您可以createArrowButton()在中覆盖BasicComboBoxUI。BasicArrowButton是一个方便的起点。

class ColorArrowUI extends BasicComboBoxUI {

    public static ComboBoxUI createUI(JComponent c) {
        return new ColorArrowUI();
    }

    @Override protected JButton createArrowButton() {
        return new BasicArrowButton(
            BasicArrowButton.SOUTH,
            Color.cyan, Color.magenta,
            Color.yellow, Color.blue);
    }
}

然后安装它。

JComboBox combo = new JComboBox();
combo.setUI(ColorArrowUI.createUI(combo));