SpringBoot整合EasyExcel实现导入导出

1、EasyExcel是什么

EasyExcel是一个基于Java的、快速、简洁、解决大文件内存溢出的Excel处理工具。
他能让你在不用考虑性能、内存的等因素的情况下，快速完成Excel的读、写等功能。

2、相关网站

官网https://easyexcel.opensource.alibaba.com/

GitHubhttps://github.com/alibaba/easyexcel

3、实现导入

pom依赖导入

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>easyexcel</artifactId>
    <version>3.3.2</version>
</dependency>

excel数据

一共包含姓名，手机号，性别，地址，状态，注册时间6列，共50条数据

数据库表结构

实体类User

package com.example.springbootdemo.entity;

import com.baomidou.mybatisplus.annotation.*;
import com.example.springbootdemo.enums.GenderEnum;
import com.fasterxml.jackson.annotation.JsonFormat;
import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateTimeDeserializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateTimeSerializer;
import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import lombok.Data;
import lombok.experimental.Accessors;

import java.io.Serializable;
import java.time.LocalDateTime;

/**
 * <p>
 *  用户实体类
 * </p>
 *
 * @author yurenwei
 * @since 2023/9/7
 */
@ApiModel(value = "用户参数", description = "用户参数")
@Data
@Accessors(chain = true)
@TableName("user")
public class User implements Serializable {

    private static final long serialVersionUID = 1L;

    /**
     * 主键id
     */
    @ApiModelProperty(value = "主键id")
    @TableId(value = "id", type = IdType.ASSIGN_ID)
    private Long id;

    /**
     * 姓名
     */
    @ApiModelProperty(value = "姓名")
    private String userName;

    /**
     * 手机号
     */
    @ApiModelProperty(value = "手机号")
    private String phone;

    /**
     * 性别
     */
    @ApiModelProperty(value = "性别")
    private GenderEnum gender;

    /**
     * 地址
     */
    @ApiModelProperty(value = "地址")
    private String address;

    /**
     * 状态(0、禁用1、启用)
     */
    @ApiModelProperty(value = "状态(0、禁用1、启用)")
    private Boolean status;

    /**
     * 注册时间
     */
    @ApiModelProperty(value = "注册时间")
    @JsonDeserialize(using = LocalDateTimeDeserializer.class)
    @JsonSerialize(using = LocalDateTimeSerializer.class)
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
    private LocalDateTime registerTime;

    /**
     * 创建人
     */
    @ApiModelProperty(value = "创建人")
    private Long createBy;

    /**
     * 创建时间
     */
    @ApiModelProperty(value = "创建时间")
    @JsonDeserialize(using = LocalDateTimeDeserializer.class)
    @JsonSerialize(using = LocalDateTimeSerializer.class)
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
    @TableField(fill = FieldFill.INSERT)
    private LocalDateTime createTime;

    /**
     * 修改人
     */
    @ApiModelProperty(value = "修改人")
    private Long updateBy;

    /**
     * 修改时间
     */
    @ApiModelProperty(value = "修改时间")
    @JsonDeserialize(using = LocalDateTimeDeserializer.class)
    @JsonSerialize(using = LocalDateTimeSerializer.class)
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
    @TableField(fill = FieldFill.INSERT_UPDATE)
    private LocalDateTime updateTime;

    /**
     * 是否删除(0、否1、是)
     */
    @ApiModelProperty(value = "是否删除(0、否1、是)")
    private Boolean isDeleted;
}

controller导入方法

@ApiOperation("导入")
@PostMapping("/importUser")
public Result importUser(@RequestParam(value = "file") MultipartFile file){
    userService.importUser(file);
    return Result.ok();
}

service导入方法

/**
 * 导入excel
 *
 * @param file excel文件
 */
public void importUser(MultipartFile file) {
    try {
        EasyExcel.read(file.getInputStream(), UserExcelDTO.class, new UserExcelListener(iUserService))
                .sheet(0)
                .headRowNumber(1)
                .doRead();
    } catch (IOException e) {
        log.error("导入用户数据异常：{}",e.getMessage());
        e.printStackTrace();
    }
}

excel对应实体类

package com.example.springbootdemo.dto;

import com.alibaba.excel.annotation.ExcelProperty;
import com.alibaba.excel.annotation.format.DateTimeFormat;
import lombok.Data;

import java.io.Serializable;
import java.time.LocalDateTime;

/**
 * <p>
 *  用户excel实体类
 * </p>
 *
 * @author yurenwei
 * @since 2023/9/7
 */
@Data
public class UserExcelDTO implements Serializable {

    private static final long serialVersionUID = 1L;

    /**
     * 姓名
     */
    @ExcelProperty(value = "姓名",index = 0)
    private String userName;

    /**
     * 手机号
     */
    @ExcelProperty(value = "手机号",index = 1)
    private String phone;

    /**
     * 性别
     */
    @ExcelProperty(value = "性别",index = 2)
    private String gender;

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

    /**
     * 状态(0、禁用1、启用)
     */
    @ExcelProperty(value = "状态",index = 4)
    private String status;

    /**
     * 注册时间
     */
    @ExcelProperty(value = "注册时间",index = 5)
    @DateTimeFormat("yyyy-MM-dd HH:mm:ss")
    private LocalDateTime registerTime;

}

此处注意# @Accessors(chain = true)与EasyExcel不兼容，不要增加此注解，要不导入数据为空

创建读取excel监听类

package com.example.springbootdemo.listener;

import cn.hutool.core.util.IdUtil;
import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.read.listener.ReadListener;
import com.alibaba.excel.util.ListUtils;
import com.alibaba.fastjson.JSON;
import com.example.springbootdemo.dto.UserExcelDTO;
import com.example.springbootdemo.entity.User;
import com.example.springbootdemo.enums.GenderEnum;
import com.example.springbootdemo.mybatisplus.IUserService;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.collections4.CollectionUtils;

import java.util.List;
import java.util.stream.Collectors;

/**
 * <p>
 *  用户excel监听类
 * </p>
 *
 * @author yurenwei
 * @since 2023/9/7
 */
@Slf4j
public class UserExcelListener implements ReadListener<UserExcelDTO> {

    /**
     * 每隔10条数据存储数据库，然后清理List,方便内存回收
     *
     */
    private static final int BATCH_COUNT = 10;

    /**
     * 缓存的数据
     */
    private List<UserExcelDTO> cacheList = ListUtils.newArrayListWithExpectedSize(BATCH_COUNT);


    private IUserService iUserService;

    public UserExcelListener(IUserService iUserService){
        this.iUserService = iUserService;
    }

    /**
     * 每一条数据解析都会调用
     *
     * @param user
     * @param analysisContext
     */
    @Override
    public void invoke(UserExcelDTO user, AnalysisContext analysisContext) {
        log.info("解析到一条数据user:{}", JSON.toJSONString(user));
        cacheList.add(user);
        // 达到BATCH_COUNT了，需要去存储一次数据库，防止数据几万条数据在内存，容易OOM
        if(cacheList.size()>=BATCH_COUNT){
            // 保存数据
            saveData();
            // 存储完成清理list
            cacheList = ListUtils.newArrayListWithExpectedSize(BATCH_COUNT);
        }
    }

    /**
     * 所有数据都解析完了才会调用
     *
     * @param analysisContext
     */
    @Override
    public void doAfterAllAnalysed(AnalysisContext analysisContext) {
        // 这里也要保存数据，确保最后遗留的数据也存储到数据库
        saveData();
        log.info("所有数据解析完成！");
    }

    /**
     * 保存数据
     */
    public void saveData(){
        log.info("一共{}条数据，开始存储数据库！",cacheList.size());
        if(CollectionUtils.isNotEmpty(cacheList)){
            List<User> userList = cacheList.stream().map(item -> new User()
                    .setId(IdUtil.getSnowflakeNextId())
                    .setUserName(item.getUserName())
                    .setPhone(item.getPhone())
                    .setGender("男".equals(item.getGender())? GenderEnum.MALE:GenderEnum.FEMALE)
                    .setAddress(item.getAddress())
                    .setRegisterTime(item.getRegisterTime())
                    .setStatus("启用".equals(item.getStatus())))
                    .collect(Collectors.toList());

            // 批量保存
            iUserService.saveBatch(userList);
        }
        log.info("存储数据库成功！");
    }
}

启动项目测试导入

控制台打印信息

查看数据库是否成功导入数据

可见50条都被成功导入到数据库表当中，并且数据都是正确的。

4、接下来实现导出

controller导出方法

@ApiOperation("导出")
@PostMapping("/export")
public void export(HttpServletResponse response){
    userService.export(response);
}

service导出方法

/**
 * 导出
 *
 * @param response 响应
 */
public void export(HttpServletResponse response) {
    // 查询所有用户
    List<User> list = iUserService.list();
    // 转换数据
    List<UserExcelDTO> excelList = list.stream().map(item ->
            {
                UserExcelDTO user = new UserExcelDTO();
                user.setUserName(item.getUserName());
                user.setPhone(item.getPhone());
                user.setGender(GenderEnum.MALE.equals(item.getGender())?"男":"女");
                user.setAddress(item.getAddress());
                user.setStatus(item.getStatus()?"启用":"禁用");
                user.setRegisterTime(item.getRegisterTime());

                return user;
            })
            .collect(Collectors.toList());
    // 调用工具类导出
    ExcelUtil.exportExcel("用户数据","用户",excelList,UserExcelDTO.class,response);
}

导出excel工具类

package com.example.springbootdemo.util;

import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.support.ExcelTypeEnum;
import lombok.extern.slf4j.Slf4j;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.util.List;

/**
 * <p>
 * excel工具类
 * </p>
 *
 * @author yurenwei
 * @since 2023/9/14
 */
@Slf4j
public class ExcelUtil {

    /**
     * 导出excel
     *
     * @param fileName excel文件名称
     * @param sheetName excel sheet名称
     * @param list 数据
     * @param clazz
     * @param response
     */
    public static void exportExcel(String fileName, String sheetName, List list, Class clazz, HttpServletResponse response){
        ServletOutputStream outputStream;
        try {
            response.setContentType("application/vnd.ms-excel");
            response.setCharacterEncoding("utf8");
            response.setHeader("Content-Disposition", "attachment; filename=" + fileName + ".xlsx");
            outputStream = response.getOutputStream();
            EasyExcel.write(outputStream)
                    .head(clazz)
                    .excelType(ExcelTypeEnum.XLSX)
                    .sheet(sheetName)
                    .doWrite(list);
            outputStream.flush();
        } catch (Exception e) {
            log.error("导出excel异常：{}",e.getMessage());
            e.printStackTrace();
        }
    }
}