(5) The upload function that comes with yii is very easy to use.

    /*
     * 下载
     */
    public function actionDownload($id){
        if ( isset($_GET['id']) ) {
            $model = new Model();//你的model
            $result = $model->find(array(
                'select' => array('字段1', '字段2'),
                'condition' => 'id=:id',//条件
                'params'    => array(':id' => $id)
                ));
            if (!$result) {
                throw new CHttpException(404, '文件不存在！');
            }
            else {
                // 服务器端文件的路径 
                $fontArr  = explode('/', $result->url);
                $fileName = end($fontArr); //得到文件名字
                if (file_exists($result->url)){ 
                    //发送两个参数一个是名称上面已经处理好，也可以改成你要的，后面是文件路径
                    yii::app ()->request->sendFile ($fileName,  file_get_contents ($result->url));
                } 
            }
        }
    }

    如果你不需要查数据库的话直接做参数传递就好了
    yii::app ()->request->sendFile (文件名,  file_get_contents (文件路径));

The above has introduced (5) Yii’s built-in upload function is very easy to use, including various aspects. I hope it will be helpful to friends who are interested in PHP tutorials.