信息
		plot.setDomainCrosshairVisible(true);
		plot.setRangeCrosshairVisible(true);
		plot.getRenderer().setSeriesToolTipGenerator(
				0,
				new StandardXYToolTipGenerator("({1}, {2})",
						new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"),
						new DecimalFormat("#,##0.00")));
		chartPanel.validate();
	}

	public void showingSeries(Timestamp ts, String pvType, String fieldName,
			long fieldValue) {

		GregorianCalendar gc = DateUtil.getGregorianCalendarFrameTimestap(ts);

		int year = gc.get(Calendar.YEAR);
		int month = gc.get(Calendar.MONTH);
		int day = gc.get(Calendar.DATE);
		int hour = gc.get(Calendar.HOUR_OF_DAY);
		int miniute = gc.get(Calendar.MINUTE);
		int second = gc.get(Calendar.SECOND);

		final Hour h = new Hour(hour, new Day(day, month + 1, year));
		series.addOrUpdate(new Second(second, new Minute(miniute, h)),
				fieldValue);

		DateAxis domainAxis = (DateAxis) plot.getDomainAxis();

		// 设置X轴最大值
		gc = new java.util.GregorianCalendar(year, month, day, hour, miniute,
				second + 10);
		domainAxis.setMaximumDate(new Date(gc.getTimeInMillis()));

		// 设置X轴最小值， 最大值和最小值之间的距离为minutes_interval_of_X_axis分钟
		gc.add(Calendar.SECOND, -seconds_interval_of_X_axis);

		domainAxis.setMinimumDate(new Date(gc.getTimeInMillis()));
	}

	public static void main(String[] args) {
		JFrame f = new JFrame();
		MyMemoryChart chart = new MyMemoryChart();
		chart.setGraphNameAndInit("Memory");
		(chart.new DataGenerator(1000)).start();
		f.add(chart);
		f.setSize(400, 500);
		f.setVisible(true);
//		for (int i = 0; i < 100; i++) {
//			GregorianCalendar gc = new GregorianCalendar();
//			Timestamp ts = DateUtil.getTimestampFromGregorianCalendar(gc);
//			chart.showingSeries(ts, "", "", getFreeMemory());
//		}
	}

	class DataGenerator extends Timer implements ActionListener {
		public void actionPerformed(ActionEvent actionevent) {
			GregorianCalendar gc = new GregorianCalendar();
			Timestamp ts = DateUtil.getTimestampFromGregorianCalendar(gc);

			long l = Runtime.getRuntime().freeMemory();
			long l1 = Runtime.getRuntime().totalMemory();
			long value = getFreeMemory();
			System.out.println("Value:"+value);
			showingSeries(ts, "", "", value);
		}
		DataGenerator(int i) {
			super(i, null);
			addActionListener(this);
		}
	}

	private static long getFreeMemory() {
		return Runtime.getRuntime().freeMemory();
	}
}