PHP文件上传封装

class FileUploader {
    private $targetDirectory;
    private $allowedExtensions;
    private $maxFileSize;

    public function __construct($targetDirectory, $allowedExtensions = array(), $maxFileSize = 1048576) {
        $this->targetDirectory = $targetDirectory;
        $this->allowedExtensions = $allowedExtensions;
        $this->maxFileSize = $maxFileSize;
    }

    public function upload($fileInputName) {
        if (!isset($_FILES[$fileInputName])) {
            throw new Exception('File input not found.');
        }

        $file = $_FILES[$fileInputName];
        $filename = $file['name'];
        $fileTmpPath = $file['tmp_name'];
        $fileSize = $file['size'];
        $fileError = $file['error'];

        // Validate file error
        if ($fileError !== UPLOAD_ERR_OK) {
            throw new Exception('File upload error: ' . $this->getFileErrorMessage($fileError));
        }

        // Validate file size
        if ($fileSize > $this->maxFileSize) {
            throw new Exception('File size exceeds the maximum limit.');
        }

        // Validate file extension
        $fileExtension = strtolower(pathinfo($filename, PATHINFO_EXTENSION));
        if (!empty($this->allowedExtensions) && !in_array($fileExtension, $this->allowedExtensions)) {
            throw new Exception('Invalid file extension.');
        }

        // Generate unique filename
        $newFilename = uniqid() . '.' . $fileExtension;
        $destinationPath = $this->targetDirectory . '/' . $newFilename;

        // Move uploaded file to destination
        if (!move_uploaded_file($fileTmpPath, $destinationPath)) {
            throw new Exception('Failed to move uploaded file.');
        }

        return $newFilename;
    }

    private function getFileErrorMessage($errorCode) {
        switch ($errorCode) {
            case UPLOAD_ERR_INI_SIZE:
                return 'The uploaded file exceeds the upload_max_filesize directive in php.ini.';
            case UPLOAD_ERR_FORM_SIZE:
                return 'The uploaded file exceeds the MAX_FILE_SIZE directive that was specified in the HTML form.';
            case UPLOAD_ERR_PARTIAL:
                return 'The uploaded file was only partially uploaded.';
            case UPLOAD_ERR_NO_FILE:
                return 'No file was uploaded.';
            case UPLOAD_ERR_NO_TMP_DIR:
                return 'Missing a temporary folder.';
            case UPLOAD_ERR_CANT_WRITE:
                return 'Failed to write file to disk.';
            case UPLOAD_ERR_EXTENSION:
                return 'A PHP extension stopped the file upload.';
            default:
                return 'Unknown error occurred.';
        }
    }
}

使用示例：

$targetDirectory = '/path/to/uploads';
$allowedExtensions = array('jpg', 'png', 'gif');
$maxFileSize = 1048576; // 1MB

$fileUploader = new FileUploader($targetDirectory, $allowedExtensions, $maxFileSize);

try {
    $uploadedFilename = $fileUploader->upload('file_input_name');
    echo 'File uploaded successfully. Filename: ' . $uploadedFilename;
} catch (Exception $e) {
    echo 'Error: ' . $e->getMessage();
}

在上述示例中，FileUploader 类封装了文件上传的功能。你可以通过在实例化 FileUploader 类时指定目标目录、允许的文件扩展名和最大文件大小来进行配置。然后，调用 `upload