10.使用EasyExcel实现课程分类存储

1、课程分类需求分析

2、整合EasyExcel

2.1 引入EasyExcel依赖

<dependencies>
        <!-- https://mvnrepository.com/artifact/com.alibaba/easyexcel -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>easyexcel</artifactId>
            <version>2.1.1</version>
        </dependency>
        <dependency>
            <groupId>cglib</groupId>
            <artifactId>cglib-nodep</artifactId>
            <version>3.2.12</version>
        </dependency>
</dependencies>

2.2 创建实体类和excel对应

@Data
public class SubjectData {
     
    @ExcelProperty(index = 0)
    private String oneSubjectName;

    @ExcelProperty(index = 1)
    private String twoSubjectName;
}

2.3 实现各层业务代码
controller层

	@ApiOperation(value = "添加课程分类")
    @PostMapping("addSubject")
    public R addSubject(MultipartFile file) {
     
        subjectService.saveSubject(file,subjectService);
        return R.ok();
    }

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
            EasyExcel.read(in, SubjectData.class,new SubjectExcelListener()).sheet().doRead();
        }catch (Exception e){
     

        }

    }
}

监听器

package com.atguigu.eduservice.listener;

import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.event.AnalysisEventListener;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.atguigu.eduservice.entity.EduSubject;
import com.atguigu.eduservice.entity.execl.SubjectData;
import com.atguigu.eduservice.service.EduSubjectService;
import com.atguigu.servicebase.exceptionhandler.GuliException;

/**
 * @author yamky
 * @create 2021-11-18
 */
public class SubjectExcelListener extends AnalysisEventListener<SubjectData> {
     

    public EduSubjectService subjectService;

    public SubjectExcelListener() {
     }
    //创建有参数构造，传递subjectService用于操作数据库
    public SubjectExcelListener(EduSubjectService subjectService) {
     
        this.subjectService = subjectService;
    }

    //一行一行去读取excle内容
    @Override
    public void invoke(SubjectData subjectData, AnalysisContext analysisContext) {
     
        if(subjectData == null){
     
            throw new GuliException(20001,"文件数据为空");
        }

        //判断一级分类是否重复
        EduSubject existOneSubject = this.existOneSubject(subjectService, subjectData.getOneSubjectName());
        if(existOneSubject == null){
     
            existOneSubject = new EduSubject();
            existOneSubject.setParentId("0");
            existOneSubject.setTitle(subjectData.getOneSubjectName());
            subjectService.save(existOneSubject);
        }

        //获取一级分类id值
        String pid = existOneSubject.getId();

        //判断二级分类是否重复
        EduSubject existTwoSubject = this.existTwoSubject(subjectService, subjectData.getTwoSubjectName(),pid);
        if(existTwoSubject == null){
     
            existTwoSubject = new EduSubject();
            existTwoSubject.setParentId(pid);
            existTwoSubject.setTitle(subjectData.getTwoSubjectName());
            subjectService.save(existTwoSubject);
        }
    }

    //判断一级分类是否重复
    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;
    }

    //判断二级分类是否重复
    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) {
     

    }
}