SpringBoot之excel导入数据库

1.导入jar

      <dependency>
           <groupId>com.alibaba</groupId>
           <artifactId>easyexcel</artifactId>
           <version>2.1.1</version>
       </dependency>

2.根据数据库创建类

3.service层

@Service
public class EduSubjectServiceImpl extends ServiceImpl<EduSubjectMapper, EduSubject> implements EduSubjectService {

    //添加课程分类
    @Override
    public void saveSubject(MultipartFile file,EduSubjectService subjectService) {
        try{
            //文件输入流
            InputStream in = file.getInputStream();
            //调用方法进行读取,SubjectExcelListener是监听器
            EasyExcel.read(in, SubjectData.class,new SubjectExcelListener(subjectService)).sheet().doRead();
        }catch (Exception e){
            e.printStackTrace();
        }

    }

4.监听器

import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.event.AnalysisEventListener;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.mine.guli.entity.EduSubject;
import com.mine.guli.entity.excel.SubjectData;
import com.mine.guli.exceptionhandler.GuliException;
import com.mine.guli.service.EduSubjectService;

public class SubjectExcelListener extends AnalysisEventListener<SubjectData> {

    //因为SubjectExcelListener没有交给spring进行管理，需要自己new，不能注入其他对象
    //不能实现数据库操作
    public EduSubjectService subjectService;

    public SubjectExcelListener(){ }
    public SubjectExcelListener(EduSubjectService subjectService){
        this.subjectService=subjectService;
    }

    //读取excel内容，一行一个进行读取
    @Override
    public void invoke(SubjectData subjectData, AnalysisContext analysisContext) {
        if(subjectData==null){
            throw new GuliException(200001,"文件数据为空");
        }
        //一行一行读取，每次读取有两个值，第一个值一级分类，第二个值二级分类
        //判断一级分类是否重复
        EduSubject existOneSubject = this.existOneSubject(subjectService, subjectData.getOneSubjectName());
        if(existOneSubject == null){    //没有相同一级分类，进行添加
            existOneSubject = new EduSubject();
            existOneSubject.setParentId("0");
            existOneSubject.setTitle(subjectData.getOneSubjectName());  //一级分类名称
            subjectService.save(existOneSubject);
        }

        //获取一级分类id值
        String pid=existOneSubject.getId();
        //添加二级分类
        //判断二级分类是否重复
        EduSubject existTwoSubject =this.existTwoSubject(subjectService,subjectData.getTwoSubjectName(),pid);
        if(existTwoSubject == null){    //没有相同一级分类，进行添加
            existTwoSubject = new EduSubject();
            existTwoSubject.setParentId(pid);
            existTwoSubject.setTitle(subjectData.getTwoSubjectName());  //二级分类名称
            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 oneSubject = subjectService.getOne(wrapper);
        return oneSubject;
    }
    //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 twoSubject = subjectService.getOne(wrapper);
        return twoSubject;
    }

    @Override
    public void doAfterAllAnalysed(AnalysisContext analysisContext) {

    }
}

5.controller层

@RestController
@RequestMapping("/eduservice/subject")
@CrossOrigin
public class EduSubjectController {

    @Autowired
    private EduSubjectService subjectService;

    //添加课程分类
    //获取上传文件，把文件读取出来
    @PostMapping("/addSubject")
    public R addSubject(MultipartFile file){
        //上传过来excel文件
        subjectService.saveSubject(file,subjectService);
        return R.ok();
    }
 }