摘要：本文使用版本為使用實際調用的是這個映射是如何做的將里的數組里面的類設置別名來自于中數組為一個類創建別名這個文件沒有，只有這里為是容器對象，實現了接口，最終調用的還是容器的方法

本文使用版本為laravel5.5

public function cache()
    {
        $c=Cache::get("app");
        if(!$c) {
            Cache::put("app", "cache", 1);
        }
        dump($c);//cache
    }
    

 "aliases" => [

        "App" => IlluminateSupportFacadesApp::class,
        "Artisan" => IlluminateSupportFacadesArtisan::class,
        "Auth" => IlluminateSupportFacadesAuth::class,
        "Blade" => IlluminateSupportFacadesBlade::class,
        "Broadcast" => IlluminateSupportFacadesBroadcast::class,
        "Bus" => IlluminateSupportFacadesBus::class,
        "Cache" => IlluminateSupportFacadesCache::class,
        
        ]

使用cache實際調用的是IlluminateSupportFacadesCache,這個映射是如何做的？

$response = $kernel->handle(
$request = IlluminateHttpRequest::capture()
);

$app->singleton(
    IlluminateContractsHttpKernel::class,
    AppHttpKernel::class
);

use IlluminateFoundationHttpKernel as HttpKernel;

class Kernel extends HttpKernel
{

}

public function handle($request)
{
    try {
        $request->enableHttpMethodParameterOverride();
        $response = $this->sendRequestThroughRouter($request);
    } catch (Exception $e) {
        $this->reportException($e);

        $response = $this->renderException($request, $e);
    } catch (Throwable $e) {
        $this->reportException($e = new FatalThrowableError($e));

        $response = $this->renderException($request, $e);
    }

    $this->app["events"]->dispatch(
        new EventsRequestHandled($request, $response)
    );

    return $response;
}
protected function sendRequestThroughRouter($request)
    {
        $this->app->instance("request", $request);

        Facade::clearResolvedInstance("request");

        $this->bootstrap();

        return (new Pipeline($this->app))
                    ->send($request)
                    ->through($this->app->shouldSkipMiddleware() ? [] : $this->middleware)
                    ->then($this->dispatchToRouter());
    }
    public function bootstrap()
    {
        if (! $this->app->hasBeenBootstrapped()) {
            $this->app->bootstrapWith($this->bootstrappers());
        }
    }

public function bootstrapWith(array $bootstrappers)
    {
        $this->hasBeenBootstrapped = true;

        foreach ($bootstrappers as $bootstrapper) {
            $this["events"]->fire("bootstrapping: ".$bootstrapper, [$this]);

            $this->make($bootstrapper)->bootstrap($this);

            $this["events"]->fire("bootstrapped: ".$bootstrapper, [$this]);
        }
    }

public function bootstrap(Application $app)
    {
        Facade::clearResolvedInstances();

        Facade::setFacadeApplication($app);
//將config/app.php 里的aliases數組里面的Facades類設置別名
        AliasLoader::getInstance(array_merge(
            $app->make("config")->get("app.aliases", []),
            $app->make(PackageManifest::class)->aliases()
        ))->register();
    }

public function load($alias)
    {
        if (static::$facadeNamespace && strpos($alias, static::$facadeNamespace) === 0) {
            $this->loadFacade($alias);

            return true;
        }

      // $alias來自于config/app.php中aliases數組 
        if (isset($this->aliases[$alias])) {
            //"Route" => IlluminateSupportFacadesRoute::class,
            // class_alias 為一個類創建別名
            return class_alias($this->aliases[$alias], $alias);
        }
    }

class Cache extends Facade
{
    /**
     * Get the registered name of the component.
     *
     * @return string
     */
    protected static function getFacadeAccessor()
    {
        return "cache";
    }
}

這個文件沒有get set ，只有__callStatic

public static function __callStatic($method, $args)
    {
        $instance = static::getFacadeRoot();

        if (! $instance) {
            throw new RuntimeException("A facade root has not been set.");
        }

        return $instance->$method(...$args);
    }
   public static function getFacadeRoot()
    {
        return static::resolveFacadeInstance(static::getFacadeAccessor());
    } 
     protected static function resolveFacadeInstance($name)
    {
    //這里$name為cache
        if (is_object($name)) {
            return $name;
        }

        if (isset(static::$resolvedInstance[$name])) {
            return static::$resolvedInstance[$name];
        }
    //$app是容器對象，實現了ArrayAccess接口，最終調用的還是容器的make方法
        return static::$resolvedInstance[$name] = static::$app[$name];
    }

public function make($abstract, array $parameters = [])
    {
        return $this->resolve($abstract, $parameters);
    }
    protected function resolve($abstract, $parameters = [])
    {
        $abstract = $this->getAlias($abstract);

        $needsContextualBuild = ! empty($parameters) || ! is_null(
            $this->getContextualConcrete($abstract)
        );

        // If an instance of the type is currently being managed as a singleton we"ll
        // just return an existing instance instead of instantiating new instances
        // so the developer can keep using the same objects instance every time.
        if (isset($this->instances[$abstract]) && ! $needsContextualBuild) {
            return $this->instances[$abstract];
        }

        $this->with[] = $parameters;

        $concrete = $this->getConcrete($abstract);

        // We"re ready to instantiate an instance of the concrete type registered for
        // the binding. This will instantiate the types, as well as resolve any of
        // its "nested" dependencies recursively until all have gotten resolved.
        if ($this->isBuildable($concrete, $abstract)) {
            $object = $this->build($concrete);
        } else {
            $object = $this->make($concrete);
        }

        // If we defined any extenders for this type, we"ll need to spin through them
        // and apply them to the object being built. This allows for the extension
        // of services, such as changing configuration or decorating the object.
        foreach ($this->getExtenders($abstract) as $extender) {
            $object = $extender($object, $this);
        }

        // If the requested type is registered as a singleton we"ll want to cache off
        // the instances in "memory" so we can return it later without creating an
        // entirely new instance of an object on each subsequent request for it.
        if ($this->isShared($abstract) && ! $needsContextualBuild) {
            $this->instances[$abstract] = $object;
        }

        $this->fireResolvingCallbacks($abstract, $object);

        // Before returning, we will also set the resolved flag to "true" and pop off
        // the parameter overrides for this build. After those two things are done
        // we will be ready to return back the fully constructed class instance.
        $this->resolved[$abstract] = true;

        array_pop($this->with);

        return $object;
    }

 public function register()
    {
        $this->app->singleton("cache", function ($app) {
            return new CacheManager($app);
        });

        $this->app->singleton("cache.store", function ($app) {
            return $app["cache"]->driver();
        });

        $this->app->singleton("memcached.connector", function () {
            return new MemcachedConnector;
        });
    }

$instance->$method(...$args)