集合：<if test="arr != null and arr.size() > 0"> 数组：<if test="col != null and col .length > 0"> 相关文章： 2022-02-12 2022-12-23 2022-12-23 2022-12-23 2021-10-12 2022-02-02 2022-12-23 2022-12-23