import java.awt.Color;
import java.io.IOException;
import java.text.SimpleDateFormat;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartUtilities;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.DateAxis;
import org.jfree.chart.axis.DateTickUnit;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.XYPlot;
import org.jfree.data.time.Day;
import org.jfree.data.time.Hour;
import org.jfree.data.time.Month;
import org.jfree.data.time.TimeSeries;
import org.jfree.data.time.TimeSeriesCollection;
import org.jfree.data.xy.XYDataset;
import org.jfree.ui.RectangleInsets;

/**
 * 用于將統計結果顯示成走勢圖
 * @author lord
 * 調用方法：
   TrendChart trendChart = new TrendChart();
   trendChart.chartTitle = "走勢圖";
   trendChart.chartSeriesDesc = "走勢曲線";
   trendChart.chartXdesc = "時間";
   trendChart.chartYdesc = "價格";
   trendChart.graphHigh = 400;
   trendChart.graphWidth = 600;
   trendChart.timeFormat = "yyyy-MM";
   trendChart.periodType = TrendChart.DAY;
   ......
   trendChart.addTimeSeriesUnitData(mYear, mMonth, mDay, mHour, (int)rData);
   trendChart.createTrendGraphByServlet(request, response);
 */

public class TrendChart {
  public final static String MONTH = "MONTH";
  public final static String DAY = "DAY";
  public final static String HOUR = "HOUR";
 
  private JFreeChart rChart = null;     //圖表對象
  public String chartTitle = "";        //圖表標題
  public String chartXdesc = "";        //X軸標題
  public String chartYdesc = "";        //Y軸標題
  public String chartSeriesDesc = "";   //曲線說明
  public int graphWidth = 600;          //默認寬度
  public int graphHigh = 400;           //默認高度
  public String timeFormat = "MM/yyyy"; // 按日：MM-dd ,按小時：hh:mm

  // 用于標志用戶選擇的是按哪種查詢統計周期類型(年、月、天、小時).
  // 年：YEAR, 月：MONTH, 天：DAY, 小時：HOUR
  public String periodType = "";

  // 用于確定時間間隔
  public int dateInterval = 0;
 
  //統計結果數據集
  TimeSeriesCollection statDataset = new TimeSeriesCollection();
 
  TimeSeries monthSeries = null;  //月份統計圖數據集合
  TimeSeries daySeries = null;    //天數統計圖數據集合
  TimeSeries hourSeries = null;   //小時統計圖數據集合
  
  
  /**
   * 創建Servlet方式走勢圖表
   * @param req
   * @param res
   * @throws IOException
   */
  public void createTrendGraphByServlet(ServletRequest req, ServletResponse res) throws IOException {
    res.setContentType("image/jpeg");
    setTimeSeriesStatType();
    rChart = createTrendChart();
    ChartUtilities.writeChartAsJPEG(res.getOutputStream(), 1, rChart, graphWidth, graphHigh, null);
  }
 
  /**
   * 創建趨勢圖表
   * @return JFreeChart 圖表對象JFreeChart
   */
  private JFreeChart createTrendChart(){
    JFreeChart _freeChart = ChartFactory.createTimeSeriesChart(chartTitle, chartXdesc, chartYdesc,
        getTimeSeriesStatDataSet(), true, false, false);
    _freeChart.setBackgroundPaint(Color.white);
   
    XYPlot _xyplot = _freeChart.getXYPlot();
    _xyplot.setOrientation(PlotOrientation.VERTICAL);
    _xyplot.setBackgroundPaint(Color.lightGray);
    _xyplot.setDomainGridlinePaint(Color.white);
    _xyplot.setRangeGridlinePaint(Color.white);
    _xyplot.setAxisOffset(new RectangleInsets(1.0, 2.0, 2.0, 10.0));
   
    DateAxis dateaxis = (DateAxis) _xyplot.getDomainAxis();
    if (periodType.equalsIgnoreCase("MONTH")){
      if (dateInterval > 0) {
        dateaxis.setTickUnit(new DateTickUnit(DateTickUnit.MONTH, dateInterval));
      }
    }else if (periodType.equalsIgnoreCase("DAY")){
      if (dateInterval > 0) {
        dateaxis.setTickUnit(new DateTickUnit(DateTickUnit.DAY, dateInterval));
      }
    }else if (periodType.equalsIgnoreCase("HOUR")){
      if (dateInterval > 0) {
        dateaxis.setTickUnit(new DateTickUnit(DateTickUnit.HOUR, dateInterval));
      }
    }
    dateaxis.setDateFormatOverride(new SimpleDateFormat(timeFormat));
    return _freeChart;
  }
 
  /**
   * 增加走勢圖數據
   * @param periodType 區間類型
   * @param year  年份
   * @param month 月份
   * @param day   日期
   * @param hour  時間
   * @param statData 統計數據
   */
  public void addTimeSeriesUnitData(int year, int month, int day, int hour, int statData) {
    if (periodType.equalsIgnoreCase("MONTH")){
      if (monthSeries == null){
        monthSeries = new TimeSeries(chartSeriesDesc, Month.class);
      }
      monthSeries.add(new Month(month, year), statData);
    }else if (periodType.equalsIgnoreCase("DAY")){
      if (daySeries == null){
        daySeries = new TimeSeries(chartSeriesDesc, Day.class);
      }
      daySeries.add(new Day(day, month, year), statData);
    }else if (periodType.equalsIgnoreCase("HOUR")){
      if (hourSeries == null){
        hourSeries = new TimeSeries(chartSeriesDesc, Hour.class);
      }
      hourSeries.add(new Hour(hour, day, month, year), statData);
    }
  }
 
  /**
   * 設置走勢圖統計的區間類型
   * @param periodType 區間類型
   */
  private void setTimeSeriesStatType() {
    if (periodType.equalsIgnoreCase("MONTH")){
      statDataset.addSeries(monthSeries);
    }else if (periodType.equalsIgnoreCase("DAY")){
      statDataset.addSeries(daySeries);
    }else if (periodType.equalsIgnoreCase("HOUR")){
      statDataset.addSeries(hourSeries);
    }
  }
 
  /**
   * 獲得時序圖的統計數據
   * @return XYDataset 統計數據
   */
  private XYDataset getTimeSeriesStatDataSet() {
    statDataset.setDomainIsPointsInTime(true);
    return statDataset;
  }

  public int getDateInterval() {
    return dateInterval;
  }

  public void setDateInterval(int dateInterval) {
    this.dateInterval = dateInterval;
  }


JSP調用代碼如下：
 TrendChart trendChart = new TrendChart();
 trendChart.chartTitle = "一年走勢圖";
 trendChart.chartSeriesDesc = "走勢曲線";
 trendChart.chartXdesc = "時間";
 trendChart.chartYdesc = "價格";
 trendChart.graphHigh = 400;
 trendChart.graphWidth = 600;
 trendChart.timeFormat = "yyyy-MM";
 trendChart.periodType = TrendChart.DAY;
 
 double baseData = 100.0;
 double rData = baseData;
 java.util.Calendar calendar = java.util.Calendar.getInstance();
 calendar.set(2007, 0, 0);
 for (int i = 1; i <= 365; i++){
  rData = rData * (1 + (Math.random() - 0.495) / 10.0);
  calendar.add(java.util.Calendar.DAY_OF_MONTH, 1);
  System.out.println(calendar.get(java.util.Calendar.YEAR) + "||" +
   (calendar.get(java.util.Calendar.MONTH) + 1) + "||" + calendar.get(java.util.Calendar.DAY_OF_MONTH) + "||" +
   (calendar.get(java.util.Calendar.HOUR_OF_DAY) + "||" + calendar.get(java.util.Calendar.MINUTE))
  );
  int mYear = calendar.get(java.util.Calendar.YEAR);
  int mMonth = calendar.get(java.util.Calendar.MONTH) + 1;
  int mDay = calendar.get(java.util.Calendar.DAY_OF_MONTH);
  int mHour = calendar.get(java.util.Calendar.HOUR_OF_DAY);
  trendChart.addTimeSeriesUnitData(mYear, mMonth, mDay, mHour, (int)rData);
 }
trendChart.createTrendGraphByServlet(request, response);

顯示圖結果如下：