如何在JTable中显示空值？

import javax.swing.*;
import javax.swing.table.DefaultTableModel;
import java.awt.*;

public class JTableExample extends JFrame {
    public JTableExample() {
        // 创建表格数据
        Object[][] data = {
                {1, "John", null},
                {2, "Alice", ""},
                {3, "Bob", "Smith"}
        };

        // 创建表格列名
        String[] columnNames = {"ID", "Name", "Address"};

        // 创建TableModel对象
        DefaultTableModel model = new DefaultTableModel(data, columnNames);

        // 创建JTable对象，并设置TableModel
        JTable table = new JTable(model);

        // 设置表格显示属性
        table.setRowHeight(30);
        table.getColumnModel().getColumn(2).setPreferredWidth(200);

        // 将JTable添加到容器中
        JScrollPane scrollPane = new JScrollPane(table);
        getContentPane().add(scrollPane, BorderLayout.CENTER);

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setTitle("JTable Example");
        pack();
        setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(JTableExample::new);
    }
}