html + layui+ php layui表格导入和导出excel php后端如何编写代码

实现 layui 表格导入和导出 Excel 的后端代码可以参考以下示例：

导出 Excel：

<?php
//连接数据库
$conn = mysqli_connect("localhost","root","","test");

//查询数据
$sql = "SELECT * FROM users";
$result = mysqli_query($conn, $sql);

//引入PHPExcel库
require_once './PHPExcel/PHPExcel.php';

//创建PHPExcel对象
$objPHPExcel = new PHPExcel();

//设置表头
$objPHPExcel->setActiveSheetIndex(0)->setCellValue('A1', 'ID');
$objPHPExcel->setActiveSheetIndex(0)->setCellValue('B1', '姓名');
$objPHPExcel->setActiveSheetIndex(0)->setCellValue('C1', '年龄');
$objPHPExcel->setActiveSheetIndex(0)->setCellValue('D1', '性别');

//循环输出数据
$i = 2;
while ($row = mysqli_fetch_array($result)) {
    $objPHPExcel->setActiveSheetIndex(0)->setCellValue('A' . $i, $row['id']);
    $objPHPExcel->setActiveSheetIndex(0)->setCellValue('B' . $i, $row['name']);
    $objPHPExcel->setActiveSheetIndex(0)->setCellValue('C' . $i, $row['age']);
    $objPHPExcel->setActiveSheetIndex(0)->setCellValue('D' . $i, $row['sex']);
    $i++;
}

//设置文件名和下载方式
$filename = '用户信息.xlsx';
header('Content-Type: application/vnd.ms-excel');
header('Content-Disposition: attachment;filename="' . $filename . '"');
header('Cache-Control: max-age=0');

//输出Excel文件
$objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'Excel2007');
$objWriter->save('php://output');

//关闭连接
mysqli_close($conn);
?>

导入 Excel：

<?php
//连接数据库
$conn = mysqli_connect("localhost","root","","test");

//引入PHPExcel库
require_once './PHPExcel/PHPExcel.php';

//获取上传的Excel文件
$file = $_FILES['file']['tmp_name'];

//创建PHPExcel对象
$objReader = PHPExcel_IOFactory::createReader('Excel2007');
$objPHPExcel = $objReader->load($file);

//获取当前工作表
$sheet = $objPHPExcel->getSheet(0);

//获取最大行数和列数
$highestRow = $sheet->getHighestRow();
$highestColumn = $sheet->getHighestColumn();

//循环读取数据
for ($i = 2; $i <= $highestRow; $i++) {
    $rowData = $sheet->rangeToArray('A' . $i . ':' . $highestColumn . $i, NULL, TRUE, FALSE);

    //插入数据到数据库
    $sql = "INSERT INTO users (name, age, sex) VALUES (
            '" . $rowData[0][1] . "',
            '" . $rowData[0][2] . "',
            '" . $rowData[0][3] . "'
            )";
    mysqli_query($conn, $sql);
}

//关闭连接
mysqli_close($conn);

//跳转到列表页面
header("Location: list.php");
?>

注意：上述代码中，需根据实际情况修改数据库连接信息、Excel 文件路径和表格列名等。