如何从java中的JTree中删除每个节点前面的文件夹符号

import javax.swing.*;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeCellRenderer;
import java.awt.*;

public class CustomTreeCellRenderer extends DefaultTreeCellRenderer {
    @Override
    public Component getTreeCellRendererComponent(JTree tree, Object value, boolean selected, boolean expanded,
                                                  boolean leaf, int row, boolean hasFocus) {
        super.getTreeCellRendererComponent(tree, value, selected, expanded, leaf, row, hasFocus);

        DefaultMutableTreeNode node = (DefaultMutableTreeNode) value;

        if (node.isRoot()) {
            setIcon(null); // 不显示文件夹符号
        } else {
            DefaultMutableTreeNode parent = (DefaultMutableTreeNode) node.getParent();

            if (parent.isRoot()) {
                setIcon(null); // 不显示文件夹符号
            } else {
                DefaultMutableTreeNode grandParent = (DefaultMutableTreeNode) parent.getParent();

                while (grandParent != null && !grandParent.isRoot()) {
                    grandParent = (DefaultMutableTreeNode) grandParent.getParent();
                }

                if (grandParent != null && grandParent.isRoot()) {
                    setIcon(null); // 不显示文件夹符号
                } else {
                    setIcon(UIManager.getIcon("FileView.directoryIcon")); // 显示文件夹符号
                }
            }
        }

        return this;
    }
}

JTree tree = new JTree();
tree.setCellRenderer(new CustomTreeCellRenderer());