使用SpringBoot+EasyExcel+Vue实现excel表格的导入和导出详解

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>easyexcel</artifactId>
            <version>2.2.0-beta2</version>
        </dependency>

    @GetMapping("/down")
    public Result down(HttpServletResponse response) throws IOException {
        List<User> userList = userMapper.selectList(null);
        System.out.println(userList);
        //返回输出流_excel格式
        response.setContentType("application/octet-stream");
        String fileName = URLEncoder.encode("用户信息表", "UTF-8").replaceAll("\\+", "%20");
        response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + fileName + ".xlsx");
        EasyExcel.write(response.getOutputStream(), User.class).autoCloseStream(Boolean.FALSE).sheet("用户信息表").doWrite(userList);
        // ExcelUtil.writerExcel(response, userList);
        return Result.success();
    }

package com.kang.domain;
import com.alibaba.excel.annotation.ExcelProperty;
import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.Data;
import lombok.EqualsAndHashCode;
import lombok.NoArgsConstructor;
@Data
@TableName("user")
@NoArgsConstructor
@EqualsAndHashCode
public class User {
    /**
     * id自增
     */
    @TableId(type = IdType.AUTO)
    @ExcelProperty(value = "ID", index = 0)
    private Integer id;
    @ExcelProperty(value = "用户名", index = 1)
    private String username;
    @ExcelProperty(value = "密码", index = 2)
    private String password;
    /**
     * 数据库中的nick_name会自动转换为驼峰
     */
    @ExcelProperty(value = "昵称", index = 3)
    private String nickName;
    @ExcelProperty(value = "年龄", index = 4)
    private Integer age;
    @ExcelProperty(value = "性别", index = 5)
    private String sex;
    @ExcelProperty(value = "住址", index = 6)
    private String address;
}

download(){
      window.location.href='http://localhost:9090/excel/down';
      this.$message.success("导出成功");
    },

      <el-upload
          class="upload-demo"
          multiple=""
          method="post"
          action="api/excel/updown"
          style="margin-left: 10px"
          accept=".xlsx,.xls"
          :show-file-list="false"
          :on-success="success"
          name="files"
      >
        <el-button type="primary">导入</el-button>
      </el-upload>

    @PostMapping("/updown")
    public Result  upload(@RequestParam("files") MultipartFile file) throws IOException {
        EasyExcel.read(file.getInputStream(), User.class, new DataListener(userMapper)).sheet().doRead();
        return Result.success();
    }

public class DataListener extends AnalysisEventListener<User> {
    /**
     * 每隔5条存储数据库，实际使用中可以100条，然后清理list ，方便内存回收
     */
    private static final int BATCH_COUNT = 100;
    private UserMapper userMapper;
    public DataListener(UserMapper userMapper){
        this.userMapper = userMapper;
    }
    List<User> list = new ArrayList<User>();
    //读取数据会执行这方法
    @Override
    public void invoke(User user, AnalysisContext analysisContext) {
        System.out.println(JSON.toJSONString(user));
        list.add(user);
        System.out.println(list);
        if (list.size() >= BATCH_COUNT){
            list.clear();
        }
    }
    @Override
    public void doAfterAllAnalysed(AnalysisContext analysisContext) {
        saveData();
        System.out.println("所有数据解析完成");
    }
    private void saveData(){
        System.out.println(this.userMapper);
        System.out.println("{" + list.size() + "}条数据，开始存储数据库" );
        for (User user : list) {
            userMapper.insert(user);
        }
        System.out.println("存储数据库成功");
    }
}