yii框架如何实现文件上传

<input type="file" class="file" style="display: none" name="business_license" />

var business_license = $('.file').get(0).files[0];
var data = new FormData();
data.append('business_license',business_license);
$.ajax({
        url:url,
        data:data,
        type:'POST',
        dataType:'json',
        processData: false,
        contentType: false,
        success:function(response){

        },
        error:function(response){
            // console.log(response);

        }

$model = new Model();//实例化数据库模型
$model->business_license = UploadedFile::getInstance($model, 'business_license')；
$model->business_license->saveAs($model->business_license->baseName . '.' . $model->business_license->extension);