```php
if (move_uploaded_file($_FILES["file"]["tmp_name"], $target_file)) {
echo "The file ". basename( $_FILES["file"]["name"]). " has been uploaded.";
} else {
echo "Sorry, there was an error uploading your file.";
}
?>
```
这段代码接收用户上传的文件,并将其移动到 "uploads/" 目录下。如果文件移动成功,将会输出 "The file [文件名] has been uploaded.",否则将会输出 "Sorry, there was an error uploading your file."。
最后,我们需要初始化 Bootstrap File Input 插件。在 HTML 文件的底部,添加以下 JavaScript 代码。
```html
```
上面的代码使用了 `bsCustomFileInput.init()` 方法来初始化插件。它会自动寻找带有 "form-control-file" class 的文件输入框,并将它们转换成文件上传界面。