java通过Excel批量上传下载数据

一、首先在前端写一个上传组件。

java 复制代码

<template>
  <!-- 文件上传 -->
  <el-upload class="upload-demo" drag action="" :on-change="onChange" :auto-upload="false">
    <el-icon class="el-icon--upload"><upload-filled /></el-icon>
    <div class="el-upload__text">
      Drop file here or <em>click to upload</em>
    </div>
  </el-upload>
</template>
 
<script lang="ts" setup>
import { ref } from "vue";
import { uploadApi } from "@/api/index";
import { ElMessage} from "element-plus";
//定义文件上传的函数
const onChange = (file: any, _uploadFiles: any) => {
  let reader = new FileReader();
  reader.readAsDataURL(file.raw);
  reader.onload = (f) => {
    callUploadApi(file.name, f.target?.result);
  };
};
//文件上传的函数
const callUploadApi = (name: any, base64: any) => {
  uploadApi.uploadExcel.call({ name, base64 }).then((res: any) => {
    ElMessage.success("上传成功");
  });
};
</script>

封装一个Api

请求配置：uploadApi.ts

java 复制代码

 uploadExcel: {
    name: "上传文件",
    url: "/api/uploade/excel",
    call: async function name(params: any) {
      return await http.post(this.url, params);
    },
  },

二、后端代码实现

准备工作：1、一个与你上传数据相对于的实体类；

2、定义一个上传信息对象；

**实体类：**为了方便演示我就定义两个字段，以供参考：

cpp 复制代码

@Data
public class Person {
    private String name;
    private Integer age;
}

上传信息对象：

cpp 复制代码

@Data
public class UploadInfo {
    private String name;
    private String base64;
}

Controller层代码：

cpp 复制代码

/*
 * Copyright (c) 2020, 2024,  All rights reserved.
 *
 */
package com.by.upload;
 
import cn.hutool.core.codec.Base64;
import cn.hutool.core.date.StopWatch;
import cn.hutool.core.util.StrUtil;
import cn.hutool.poi.excel.ExcelReader;
import cn.hutool.poi.excel.ExcelUtil;
import cn.hutool.poi.excel.ExcelWriter;
import com.by.dao.PersonMapper;
import com.by.model.FileInfo;
import com.by.model.Upload;
import com.by.service.UploadService;
import org.apache.ibatis.session.ExecutorType;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
 
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.util.List;
import java.util.stream.Collectors;
 
/**
 * <p>Project: wms-root - Upload</p>
 * <p>Powered by scl On 2024-02-29 19:07:05</p>
 * <p>描述：<p>
 *
 * @author 孙臣龙 [1846080280@qq.com]
 * @version 1.0
 * @since 17
 */
@RestController
@RequestMapping("/api/uploade")
public class UploadExcel {
 
    @Autowired
    private SqlSessionFactory sqlSessionFactory;
    @Autowired
    private PersonMapper personMapper;
    @Autowired
    private UploadService uploadService;
 
 
    /**
     * 导入excle
     * @param uploadInfo
     * @return
     * @throws Exception
     */
    @PostMapping("/excel")
    public String upload(@RequestBody Upload uploadInfo) throws Exception {
        String name = uploadInfo.getName();
        String base64 = uploadInfo.getBase64();
        String[] strArray = StrUtil.splitToArray(base64, "base64,");
        byte[] bytes = Base64.decode(strArray[1]);
 
        //用于创建一个基于字节数组的输入流。它允许你从一个字节数组中读取数据。
        ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(bytes);
        // 使用Hutool读取Excel文件
        ExcelReader reader = ExcelUtil.getReader(byteArrayInputStream);
        //将读取到的 reader 转化为 List<Man>集合
        List<Person> persons = reader.readAll(Person.class);
 
        //StopWatch类是 Hutool 工具库中的类,用于测量代码执行时间
        StopWatch stopWatch = new StopWatch();
        //读取数据的结束时间同时也是写入数据库的开始时间
        stopWatch.start();
 
        //sqlSessionFactory是通过ioc容器注入的  设置其SqlSession的执行器格式ExecutorType.SIMPLE（默认）
        SqlSession sqlSession = sqlSessionFactory.openSession(ExecutorType.BATCH);
        PersonMapper mapper = sqlSession.getMapper(PersonMapper.class);
        //循环将List<Man>中的数据插入数据库 方法一
        //for (Person person : persons) {
        //    PoItemMapper.xml.insert(person);
        //}
        //方法二：
        mapper.insertBatch(persons);
        sqlSession.commit();
        stopWatch.stop();
        sqlSession.close();
        System.out.println("插入数据库最终的结果为：" + stopWatch.getTotalTimeSeconds());
 
        return "ok";
    }
 
    /**
     * 导出Excel
     * @param response
     * @throws IOException
     */
    @GetMapping("/write")
    public void exportExcel(HttpServletResponse response) throws IOException {
        // 创建Excel写入器   参数 true 表示追加数据，即在已有的 Excel 文件上追加新数据。如果设为 false，则会覆盖已有的数据。
        List<Person> person = personMapper.selectAll();
        // 创建ExcelWriter对象
        ExcelWriter writer = ExcelUtil.getWriter(true);
        int i = 0;
        while (true) {
            List<Person> list = person.stream().skip(i * 100000).limit(100000).parallel().collect(Collectors.toList());
            if (list.isEmpty()) {
                break;
            }
            writer.setSheet("person" + i);
            // 写入表头
            writer.addHeaderAlias("id", "Id");
            writer.addHeaderAlias("name", "姓名");
            writer.addHeaderAlias("age", "年龄");
            // 写入当前批次的数据
            writer.write(list, true);
            i++;
        }
        //response为HttpServletResponse对象   设置响应的内容类型为Excel文件
        response.setContentType("application/xlsx;charset=utf-8");
        //test.xls是弹出下载对话框的文件名，不能为中文，中文请自行编码
        //设置响应头，告诉浏览器以附件形式下载文件，文件名为test.xlsx。这样设置可以让浏览器弹出文件下载对话框。
        response.setHeader("Content-Disposition", "attachment;filename="+"test.xlsx");
        //获取响应输出流，它是用于将响应的数据发送给客户端的流。
        ServletOutputStream out = response.getOutputStream();
        //将Excel数据写入输出流。第二个参数为true表示追加写入，即将数据追加到已有的Excel文件中。
        writer.flush(out, true);
        writer.close();
        //关闭输出流
        out.close();
    }
}

dao层代码：

cpp 复制代码

/*
 * Copyright (c) 2020, 2024,  All rights reserved.
 *
 */
package com.by.dao;
 
import com.by.upload.Person;
import org.apache.ibatis.annotations.Mapper;
 
import java.util.List;
 
/**
 * <p>Project: wms-root - PersonMapper</p>
 * <p>Powered by scl On 2024-03-02 10:51:08</p>
 * <p>描述：<p>
 *
 * @author 孙臣龙 [1846080280@qq.com]
 * @version 1.0
 * @since 17
 */
@Mapper
public interface PersonMapper {
    
    void insert(Person person);
 
    void insertBatch(List<Person> persons);
 
    List<Person> selectAll();
 
}

Mapper.xml:

cpp 复制代码

<?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.by.dao.PersonMapper">
    <!--新增数据-->
    <insert id="insert">
        insert into person(name,age)
        values (#{name},#{age})
    </insert>
    <!-- 批量新增数据 -->
    <insert id="insertBatch" >
        insert into person(name,age)
        values
        <foreach collection="persons" item="entity" separator=",">
            (#{entity.name},#{entity.age})
        </foreach>
    </insert>
    <select id="selectAll" resultType="com.by.upload.Person">
        select * from person
    </select>
</mapper>

注意：poi的版本号

cpp 复制代码

<!--poi-->
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>5.0.0</version>
</dependency>

三、文件导出。

前端代码：

cpp 复制代码

<template>
  <a type="success" href="/api/uploade/write" >导出Excle</a>
</template>