SpringBoot集成EasyExcel的应用场景分析

2024-04-02 19:55

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1、介绍

官网地址：https://www.yuque.com/easyexcel
特点：

1、Java领域解析、生成Excel比较有名的框架有Apache poi、jxl等。但他们都存在一个严重的问题就是非常的耗内存。如果你的系统并发量不大的话可能还行，但是一旦并发上来后一定会OOM或者JVM频繁的full gc。
2、EasyExcel是阿里巴巴开源的一个excel处理框架，以使用简单、节省内存著称。EasyExcel能大大减少占用内存的主要原因是在解析Excel时没有将文件数据一次性全部加载到内存中，而是从磁盘上一行行读取数据，逐个解析。
3、EasyExcel采用一行一行的解析模式，并将一行的解析结果以观察者的模式通知处理 (AnalysisEventListener)。

2、应用场景

1、数据导入:减轻录入工作量
2、数据导出:统计信息归档
3、数据传输:异构系统之间数据传输

3、要实现的效果

sql


CREATE TABLE `edu_subject` (
  `id` char(19) NOT NULL COMMENT '课程类别ID',
  `title` varchar(10) NOT NULL COMMENT '类别名称',
  `parent_id` char(19) NOT NULL DEFAULT '0' COMMENT '父ID',
  `sort` int unsigned NOT NULL DEFAULT '0' COMMENT '排序字段',
  `gmt_create` datetime NOT NULL COMMENT '创建时间',
  `gmt_modified` datetime NOT NULL COMMENT '更新时间',
  PRIMARY KEY (`id`),
  KEY `idx_parent_id` (`parent_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci ROW_FORMAT=COMPACT COMMENT='课程科目';

在这里插入图片描述

转成->

在这里插入图片描述

3、使用

3.1、pom依赖导入

温馨提示：以下版本不能更换，换了可能会不行


<dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>easyexcel</artifactId>
            <version>2.1.1</version>
        </dependency>
		<!--xls-->
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>3.17</version>
        </dependency>
		
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml</artifactId>
            <version>3.17</version>
        </dependency>

3.2、controller


package com.zhz.serviceedu.controller;

import com.zhz.common.utils.R;
import com.zhz.serviceedu.service.EduSubjectService;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;


@RestController
@RequestMapping("/eduservice/subject")
@CrossOrigin
@Api(tags = "课程科目")
public class EduSubjectController {

    @Autowired
    private EduSubjectService eduSubjectService;

    
    @PostMapping("/addSubject")
    @ApiOperation(value = "添加课程分类，获取上传过来的文件，把文件内容读取出来")
    public R addSubject(MultipartFile file){
        //上传过来的excel文件
        eduSubjectService.saveSubject(file,eduSubjectService);
        return R.ok();
    }
}

3.3、interface


package com.zhz.serviceedu.service;

import com.zhz.serviceedu.entity.EduSubject;
import com.baomidou.mybatisplus.extension.service.IService;
import org.springframework.web.multipart.MultipartFile;


public interface EduSubjectService extends IService<EduSubject> {

    
    void saveSubject(MultipartFile file, EduSubjectService eduSubjectService);
}

3.4、impl


package com.zhz.serviceedu.service.impl;

import com.alibaba.excel.EasyExcel;
import com.zhz.serviceedu.entity.EduSubject;
import com.zhz.serviceedu.entity.excel.SubjectData;
import com.zhz.serviceedu.listener.SubjectExcelListener;
import com.zhz.serviceedu.mapper.EduSubjectMapper;
import com.zhz.serviceedu.service.EduSubjectService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;

import java.io.InputStream;


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

    
    @Override
    public void saveSubject(MultipartFile file, EduSubjectService eduSubjectService) {
        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(eduSubjectService)).sheet().doRead();
        }catch (Exception e){
            e.printStackTrace();
        }
    }
}

3.5、listener


package com.zhz.serviceedu.listener;

import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.event.AnalysisEventListener;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.zhz.servicebase.execptionhandler.GuliException;
import com.zhz.serviceedu.entity.EduSubject;
import com.zhz.serviceedu.entity.excel.SubjectData;
import com.zhz.serviceedu.service.EduSubjectService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.StringUtils;


@Slf4j
public class SubjectExcelListener extends AnalysisEventListener<SubjectData> {

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

    
    @Override
    public void invoke(SubjectData subjectData, AnalysisContext analysisContext) {
        log.info("进入方法调用");
        if (StringUtils.isEmpty(subjectData)){
            throw new GuliException(20001,"文件数据为空");
        }
        //一行一行去读取excel内容，每次读取有两个值，第一个值为一级分类，第二个值为二级分类
        //判断一级分类是否重复
        EduSubject existOneSubject = this.existOneSubject(eduSubjectService, subjectData.getOneSubjectName());
        if (StringUtils.isEmpty(existOneSubject)){
            existOneSubject=new EduSubject();
            existOneSubject.setParentId("0");
            //一级分类名称
            existOneSubject.setTitle(subjectData.getOneSubjectName());
            eduSubjectService.save(existOneSubject);
        }
        //获取一级分类的pid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(eduSubjectService, subjectData.getTwoSubjectName(), pid);
        if (StringUtils.isEmpty(existTwoSubject)){
            existTwoSubject=new EduSubject();
            existTwoSubject.setParentId(pid);
            //二级分类名称
            existTwoSubject.setTitle(subjectData.getTwoSubjectName());
            eduSubjectService.save(existTwoSubject);
        }

    }

    
    @Override
    public void doAfterAllAnalysed(AnalysisContext analysisContext) {

    }

    
    private EduSubject existOneSubject(EduSubjectService eduSubjectService,String name){
        QueryWrapper<EduSubject> wrapper=new QueryWrapper<>();
        wrapper.eq("title",name);
        wrapper.eq("parent_id","0");
        EduSubject subject = eduSubjectService.getOne(wrapper);
        return subject;
    }
    
    private EduSubject existTwoSubject(EduSubjectService eduSubjectService,String name,String pid){
        QueryWrapper<EduSubject> wrapper=new QueryWrapper<>();
        wrapper.eq("title",name);
        wrapper.eq("parent_id",pid);
        EduSubject eduSubject = eduSubjectService.getOne(wrapper);
        return eduSubject;
    }
}

3.6、小细节，实体类pojo

因为mybatisplus生成的实体类的主键生成策略是IdType.ID_WORKER，所以需要修改成IdType.ID_WORKER_STR，否则会有转换问题


package com.zhz.serviceedu.entity;

import com.baomidou.mybatisplus.annotation.FieldFill;
import com.baomidou.mybatisplus.annotation.IdType;
import java.util.Date;

import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import java.io.Serializable;
import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import lombok.Data;
import lombok.EqualsAndHashCode;
import lombok.experimental.Accessors;


@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;

}

3.7、其余，swagger集成，R类统一返回，统一日志等，请看我其他博客

统一日志：https://blog.csdn.net/zhouhengzhe/article/details/118078080
统一返回值：https://blog.csdn.net/zhouhengzhe/article/details/118065066
统一异常：https://blog.csdn.net/zhouhengzhe/article/details/118064739
swagger集成：https://blog.csdn.net/zhouhengzhe/article/details/118063779

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