public function send()
 {
     $name = isset($_POST['name']) ? trim($_POST['name']) : '';
     $email = isset($_POST['email']) ? trim($_POST['email']) : '';
     $content = isset($_POST['content']) ? trim($_POST['content']) : '';
     // 过滤
     $name = htmlspecialchars($name, ENT_QUOTES);
     $email = htmlspecialchars($email, ENT_QUOTES);
     $content = htmlspecialchars($content, ENT_QUOTES);
     if (empty($name) || empty($email) || empty($content)) {
         $this->error('index.php?c=public&a=message', '留言失败,不允许出现空内容...');
     }
     $message = new MessageModel();
     if ($message->insertMessage($name, $email, $content)) {
         $this->success('index.php?c=public&a=message', '留言成功!');
     } else {
         $this->error('index.php?c=public&a=message', '留言失败...');
     }
 }