问题1：只修改了商品评分，没有修改商品评论数

问题2：执行队列处理器之后执行成功过一次，成功之后这个监听器一直自动触发。与问题 https://learnku.com/laravel/t/22110 相同。

仔细对照过代码，完全一样的。
这是监听器的代码

错误日志：

[2019-04-26 10:44:23] local.ERROR: Call to a member function items() on null {"exception":"[object] (Symfony\Component\Debug\Exception\FatalThrowableError(code: 0): Call to a member function items() on null at /home/vagrant/code/Laravel/app/Listeners/UpdateProductRating.php:16)\
[stacktrace]\

0 [internal function]: App\Listeners\UpdateProductRating->handle(Object(App\Events\OrderReviewed))\

1 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Events/CallQueuedListener.php(86): call_user_func_array(Array, Array)\

2 [internal function]: Illuminate\Events\CallQueuedListener->handle(Object(Illuminate\Foundation\Application))\

3 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(29): call_user_func_array(Array, Array)\

4 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(87): Illuminate\Container\BoundMethod::Illuminate\Container\{closure}()\

5 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(31): Illuminate\Container\BoundMethod::callBoundMethod(Object(Illuminate\Foundation\Application), Array, Object(Closure))\

6 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Container/Container.php(572): Illuminate\Container\BoundMethod::call(Object(Illuminate\Foundation\Application), Array, Array, NULL)\

7 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Bus/Dispatcher.php(94): Illuminate\Container\Container->call(Array)\

8 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(128): Illuminate\Bus\Dispatcher->Illuminate\Bus\{closure}(Object(Illuminate\Events\CallQueuedListener))\

9 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(104): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Events\CallQueuedListener))\

10 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Bus/Dispatcher.php(98): Illuminate\Pipeline\Pipeline->then(Object(Closure))\

11 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Queue/CallQueuedHandler.php(49): Illuminate\Bus\Dispatcher->dispatchNow(Object(Illuminate\Events\CallQueuedListener), false)\

12 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Queue/Jobs/Job.php(83): Illuminate\Queue\CallQueuedHandler->call(Object(Illuminate\Queue\Jobs\RedisJob), Array)\

13 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Queue/Worker.php(327): Illuminate\Queue\Jobs\Job->fire()\

14 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Queue/Worker.php(277): Illuminate\Queue\Worker->process('redis', Object(Illuminate\Queue\Jobs\RedisJob), Object(Illuminate\Queue\WorkerOptions))\

15 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Queue/Worker.php(118): Illuminate\Queue\Worker->runJob(Object(Illuminate\Queue\Jobs\RedisJob), 'redis', Object(Illuminate\Queue\WorkerOptions))\

16 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Queue/Console/WorkCommand.php(102): Illuminate\Queue\Worker->daemon('redis', 'default', Object(Illuminate\Queue\WorkerOptions))\

17 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Queue/Console/WorkCommand.php(86): Illuminate\Queue\Console\WorkCommand->runWorker('redis', 'default')\

18 [internal function]: Illuminate\Queue\Console\WorkCommand->handle()\

19 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(29): call_user_func_array(Array, Array)\

20 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(87): Illuminate\Container\BoundMethod::Illuminate\Container\{closure}()\

21 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(31): Illuminate\Container\BoundMethod::callBoundMethod(Object(Illuminate\Foundation\Application), Array, Object(Closure))\

22 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Container/Container.php(572): Illuminate\Container\BoundMethod::call(Object(Illuminate\Foundation\Application), Array, Array, NULL)\

23 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Console/Command.php(183): Illuminate\Container\Container->call(Array)\

24 /home/vagrant/code/Laravel/vendor/symfony/console/Command/Command.php(255): Illuminate\Console\Command->execute(Object(Symfony\Component\Console\Input\ArgvInput), Object(Illuminate\Console\OutputStyle))\

25 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Console/Command.php(170): Symfony\Component\Console\Command\Command->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Illuminate\Console\OutputStyle))\

26 /home/vagrant/code/Laravel/vendor/symfony/console/Application.php(908): Illuminate\Console\Command->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))\

27 /home/vagrant/code/Laravel/vendor/symfony/console/Application.php(269): Symfony\Component\Console\Application->doRunCommand(Object(Illuminate\Queue\Console\WorkCommand), Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))\

28 /home/vagrant/code/Laravel/vendor/symfony/console/Application.php(145): Symfony\Component\Console\Application->doRun(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))\

29 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Console/Application.php(89): Symfony\Component\Console\Application->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))\

30 /home/vagrant/code/Laravel/vendor/laravel/framework/src/Illuminate/Foundation/Console/Kernel.php(122): Illuminate\Console\Application->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))\

31 /home/vagrant/code/Laravel/artisan(37): Illuminate\Foundation\Console\Kernel->handle(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))\

32 {main}\

"}

谢谢解答