MyBaseMapper需要从com.baomidou.mybatisplus.test.mysql.mapper中移除，因为它不是某具体表的mapper，无法扫描注入CRUD代码

mybatis-plus/src/test/java/com/baomidou/mybatisplus/test/mysql/mapper/MyBaseMapper.java → mybatis-plus/src/test/java/com/baomidou/mybatisplus/test/mysql/MyBaseMapper.java

@@ -13,7 +13,7 @@
  * License for the specific language governing permissions and limitations under
  * the License.
  */
-package com.baomidou.mybatisplus.test.mysql.mapper;
+package com.baomidou.mybatisplus.test.mysql;
 
 import com.baomidou.mybatisplus.mapper.BaseMapper;
 

mybatis-plus/src/test/java/com/baomidou/mybatisplus/test/mysql/mapper/UserMapper.java

@@ -17,6 +17,7 @@ package com.baomidou.mybatisplus.test.mysql.mapper;
 
 import java.util.List;
 
+import com.baomidou.mybatisplus.test.mysql.MyBaseMapper;
 import org.apache.ibatis.annotations.Insert;
 import org.apache.ibatis.annotations.Param;
 import org.apache.ibatis.session.RowBounds;