导入easyExcel依赖，而且easyExcel依赖于 阿帕奇poi，因为是对阿帕奇poi的再次封装

    <dependencies><!--EasyExcel依赖--><!-- https://mvnrepository.com/artifact/com.alibaba/easyexcel --><dependency><groupId>com.alibaba</groupId><artifactId>easyexcel</artifactId><version>2.1.1</version></dependency></dependencies>

excel文件，我们做的就是把文件的信息及分类添加到数据库

excel对应的实体类，后面读取excel文件时会用到，和 excel 文件一一对应 @ExcelProperty（index= 0）表示第一列

package com.atguigu.eduservice.entity.excel;import com.alibaba.excel.annotation.ExcelProperty;
import lombok.Data;@Data
public class SubjectData {@ExcelProperty(index = 0)private String oneSubjectName;@ExcelProperty(index = 1)private String twoSubjectName;
}

数据库对应的实体类

@Data
@EqualsAndHashCode(callSuper = false)
@Accessors(chain = true)
@ApiModel(value="EduSubject对象", description="课程科目")
public class EduSubject implements Serializable {private static final long serialVersionUID = 1L;@ApiModelProperty(value = "课程类别ID")@TableId(value = "id", type = IdType.ID_WORKER_STR)private String id;@ApiModelProperty(value = "类别名称")private String title;@ApiModelProperty(value = "父ID")private String parentId;@ApiModelProperty(value = "排序字段")private Integer sort;@ApiModelProperty(value = "创建时间")@TableField(fill = FieldFill.INSERT)private Date gmtCreate;@ApiModelProperty(value = "更新时间")@TableField(fill = FieldFill.INSERT_UPDATE)private Date gmtModified;}

EduSubjectController层在controller中调用service的saveSubject，把文件传到service

@RestController
@RequestMapping("/eduservice/edu-subject")
@CrossOrigin
public class EduSubjectController {//注入service@Autowiredprivate EduSubjectService subjectService;//添加课程分类@PostMapping("addSubject")public R addSubject(MultipartFile file){//调用service读取文件subjectService.saveSubject(file,subjectService);return R.ok();}
}

service层

public interface EduSubjectService extends IService<EduSubject> {void saveSubject(MultipartFile file,EduSubjectService subjectService);}

service实现层，在serviceImlp中调用EasyExcel对象进行文件数据的读取

@Service
public class EduSubjectServiceImpl extends ServiceImpl<EduSubjectMapper, EduSubject> implements EduSubjectService {@Overridepublic void saveSubject(MultipartFile file,EduSubjectService subjectService) {try{//获取文件输入流InputStream inputStream = file.getInputStream();//调用EasyExcelEasyExcel.read(inputStream, SubjectData.class,new SubjectExcelListener(subjectService)).sheet().doRead();}catch (Exception e){e.printStackTrace();}}
}

创建listener包 SubjectExcelListener类实现 AnalysisEventListener<SubjectData这里放与excel文件对应的实体类>接口的 easyExcel监听器

package com.atguigu.eduservice.listener;import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.event.AnalysisEventListener;
import com.atguigu.eduservice.entity.EduSubject;
import com.atguigu.eduservice.entity.excel.SubjectData;
import com.atguigu.eduservice.service.EduSubjectService;
import com.atguigu.servicebase.exceptionhandler.GuliException;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;public class SubjectExcelListener extends AnalysisEventListener<SubjectData> {//监听器没有被spring容器管理，不能直接操作数据库，通过new监听器时，传入subjectService调用有参构造注入servicepublic EduSubjectService subjectService;public SubjectExcelListener() {}public SubjectExcelListener(EduSubjectService subjectService) {this.subjectService = subjectService;}/*** 读取 Excel 文件内容，一行一行的读取* */@Overridepublic void invoke(SubjectData subjectData, AnalysisContext analysisContext) {//判断文件是否为空if(subjectData == null){throw new GuliException(20001,"文件数据为空");}//不为空插入数据库//插入一级分类EduSubject existOneSubject = this.existOneSubject(subjectService, subjectData.getOneSubjectName());//如果一级分类不存在插入数据库if(existOneSubject == null){//为空，new 一个 EduSubject 插入数据库existOneSubject = new EduSubject();existOneSubject.setParentId("0");existOneSubject.setTitle(subjectData.getOneSubjectName());  //一级分类名称subjectService.save(existOneSubject);}//插入二级分类String pid = existOneSubject.getId();  //如果一级分类不为空，获取一级分类ID，如果一级分类不存在，插入数据库成功一定不为空，获取IDEduSubject existTwoSubject = this.existTwoSubject(subjectService,subjectData.getTwoSubjectName(),pid);//如果二级分类不存在插入数据库if(existTwoSubject == null){//为空，new 一个 EduSubject 插入数据库existTwoSubject = new EduSubject();existTwoSubject.setParentId(pid);existTwoSubject.setTitle(subjectData.getTwoSubjectName());  //一级分类名称subjectService.save(existTwoSubject);}}//判断一级分类不能重复添加private EduSubject existOneSubject(EduSubjectService subjectService,String name){QueryWrapper<EduSubject> wrapper = new QueryWrapper<>();wrapper.eq("title",name);wrapper.eq("parent_id","0");EduSubject oneEduSubject = subjectService.getOne(wrapper);return oneEduSubject;}//判断二级分类不能重复添加private EduSubject existTwoSubject(EduSubjectService subjectService,String name,String pid){QueryWrapper<EduSubject> wrapper = new QueryWrapper<>();wrapper.eq("title",name);wrapper.eq("parent_id",pid);EduSubject twoEduSubject = subjectService.getOne(wrapper);return twoEduSubject;}@Overridepublic void doAfterAllAnalysed(AnalysisContext analysisContext) {}
}

在丝袜哥中测试接口

数据库刷新