我要添加JFreeChart到JPanel，然后添加JPanel到JTabbedPane。我設法顯示JFreeChart上JFrame，但我想添加JFreeChart為一個4片JTabbedPane。顯示圖表的代碼：public class Chart extends javax.swing.JPanel {  private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {        JPanel jPanel1 = new JPanel();        DefaultCategoryDataset dataset = new DefaultCategoryDataset();        dataset.setValue(60, "Marks", "Student 1");        dataset.setValue(40, "Marks", "Student 2");        dataset.setValue(90, "Marks", "Student 3");        dataset.setValue(50, "Marks", "Student 4");        dataset.setValue(70, "Marks", "Student 5");        dataset.setValue(30, "Marks", "Student 6");        JFreeChart chart = ChartFactory.createBarChart(            "Student Marks", "Student Name", "Marks", dataset,            PlotOrientation.VERTICAL, false, true, false);        CategoryPlot p = chart.getCategoryPlot();        p.setRangeGridlinePaint(Color.BLACK);        ChartPanel panel = new ChartPanel(chart);        panel.setDomainZoomable(true);        jPanel1.add(panel, BorderLayout.CENTER);        panel.setPreferredSize(new java.awt.Dimension(500, 270));  }添加到TabbedPane的代碼：tabStoreTrans.add("chart", new Chart());