JFreeChart入门

JFreeChart主要用来各种各样的图表，这些图表包括：饼图、柱状图(普通柱状图以及堆栈柱状图)、线图、区域图、分布图、混合图、甘特图以及一些仪表盘等等

(源代码下载)

示例程序运用的jar包：

• jcommon-1.0.17.jar
• jfreechart-1.0.14.jar

1:普通柱状图

这是程序调用CategoryDataset dataset = getDataSet2(); 后所生产的图片

BarChartDemo.java柱状图代码

 /**
 * 该类用于演示最简单的柱状图生成
 * @author Winter Lau
 */
 public class BarChartDemo {
     public static void main(String[] args) throws IOException{

         CategoryDataset dataset = getDataSet2();
         JFreeChart chart = ChartFactory.createBarChart3D(
                            "水果产量图", // 图表标题
                            "水果", // 目录轴的显示标签
                            "产量", // 数值轴的显示标签
                             dataset, // 数据集
                             PlotOrientation.VERTICAL, // 图表方向：水平、垂直
                             true,  // 是否显示图例(对于简单的柱状图必须是 false)
                             false, // 是否生成工具
                             false  // 是否生成 URL 链接
                             );
         //中文乱码
         CategoryPlot categoryplot = (CategoryPlot) chart.getPlot();
         NumberAxis numberaxis = (NumberAxis) categoryplot.getRangeAxis();
         CategoryAxis domainAxis = categoryplot.getDomainAxis();
         TextTitle textTitle = chart.getTitle();
         textTitle.setFont(new Font("黑体", Font.PLAIN, 20));
         domainAxis.setTickLabelFont(new Font("sans-serif", Font.PLAIN, 11));
         domainAxis.setLabelFont(new Font("宋体", Font.PLAIN, 12));
         numberaxis.setTickLabelFont(new Font("sans-serif", Font.PLAIN, 12));
         numberaxis.setLabelFont(new Font("黑体", Font.PLAIN, 12));
         chart.getLegend().setItemFont(new Font("宋体", Font.PLAIN, 12));

         FileOutputStream fos_jpg = null;
         try {
             fos_jpg = new FileOutputStream("D:\\BarChart.jpg");
             ChartUtilities.writeChartAsJPEG(fos_jpg, 1.0f,chart,400,300,null);
         } finally {
             try {
                 fos_jpg.close();
             } catch (Exception e) {}
         }
     }
     /**
     * 获取一个演示用的简单数据集对象
     * @return
     */
     private static CategoryDataset getDataSet() {
         DefaultCategoryDataset dataset = new DefaultCategoryDataset();
         dataset.addValue(100, "", "苹果");
         dataset.addValue(200, "", "梨子");
         dataset.addValue(300, "", "葡萄");
         dataset.addValue(400, "", "香蕉");
         dataset.addValue(500, "", "荔枝");
         return dataset;
     }
     /**
     * 获取一个演示用的组合数据集对象
     * @return
     */
     private static CategoryDataset getDataSet2() {
         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");
         return dataset;
     }
 }

2：饼状图

PieChartDemo.java饼状图源代码

 /**
  * 用于演示饼图的生成
  */
 public class PieChartDemo {
     public static void main(String[] args) throws IOException {
         DefaultPieDataset data = getDataSet();
         JFreeChart chart = ChartFactory.createPieChart3D("水果产量图", // 图表标题
                 data, // 数据集
                 true, // 是否显示图例(对于简单的柱状图必须是 false)
                 false, // 是否生成工具
                 false // 是否生成 URL 链接
                 );

         //中文乱码
         PiePlot3D plot = (PiePlot3D) chart.getPlot();
         plot.setLabelFont(new Font("黑体", Font.PLAIN, 20));
         TextTitle textTitle = chart.getTitle();
         textTitle.setFont(new Font("黑体", Font.PLAIN, 20));
         chart.getLegend().setItemFont(new Font("宋体", Font.PLAIN, 12));

         // 写图表对象到文件，参照柱状图生成源码
         FileOutputStream fos_jpg = null;
         try {
             fos_jpg = new FileOutputStream("D:\\Pie3DChart.jpg");
             ChartUtilities.writeChartAsJPEG(fos_jpg, 1.0f, chart, 400, 300,
                     null);
         } finally {
             try {
                 fos_jpg.close();
             } catch (Exception e) {
             }
         }
     }

     /**
      * 获取一个演示用的简单数据集对象
      *
      * @return
      */
     private static DefaultPieDataset getDataSet() {
         DefaultPieDataset dataset = new DefaultPieDataset();
         dataset.setValue("苹果", 100);
         dataset.setValue("梨子", 200);
         dataset.setValue("葡萄", 300);
         dataset.setValue("香蕉", 400);
         dataset.setValue("荔枝", 500);
         return dataset;
     }
 }

其他的图表类型暂时不写了，其实写法也差不多。这里注意两种图形的中文乱码解决方法是不一样的，具体查看源代码中的红色部分

3：将数据库的内容用图形表示出来

index.jsp

 <body>
     <form action="servlet/ShowChartServlet" method="get" >
       <input type="submit" value="jfreechart访问数据库生成图表">
     </form>
   </body>

showJfreeChart.jsp

 <body>
     <center>
     <img alt="" src="<%=path %>/reports/productSales.jpg">
     </center>
   </body>

ShowChartServlet.java

 public class ShowChartServlet extends HttpServlet {

     /**
      * 获取一个演示用的组合数据集对象
      *
      * @return
      */
     private static CategoryDataset getDataSet() {
         DefaultCategoryDataset dataset = new DefaultCategoryDataset();
         // 从数据库中获取
         Connection conn = null;
         PreparedStatement ps = null;
         ResultSet rs = null;
         try {
             Class.forName("com.mysql.jdbc.Driver"); // 加载驱动程序
             conn = DriverManager
                     .getConnection(
                             "jdbc:mysql://localhost:3306/shopping?useUnicode=true&characterEncoding=utf8",
                             "root", "root");
             ps = conn.prepareStatement("select p.name, count(pcount) from product p join salesitem si on (p.id = si.productid) group by p.id");
             rs = ps.executeQuery();
             while (rs.next()) {
                 dataset.addValue(rs.getInt(2), "", rs.getString(1));
             }
             rs.close();
             rs = null;
         } catch (SQLException e) {
             e.printStackTrace();
         }catch (ClassNotFoundException e) {
             e.printStackTrace();
         }
         finally {
             if(ps != null){
                 try {
                     ps.close();
                 } catch (SQLException e) {
                     e.printStackTrace();
                 }
             }
             if(conn != null){
                 try {
                     conn.close();
                 } catch (SQLException e) {
                     e.printStackTrace();
                 }
             }

         }

         return dataset;
     }

     public void doGet(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {

         CategoryDataset dataset = getDataSet();
         JFreeChart chart = ChartFactory.createBarChart3D(
                            "产品销量图", // 图表标题
                            "产品", // 目录轴的显示标签
                            "销量", // 数值轴的显示标签
                             dataset, // 数据集
                             PlotOrientation.VERTICAL, // 图表方向：水平、垂直
                             true,  // 是否显示图例(对于简单的柱状图必须是 false)
                             false, // 是否生成工具
                             false  // 是否生成 URL 链接
                             );
         //中文乱码
         CategoryPlot categoryplot = (CategoryPlot) chart.getPlot();
         NumberAxis numberaxis = (NumberAxis) categoryplot.getRangeAxis();
         CategoryAxis domainAxis = categoryplot.getDomainAxis();
         TextTitle textTitle = chart.getTitle();
         textTitle.setFont(new Font("黑体", Font.PLAIN, 20));
         domainAxis.setTickLabelFont(new Font("sans-serif", Font.PLAIN, 11));
         domainAxis.setLabelFont(new Font("宋体", Font.PLAIN, 12));
         numberaxis.setTickLabelFont(new Font("sans-serif", Font.PLAIN, 12));
         numberaxis.setLabelFont(new Font("黑体", Font.PLAIN, 12));
         chart.getLegend().setItemFont(new Font("宋体", Font.PLAIN, 12));

         FileOutputStream fos_jpg = null;
         try {
             fos_jpg = new FileOutputStream("E:\\Workspaces\\MyEclipse 9\\WebProjects\\JFreeChart\\WebRoot\\reports\\productSales.jpg");
             ChartUtilities.writeChartAsJPEG(fos_jpg, 1.0f,chart,400,300,null);
              String path = this.getServletContext().getContextPath();
              System.out.println(path+"mmmmmmmmmmm");
             this.getServletContext().getRequestDispatcher("/showJfreeChart.jsp").forward(request, response);
         } finally {
             try {
                 fos_jpg.close();
             } catch (Exception e) {}
         }
     }

 }

注：本文来源于：cnblogs：牛奶、不加糖