public function publishAnswer()
 {
     $request = Request::capture();
     $token = $request->input('token');
     $content = $request->input('content');
     $questionId = $request->input('questionId');
     $brief = $request->input('brief');
     $pictures = $request->input('picids');
     if ($content == null) {
         return Utility::response_format(Utility::RESPONSE_CODE_Error, '', '内容不能为空');
     }
     $userId = AuthController::getUserIdByToken($token);
     if ($userId == null) {
         return Utility::response_format(Utility::RESPONSE_CODE_AUTH_ERROR, '', '认证失败');
     }
     DB::beginTransaction();
     try {
         $answer = Answer::create(['answer_content' => $content, 'answer_brief' => $brief, 'user_id' => $userId, 'question_id' => $questionId, 'answer_time' => time()]);
         if ($pictures != null) {
             $picArray = explode(',', $pictures);
             foreach ($picArray as $pic) {
                 AnswerPictures::create(['answer_id' => $answer->id, 'pic_id' => $pic]);
             }
         }
         DB::commit();
         return Utility::response_format(Utility::RESPONSE_CODE_SUCCESS, '', '发布成功');
     } catch (Exception $e) {
         DB::rollBack();
         return Utility::response_format(Utility::RESPONSE_CODE_DB_ERROR, '', $e->getMessage());
     }
 }