/**
  * 文件下载
  */
 public function downloadAction()
 {
     try {
         $this->file->download($this->_getParam('id'));
     } catch (Exception $e) {
         $this->view->feedback(array('title' => '发生错误', 'message' => '指定的文件不存在或者已经被删除', 'linktext' => '点击继续'));
     }
     $this->isload = false;
 }