如果它是用户定义的文件夹，很有可能您必须动态创建目录，UploadedFile 方法不行.对于 Yii2，我将使用yii\helpers\BaseFileHelper"类中的 createDirectory() 方法.例如:

If its a user defined folder, chances are pretty good you will have to create the directory on the fly, which the UploadedFile method does not do. For Yii2 I would use the createDirectory() method in the "yii\helpers\BaseFileHelper" class. ex:

use yii\web\UploadedFile;
use yii\helpers\BaseFileHelper;

$model->uploaded_file = UploadedFile::getInstance($model, 'uploaded_file');

$unique_name = uniqid('file_');
$model->file_type = $model->uploaded_file->extension;
$model->file_name = $unique_name.'.'.$model->file_type;
$model->file_path = 'uploads/projects/'. $project_id;

BaseFileHelper::createDirectory($model->file_path);

$model->uploaded_file->saveAs($model->file_path .'/'. $model->file_name);
$model->save();

查看createDirectory