[英]Call to a parent class member from child without calling constructor dependencies
我有我的基本控制器和我的内容控制器像下面一样扩展它,我Call to a member function error() on null
收到Call to a member function error() on null
的Call to a member function error() on null
所以我的问题是:
我必须调用父构造函数吗?
如果“是”,那么最好提供服务,因为父控制器有一些注入的依赖项,我不想通过调用父构造函数来注入自己
use Psr\Log\LoggerInterface;
class BaseController extends AbstractController
{
/** @var LoggerInterface */
protected $logger;
/**
* BaseController constructor.
*/
public function __construct(LoggerInterface $logger)
{
$this->logger = $logger;
}
}
class ContentController extends BaseController
{
private $contentRepository;
private $breadcrumbService;
public function __construct(
ContentRepository $contentRepository,
BreadcrumbInterface $breadcrumbService
) {
$this->contentRepository = $contentRepository;
$this->breadcrumbService = $breadcrumbService;
}
public function contentPage(...)
{
try {
....
} catch (\Throwable $exception) {
$this->logger->error(...);
throw $exception;
}
}
您不需要调用构造函数。 但是如果你想使用它,你确实需要设置$logger
属性。
class ContentController extends BaseController
{
private $contentRepository;
private $breadcrumbService;
public function __construct(
LoggerInterface $logger,
ContentRepository $contentRepository,
BreadcrumbInterface $breadcrumbService
) {
$this->contentRepository = $contentRepository;
$this->breadcrumbService = $breadcrumbService;
$this->logger = $logger;
}
}
有了上面的内容,您不再需要调用parent::__construct()
。 但这只是一种很好的做法,无痛无害:
做就是了:
public function __construct(
LoggerInterface $logger,
ContentRepository $contentRepository,
BreadcrumbInterface $breadcrumbService
) {
$this->contentRepository = $contentRepository;
$this->breadcrumbService = $breadcrumbService;
parent::__construct($logger);
}
但是如果BaseController
的唯一目的是提供一些日志记录方法,那么在ContentController
简单地注入记录器服务并直接使用它可能会更好。
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