SpringBoot项目中集成EasyExcel实现Excel文件上传至MySQL

一、背景

最近项目中遇到了这样的需求，要实现从前端导入Excel文件至MySQL数据库。开始我的第一想法就是用 POI，毕竟我之前有用过 POI 来实现这样类似的功能。不同的是 POI 是导入前端传来的 JSON 数据，而这次的需求直接传个 Excel 文件，还想着怎么把 Excel 里的数据怎么解析出来呢？这时无意间发现了 alibaba 开源的 EasyExcel。哈哈哈，来的早不如来得巧。想着之前用 POI 解析的感觉好麻烦，所以就开始整 EasyExcel 了。

对 POI 感兴趣的可以看我这一篇博文：post请求实现excel导出下载功能

阿里是这样对 EasyExcel 定义的：

Java解析、生成Excel比较有名的框架有Apache poi、jxl。但他们都存在一个严重的问题就是非常的耗内存，poi有一套SAX模式的API可以一定程度的解决一些内存溢出的问题，但POI还是有一些缺陷，比如07版Excel解压缩以及解压后存储都是在内存中完成的，内存消耗依然很大。easyexcel重写了poi对07版Excel的解析，能够原本一个3M的excel用POI sax依然需要100M左右内存降低到几M，并且再大的excel不会出现内存溢出，03版依赖POI的sax模式。在上层做了模型转换的封装，让使用者更加简单方便。

好了，了解了 EasyExcel 相对于 POI 有这么多好处了，那我们也废话不多说，下面直接开搞了。

二、集成 EasyExcel

1、pom.xml 加上 easyexcel 的依赖

<!--alibaba easyexcel-->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>easyexcel</artifactId>
    <version>2.1.3</version>
</dependency>

2、Controller 类

package com.riemann.springbootdemo.controller;

import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.ExcelReader;
import com.alibaba.excel.read.metadata.ReadSheet;
import com.riemann.springbootdemo.listener.UploadEasyExcelListener;
import com.riemann.springbootdemo.model.ReturnT;
import com.riemann.springbootdemo.model.UploadEasyExcelData;
import com.riemann.springbootdemo.service.UploadEasyExcelService;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiImplicitParam;
import io.swagger.annotations.ApiOperation;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;

/**
 * @author riemann
 * @date 2019/12/19 22:10
 */
@RestController
public class UploadEasyExcelController {

    private static final Logger LOGGER = LoggerFactory.getLogger(UploadEasyExcelController.class);

    @Autowired
    private UploadEasyExcelService ueeService;

    @PostMapping(value = "/uploadEasyExcel",produces = "application/json;charset=UTF-8")
    public ResponseEntity<ReturnT<String>> UploadEasyExcel(@RequestParam(value = "serviceFile") MultipartFile serviceFile) {
        if (serviceFile == null) {
            return new ResponseEntity<>(new ReturnT<>(ReturnT.BAD_REQUEST, "Params can not be null"), HttpStatus.BAD_REQUEST);
        }
        ExcelReader excelReader = null;
        InputStream in = null;
        try {
            in = serviceFile.getInputStream();
            excelReader = EasyExcel.read(in, UploadEasyExcelData.class,
                    new UploadEasyExcelListener(ueeService)).build();
            ReadSheet readSheet = EasyExcel.readSheet(0).build();
            excelReader.read(readSheet);
        } catch (IOException ex) {
            LOGGER.error("import excel to db fail", ex);
        } finally {
            close(in);
            // 这里一定别忘记关闭，读的时候会创建临时文件，到时磁盘会崩
            if (excelReader != null) {
                excelReader.finish();
            }
        }
        return new ResponseEntity<>(new ReturnT<>("upload easyexcel success"), HttpStatus.OK);
    }

    private void close(Closeable closeable) {
        if (closeable != null) {
            try {
                closeable.close();
            } catch (IOException e) {
                LOGGER.error("Close io stream error", e);
            }
        }
    }
}

(@RequestParam(value = "serviceFile") MultipartFile serviceFile)

这里上传 Excel 文件用的是 MultipartFile

3、实体类 UploadEasyExcelData

package com.riemann.springbootdemo.model;

import com.alibaba.excel.annotation.ExcelProperty;
import lombok.Data;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;

/**
 * @author riemann
 * @date 2019/12/19 23:08
 */
@NoArgsConstructor
@Data
@Getter
@Setter
public class UploadEasyExcelData {

    @ExcelProperty(value = "name", index = 0)
    private String name;

    @ExcelProperty(value = "sex", index = 1)
    private String sex;

    @ExcelProperty(value = "age", index = 2)
    private Integer age;

    @ExcelProperty(value = "address", index = 3)
    private String address;

    @ExcelProperty(value = "phone", index = 4)
    private String phone;

}

这里的实体类是是与上传的 Excel 的信息相对应，这里也用了 lombok，lombok能通过注解的方式，在编译时自动为属性生成构造器、getter/setter、equals、hashcode、toString方法。出现的神奇就是在源码中没有getter和setter方法，但是在编译生成的字节码文件中有getter和setter方法。这样就省去了手动重建这些代码的麻烦，使代码看起来更简洁些。

这是它的 maven 依赖

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <optional>true</optional>
</dependency>

4、监听类 UploadEasyExcelListener

EasyExcel.read(in, UploadEasyExcelData.class,
                    new UploadEasyExcelListener(ueeService)).build();

注意，EasyExcel这里的 read函数，除了传流、实体类还有监听类。

package com.riemann.springbootdemo.listener;

import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.event.AnalysisEventListener;
import com.riemann.springbootdemo.model.UploadEasyExcelData;
import com.riemann.springbootdemo.service.UploadEasyExcelService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;

import java.util.ArrayList;
import java.util.List;

/**
 * 上传Excel的监听类
 * @author riemann
 * @date 2019/12/19 23:26
 */
public class UploadEasyExcelListener extends AnalysisEventListener<UploadEasyExcelData> {

    private static final Logger LOGGER = LoggerFactory.getLogger(UploadEasyExcelListener.class);

    // 每隔1000条存储数据库，然后清理list，方便内存回收
    private static final int BATCH_COUNT = 1000;

    // 存储解析excel条数
    private int count = 0;

    @Autowired
    private UploadEasyExcelService ueeService;

    List<UploadEasyExcelData> ueeDatas = new ArrayList<>();

    public UploadEasyExcelListener(UploadEasyExcelService ueeService) {
        super();
        this.ueeService = ueeService;
    }

    @Override
    public void invoke(UploadEasyExcelData ueeData, AnalysisContext analysisContext) {
        if (LOGGER.isDebugEnabled()) {
            LOGGER.debug("One record was Parsed, uploadEasyExcelData:{}", ueeData);
        }
        count += 1;
        ueeDatas.add(ueeData);
        if (ueeDatas.size() >= BATCH_COUNT) {
            ueeService.saveEasyExcelMappingData(ueeDatas);
            ueeDatas.clear();
        }
    }

    @Override
    public void doAfterAllAnalysed(AnalysisContext analysisContext) {
        ueeService.saveEasyExcelMappingData(ueeDatas);
        LOGGER.info("all excel data parsed, count:{}", count);
    }
}

5、接口、实现类、Dao层

比较简单我就直接放了

UploadEasyExcelService.java

package com.riemann.springbootdemo.service;

import com.riemann.springbootdemo.model.UploadEasyExcelData;

import java.util.List;

/**
 * @author riemann
 * @date 2019/12/19 23:31
 */
public interface UploadEasyExcelService {

    /**
     * 通过easy excel上传excel数据至mysql
     * @param ueeDatas
     */
    void saveEasyExcelMappingData(List<UploadEasyExcelData> ueeDatas);

}

UploadEasyExcelServiceImpl.java

package com.riemann.springbootdemo.service.impl;

import com.riemann.springbootdemo.dao.EasyExcelDao;
import com.riemann.springbootdemo.model.UploadEasyExcelData;
import com.riemann.springbootdemo.service.UploadEasyExcelService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

/**
 * @author riemann
 * @date 2019/12/19 23:40
 */
@Service
public class UploadEasyExcelServiceImpl implements UploadEasyExcelService {

    @Autowired
    private EasyExcelDao easyExcelDao;

    @Override
    public void saveEasyExcelMappingData(List<UploadEasyExcelData> ueeDatas) {
        easyExcelDao.saveEasyExcelMappingData(ueeDatas);
    }
}

EasyExcelDao.java

package com.riemann.springbootdemo.dao;

import com.riemann.springbootdemo.model.UploadEasyExcelData;
import org.apache.ibatis.annotations.Param;

import java.util.List;

/**
 * @author riemann
 * @date 2019/12/19 23:42
 */
public interface EasyExcelDao {

    void saveEasyExcelMappingData(@Param("ueeDatas") List<UploadEasyExcelData> ueeDatas);

}

6、EasyExcelMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.riemann.springbootdemo.dao.EasyExcelDao" >
    <sql id="BASE_TABLE">
      easy_excel_data
    </sql>

    <sql id="BASE_COLUMN">
      name,sex,age,address,phone
    </sql>

    <insert id="saveEasyExcelMappingData" parameterType="com.riemann.springbootdemo.model.UploadEasyExcelData">
        <selectKey keyProperty="pid" resultType="long">
            select LAST_INSERT_ID()
        </selectKey>
        INSERT INTO
        <include refid="BASE_TABLE"/>
        (
            name,sex,age,address,phone
        )
        VALUES
        <foreach collection="ueeDatas" item="ueeDatas" separator=",">
        (
            #{ueeDatas.name, jdbcType=VARCHAR},
            #{ueeDatas.sex, jdbcType=INTEGER},
            #{ueeDatas.age, jdbcType=VARCHAR},
            #{ueeDatas.address, jdbcType=INTEGER},
            #{ueeDatas.phone, jdbcType=VARCHAR}
        )
        </foreach>

    </insert>

</mapper>

这里的数据是我为了演示这个功能测试的，做的需求比这个复杂很多。

7、数据库与 Excel

8、postman 请求测试

选好了 Excel 文件后，直接请求。

postman 这里请求成功了

我们再去 MySQL 数据库看看

数据库也成功导入了，这样我们就成功集成EasyExcel实现了Excel文件导入至MySQL。