Module类，属性的注释和构造函数的注释：
<?php
/**
* @link http://www.yiiframework.com/
* @copyright Copyright (c) 2008 Yii Software LLC
* @license http://www.yiiframework.com/license/
*/
namespace yii\base;
use Yii;
use yii\di\ServiceLocator;
/**
* Module is the base class for module and application classes.
* Module是模块和应用类的基类
*
* A module represents a sub-application which contains MVC elements by itself, such as
* models, views, controllers, etc.
* 模块代表一个由模型、视图、控制器等组成的子应用
*
* A module may consist of [[modules|sub-modules]].
* 模块内也可以包含模块或子模块
*
* [[components|Components]] may be registered with the module so that they are globally
* accessible within the module.
* 组件可以注册到模块，以便在模块内全局访问
*
* @property array $aliases List of path aliases to be defined. The array keys are alias names (must start
* with '@') and the array values are the corresponding paths or aliases. See [[setAliases()]] for an example.
* This property is write-only.
* @property array $aliases 别名数组 只读
* @property string $basePath The root directory of the module.
* @property string $basePath 模块的根路径
* @property string $controllerPath The directory that contains the controller classes. This property is
* read-only.
* @property string $controllerPath 控制的路径数组 只读
* @property string $layoutPath The root directory of layout files. Defaults to "[[viewPath]]/layouts".
* @property string $layoutPath 模板路径数组 只读
* @property array $modules The modules (indexed by their IDs).
* @property array $modules 模块数组
* @property string $uniqueId The unique ID of the module. This property is read-only.
* @property string $uniqueId 模块的唯一ID 只读
* @property string $viewPath The root directory of view files. Defaults to "[[basePath]]/views".
* @property string $viewPath 模块下的视图文件路径
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @since 2.0
*/
class Module extends ServiceLocator
{
/**
* @event ActionEvent an event raised before executing a controller action.
* @event ActionEvent Action事件，在执行控制的的action方法时触发
* You may set [[ActionEvent::isValid]] to be false to cancel the action execution.
*/
const EVENT_BEFORE_ACTION = 'beforeAction';
/**
* @event ActionEvent an event raised after executing a controller action.
* @event ActionEvent Action事件，在执行控制的的action方法后触发
*/
const EVENT_AFTER_ACTION = 'afterAction';
/**
* @var array custom module parameters (name => value).
* @var array 自定义模块参数
*/
public $params = [];
/**
* @var string an ID that uniquely identifies this module among other modules which have the same [[module|parent]].
* @var string 模块的唯一ID，用于区分同一父模块下的模块
*/
public $id;
/**
* @var Module the parent module of this module. Null if this module does not have a parent.
* @var 当前模块的父模块
*/
public $module;
/**
* @var string|boolean the layout that should be applied for views within this module. This refers to a view name
* relative to [[layoutPath]]. If this is not set, it means the layout value of the [[module|parent module]]
* will be taken. If this is false, layout will be disabled within this module.
* @var string|boolean 布局文件
*/
public $layout;
/**
* @var array mapping from controller ID to controller configurations.
* @var array 控制器ID到控制器配置的映射
* Each name-value pair specifies the configuration of a single controller.
* A controller configuration can be either a string or an array.
* If the former, the string should be the fully qualified class name of the controller.
* If the latter, the array must contain a 'class' element which specifies
* the controller's fully qualified class name, and the rest of the name-value pairs
* in the array are used to initialize the corresponding controller properties. For example,
* 每一个键值对指定一个单独的控制器，控制器配置可以是一个字符串或者数组，如果是前者，该字符串是指定控制的的全路径（即带命名空间的）
* 如果是后者，则数组中包含一个‘class’元素，该元素指定控制器的全路径，其余的参数用于初始化对应的属性，例子如下：
*
* ```php
* [
* 'account' => 'app\controllers\UserController',//字符串形式，指定了accout控制器的路径
* 'article' => [
* 'class' => 'app\controllers\PostController',//指定article控制器的路径
* 'pageTitle' => 'something new',//提供了pageTitle参数
* ],
* ]
* ```
*/
public $controllerMap = [];
/**
* @var string the namespace that controller classes are in.
* @var string 控制器的命名空间
* This namespace will be used to load controller classes by prepending it to the controller
* class name.
* 该命名空间用于加在控制器类的前面加载控制器类
*
* If not set, it will use the `controllers` sub-namespace under the namespace of this module.
* For example, if the namespace of this module is "foo\bar", then the default
* controller namespace would be "foo\bar\controllers".
* 如果没有给定，默认为当前模块的命名空间加上 `controllers`构成的子命名空间
* 如当前模块的命名空间为"foo\bar"，那么控制器的默认命名空间为"foo\bar\controllers"
*
* See also the [guide section on autoloading](guide:concept-autoloading) to learn more about
* defining namespaces and how classes are loaded.
*/
public $controllerNamespace;
/**
* @var string the default route of this module. Defaults to 'default'.
* @var string 当前模块的默认路由 默认为'default'
* The route may consist of child module ID, controller ID, and/or action ID.
* route 可能包含子模块ID，控制器ID，和/或 action ID，如果action ID未给定，则会调用[Controller::defaultAction]指定的action
* For example, `help`, `post/create`, `admin/post/create`.
* If action ID is not given, it will take the default value as specified in
* [[Controller::defaultAction]].
*/
public $defaultRoute = 'default';
/**
* @var string the root directory of the module.
* @var string 当前模块的根路径
*/
private $_basePath;
/**
* @var string the root directory that contains view files for this module
* @var string 当前模块下视图文件的路径数组
*/
private $_viewPath;
/**
* @var string the root directory that contains layout view files for this module.
* @var string 当前模块下的布局文件路径数组
*/
private $_layoutPath;
/**
* @var array child modules of this module
* @var array 当前模块的子模块数组
*/
private $_modules = [];
/**
* Constructor.
* 构造函数
* @param string $id the ID of this module
* @param string $id 当前模块的ID
* @param Module $parent the parent module (if any)
* @param Module $parent 当前模块的父模块（如果有的话）
* @param array $config name-value pairs that will be used to initialize the object properties
* @param array $config 配置文件|数组
*/
public function __construct($id, $parent = null, $config = [])
{
$this->id = $id;//给当前模块赋值唯一ID
$this->module = $parent;//给module属性（即当前模块的父模块）赋值
parent::__construct($config);//将配置文件赋值到Object的属性中，因为Object是所有类的基类，理论可以整个项目中访问
}
/**
* Returns the currently requested instance of this module class.
* 从Yii::$app->loadedModules['yii\web\Application']数组中取得当前类的实例
* If the module class is not currently requested, null will be returned.
* This method is provided so that you access the module instance from anywhere within the module.
* 该方法可以在模块内的任何地方访问类的实例
* @return static|null the currently requested instance of this module class, or null if the module class is not requested.
*/
public static function getInstance()
{
$class = get_called_class();
return isset(Yii::$app->loadedModules[$class]) ? Yii::$app->loadedModules[$class] : null;
}
/**
* Sets the currently requested instance of this module class.
* 将当前类名和存储类的对象变量加入Yii::$app->loadedModules['yii\web\Application']数组中
* 这样直接通过Yii::$app->loadedModules['yii\web\Application']就可以直接调用这个类
* @param Module|null $instance the currently requested instance of this module class.
* If it is null, the instance of the calling class will be removed, if any.
*/
public static function setInstance($instance)//module模块里会用到，为getInstance提供数据
{
if ($instance === null) {
unset(Yii::$app->loadedModules[get_called_class()]);//如果没有传入参数，说明是删除，直接unset
} else {
Yii::$app->loadedModules[get_class($instance)] = $instance;//否则将该类和类的实例存入loadedModules数组中
}
}
/**
* Initializes the module.
* 初始化模块，取出控制器的命名空间，也可以理解为路径 注：第一次加载的时候才会执行
* This method is called after the module is created and initialized with property values
* given in configuration. The default implementation will initialize [[controllerNamespace]]
* if it is not set.
*
* If you override this method, please make sure you call the parent implementation.
*/
public function init()
{
if ($this->controllerNamespace === null) {//判断controllerNamespace属性是否被赋值，没有赋值才执行
$class = get_class($this);//获取类名
if (($pos = strrpos($class, '\\')) !== false) {
$this->controllerNamespace = substr($class, 0, $pos) . '\\controllers';//取得命名空间
}
}
}