Java的统计图表（JFreeChart的应用）
第一步、导入库文件（jar包）：
jcommon-1.0.23.jar
jfreechart-1.0.19.jar
第二步：配置web.xml文件（将JFreeChart组件中已有的DisplayChart在web.xml文件进行声明）
<servlet-name>DisplayChart</servlet-name>
<servlet-class>org.jfree.chart.servlet.DisplayChart</servlet-class>
<servlet-name>DisplayChart</servlet-name>
<url-pattern>/DisplayChart</url-pattern>
第三步：创建数据集： 1、设计数据库（明确需要提取的数据） 2、Dao层设计：实体类、查询方法 public int chart(String sql) { int count = 0; try { ps = DBUtils.getConn().prepareStatement(sql); ResultSet rs = ps.executeQuery(); while(rs.next()) { count = rs.getInt(1); } } catch (SQLException e) { e.printStackTrace(); } return count; } 3、 创建一个类：用于生成不同类型的图表 public class ChartUtil { private static PieDataset getPieDataset() throws Exception{ DefaultPieDataset dataset=new DefaultPieDataset(); String s1="SELECT COUNT(*) FROM student WHERE Education='高中'"; String s2="SELECT COUNT(*) FROM student WHERE Education='大专'"; String s3="SELECT COUNT(*) FROM student WHERE Education='本科'"; String s4="SELECT COUNT(*) FROM student WHERE Education='硕士'"; IStuDAO dao=DaoFactory.getStudentDao(); dataset.setValue("硕士",dao.select(s4)); dataset.setValue("专科",dao.select(s2)); dataset.setValue("本科",dao.select(s3)); dataset.setValue("高中",dao.select(s1)); return dataset; } public static JFreeChart getPieJFreeChart() throws Exception{ // 以下是饼图 PieDataset dataset=getPieDataset();//获得饼图 JFreeChart chart=ChartFactory.createPieChart("学历分布情况",dataset,true,true,false);//调用工厂类创建饼图 PiePlot piePlot=(PiePlot)chart.getPlot(); piePlot.setLabelFont(new Font("宋体",Font.PLAIN,14));//设置图表字体 TextTitle textTitle=chart.getTitle(); textTitle.setFont(new Font("宋体",Font.BOLD,20));//设置标题 LegendTitle legendTitle=chart.getLegend(); legendTitle.setItemFont(new Font("宋体",Font.PLAIN,12));//设置图例 piePlot.setLabelGenerator(new StandardPieSectionLabelGenerator("{0}({1}人):{2}"));//当前类别的百分比 //分离饼图 piePlot.setExplodePercent("本科",0.1); piePlot.setExplodePercent("专科",0.1); piePlot.setExplodePercent("高中",0.1); piePlot.setExplodePercent("硕士",0.1); //piePlot.setSimpleLabels(true); //piePlot.setForegroundAlpha(0.7f);//设置3D饼图的透明度 //piePlot.setDepthFactor(0.1f);//设置Z轴的高度，取值范围在0~1之间,值越小，Z轴越低 piePlot.setBackgroundPaint(Color.white); piePlot.setOutlineVisible(false); chart.setAntiAlias(false); return chart; } //以下是柱形图 public static JFreeChart getCatJFreeChart() throws Exception{ CategoryDataset dataset=getCategoryDataset(); JFreeChart chart=ChartFactory.createBarChart("年龄分布情况","年龄段","人数",dataset,PlotOrientation.VERTICAL,false,false,false); //图表标题 TextTitle textTitle=chart.getTitle(); textTitle.setFont(new Font("宋体",Font.PLAIN,20)); //图表(柱形图) CategoryPlot categoryPlot=chart.getCategoryPlot(); CategoryAxis categoryAxis=categoryPlot.getDomainAxis(); //设置柱形的颜色 BarRenderer renderer=(BarRenderer)categoryPlot.getRenderer(); renderer.setSeriesPaint(0,Color.RED); //X轴字体 categoryAxis.setTickLabelFont(new Font("宋体",Font.PLAIN,14)); //X轴标签字体 categoryAxis.setLabelFont(new Font("宋体",Font.PLAIN,14)); //categoryAxis.setAxisLinePaint(Color.BLUE);// //Y轴字体 ValueAxis valueAxis=categoryPlot.getRangeAxis(); valueAxis.setLabelFont(new Font("宋体",Font.PLAIN,14)); //valueAxis.setAxisLinePaint(Color.BLUE);*/ return chart; } public static CategoryDataset getCategoryDataset() throws Exception{ DefaultKeyedValues keyedValues=new DefaultKeyedValues(); String s1="SELECT COUNT(*) FROM student WHERE Age<20"; String s2="SELECT COUNT(*) FROM student WHERE Age between 20 and 25"; String s3="SELECT COUNT(*) FROM student WHERE Age between 25 and 30"; String s4="SELECT COUNT(*) FROM student WHERE Age between 30 and 35"; String s5="SELECT COUNT(*) FROM student WHERE Age>35"; IStuDAO dao=DaoFactory.getStudentDao(); keyedValues.addValue("20岁以下",dao.select(s1)); keyedValues.addValue("20~25岁",dao.select(s2)); keyedValues.addValue("25~30岁",dao.select(s3)); keyedValues.addValue("30~35岁",dao.select(s4)); keyedValues.addValue("35岁以上",dao.select(s5)); CategoryDataset dataset=DatasetUtilities.createCategoryDataset("年龄分布情况",keyedValues); return dataset; } } 第四步、创建图表对象 String filename=null; //饼图对象 filename=ServletUtilities.saveChartAsJPEG(ChartUtil.getPieJFreeChart(),500, 350, session); //柱状图对象 filename=ServletUtilities.saveChartAsJPEG(ChartUtil.getCatJFreeChart(),500, 350, session)； 第五步、获取图片： String charUrl="DisplayChart?filename="+filename; 第六步、在web中显示图片：
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第三步：创建数据集： 1、设计数据库（明确需要提取的数据） 2、Dao层设计：实体类、查询方法 public int chart(String sql) { int count = 0; try { ps = DBUtils.getConn().prepareStatement(sql); ResultSet rs = ps.executeQuery(); while(rs.next()) { count = rs.getInt(1); } } catch (SQLException e) { e.printStackTrace(); } return count; } 3、 创建一个类：用于生成不同类型的图表 public class ChartUtil { private static PieDataset getPieDataset() throws Exception{ DefaultPieDataset dataset=new DefaultPieDataset(); String s1="SELECT COUNT(*) FROM student WHERE Education='高中'"; String s2="SELECT COUNT(*) FROM student WHERE Education='大专'"; String s3="SELECT COUNT(*) FROM student WHERE Education='本科'"; String s4="SELECT COUNT(*) FROM student WHERE Education='硕士'"; IStuDAO dao=DaoFactory.getStudentDao(); dataset.setValue("硕士",dao.select(s4)); dataset.setValue("专科",dao.select(s2)); dataset.setValue("本科",dao.select(s3)); dataset.setValue("高中",dao.select(s1)); return dataset; } public static JFreeChart getPieJFreeChart() throws Exception{ // 以下是饼图 PieDataset dataset=getPieDataset();//获得饼图 JFreeChart chart=ChartFactory.createPieChart("学历分布情况",dataset,true,true,false);//调用工厂类创建饼图 PiePlot piePlot=(PiePlot)chart.getPlot(); piePlot.setLabelFont(new Font("宋体",Font.PLAIN,14));//设置图表字体 TextTitle textTitle=chart.getTitle(); textTitle.setFont(new Font("宋体",Font.BOLD,20));//设置标题 LegendTitle legendTitle=chart.getLegend(); legendTitle.setItemFont(new Font("宋体",Font.PLAIN,12));//设置图例 piePlot.setLabelGenerator(new StandardPieSectionLabelGenerator("{0}({1}人):{2}"));//当前类别的百分比 //分离饼图 piePlot.setExplodePercent("本科",0.1); piePlot.setExplodePercent("专科",0.1); piePlot.setExplodePercent("高中",0.1); piePlot.setExplodePercent("硕士",0.1); //piePlot.setSimpleLabels(true); //piePlot.setForegroundAlpha(0.7f);//设置3D饼图的透明度 //piePlot.setDepthFactor(0.1f);//设置Z轴的高度，取值范围在0~1之间,值越小，Z轴越低 piePlot.setBackgroundPaint(Color.white); piePlot.setOutlineVisible(false); chart.setAntiAlias(false); return chart; } //以下是柱形图 public static JFreeChart getCatJFreeChart() throws Exception{ CategoryDataset dataset=getCategoryDataset(); JFreeChart chart=ChartFactory.createBarChart("年龄分布情况","年龄段","人数",dataset,PlotOrientation.VERTICAL,false,false,false); //图表标题 TextTitle textTitle=chart.getTitle(); textTitle.setFont(new Font("宋体",Font.PLAIN,20)); //图表(柱形图) CategoryPlot categoryPlot=chart.getCategoryPlot(); CategoryAxis categoryAxis=categoryPlot.getDomainAxis(); //设置柱形的颜色 BarRenderer renderer=(BarRenderer)categoryPlot.getRenderer(); renderer.setSeriesPaint(0,Color.RED); //X轴字体 categoryAxis.setTickLabelFont(new Font("宋体",Font.PLAIN,14)); //X轴标签字体 categoryAxis.setLabelFont(new Font("宋体",Font.PLAIN,14)); //categoryAxis.setAxisLinePaint(Color.BLUE);// //Y轴字体 ValueAxis valueAxis=categoryPlot.getRangeAxis(); valueAxis.setLabelFont(new Font("宋体",Font.PLAIN,14)); //valueAxis.setAxisLinePaint(Color.BLUE);*/ return chart; } public static CategoryDataset getCategoryDataset() throws Exception{ DefaultKeyedValues keyedValues=new DefaultKeyedValues(); String s1="SELECT COUNT(*) FROM student WHERE Age<20"; String s2="SELECT COUNT(*) FROM student WHERE Age between 20 and 25"; String s3="SELECT COUNT(*) FROM student WHERE Age between 25 and 30"; String s4="SELECT COUNT(*) FROM student WHERE Age between 30 and 35"; String s5="SELECT COUNT(*) FROM student WHERE Age>35"; IStuDAO dao=DaoFactory.getStudentDao(); keyedValues.addValue("20岁以下",dao.select(s1)); keyedValues.addValue("20~25岁",dao.select(s2)); keyedValues.addValue("25~30岁",dao.select(s3)); keyedValues.addValue("30~35岁",dao.select(s4)); keyedValues.addValue("35岁以上",dao.select(s5)); CategoryDataset dataset=DatasetUtilities.createCategoryDataset("年龄分布情况",keyedValues); return dataset; } } 第四步、创建图表对象 String filename=null; //饼图对象 filename=ServletUtilities.saveChartAsJPEG(ChartUtil.getPieJFreeChart(),500, 350, session); //柱状图对象 filename=ServletUtilities.saveChartAsJPEG(ChartUtil.getCatJFreeChart(),500, 350, session)； 第五步、获取图片： String charUrl="DisplayChart?filename="+filename; 第六步、在web中显示图片：
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