JFreeChart入门

2023-08-23 14:02:28

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

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&amp;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

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