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) {}         }     }}