前言

JFreeChart是一个免费的Java开源绘图库，可以绘制折线图、条形图、饼图等，同时支持多种输出格式，包括PNG，JPEG，PDF和SVG

导入依赖

        <dependency>
            <groupId>org.jfree</groupId>
            <artifactId>jfreechart</artifactId>
            <version>1.5.4</version>
        </dependency>

折线图

public class LineChartDemo {

    public static void main(String[] args) {
        XYSeriesCollection dataset = new XYSeriesCollection();
        XYSeries series1 = new XYSeries("Line 1");
        series1.add(1,4);
        series1.add(3,7);
        series1.add(5,5);
        dataset.addSeries(series1);

        XYSeries series2 = new XYSeries("Line 2");
        series2.add(1,7);
        series2.add(3,4);
        series2.add(5,6);
        dataset.addSeries(series2);

        JFreeChart xyLineChart = ChartFactory.createXYLineChart("XY Line Chart", "X",
                "Y", dataset);

        ChartFrame frame = new ChartFrame("Demo", xyLineChart);
        frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
        frame.pack();
        frame.setLocation(300, 100);//窗口位置
        frame.setSize(800, 400);//窗口大小
        frame.setVisible(true);
    }
}

柱状图

public class BarChartDemo {
    public static void main(String[] args) {
        DefaultCategoryDataset dataset = new DefaultCategoryDataset();
        dataset.addValue(7445, "A", "I");
        dataset.addValue(24448, "B", "I");
        dataset.addValue(4297, "A", "II");
        dataset.addValue(21022, "B", "II");

        JFreeChart barChart = ChartFactory.createBarChart("Bar Chart", "category",
                "value", dataset);

        ChartFrame frame = new ChartFrame("Demo", barChart);
        frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
        frame.pack();
        frame.setLocation(300, 100);//窗口位置
        frame.setSize(800, 400);//窗口大小
        frame.setVisible(true);
    }
}

饼图

public class PieChartDemo {
    public static void main(String[] args) {
        DefaultPieDataset dataset = new DefaultPieDataset();
        dataset.setValue("Samsung", 27.8d);
        dataset.setValue("Others", 55.3d);
        dataset.setValue("Nokia", 16.8d);
        dataset.setValue("Apple", 17.1d);

        JFreeChart barChart = ChartFactory.createPieChart("Pie Chart", dataset);

        ChartFrame frame = new ChartFrame("Demo", barChart);
        frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
        frame.pack();
        frame.setLocation(300, 100);//窗口位置
        frame.setSize(800, 400);//窗口大小
        frame.setVisible(true);
    }
}