Java-递归查询部门下所有子部门（包括本部门）

Java-递归查询部门下所有子部门（包括本部门）,会得到一个部门id的集合：List deptIds

具体代码如下：

//递归1
    public List<Long> queryAllSubInstitutionIds(Long institutionId) {
        List<Long> subInstitutionIds = new ArrayList<>();
        querySubInstitutionIds(institutionId, subInstitutionIds);
        return subInstitutionIds;
    }

    //递归2
    private void querySubInstitutionIds(Long institutionId, List<Long> subInstitutionIds) {
        // 添加当前机构ID
        subInstitutionIds.add(institutionId);
        // 获取当前机构的子机构
        List<Long> childrenIds = deptList(institutionId);
        // 递归查询子机构的子机构
        for (Long deptId : childrenIds) {
            querySubInstitutionIds(deptId, subInstitutionIds);
        }
    }
    //递归3
    private  List<Long> deptList(Long deptId){
        List<Long> list=baseMapper.getDeptList(deptId);
        return  list;
    }

其中：baseMapper.getDeptList()方法，查询数据库数据，代码如下：

/**
     * 查询机构下子机构
     * @param deptId
     * @return
     */
    List<Long> getDeptList(Long deptId);

sql如下：

select dept_id
        from sys_dept
        where del_flag = 0
          and status = 0
          and parent_id = #{deptId}

表结构如下：

拿到部门id list之后,代码如下：

1.接口方法：

 params.put("deptIds",deptIds);
            classUserList = baseMapper.getUserListByAllDept(params);

2.dao：

/**
     * 查询机构下所有子机构的学生
     * @param params
     * @return
     */
    List<ClassStudentListVO> getUserListByAllDept(Map<String, Object> params);

3.sql:

select
        A.user_id,
        A.user_name,
        A.nick_name,
        A.phonenumber,
        A.status,
        A.sex,
        B.dept_name,
        C.grade,
        C.school,
        C.lessons,
        C.lessons30
        from
        sys_user A
        left join sys_dept B ON A.dept_id=B.dept_id
        left join student_info C ON A.user_id=C.user_id
        <where>
            A.del_flag=0 and A.user_type=1 and A.status=0
            and B.del_flag=0
            and C.is_del=0
            <if test="deptIds != null">
                AND A.dept_id in
                <foreach collection="deptIds" index="index" item="item" open="(" separator="," close=")">
                    #{item}
                </foreach>
            </if>
            <if test="nickName != null and nickName.trim() != ''">
                AND A.nick_name like concat('%',#{nickName},'%')
            </if>
            <if test="sex != null and sex.trim() != ''">
                AND A.sex=#{sex}
            </if>
            <if test="phoneNumber != null and phoneNumber.trim() != ''">
                AND A.phonenumber=#{phoneNumber}
            </if>
        </where>

其中，主要sql如下：

 <if test="deptIds != null">
                AND A.dept_id in
                <foreach collection="deptIds" index="index" item="item" open="(" separator="," close=")">
                    #{item}
                </foreach>
            </if>