java数据库动态树形菜单

// 示例代码：递归生成树形菜单
public List<Menu> generateTree(List<Menu> menuList) {
    Map<Integer, Menu> map = new HashMap<>();
    List<Menu> rootMenus = new ArrayList<>();
    
    for (Menu menu : menuList) {
        map.put(menu.getId(), menu);
    }
    
    for (Menu menu : menuList) {
        if (menu.getParentId() == null) {
            rootMenus.add(menu);
        } else {
            Menu parent = map.get(menu.getParentId());
            if (parent != null) {
                parent.addChild(menu);
            }
        }
    }
    
    return rootMenus;
}

// 示例代码：优化数据库查询
public List<Menu> getMenuList() {
    String sql = "SELECT * FROM menu ORDER BY parent_id, id";
    // 执行查询并返回结果
}