说明：只是笔者自身对这些概念的理解，不妥之处欢迎纠正。
1、什么叫做服务(Service)?
服务其实就是一个组件，再通俗点讲，composer里的一个package就是一个服务，有的地方把服务称之为bundle，或者Componet。
config/app.php
app.php内容：
return [
/*
|--------------------------------------------------------------------------
| Application Name
|--------------------------------------------------------------------------
|
| This value is the name of your application. This value is used when the
| framework needs to place the application's name in a notification or
| any other location as required by the application or its packages.
*/
'name' => 'Laravel',
/*
|--------------------------------------------------------------------------
| Application Environment
|--------------------------------------------------------------------------
|
| This value determines the "environment" your application is currently
| running in. This may determine how you prefer to configure various
| services your application utilizes. Set this in your ".env" file.
|
*/
'env' => env('APP_ENV', 'production'),
/*
|--------------------------------------------------------------------------
| Application Debug Mode
|--------------------------------------------------------------------------
|
| When your application is in debug mode, detailed error messages with
| stack traces will be shown on every error that occurs within your
| application. If disabled, a simple generic error page is shown.
|
*/
'debug' => env('APP_DEBUG', false),
/*
|--------------------------------------------------------------------------
| Application URL
|--------------------------------------------------------------------------
|
| This URL is used by the console to properly generate URLs when using
| the Artisan command line tool. You should set this to the root of
| your application so that it is used when running Artisan tasks.
|
*/
'url' => env('APP_URL', 'http://localhost'),
/*
|--------------------------------------------------------------------------
| Application Timezone
|--------------------------------------------------------------------------
|
| Here you may specify the default timezone for your application, which
| will be used by the PHP date and date-time functions. We have gone
| ahead and set this to a sensible default for you out of the box.
|
*/
'timezone' => 'UTC',
/*
|--------------------------------------------------------------------------
| Application Locale Configuration
|--------------------------------------------------------------------------
|
| The application locale determines the default locale that will be used
| by the translation service provider. You are free to set this value
| to any of the locales which will be supported by the application.
|
*/
'locale' => 'en',
/*
|--------------------------------------------------------------------------
| Application Fallback Locale
|--------------------------------------------------------------------------
|
| The fallback locale determines the locale to use when the current one
| is not available. You may change the value to correspond to any of
| the language folders that are provided through your application.
|
*/
'fallback_locale' => 'en',
/*
|--------------------------------------------------------------------------
| Encryption Key
|--------------------------------------------------------------------------
|
| This key is used by the Illuminate encrypter service and should be set
| to a random, 32 character string, otherwise these encrypted strings
| will not be safe. Please do this before deploying an application!
|
*/
'key' => env('APP_KEY'),
'cipher' => 'AES-256-CBC',
/*
|--------------------------------------------------------------------------
| Logging Configuration
|--------------------------------------------------------------------------
|
| Here you may configure the log settings for your application. Out of
| the box, Laravel uses the Monolog PHP logging library. This gives
| you a variety of powerful log handlers / formatters to utilize.
|
| Available Settings: "single", "daily", "syslog", "errorlog"
|
*/
'log' => env('APP_LOG', 'single'),
'log_level' => env('APP_LOG_LEVEL', 'debug'),
/*
|--------------------------------------------------------------------------
| Autoloaded Service Providers
|--------------------------------------------------------------------------
|
| The service providers listed here will be automatically loaded on the
| request to your application. Feel free to add your own services to
| this array to grant expanded functionality to your applications.
|
*/
'providers' => [
/*
* Laravel Framework Service Providers...
*/
Illuminate\Auth\AuthServiceProvider::class,
Illuminate\Broadcasting\BroadcastServiceProvider::class,
Illuminate\Bus\BusServiceProvider::class,
Illuminate\Cache\CacheServiceProvider::class,
Illuminate\Foundation\Providers\ConsoleSupportServiceProvider::class,
Illuminate\Cookie\CookieServiceProvider::class,
Illuminate\Database\DatabaseServiceProvider::class,
Illuminate\Encryption\EncryptionServiceProvider::class,
Illuminate\Filesystem\FilesystemServiceProvider::class,
Illuminate\Foundation\Providers\FoundationServiceProvider::class,
Illuminate\Hashing\HashServiceProvider::class,
Illuminate\Mail\MailServiceProvider::class,
Illuminate\Notifications\NotificationServiceProvider::class,
Illuminate\Pagination\PaginationServiceProvider::class,
Illuminate\Pipeline\PipelineServiceProvider::class,
Illuminate\Queue\QueueServiceProvider::class,
Illuminate\Redis\RedisServiceProvider::class,
Illuminate\Auth\Passwords\PasswordResetServiceProvider::class,
Illuminate\Session\SessionServiceProvider::class,
Illuminate\Translation\TranslationServiceProvider::class,
Illuminate\Validation\ValidationServiceProvider::class,
Illuminate\View\ViewServiceProvider::class,
/*
* Package Service Providers...
*/
//
/*
* Application Service Providers...
*/
App\Providers\AppServiceProvider::class,
App\Providers\AuthServiceProvider::class,
// App\Providers\BroadcastServiceProvider::class,
App\Providers\EventServiceProvider::class,
App\Providers\RouteServiceProvider::class,
],
/*
|--------------------------------------------------------------------------
| Class Aliases
|--------------------------------------------------------------------------
|
| This array of class aliases will be registered when this application
| is started. However, feel free to register as many as you wish as
| the aliases are "lazy" loaded so they don't hinder performance.
|
*/
'aliases' => [
'App' => Illuminate\Support\Facades\App::class,
'Artisan' => Illuminate\Support\Facades\Artisan::class,
'Auth' => Illuminate\Support\Facades\Auth::class,
'Blade' => Illuminate\Support\Facades\Blade::class,
'Bus' => Illuminate\Support\Facades\Bus::class,
'Cache' => Illuminate\Support\Facades\Cache::class,
'Config' => Illuminate\Support\Facades\Config::class,
'Cookie' => Illuminate\Support\Facades\Cookie::class,
'Crypt' => Illuminate\Support\Facades\Crypt::class,
'DB' => Illuminate\Support\Facades\DB::class,
'Eloquent' => Illuminate\Database\Eloquent\Model::class,
'Event' => Illuminate\Support\Facades\Event::class,
'File' => Illuminate\Support\Facades\File::class,
'Gate' => Illuminate\Support\Facades\Gate::class,
'Hash' => Illuminate\Support\Facades\Hash::class,
'Lang' => Illuminate\Support\Facades\Lang::class,
'Log' => Illuminate\Support\Facades\Log::class,
'Mail' => Illuminate\Support\Facades\Mail::class,
'Notification' => Illuminate\Support\Facades\Notification::class,
'Password' => Illuminate\Support\Facades\Password::class,
'Queue' => Illuminate\Support\Facades\Queue::class,
'Redirect' => Illuminate\Support\Facades\Redirect::class,
'Redis' => Illuminate\Support\Facades\Redis::class,
'Request' => Illuminate\Support\Facades\Request::class,
'Response' => Illuminate\Support\Facades\Response::class,
'Route' => Illuminate\Support\Facades\Route::class,
'Schema' => Illuminate\Support\Facades\Schema::class,
'Session' => Illuminate\Support\Facades\Session::class,
'Storage' => Illuminate\Support\Facades\Storage::class,
'URL' => Illuminate\Support\Facades\URL::class,
'Validator' => Illuminate\Support\Facades\Validator::class,
'View' => Illuminate\Support\Facades\View::class,
],
];
这个文件是laravel框架组重要的文件之一，composer的包使用前都要在这里绑定一下，也就是说服务需要在这里绑定一下才会被启动加载到。
2、什么叫服务提供者(Service Providers)?
服务不仅要加载，而且还要先注册一下才能被使用，什么叫注册呢？其实就是一个外部服务（包）和Laravel核心程序的连接行为，这个连接器就叫做服务提供者（Service Provider）。
他的位置位于：
app/Providers
Service Provider 里面一般有两个重要的方法：boot()和register();
- 前者是用来启动前期加载一些程序逻辑。
- 后者则是用来注册外部的服务。
注意：boot()非常常用，请记住,Service Providers 和 Service Container 有密度关系，下面会讲。
3、什么叫做依赖注入?
大多数面向对象的编程语言，在调用一个类的时候，先要实例化这个类，生成一个对象。
如果你在写一个类，过程中要调用到很多类，甚至这里的“其他类”也要“依赖”于更多的其他类，那么可以想象，你要进行多少次实例化。这就是“依赖“的意思。
依赖注入，全称是”依赖注入到容器“，容器（IOC容器）是一个设计模式，他也是个对象，你把某个类（不管有多少个依赖关系）放入到这个容器中，可以”解析“出这个类的实例。所以”依赖注入“就是把所有有依赖关系（或者没有）的类放入容器（IOC）容器中，然后解析出这个类的实例，仅此而已。
4、什么叫做IOC容器?
容器是个对象，Laravel有一个核心类，叫做application，程序启动的时候就实例化了这个类，放到$app，这个类就是IOC容器。
注意：转载请标明出处，并以链接方式标出，否则后果自负。
