mytbatis mapper.xml报错:java.lang.UnsupportedOperationException] with root cause

女爷i 2023-10-01 19:54 3阅读 0赞

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> ### Cause: java.lang.UnsupportedOperationException\] with root cause java.lang.UnsupportedOperationException: null ###

mapper层接口

List selectRolePredict(@Param("organId") String organId,@Param("businessId") String businessId);

mybatis.xml sql结构

<select id="selectRolePredict" resultType="list">
                select  DISTINCT  next_approval_role from business_node_approval_role
                <where>
                    organ_id=#{
        organId} and business_id=#{
        businessId} and !isnull(next_approval_role)
                </where>
        </select>

**解决方法**：把resultType=“java.util.List” 改为String

**原因:**  
resultType返回的是集合中的元素类型，而不是集合本身

<select id="selectRolePredict" resultType="string">
                select  DISTINCT  next_approval_role from business_node_approval_role
                <where>
                    organ_id=#{
        organId} and business_id=#{
        businessId} and !isnull(next_approval_role)
                </where>
        </select>

修改之后重新启动项目再次测试接口  
![在这里插入图片描述][watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA6Jyc5qGD5am35am36YWx_size_20_color_FFFFFF_t_70_g_se_x_16 1]  
解决

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