Jfreechart可以用来制作各种类型的图表，这些图标包括饼图，柱状图，线图，区域图，分布图，混合图，甘特图及一些仪表盘。
jfreechart的maven引用如下：
org.jfree jfreechart 1.0.15 org.jfree jfreechart 1.0.15 sources org.jfree jfreechart 1.0.15 javadoc
官方地址为
jfreechart的图形可以导出为jpg和png格式，也可以和pdf和excel关联。
jfreechart主要两个大的包组成：org.jfree.chart,org.jfree.data。其中前者主要与图形本身有关，后者与图形显示的数据有关。
核心的类有
org.jfree.chart.JFreeChart ：图表对象，任何类型的图表的最终表现形式都是在该对象进行一些属性的定制。JFreeChart引擎本身提供了一个工厂类用于创建不同类型的图表对象
org.jfree.data.category.XXXDataSet: 数据集对象，用于提供显示图表所用的数据。根据不同类型的图表对应着很多类型的数据集对象类
org.jfree.chart.plot.XXXPlot ：图表区域对象，基本上这个对象决定着什么样式的图表，创建该对象的时候需要Axis、Renderer以及数据集对象的支持
org.jfree.chart.axis.XXXAxis ：用于处理图表的两个轴：纵轴和横轴
org.jfree.chart.render.XXXRender ：负责如何显示一个图表对象
org.jfree.chart.urls.XXXURLGenerator: 用于生成Web图表中每个项目的鼠标点击链接
XXXXXToolTipGenerator: 用于生成图象的帮助提示，不同类型图表对应不同类型的工具提示类
这里有一个完整的jfreechart的代码
public class JfreeChartTest { public static void main(String [] args){ test(); test2(); test3(); test4(); test5(); test6(); test7(); } public static void test() { //创建饼图数据对象 DefaultPieDataset dfp=new DefaultPieDataset(); dfp.setValue("管理人员", 25); dfp.setValue("市场人员", 35); dfp.setValue("开发人员", 20); dfp.setValue("后勤人员", 5); dfp.setValue("财务人员", 15); //Create JFreeChart object JFreeChart a =ChartFactory.createPieChart("CityInfoPort公司组织架构图",dfp, true, true, true); ChartFrame frame=new ChartFrame ("CityInfoPort公司组织架构图 ",a,true); frame.pack(); frame.setVisible(true); } public static void test2() { //创建类别图（Category）数据对象 DefaultCategoryDataset dataset = new DefaultCategoryDataset(); dataset.addValue(100, "北京", "苹果"); dataset.addValue(100, "上海", "苹果"); dataset.addValue(100, "广州", "苹果"); dataset.addValue(200, "北京", "梨子"); dataset.addValue(200, "上海", "梨子"); dataset.addValue(200, "广州", "梨子"); dataset.addValue(300, "北京", "葡萄"); dataset.addValue(300, "上海", "葡萄"); dataset.addValue(300, "广州", "葡萄"); dataset.addValue(400, "北京", "香蕉"); dataset.addValue(400, "上海", "香蕉"); dataset.addValue(400, "广州", "香蕉"); dataset.addValue(500, "北京", "荔枝"); dataset.addValue(500, "上海", "荔枝"); dataset.addValue(500, "广州", "荔枝"); JFreeChart chart=ChartFactory.createBarChart3D("水果产量图", "水果", "水果", dataset, PlotOrientation.VERTICAL, true, true, true); ChartFrame frame=new ChartFrame ("水果产量图 ",chart,true); frame.pack(); frame.setVisible(true); } private static void test3() { String series1 = "First"; String series2 = "Second"; String series3 = "Third"; String type1 = "2001"; String type2 = "2002"; String type3 = "2003"; String type4 = "2004"; String type5 = "2005"; String type6 = "2006"; String type7 = "2007"; String type8 = "2008"; DefaultCategoryDataset defaultcategorydataset = new DefaultCategoryDataset(); defaultcategorydataset.addValue(1.0D, series1, type1); defaultcategorydataset.addValue(4D, series1, type2); defaultcategorydataset.addValue(3D, series1, type3); defaultcategorydataset.addValue(5D, series1, type4); defaultcategorydataset.addValue(5D, series1, type5); defaultcategorydataset.addValue(7D, series1, type6); defaultcategorydataset.addValue(7D, series1, type7); defaultcategorydataset.addValue(8D, series1, type8); defaultcategorydataset.addValue(5D, series2, type1); defaultcategorydataset.addValue(7D, series2, type2); defaultcategorydataset.addValue(6D, series2, type3); defaultcategorydataset.addValue(8D, series2, type4); defaultcategorydataset.addValue(4D, series2, type5); defaultcategorydataset.addValue(4D, series2, type6); defaultcategorydataset.addValue(2D, series2, type7); defaultcategorydataset.addValue(1.0D, series2, type8); defaultcategorydataset.addValue(4D, series3, type1); defaultcategorydataset.addValue(3D, series3, type2); defaultcategorydataset.addValue(2D, series3, type3); defaultcategorydataset.addValue(3D, series3, type4); defaultcategorydataset.addValue(6D, series3, type5); defaultcategorydataset.addValue(3D, series3, type6); defaultcategorydataset.addValue(4D, series3, type7); defaultcategorydataset.addValue(3D, series3, type8); JFreeChart jfreechart = ChartFactory.createLineChart("折线图 Demo 1", "Type","Value", defaultcategorydataset,PlotOrientation.VERTICAL, true,true,false); CategoryPlot categoryplot = (CategoryPlot)jfreechart.getPlot(); categoryplot.setBackgroundPaint(Color.lightGray); categoryplot.setRangeGridlinePaint(Color.white); ChartFrame frame=new ChartFrame ("折线图 ",jfreechart,true); frame.pack(); frame.setVisible(true); } private static void test4() { XYSeries xyseries = new XYSeries("First"); //先产生XYSeries 对象 xyseries.add(1.0D, 1.0D); xyseries.add(2D, 4D); xyseries.add(3D, 3D); xyseries.add(4D, 5D); xyseries.add(5D, 5D); xyseries.add(6D, 7D); xyseries.add(7D, 7D); xyseries.add(8D, 8D); XYSeries xyseries1 = new XYSeries("Second"); xyseries1.add(1.0D, 5D); xyseries1.add(2D, 7D); xyseries1.add(3D, 6D); xyseries1.add(4D, 8D); xyseries1.add(5D, 4D); xyseries1.add(6D, 4D); xyseries1.add(7D, 2D); xyseries1.add(8D, 1.0D); XYSeries xyseries2 = new XYSeries("Third"); xyseries2.add(3D, 4D); xyseries2.add(4D, 3D); xyseries2.add(5D, 2D); xyseries2.add(6D, 3D); xyseries2.add(7D, 6D); xyseries2.add(8D, 3D); xyseries2.add(9D, 4D); xyseries2.add(10D, 3D); XYSeriesCollection xyseriescollection = new XYSeriesCollection(); //再用XYSeriesCollection添加入XYSeries 对象 xyseriescollection.addSeries(xyseries); xyseriescollection.addSeries(xyseries1); xyseriescollection.addSeries(xyseries2); JFreeChart jfreechart = ChartFactory.createXYLineChart("Line Chart Demo 2", "X", "Y", xyseriescollection, PlotOrientation.VERTICAL, true, true, false); ChartFrame frame=new ChartFrame ("折线图 ",jfreechart,true); frame.pack(); frame.setVisible(true); } private static void test5() { TimeSeries timeseries = new TimeSeries("L&G European Index Trust",Month.class); timeseries.add(new Month(2, 2001), 181.8D);//这里用的是Month.class，同样还有Day.class Year.class 等等 timeseries.add(new Month(3, 2001), 167.3D); timeseries.add(new Month(4, 2001), 153.8D); timeseries.add(new Month(5, 2001), 167.6D); timeseries.add(new Month(6, 2001), 158.8D); timeseries.add(new Month(7, 2001), 148.3D); timeseries.add(new Month(8, 2001), 153.9D); timeseries.add(new Month(9, 2001), 142.7D); timeseries.add(new Month(10, 2001), 123.2D); timeseries.add(new Month(11, 2001), 131.8D); timeseries.add(new Month(12, 2001), 139.6D); timeseries.add(new Month(1, 2002), 142.9D); timeseries.add(new Month(2, 2002), 138.7D); timeseries.add(new Month(3, 2002), 137.3D); timeseries.add(new Month(4, 2002), 143.9D); timeseries.add(new Month(5, 2002), 139.8D); timeseries.add(new Month(6, 2002), 137D); timeseries.add(new Month(7, 2002), 132.8D); TimeSeries timeseries1 = new TimeSeries("L&G UK Index Trust",Month.class); timeseries1.add(new Month(2, 2001), 129.6D); timeseries1.add(new Month(3, 2001), 123.2D); timeseries1.add(new Month(4, 2001), 117.2D); timeseries1.add(new Month(5, 2001), 124.1D); timeseries1.add(new Month(6, 2001), 122.6D); timeseries1.add(new Month(7, 2001), 119.2D); timeseries1.add(new Month(8, 2001), 116.5D); timeseries1.add(new Month(9, 2001), 112.7D); timeseries1.add(new Month(10, 2001), 101.5D); timeseries1.add(new Month(11, 2001), 106.1D); timeseries1.add(new Month(12, 2001), 110.3D); timeseries1.add(new Month(1, 2002), 111.7D); timeseries1.add(new Month(2, 2002), 111D); timeseries1.add(new Month(3, 2002), 109.6D); timeseries1.add(new Month(4, 2002), 113.2D); timeseries1.add(new Month(5, 2002), 111.6D); timeseries1.add(new Month(6, 2002), 108.8D); timeseries1.add(new Month(7, 2002), 101.6D); TimeSeriesCollection timeseriescollection = new TimeSeriesCollection(); timeseriescollection.addSeries(timeseries); timeseriescollection.addSeries(timeseries1); timeseriescollection.setDomainIsPointsInTime(true); //domain轴上的刻度点代表的是时间点而不是时间段 JFreeChart jfreechart = ChartFactory.createTimeSeriesChart("Legal & General Unit Trust Prices", "Date", "Price Per Unit", timeseriescollection, true, true, false); jfreechart.setBackgroundPaint(Color.white); XYPlot xyplot = (XYPlot)jfreechart.getPlot(); //获得 plot : XYPlot!! xyplot.setBackgroundPaint(Color.lightGray); xyplot.setDomainGridlinePaint(Color.white); xyplot.setRangeGridlinePaint(Color.white); xyplot.setAxisOffset(new RectangleInsets(5D, 5D, 5D, 5D)); xyplot.setDomainCrosshairVisible(true); xyplot.setRangeCrosshairVisible(true); ChartFrame frame=new ChartFrame ("折线图 ",jfreechart,true); frame.pack(); frame.setVisible(true); } private static void test6() { DefaultPieDataset dataset = new DefaultPieDataset(); dataset.setValue(" 市场前期", new Double(10)); dataset.setValue(" 立项", new Double(15)); dataset.setValue(" 计划", new Double(10)); dataset.setValue(" 需求与设计", new Double(10)); dataset.setValue(" 执行控制", new Double(35)); dataset.setValue(" 收尾", new Double(10)); dataset.setValue(" 运维",new Double(10)); JFreeChart chart = ChartFactory.createPieChart3D( " 项目进度分布", // chart title dataset,// data true,// include legend true, false ); PiePlot3D plot=(PiePlot3D)chart.getPlot(); // 图片中显示百分比:默认方式 //plot.setLabelGenerator(new StandardPieSectionLabelGenerator(StandardPieToolTipGenerator.DEFAULT_TOOLTIP_FORMAT)); // 图片中显示百分比:自定义方式，{0} 表示选项， {1} 表示数值， {2} 表示所占比例 ,小数点后两位 plot.setLabelGenerator(new StandardPieSectionLabelGenerator("{0}={1}({2})", NumberFormat.getNumberInstance(), new DecimalFormat("0.00%"))); // 图例显示百分比:自定义方式， {0} 表示选项， {1} 表示数值， {2} 表示所占比例 plot.setLegendLabelGenerator(new StandardPieSectionLabelGenerator("{0}={1}({2})")); // 设置背景色为白色 chart.setBackgroundPaint(Color.white); // 指定图片的透明度(0.0-1.0) plot.setForegroundAlpha(1.0f); // 指定显示的饼图上圆形(false)还椭圆形(true) plot.setCircular(true); // 设置图标题的字体 Font font = new Font(" 黑体",Font.CENTER_BASELINE,20); TextTitle title = new TextTitle(" 项目状态分布"); title.setFont(font); chart.setTitle(title); FileOutputStream fos_jpg = null; try { fos_jpg=new FileOutputStream("D:\\ 项目状态分布.jpg"); ChartUtilities.writeChartAsJPEG(fos_jpg, 100, chart, 640, 480, null); fos_jpg.close(); } catch (Exception e) { } } private static void test7() { JfreeChartOne one=new JfreeChartOne("CityInfoPort公司组织架构图"); one.pack(); one.setVisible(true); }}
class JfreeChartOne extends ApplicationFrame { private static final long serialVersionUID = 1L; public JfreeChartOne(String s) { super(s); setContentPane(createJPanel()); } //利用静态方法设定数据源(饼状图) public static PieDataset createPieDataset() { DefaultPieDataset defaultpiedataset = new DefaultPieDataset(); defaultpiedataset.setValue("管理人员", 10.02D); defaultpiedataset.setValue("市场人员", 20.23D); defaultpiedataset.setValue("开发人员", 60.02D); defaultpiedataset.setValue("OEM人员", 10.02D); defaultpiedataset.setValue("其他人员", 5.11D); return defaultpiedataset; } // 通过ChartFactory创建JFreeChart的实例 public static JFreeChart createJFreeChart(PieDataset p) { JFreeChart a = ChartFactory.createPieChart("CityInfoPort公司组织架构图", p, true, true, true); PiePlot pie=(PiePlot)a.getPlot(); pie.setLabelFont(new Font("SansSerif",Font.BOLD,12)); pie.setNoDataMessage("No data available"); pie.setCircular(true); pie.setLabelGap(0.01D);//间距 return a; } public static JPanel createJPanel (){ JFreeChart jfreechart = createJFreeChart(createPieDataset()); return new ChartPanel(jfreechart); }} 参考文档：
总结一些，这里主要就介绍了如何用jfreechart输出图像，并没有和servlet结合起来。以后可以再试试如何和servlet或者web项目结合。