项目实战6—没有复用思想的反例

@PostMapping("/queryCourseContent")
    public List<CourseContentEntity> queryCourseContent(@RequestBody CourseContentEntity courseContent){
        return iCourseContentService.queryCourseContent(courseContent);
    }

List<CourseContentEntity> queryCourseContent(CourseContentEntity courseContent);

@Resource
    CourseContentMapper courseContentMapper;
    @Override
    public List<CourseContentEntity> queryCourseContent(CourseContentEntity courseContent) {
        return courseContentMapper.queryCourseContentRecord(courseContent);
    }

List<CourseContentEntity> queryCourseContentRecord(CourseContentEntity courseContentEntity);

<select id="queryCourseContentRecord" resultMap="courseContentMap">
        SELECT id,course_assembly_id,assembly_content,create_time,created_id,created_by,update_time,updated_id,updated_by
        FROM  tar_course_content_info
        WhERE
        is_delete=0
        <if test="id != null"> and id = #{id} </if>
        <if test="courseAssemblyId != null">and course_assembly_id = #{courseAssemblyId}</if>
        <if test="assemblyContent != null">and assembly_content = #{assemblyContent}</if>
        <if test="createdBy != null">and created_by = #{createdBy}</if>
        <if test="updatedBy != null">and updated_by = #{updatedBy}</if>
        <if test="remark != null">and remark = #{remark}</if>
    </select>

        <where>
            course_id = #{course_id}
            and class_id = #{class_id}
            and is_delete = 0
            <choose>
                <when test="id !='' and id != null">
                    and id=#{id}
                </when>
                <when test="user_answer !='' and user_answer != null">
                    and user_answer=#{user_answer}
                </when>
                <when test="questionnaire_id !='' and questionnaire_id != null">
                    and questionnaire_id=#{questionnaire_id}
                </when>
            </choose>
        </where>