如何使用转换器设置comboBox项目的文本？

import javax.swing.*;
import java.awt.*;
import java.util.ArrayList;
import java.util.List;

public class ComboBoxExample {
    public static void main(String[] args) {
        JFrame frame = new JFrame("ComboBox Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLayout(new FlowLayout());

        // 创建一个转换器实例
        MyComboBoxModel model = new MyComboBoxModel();

        // 创建一个comboBox，并设置转换器作为其模型
        JComboBox<String> comboBox = new JComboBox<>(model);
        comboBox.setPreferredSize(new Dimension(200, 30));

        frame.add(comboBox);
        frame.pack();
        frame.setVisible(true);
    }
}

// 转换器类
class MyComboBoxModel extends AbstractListModel<String> implements ComboBoxModel<String> {
    private List<String> items;
    private String selectedItem;

    public MyComboBoxModel() {
        items = new ArrayList<>();
        items.add("Item 1");
        items.add("Item 2");
        items.add("Item 3");
        selectedItem = null;
    }

    @Override
    public int getSize() {
        return items.size();
    }

    @Override
    public String getElementAt(int index) {
        return items.get(index);
    }

    @Override
    public Object getSelectedItem() {
        return selectedItem;
    }

    @Override
    public void setSelectedItem(Object anItem) {
        selectedItem = (String) anItem;
    }
}