之前我们梳理了Laravel控制反转和依赖注入的概念，这篇我们结合Laravel框架，看看它是如何实现的。
1, 入口文件
<?php
/**
* Laravel - A PHP Framework For Web Artisans
*
* @package Laravel
* @author Taylor Otwell <taylor@laravel.com>
*/
define('LARAVEL_START', microtime(true));1.1 注册自动加载器，也就是 Laravel的自动加载机制，可参看 Laravel Composer自动加载机制
/*
|--------------------------------------------------------------------------
| Register The Auto Loader
|--------------------------------------------------------------------------
|
| Composer provides a convenient, automatically generated class loader for
| our application. We just need to utilize it! We'll simply require it
| into the script here so that we don't have to worry about manual
| loading any of our classes later on. It feels great to relax.
|
*/
require __DIR__.'/../vendor/autoload.php';1.2 把灯打开。将框架运行起来，并让它就绪，这样它就可以加载应用，跑起来，然后返回响应。
/*
|--------------------------------------------------------------------------
| Turn On The Lights
|--------------------------------------------------------------------------
|
| We need to illuminate PHP development, so let us turn on the lights.
| This bootstraps the framework and gets it ready for use, then it
| will load up this application so that we can run it and send
| the responses back to the browser and delight our users.
|
*/
$app = require_once __DIR__.'/../bootstrap/app.php';在这一步，服务容器$app 就被实例化出来了。
1.3 运行应用。一旦我们获取到了应用程序，我们可以通过 kernel内核 来处理进来的请求，然后返回相关的响应结果。
/*
|--------------------------------------------------------------------------
| Run The Application
|--------------------------------------------------------------------------
|
| Once we have the application, we can handle the incoming request
| through the kernel, and send the associated response back to
| the client's browser allowing them to enjoy the creative
| and wonderful application we have prepared for them.
|
*/
$kernel = $app->make(Illuminate\Contracts\Http\Kernel::class);
$response = $kernel->handle(
$request = Illuminate\Http\Request::capture()
);
$response->send();
$kernel->terminate($request, $response);在这一步，通过服务容器$app示例化出了内核对象，内核又去处理被Request捕获到的请求，然后将响应结果发送回去，最后本次请求的内核对象停止工作。
2，如何运行
2.1 app/bootstrap/app.php 文件
2.1.1 创建应用：我们第一件要做的事情就是创建一个新的Laravel应用实例，这个实例会像 胶水 一样为Laravel的所有部件服务，同时它也是 绑定了所有各种各样的部分的系统 的 IOC容器。
/*
|--------------------------------------------------------------------------
| Create The Application
|--------------------------------------------------------------------------
|
| The first thing we will do is create a new Laravel application instance
| which serves as the "glue" for all the components of Laravel, and is
| the IoC container for the system binding all of the various parts.
|
*/
$app = new Illuminate\Foundation\Application(
$_ENV['APP_BASE_PATH'] ?? dirname(__DIR__)
);2.1.1 我们来看看这个容器是如何被创建出来的
这个构造方法在vendor/laravel/framework/src/Illuminate/Foundation/Application.php目录下，作用是创造一个新的容器
/**
* Create a new Illuminate application instance.
*
* @param string|null $basePath
* @return void
*/
public function __construct($basePath = null)
{
if ($basePath) {
$this->setBasePath($basePath);
}
$this->registerBaseBindings();
$this->registerBaseServiceProviders();
$this->registerCoreContainerAliases();
}2.1.1.1 设置基本的路径
2.2.1.2 注册 基本的绑定 到 容器中
/**
* Register the basic bindings into the container.
*
* @return void
*/
protected function registerBaseBindings()
{
static::setInstance($this);
$this->instance('app', $this);
$this->instance(Container::class, $this);
$this->instance(PackageManifest::class, new PackageManifest(
new Filesystem, $this->basePath(), $this->getCachedPackagesPath()
));
}第一步 把当前对象设置成共享的容器示例
第二步 将 'app' 抽象类 绑定到当前对象上
第三步 把 容器抽象类 绑定到当前对象上
第四步 把 货物清单 绑定到 PackageManifest() 中
2.2.1.3 注册 基础服务提供者
/**
* Register all of the base service providers.
*
* @return void
*/
protected function registerBaseServiceProviders()
{
$this->register(new EventServiceProvider($this));
$this->register(new LogServiceProvider($this));
$this->register(new RoutingServiceProvider($this));
}将 事件，日志，路由这三个 基础服务提供者 注册到当前对象中
2.2.1.4 注册核心类别名到容器中
/**
* Register the core class aliases in the container.
*
* @return void
*/
public function registerCoreContainerAliases()
{
foreach ([
'app' => [\Illuminate\Foundation\Application::class, \Illuminate\Contracts\Container\Container::class, \Illuminate\Contracts\Foundation\Application::class, \Psr\Container\ContainerInterface::class],
'auth' => [\Illuminate\Auth\AuthManager::class, \Illuminate\Contracts\Auth\Factory::class],
'auth.driver' => [\Illuminate\Contracts\Auth\Guard::class],
'blade.compiler' => [\Illuminate\View\Compilers\BladeCompiler::class],
'cache' => [\Illuminate\Cache\CacheManager::class, \Illuminate\Contracts\Cache\Factory::class],
'cache.store' => [\Illuminate\Cache\Repository::class, \Illuminate\Contracts\Cache\Repository::class],
'config' => [\Illuminate\Config\Repository::class, \Illuminate\Contracts\Config\Repository::class],
'cookie' => [\Illuminate\Cookie\CookieJar::class, \Illuminate\Contracts\Cookie\Factory::class, \Illuminate\Contracts\Cookie\QueueingFactory::class],
'encrypter' => [\Illuminate\Encryption\Encrypter::class, \Illuminate\Contracts\Encryption\Encrypter::class],
'db' => [\Illuminate\Database\DatabaseManager::class],
'db.connection' => [\Illuminate\Database\Connection::class, \Illuminate\Database\ConnectionInterface::class],
'events' => [\Illuminate\Events\Dispatcher::class, \Illuminate\Contracts\Events\Dispatcher::class],
'files' => [\Illuminate\Filesystem\Filesystem::class],
'filesystem' => [\Illuminate\Filesystem\FilesystemManager::class, \Illuminate\Contracts\Filesystem\Factory::class],
'filesystem.disk' => [\Illuminate\Contracts\Filesystem\Filesystem::class],
'filesystem.cloud' => [\Illuminate\Contracts\Filesystem\Cloud::class],
'hash' => [\Illuminate\Hashing\HashManager::class],
'hash.driver' => [\Illuminate\Contracts\Hashing\Hasher::class],
'translator' => [\Illuminate\Translation\Translator::class, \Illuminate\Contracts\Translation\Translator::class],
'log' => [\Illuminate\Log\LogManager::class, \Psr\Log\LoggerInterface::class],
'mailer' => [\Illuminate\Mail\Mailer::class, \Illuminate\Contracts\Mail\Mailer::class, \Illuminate\Contracts\Mail\MailQueue::class],
'auth.password' => [\Illuminate\Auth\Passwords\PasswordBrokerManager::class, \Illuminate\Contracts\Auth\PasswordBrokerFactory::class],
'auth.password.broker' => [\Illuminate\Auth\Passwords\PasswordBroker::class, \Illuminate\Contracts\Auth\PasswordBroker::class],
'queue' => [\Illuminate\Queue\QueueManager::class, \Illuminate\Contracts\Queue\Factory::class, \Illuminate\Contracts\Queue\Monitor::class],
'queue.connection' => [\Illuminate\Contracts\Queue\Queue::class],
'queue.failer' => [\Illuminate\Queue\Failed\FailedJobProviderInterface::class],
'redirect' => [\Illuminate\Routing\Redirector::class],
'redis' => [\Illuminate\Redis\RedisManager::class, \Illuminate\Contracts\Redis\Factory::class],
'request' => [\Illuminate\Http\Request::class, \Symfony\Component\HttpFoundation\Request::class],
'router' => [\Illuminate\Routing\Router::class, \Illuminate\Contracts\Routing\Registrar::class, \Illuminate\Contracts\Routing\BindingRegistrar::class],
'session' => [\Illuminate\Session\SessionManager::class],
'session.store' => [\Illuminate\Session\Store::class, \Illuminate\Contracts\Session\Session::class],
'url' => [\Illuminate\Routing\UrlGenerator::class, \Illuminate\Contracts\Routing\UrlGenerator::class],
'validator' => [\Illuminate\Validation\Factory::class, \Illuminate\Contracts\Validation\Factory::class],
'view' => [\Illuminate\View\Factory::class, \Illuminate\Contracts\View\Factory::class],
] as $key => $aliases) {
foreach ($aliases as $alias) {
$this->alias($key, $alias);
}
}
}至此，就把各种基础的路径，基础的绑定，基础服务提供者，核心类别名 都 注册或者绑定到了当前的应用对象中，返回了 $app 这个 应用实例，也就是容器示例。
2.1.2 然后将重要的接口绑定到这 应用实例/容器实例 中 ，
/*
|--------------------------------------------------------------------------
| Bind Important Interfaces
|--------------------------------------------------------------------------
|
| Next, we need to bind some important interfaces into the container so
| we will be able to resolve them when needed. The kernels serve the
| incoming requests to this application from both the web and CLI.
|
*/
$app->singleton(
Illuminate\Contracts\Http\Kernel::class,
App\Http\Kernel::class
);
$app->singleton(
Illuminate\Contracts\Console\Kernel::class,
App\Console\Kernel::class
);
$app->singleton(
Illuminate\Contracts\Debug\ExceptionHandler::class,
App\Exceptions\Handler::class
);
2.1.3 然后返回 应用实例。这个应用实例将会给到 被调用的脚本，所以这里我们得以将 应用实例的构建 和 真正的应用运行 及 发送响应 这两个步骤分开来。
/*
|--------------------------------------------------------------------------
| Return The Application
|--------------------------------------------------------------------------
|
| This script returns the application instance. The instance is given to
| the calling script so we can separate the building of the instances
| from the actual running of the application and sending responses.
|
*/
return $app;至此，应用实例构造完成。
回到 index.php 入口文件，我们获取到了应用实例 / 容器示例 ，接下来，就是去运行应用实例了。
/*
|--------------------------------------------------------------------------
| Run The Application
|--------------------------------------------------------------------------
|
| Once we have the application, we can handle the incoming request
| through the kernel, and send the associated response back to
| the client's browser allowing them to enjoy the creative
| and wonderful application we have prepared for them.
|
*/
$kernel = $app->make(Illuminate\Contracts\Http\Kernel::class);
$response = $kernel->handle(
$request = Illuminate\Http\Request::capture()
);
$response->send();
$kernel->terminate($request, $response);
来源：oschina
链接：https://my.oschina.net/u/3412738/blog/3159587