PHP中如何处理和操作文件上传的数据类型

// 获取上传文件的信息
$fileName = $_FILES['file']['name'];
$fileType = $_FILES['file']['type'];
$fileSize = $_FILES['file']['size'];
$fileTemp = $_FILES['file']['tmp_name'];

// 验证文件类型
$allowedTypes = ['image/png', 'image/jpeg', 'image/gif'];
if (!in_array($fileType, $allowedTypes)) {
    echo "只允许上传PNG、JPEG和GIF文件";
    exit;
}

// 验证文件大小
$maxSize = 2 * 1024 * 1024; // 2MB
if ($fileSize > $maxSize) {
    echo "文件过大，最大只允许2MB";
    exit;
}

// 验证文件是否上传成功
if (!is_uploaded_file($fileTemp)) {
    echo "文件上传失败";
    exit;
}

// 设置目标存储位置
$targetDirectory = "uploads/";
$targetFile = $targetDirectory . $fileName;

// 将文件保存到目标位置
if (move_uploaded_file($fileTemp, $targetFile)) {
    echo "文件上传成功";
} else {
    echo "文件保存失败";
}

// 文件重命名
$newFileName = "new_file_name.jpg";
if (rename($targetFile, $targetDirectory . $newFileName)) {
    echo "文件重命名成功";
} else {
    echo "文件重命名失败";
}

// 文件裁剪
$width = 200;
$height = 200;
$newFile = "cropped_image.jpg";
$image = imagecreatefromjpeg($targetFile);
$croppedImage = imagecrop($image, ['x' => 0, 'y' => 0, 'width' => $width, 'height' => $height]);
if ($croppedImage !== false && imagejpeg($croppedImage, $targetDirectory . $newFile)) {
    echo "文件裁剪成功";
} else {
    echo "文件裁剪失败";
    imagedestroy($image);
}

// 图片加水印
$watermark = imagecreatefrompng("watermark.png");
$transparent = imagecolorallocatealpha($watermark, 0, 0, 0, 0);
imagefill($watermark, 0, 0, $transparent);
imagecolortransparent($watermark, $transparent);
imagettftext($watermark, 36, 0, 10, 40, imagecolorallocate($watermark, 255, 255, 255), "font.ttf", "Watermark");
imagecopymerge($image, $watermark, 0, 0, 0, 0, imagesx($watermark), imagesy($watermark), 50);
imagejpeg($image, $targetDirectory . "watermarked_image.jpg");
imagedestroy($image);
imagedestroy($watermark);