话不多说，直接上代码

依赖文档

找到pom文件，如下图所示

引入需要的依赖

<!--		hutool-->
		<dependency>
			<groupId>cn.hutool</groupId>
			<artifactId>hutool-all</artifactId>
			<version>5.7.20</version>
		</dependency>
		<dependency>
			<groupId>org.apache.poi</groupId>
			<artifactId>poi-ooxml</artifactId>
			<version>4.1.2</version>
		</dependency>

导出写法：

@GetMapping("/export")
    public void export(HttpServletResponse response) throws Exception {
        // 从数据库查询出所有的数据
        List<User> list = userService.list();

        // 左内存操作，写出到浏览器
        ExcelWriter writer = ExcelUtil.getWriter(true);
        // 自定义标题别名
        writer.addHeaderAlias("username", "用户名");
        writer.addHeaderAlias("password", "密码");
        writer.addHeaderAlias("nickname", "昵称");
        writer.addHeaderAlias("email", "邮箱");
        writer.addHeaderAlias("phone", "电话");
        writer.addHeaderAlias("address", "地址");
        writer.addHeaderAlias("createTime", "创建时间");
        // 一次性写出list内的对象到Excel，使用默认样式，强制输出标题
        writer.write(list, true);

        // 设置浏览器响应的格式
        response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;charset=utf-8");
        String fileName = URLEncoder.encode("用户信息", "UTF-8");
        response.setHeader("Content-Disposition", "attachment;filename=" + fileName + ".xlsx");

        ServletOutputStream out = response.getOutputStream();
        writer.flush(out, true);
        out.close();
        writer.close();
    }

导入写法：

//    export 导入
    @PostMapping("/import")
    public Result imp(MultipartFile file) throws Exception {
        InputStream inputStream = file.getInputStream();
        ExcelReader reader = ExcelUtil.getReader(inputStream);
        reader.addHeaderAlias("用户名", "username");
        reader.addHeaderAlias("密码", "password");
        reader.addHeaderAlias("昵称", "nickname");
        reader.addHeaderAlias("邮箱", "email");
        reader.addHeaderAlias("电话", "phone");
        reader.addHeaderAlias("地址", "address");
        List<User> list = reader.readAll(User.class);
        return Result.success(userService.saveBatch(list), "'返回成功'");
    }

已上就是导入导出