mysql数据库实现jsp树状图

CREATE TABLE tree (
  node_id INT PRIMARY KEY,
  parent_id INT,
  node_name VARCHAR(255)
);

WITH RECURSIVE cte AS (
  SELECT node_id, parent_id, node_name, 0 AS level
  FROM tree
  WHERE parent_id IS NULL
  UNION ALL
  SELECT t.node_id, t.parent_id, t.node_name, cte.level + 1
  FROM tree AS t
  INNER JOIN cte ON t.parent_id = cte.node_id
)
SELECT node_id, parent_id, node_name, level
FROM cte
ORDER BY level, node_id;

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<ul>
  <c:forEach var="node" items="${nodes}">
    <li>${node.node_name}</li>
    <ul>
      <c:forEach var="childNode" items="${node.children}">
        <li>${childNode.node_name}</li>
        <ul>
          <!-- 继续递归展示子节点 -->
        </ul>
      </c:forEach>
    </ul>
  </c:forEach>
</ul>