for check

docs/guide-zh-CN/structure-application-components.md

@@ -0,0 +1,128 @@
+应用组件
+======================
+
+应用主体是 [服务定位器](concept-service-locator.md)，它部署一组提供各种不同功能的 *应用组件* 来处理请求。
+例如，`urlManager`组件负责处理网页请求路由到对应的控制器。`db`组件提供数据库相关服务等等。
+
+在同一个应用中，每个应用组件都有一个独一无二的 ID 用来区分其他应用组件，你可以通过如下表达式访问应用组件。
+Each application component has an ID that uniquely identifies itself among other application components
+in the same application. You can access an application component through the expression
+
+```php
+\Yii::$app->componentID
+```
+
+例如，可以使用 `\Yii::$app->db` 来获取到已注册到应用的 [[yii\db\Connection|DB connection]]，
+使用 `\Yii::$app->cache` 来获取到已注册到应用的 [[yii\caching\Cache|primary cache]]。 
+and `\Yii::$app->cache` to get the [[yii\caching\Cache|primary cache]] registered with the application.
+For example, you can use `\Yii::$app->db` to get the [[yii\db\Connection|DB connection]],
+and `\Yii::$app->cache` to get the [[yii\caching\Cache|primary cache]] registered with the application.
+
+第一次使用以上表达式时候会创建应用组件实例，后续再访问会返回此实例，无需再次创建。
+An application component is created the first time it is accessed through the above expression. Any
+further accesses will return the same component instance.
+
+应用组件可以是任意对象，可以在 [应用主体配置](structure-applications.md#application-configurations) 配置 [[yii\base\Application::components]] 属性 .
+例如：
+Application components can be any objects. You can register them by configuring
+the [[yii\base\Application::components]] property in [application configurations](structure-applications.md#application-configurations).
+For example,
+
+```php
+[
+    'components' => [
+        // 使用类名注册 "cache" 组件
+        'cache' => 'yii\caching\ApcCache',
+
+        // 使用配置数组注册 "db" 组件
+        'db' => [
+            'class' => 'yii\db\Connection',
+            'dsn' => 'mysql:host=localhost;dbname=demo',
+            'username' => 'root',
+            'password' => '',
+        ],
+
+        // 使用函数注册"search" 组件
+        'search' => function () {
+            return new app\components\SolrService;
+        },
+    ],
+]
+```
+
+> 补充：请谨慎注册太多应用组件，应用组件就像全局变量，使用太多可能加大测试和维护的难度。
+  一般情况下可以在需要时再创建本地组件。
+> Info: While you can register as many application components as you want, you should do this judiciously.
+  Application components are like global variables. Using too many application components can potentially
+  make your code harder to test and maintain. In many cases, you can simply create a local component
+  and use it when needed.
+
+
+## 引导启动组件 <a name="bootstrapping-components"></a>
+## Bootstrapping Components <a name="bootstrapping-components"></a>
+
+上面提到一个应用组件只会在第一次访问时实例化，如果处理请求过程没有访问的话就不实例化。
+有时你想在每个请求处理过程都实例化某个组件即便它不会被访问，
+可以将该组件ID加入到应用主体的 [[yii\base\Application::bootstrap|bootstrap]] 属性中。
+As mentioned above, an application component will only be instantiated when it is being accessed the first time.
+If it is not accessed at all during a request, it will not be instantiated. Sometimes, however, you may want
+to instantiate an application component for every request, even if it is not explicitly accessed.
+To do so, you may list its ID in the [[yii\base\Application::bootstrap|bootstrap]] property of the application.
+
+例如, 如下的应用主体配置保证了 `log` 组件一直被加载。
+For example, the following application configuration makes sure the `log` component is always loaded:
+
+```php
+[
+    'bootstrap' => [
+        'log',
+    ],
+    'components' => [
+        'log' => [
+            // "log" 组件的配置
+        ],
+    ],
+]
+```
+
+
+## 核心应用组件 <a name="core-application-components"></a>
+## Core Application Components <a name="core-application-components"></a>
+
+Yii 定义了一组固定ID和默认配置的 *核心* 组件，例如 [[yii\web\Application::request|request]] 组件用来收集用户请求并解析 [路由](runtime-routing.md)；
+[[yii\base\Application::db|db]] 代表一个可以执行数据库操作的数据库连接。
+通过这些组件，Yii应用主体能处理用户请求。
+Yii defines a set of *core* application components with fixed IDs and default configurations. For example,
+the [[yii\web\Application::request|request]] component is used to collect information about
+a user request and resolve it into a [route](runtime-routing.md); the [[yii\base\Application::db|db]]
+component represents a database connection through which you can perform database queries.
+It is with help of these core application components that Yii applications are able to handle user requests.
+
+下面是预定义的核心应用组件列表，可以和普通应用组件一样配置和自定义它们。
+当你配置一个核心组件，不指定它的类名的话就会使用Yii默认指定的类。
+Below is the list of the predefined core application components. You may configure and customize them
+like you do with normal application components. When you are configuring a core application component,
+if you do not specify its class, the default one will be used.
+
+* [[yii\web\AssetManager|assetManager]]: 管理资源包和资源发布，详情请参考 [管理资源](output-assets.md) 一节。
+* [[yii\db\Connection|db]]: 代表一个可以执行数据库操作的数据库连接，
+  注意配置该组件时必须指定组件类名和其他相关组件属性，如[[yii\db\Connection::dsn]]。
+  详情请参考 [数据访问对象](db-dao.md) 一节。
+* [[yii\base\Application::errorHandler|errorHandler]]: 处理 PHP 错误和异常，
+  详情请参考 [错误处理](tutorial-handling-errors.md) 一节。
+* [[yii\i18n\Formatter|formatter]]: 格式化输出显示给终端用户的数据，例如数字可能要带分隔符，
+  日期使用长格式。详情请参考 [格式化输出数据](output-formatting.md) 一节。
+* [[yii\i18n\I18N|i18n]]: 支持信息翻译和格式化。详情请参考 [国际化](tutorial-i18n.md) 一节。
+* [[yii\log\Dispatcher|log]]: 管理日志对象。详情请参考 [日志](tutorial-logging.md) 一节。
+* [[yii\swiftmailer\Mailer|mail]]: 支持生成邮件结构并发送，详情请参考 [邮件](tutorial-mailing.md) 一节。
+* [[yii\base\Application::response|response]]: 代表发送给用户的响应，
+  详情请参考 [响应](runtime-responses.md) 一节。
+* [[yii\base\Application::request|request]]: 代表从终端用户处接收到的请求，
+  详情请参考 [请求](runtime-requests.md) 一节。
+* [[yii\web\Session|session]]: 代表会话信息，仅在[[yii\web\Application|Web applications]] 网页应用中可用，
+  详情请参考 [Sessions (会话) and Cookies](runtime-sessions-cookies.md) 一节。
+* [[yii\web\UrlManager|urlManager]]: 支持URL地址解析和创建，
+  详情请参考 [URL 解析和生成](runtime-url-handling.md) 一节。
+* [[yii\web\User|user]]: 代表认证登录用户信息，仅在[[yii\web\Application|Web applications]] 网页应用中可用，
+  详情请参考 [认证](security-authentication.md) 一节。
+* [[yii\web\View|view]]: 支持渲染视图，详情请参考 [Views](structure-views.md) 一节。

docs/guide-zh-CN/structure-applications.md

@@ -0,0 +1,744 @@
+应用主体
+============
+
+应用主体是管理Yii应用系统整体结构和生命周期的对象。
+每个Yii应用系统只能包含一个应用主体，应用主体在 [入口脚本](structure-entry-scripts.md) 中创建并能通过表达式 `\Yii::$app` 全局范围内访问。
+Applications are objects that govern the overall structure and lifecycle of Yii application systems.
+Each Yii application system contains a single application object which is created in
+the [entry script](structure-entry-scripts.md) and is globally accessible through the expression `\Yii::$app`.
+
+> 补充: 当我们说"一个应用"，它可能是一个应用对象，也可能是一个应用系统，是根据上下文来决定。
+> Info: Depending on the context, when we say "an application", it can mean either an application
+  object or an application system.
+
+Yii有两种应用主体: [[yii\web\Application|网页应用主体]] and
+[[yii\console\Application|控制台应用主体]]， 如名称所示，前者主要处理网页请求，后者处理控制台请求。
+There are two types of applications: [[yii\web\Application|Web applications]] and
+[[yii\console\Application|console applications]]. As the names indicate, the former mainly handles
+Web requests while the latter console command requests.
+
+
+## 应用主体配置 <a name="application-configurations"></a>
+## Application Configurations <a name="application-configurations"></a>
+
+如下所示，当 [入口脚本](structure-entry-scripts.md) 创建了一个应用主体，它会加载一个 [配置](concept-configurations.md) 文件并传给应用主体。
+When an [entry script](structure-entry-scripts.md) creates an application, it will load
+a [configuration](concept-configurations.md) and apply it to the application, like the following:
+
+```php
+require(__DIR__ . '/../vendor/autoload.php');
+require(__DIR__ . '/../vendor/yiisoft/yii2/Yii.php');
+
+// 加载应用主体配置
+$config = require(__DIR__ . '/../config/web.php');
+
+// 实例化应用主体、配置应用主体
+(new yii\web\Application($config))->run();
+```
+
+类似其他 [配置](concept-configurations.md) 文件, 应用主体配置文件标明如何设置应用对象初始属性。
+由于应用主体配置比较复杂，一般保存在多个类似如上web.php的 [配置文件](concept-configurations.md#configuration-files) 当中。
+Like normal [configurations](concept-configurations.md), application configurations specify how
+to initialize properties of application objects. Because application configurations are often
+very complex, they usually are kept in [configuration files](concept-configurations.md#configuration-files),
+like the `web.php` file in the above example.
+
+## 应用主体属性 <a name="application-properties"></a>
+## Application Properties <a name="application-properties"></a>
+
+应用主体配置文件中有许多重要的属性要配置，这些属性指定应用主体的运行环境。
+比如，应用主体需要知道如何加载 [控制器](structure-controllers.md) ，临时文件保存到哪儿等等。
+以下我们简述这些属性。
+There are many important application properties that you should configure in application configurations.
+These properties typically describe the environment that applications are running in.
+For example, applications need to know how to load [controllers](structure-controllers.md),
+where to store temporary files, etc. In the following, we will summarize these properties.
+
+### 必要属性 <a name="required-properties"></a>
+### Required Properties <a name="required-properties"></a>
+
+在一个应用中，至少要配置2个属性: [[yii\base\Application::id|id]] 和 [[yii\base\Application::basePath|basePath]]。
+In any application, you should at least configure two properties: [[yii\base\Application::id|id]]
+and [[yii\base\Application::basePath|basePath]].
+
+
+#### [[yii\base\Application::id|id]] <a name="id"></a>
+
+[[yii\base\Application::id|id]] 属性用来区分其他应用的唯一标识ID。主要给程序使用。
+为了方便协作，最好使用数字作为应用主体ID，但不强制要求为数字。
+The [[yii\base\Application::id|id]] property specifies a unique ID that differentiates an application
+from others. It is mainly used programmatically. Although not a requirement, for best interoperability
+it is recommended that you use alphanumeric characters only when specifying an application ID.
+
+
+#### [[yii\base\Application::basePath|basePath]] <a name="basePath"></a>
+
+
+[[yii\base\Application::basePath|basePath]] 指定该应用的根目录。根目录包含应用系统所有受保护的源代码。
+在根目录下可以看到对应MVC设计模式的`models`, `views`, `controllers`等子目录。
+The [[yii\base\Application::basePath|basePath]] property specifies the root directory of an application.
+It is the directory that contains all protected source code of an application system. Under this directory,
+you normally will see sub-directories such as `models`, `views`, `controllers`, which contain source code
+corresponding to the MVC pattern.
+
+可以使用路径或 [路径别名](concept-aliases.md) 来在配置 [[yii\base\Application::basePath|basePath]] 属性。
+两种格式所对应的目录都必须存在，否则系统会抛出一个异常。 系统会使用 `realpath()` 函数规范化配置的路径.
+You may configure the [[yii\base\Application::basePath|basePath]] property using a directory path
+or a [path alias](concept-aliases.md). In both forms, the corresponding directory must exist, or an exception
+will be thrown. The path will be normalized by calling the `realpath()` function.
+
+[[yii\base\Application::basePath|basePath]] 属性经常用于派生一些其他重要路径（如runtime路径），因此，系统预定义 `@app` 代表这个路径。
+派生路径可以通过这个别名组成（如`@app/runtime`代表runtime的路径）。
+The [[yii\base\Application::basePath|basePath]] property is often used to derive other important
+paths (e.g. the runtime path). For this reason, a path alias named `@app` is predefined to represent this
+path. Derived paths may then be formed using this alias (e.g. `@app/runtime` to refer to the runtime directory).
+
+
+### 重要属性 <a name="important-properties"></a>
+### Important Properties <a name="important-properties"></a>
+
+本小节所描述的属性通常需要设置，因为不用的应用属性不同。
+The properties described in this subsection often need to be configured because they differ across
+different applications.
+
+
+#### [[yii\base\Application::aliases|aliases]] <a name="aliases"></a>
+
+该属性允许你用一个数组定义多个 [别名](concept-aliases.md)。数组的key为别名名称，值为对应的路径。例如：
+This property allows you to define a set of [aliases](concept-aliases.md) in terms of an array.
+The array keys are alias names, and the array values are the corresponding path definitions.
+For example,
+
+```php
+[
+    'aliases' => [
+        '@name1' => 'path/to/path1',
+        '@name2' => 'path/to/path2',
+    ],
+]
+```
+
+使用这个属性来定义别名，代替 [[Yii::setAlias()]] 方法来设置。
+This property is provided such that you can define aliases in terms of application configurations instead of
+the method calls [[Yii::setAlias()]].
+
+
+#### [[yii\base\Application::bootstrap|bootstrap]] <a name="bootstrap"></a>
+
+这个属性很实用，它允许你用数组指定启动阶段[[yii\base\Application::bootstrap()|bootstrapping process]]需要运行的组件。
+比如，如果你希望一个 [模块](structure-modules.md) 自定义 [URL 规则](runtime-url-handling.md)，你可以将模块ID加入到bootstrap数组中。
+This is a very useful property. It allows you to specify an array of components that should
+be run during the application [[yii\base\Application::bootstrap()|bootstrapping process]].
+For example, if you want a [module](structure-modules.md) to customize the [URL rules](runtime-url-handling.md),
+you may list its ID as an element in this property.
+
+属性中的每个组件需要指定以下一项:
+Each component listed in this property may be specified in one of the following formats:
+
+- 应用 [组件](#components) ID.
+- [模块](#modules) ID.
+- 类名.
+- 配置数组.
+- 创建并返回一个组件的无名称函数.
+- an application component ID as specified via [components](#components).
+- a module ID as specified via [modules](#modules).
+- a class name.
+- a configuration array.
+- an anonymous function that creates and returns a component.
+
+例如：
+For example,
+
+```php
+[
+    'bootstrap' => [
+        // 应用组件ID或模块ID
+        'demo',
+
+        // 类名
+        'app\components\Profiler',
+
+        // 配置数组
+        [
+            'class' => 'app\components\Profiler',
+            'level' => 3,
+        ],
+
+        // 无名称函数
+        function () {
+            return new app\components\Profiler();
+        }
+    ],
+]
+```
+
+> 补充: 如果模块ID和应用组件ID同名，优先使用应用组件ID，如果你想用模块ID，可以使用如下无名称函数返回模块ID。
+> Info: If a module ID is the same as an application component ID, the application component will be used during
+  the bootstrapping process. If you want to use the module instead, you may specify it using an anonymous function
+  like the following:
+>```php
+[
+    function () {
+        return Yii::$app->getModule('user');
+    },
+]
+```
+
+
+在启动阶段，每个组件都会实例化。如果组件类实现接口 [[yii\base\BootstrapInterface]], 也会调用 [[yii\base\BootstrapInterface::bootstrap()|bootstrap()]] 方法。
+During the bootstrapping process, each component will be instantiated. If the component class
+implements [[yii\base\BootstrapInterface]], its [[yii\base\BootstrapInterface::bootstrap()|bootstrap()]] method
+will also be called.
+
+举一个实际的例子，[Basic Application Template](start-installation.md) 应用主体配置中，开发环境下会在启动阶段运行 `debug` 和 `gii` 模块。
+Another practical example is in the application configuration for the [Basic Application Template](start-installation.md),
+where the `debug` and `gii` modules are configured as bootstrapping components when the application is running
+in development environment,
+
+```php
+if (YII_ENV_DEV) {
+    // configuration adjustments for 'dev' environment
+    $config['bootstrap'][] = 'debug';
+    $config['modules']['debug'] = 'yii\debug\Module';
+
+    $config['bootstrap'][] = 'gii';
+    $config['modules']['gii'] = 'yii\gii\Module';
+}
+```
+
+> 注: 启动太多的组件会降低系统性能，因为每次请求都需要重新运行启动组件，因此谨慎配置启动组件。
+> Note: Putting too many components in `bootstrap` will degrade the performance of your application because
+  for each request, the same set of components need to be run. So use bootstrapping components judiciously.
+
+
+#### [[yii\web\Application::catchAll|catchAll]] <a name="catchAll"></a>
+
+该属性仅 [[yii\web\Application|Web applications]] 网页应用支持。
+它指定一个要处理所有用户请求的 [控制器方法](structure-controllers.md)，通常在维护模式下使用，同一个方法处理所有用户请求。
+This property is supported by [[yii\web\Application|Web applications]] only. It specifies
+a [controller action](structure-controllers.md) which should handle all user requests. This is mainly
+used when the application is in maintenance mode and needs to handle all incoming requests via a single action.
+
+该配置为一个数组，第一项指定动作的路由，剩下的数组项(key-value 成对)指定传递给动作的参数，例如：
+The configuration is an array whose first element specifies the route of the action.
+The rest of the array elements (key-value pairs) specify the parameters to be bound to the action. For example,
+
+```php
+[
+    'catchAll' => [
+        'offline/notice',
+        'param1' => 'value1',
+        'param2' => 'value2',
+    ],
+]
+```
+
+
+#### [[yii\base\Application::components|components]] <a name="components"></a>
+
+这是最重要的属性，它允许你注册多个在其他地方使用的[应用组件](#structure-application-components.md). 例如
+This is the single most important property. It allows you to register a list of named components
+called [application components](#structure-application-components.md) that you can use in other places. For example,
+
+```php
+[
+    'components' => [
+        'cache' => [
+            'class' => 'yii\caching\FileCache',
+        ],
+        'user' => [
+            'identityClass' => 'app\models\User',
+            'enableAutoLogin' => true,
+        ],
+    ],
+]
+```
+
+每一个应用组件指定一个key-value对的数组，key代表组件ID，value代表组件类名或 [配置](concept-configurations.md)。
+Each application component is specified as a key-value pair in the array. The key represents the component ID,
+while the value represents the component class name or [configuration](concept-configurations.md).
+
+在应用中可以任意注册组件，并可以通过表达式 `\Yii::$app->ComponentID` 全局访问。
+You can register any component with an application, and the component can later be accessed globally
+using the expression `\Yii::$app->ComponentID`.
+
+详情请阅读 [应用组件](structure-application-components.md) 一节.
+
+
+#### [[yii\base\Application::controllerMap|controllerMap]] <a name="controllerMap"></a>
+
+该属性允许你指定一个控制器ID到任意控制器类。Yii遵循一个默认的 [规则](#controllerNamespace) 指定控制器ID到任意控制器类（如`post`对应`app\controllers\PostController`）。
+通过配置这个属性，可以打破这个默认规则，在下面的例子中，`account`对应到`app\controllers\UserController`，
+`article` 对应到 `app\controllers\PostController`。
+This property allows you to map a controller ID to an arbitrary controller class. By default, Yii maps
+controller IDs to controller classes based on a [convention](#controllerNamespace) (e.g. the ID `post` would be mapped
+to `app\controllers\PostController`). By configuring this property, you can break the convention for
+specific controllers. In the following example, `account` will be mapped to
+`app\controllers\UserController`, while `article` will be mapped to `app\controllers\PostController`.
+
+```php
+[
+    'controllerMap' => [
+        [
+            'account' => 'app\controllers\UserController',
+            'article' => [
+                'class' => 'app\controllers\PostController',
+                'enableCsrfValidation' => false,
+            ],
+        ],
+    ],
+]
+```
+
+数组的键代表控制器ID，数组的值代表对应的类名。
+The array keys of this property represent the controller IDs, while the array values represent the corresponding
+controller class names or [configurations](concept-configurations.md).
+
+
+#### [[yii\base\Application::controllerNamespace|controllerNamespace]] <a name="controllerNamespace"></a>
+
+该属性指定控制器类默认的命名空间，默认为`app\controllers`。比如控制器ID为 `post` 默认对应 `PostController` （不带命名空间），
+类全名为 `app\controllers\PostController`。
+This property specifies the default namespace under which controller classes should be located. It defaults to
+`app\controllers`. If a controller ID is `post`, by convention the corresponding controller class name (without
+namespace) would be `PostController`, and the fully qualified class name would be `app\controllers\PostController`.
+
+控制器类文件可能放在这个命名空间对应目录的子目录下，例如，控制器ID `admin/post` 对应的控制器类全名为 `app\controllers\admin\PostController`。
+Controller classes may also be located under sub-directories of the directory corresponding to this namespace.
+For example, given a controller ID `admin/post`, the corresponding fully qualified controller class would
+be `app\controllers\admin\PostController`.
+
+控制器类全面能被 [自动加载](concept-autoloading.md)，这点是非常重要的，控制器类的实际命名空间对应这个属性，
+否则，访问时你会收到"Page Not Found"[译：页面找不到]。
+It is important that the fully qualified controller classes should be [autoloadable](concept-autoloading.md)
+and the actual namespace of your controller classes match the value of this property. Otherwise,
+you will receive "Page Not Found" error when accessing the application.
+
+如果你想打破上述的规则，可以配置 [controllerMap](#controllerMap) 属性。
+In case you want to break the convention as described above, you may configure the [controllerMap](#controllerMap)
+property.
+
+
+#### [[yii\base\Application::language|language]] <a name="language"></a>
+
+该属性指定应用展示给终端用户的语言，默认为 `en` 标识英文。如果需要之前其他语言可以配置该属性。
+This property specifies the language in which the application should display content to end users.
+The default value of this property is `en`, meaning English. You should configure this property
+if your application needs to support multiple languages.
+
+该属性影响各种 [国际化](tutorial-i18n.md) ，包括信息翻译、日期格式、数字格式等。
+例如 [[yii\jui\DatePicker]] 小部件会根据该属性展示对应语言的日历以及日期格式。
+The value of this property determines various [internationalization](tutorial-i18n.md) aspects,
+including message translation, date formatting, number formatting, etc. For example, the [[yii\jui\DatePicker]] widget
+will use this property value by default to determine in which language the calendar should be displayed and how
+should the date be formatted.
+
+推荐遵循 [IETF language tag](http://en.wikipedia.org/wiki/IETF_language_tag) 来设置语言，例如 `en` 代表英文， `en-US` 代表英文(美国).
+It is recommended that you specify a language in terms of an [IETF language tag](http://en.wikipedia.org/wiki/IETF_language_tag).
+For example, `en` stands for English, while `en-US` stands for English (United States).
+
+该属性的更多信息可参考 [国际化](tutorial-i18n.md) 一节.
+
+
+#### [[yii\base\Application::modules|modules]] <a name="modules"></a>
+
+该属性指定应用所包含的 [模块](structure-modules.md)。
+This property specifies the [modules](structure-modules.md) that the application contains.
+
+该属性使用数组包含多个模块类 [配置](concept-configurations.md)，数组的键为模块ID，例：
+The property takes an array of module classes or [configurations](concept-configurations.md) with the array keys
+being the module IDs. For example,
+
+```php
+[
+    'modules' => [
+        // "booking" 模块以及对应的类
+        'booking' => 'app\modules\booking\BookingModule',
+
+        // "comment" 模块以及对应的配置数组
+        'comment' => [
+            'class' => 'app\modules\comment\CommentModule',
+            'db' => 'db',
+        ],
+    ],
+]
+```
+
+更多详情请参考 [模块](structure-modules.md) 一节。
+
+
+#### [[yii\base\Application::name|name]] <a name="name"></a>
+
+该属性指定你可能想展示给终端用户的应用名称，不同于需要唯一性的 [[yii\base\Application::id|id]] 属性，
+该属性可以不唯一，该属性用于显示应用的用途。
+This property specifies the application name that may be displayed to end users. Unlike the
+[[yii\base\Application::id|id]] property which should take a unique value, the value of this property is mainly for
+display purpose and does not need to be unique.
+
+如果其他地方的代码没有用到，可以不配置该属性。
+You do not always need to configure this property if none of your code is using it.
+
+
+#### [[yii\base\Application::params|params]] <a name="params"></a>
+
+该属性为一个数组，指定可以全局访问的参数，代替程序中硬编码的数字和字符，应用中的参数定义到一个单独的文件并随时可以访问是一个好习惯。
+例如用参数定义缩略图的长宽如下：
+This property specifies an array of globally accessible application parameters. Instead of using hardcoded
+numbers and strings everywhere in your code, it is a good practice to define them as application parameters
+in a single place and use the parameters in places where needed. For example, you may define the thumbnail
+image size as a parameter like the following:
+
+```php
+[
+    'params' => [
+        'thumbnail.size' => [128, 128],
+    ],
+]
+```
+
+然后简单的使用如下代码即可获取到你需要的长宽参数：
+Then in your code where you need to use the size value, you can simply use the code like the following:
+
+```php
+$size = \Yii::$app->params['thumbnail.size'];
+$width = \Yii::$app->params['thumbnail.size'][0];
+```
+
+以后想修改缩略图长宽，只需要修改该参数而不需要相关的代码。
+Later if you decide to change the thumbnail size, you only need to modify it in the application configuration
+without touching any dependent code.
+
+
+#### [[yii\base\Application::sourceLanguage|sourceLanguage]] <a name="sourceLanguage"></a>
+
+该属性指定应用代码的语言，默认为 `'en-US'` 标识英文（美国），如果应用不是英文请修改该属性。
+This property specifies the language that the application code is written in. The default value is `'en-US'`,
+meaning English (United States). You should configure this property if the text content in your code is not in English.
+
+和 [语言](#language) 属性类似，配置该属性需遵循 [IETF language tag](http://en.wikipedia.org/wiki/IETF_language_tag). 例如 `en` 代表英文， `en-US` 代表英文(美国)。
+Like the [language](#language) property, you should configure this property in terms of
+an [IETF language tag](http://en.wikipedia.org/wiki/IETF_language_tag). For example, `en` stands for English,
+while `en-US` stands for English (United States).
+
+该属性的更多信息可参考 [国际化](tutorial-i18n.md) 一节.
+More details about this property can be found in the [Internationalization](tutorial-i18n.md) section.
+
+
+#### [[yii\base\Application::timeZone|timeZone]] <a name="timeZone"></a>
+
+该属性提供一种方式修改PHP运行环境中的默认时区，配置该属性本质上就是调用PHP函数
+[date_default_timezone_set()](http://php.net/manual/en/function.date-default-timezone-set.php)，例如：
+This property is provided as an alternative way of setting the default time zone of PHP runtime.
+By configuring this property, you are essentially calling the PHP function
+[date_default_timezone_set()](http://php.net/manual/en/function.date-default-timezone-set.php). For example,
+
+```php
+[
+    'timeZone' => 'America/Los_Angeles',
+]
+```
+
+
+#### [[yii\base\Application::version|version]] <a name="version"></a>
+
+该属性指定应用的版本，默认为`'1.0'`，其他代码不使用的话可以不配置。
+This property specifies the version of the application. It defaults to `'1.0'`. You do not always need to configure
+this property if none of your code is using it.
+
+
+### 实用属性 <a name="useful-properties"></a>
+
+本小节描述的属性不经常设置，通常使用系统默认值。如果你想改变默认值，可以配置这些属性。
+The properties described in this subsection are not commonly configured because their default values
+stipulate common conventions. However, you may still configure them in case you want to break the conventions.
+
+
+#### [[yii\base\Application::charset|charset]] <a name="charset"></a>
+
+该属性指定应用使用的字符集，默认值为 `'UTF-8'`，绝大部分应用都在使用，除非已有的系统大量使用非unicode数据才需要更改该属性。
+This property specifies the charset that the application uses. The default value is `'UTF-8'` which should
+be kept as is for most applications unless you are working with some legacy systems that use a lot of non-unicode data.
+
+
+#### [[yii\base\Application::defaultRoute|defaultRoute]] <a name="defaultRoute"></a>
+
+该属性指定未配置的请求的响应 [路由](runtime-routing.md) 规则，路由规则可能包含模块ID，控制器ID，动作ID。
+例如`help`, `post/create`, `admin/post/create`，如果动作ID没有指定，会使用[[yii\base\Controller::defaultAction]]中指定的默认值。
+This property specifies the [route](runtime-routing.md) that an application should use when a request
+does not specify one. The route may consist of child module ID, controller ID, and/or action ID.
+For example, `help`, `post/create`, `admin/post/create`. If action ID is not given, it will take the default
+value as specified in [[yii\base\Controller::defaultAction]].
+
+对于 [[yii\web\Application|Web applications]] 网页应用，默认值为 `'site'` 对应 `SiteController` 控制器，并使用默认的动作。
+因此你不带路由的访问应用，默认会显示 `app\controllers\SiteController::actionIndex()` 的结果。
+For [[yii\web\Application|Web applications]], the default value of this property is `'site'`, which means
+the `SiteController` controller and its default action should be used. As a result, if you access
+the application without specifying a route, it will show the result of `app\controllers\SiteController::actionIndex()`.
+
+对于 [[yii\console\Application|console applications]] 控制台应用，默认值为 `'help'` 对应 [[yii\console\controllers\HelpController::actionIndex()]]。
+因此，如果执行的命令不带参数，默认会显示帮助信息。
+For [[yii\console\Application|console applications]], the default value is `'help'`, which means the core command
+[[yii\console\controllers\HelpController::actionIndex()]] should be used. As a result, if you run the command `yii`
+without providing any arguments, it will display the help information.
+
+
+#### [[yii\base\Application::extensions|extensions]] <a name="extensions"></a>
+
+该属性用数组列表指定应用安装和使用的 [扩展](structure-extensions.md)，默认使用`@vendor/yiisoft/extensions.php`文件返回的数组。
+当你使用 [Composer](http://getcomposer.org) 安装扩展，`extensions.php` 会被自动生成和维护更新。
+所以大多数情况下，不需要配置该属性。
+This property specifies the list of [extensions](structure-extensions.md) that are installed and used by the application.
+By default, it will take the array returned by the file `@vendor/yiisoft/extensions.php`. The `extensions.php` file
+is generated and maintained automatically when you use [Composer](http://getcomposer.org) to install extensions.
+So in most cases, you do not need to configure this property.
+
+特殊情况下你想自己手动维护扩展，可以参照如下配置该属性：
+In the special case when you want to maintain extensions manually, you may configure this property like the following:
+
+```php
+[
+    'extensions' => [
+        [
+            'name' => 'extension name',
+            'version' => 'version number',
+            'bootstrap' => 'BootstrapClassName',  // 可选配，可为配置数组
+            'alias' => [  // 可选配
+                '@alias1' => 'to/path1',
+                '@alias2' => 'to/path2',
+            ],
+        ],
+
+        // ... 更多像上面的扩展 ...
+
+    ],
+]
+```
+
+如上所示，该属性包含一个扩展定义数组，每个扩展为一个包含 `name` 和 `version` 项的数组。
+如果扩展要在 [引导启动](runtime-bootstrapping.md) 阶段运行，需要配置 `bootstrap`以及对应的引导启动类名或 [configuration](concept-configurations.md) 数组。
+扩展也可以定义 [别名](concept-aliases.md)
+As you can see, the property takes an array of extension specifications. Each extension is specified with an array
+consisting of `name` and `version` elements. If an extension needs to run during the [bootstrap](runtime-bootstrapping.md)
+process, a `bootstrap` element may be specified with a bootstrapping class name or a [configuration](concept-configurations.md)
+array. An extension may also define a few [aliases](concept-aliases.md).
+
+
+#### [[yii\base\Application::layout|layout]] <a name="layout"></a>
+
+该属性指定渲染 [视图](structure-views.md) 默认使用的布局名字，默认值为 `'main'` 对应[布局路径](#layoutPath)下的 `main.php` 文件，
+如果 [布局路径](#layoutPath) 和 [视图路径](#viewPath) 都是默认值，默认布局文件可以使用路径别名`@app/views/layouts/main.php`
+This property specifies the name of the default layout that should be used when rendering a [view](structure-views.md).
+The default value is `'main'`, meaning the layout file `main.php` under the [layout path](#layoutPath) should be used.
+If both of the [layout path](#layoutPath) and the [view path](#viewPath) are taking the default values,
+the default layout file can be represented as the path alias `@app/views/layouts/main.php`.
+
+如果不想设置默认布局文件，可以设置该属性为 `false`，这种做法比较罕见。
+You may configure this property to be `false` if you want to disable layout by default, although this is very rare.
+
+
+#### [[yii\base\Application::layoutPath|layoutPath]] <a name="layoutPath"></a>
+
+该属性指定查找布局文件的路径，默认值为 [视图路径](#viewPath) 下的 `layouts` 子目录。
+如果 [视图路径](#viewPath) 使用默认值，默认的布局路径别名为`@app/views/layouts`。
+This property specifies the path where layout files should be looked for. The default value is
+the `layouts` sub-directory under the [view path](#viewPath). If the [view path](#viewPath) is taking
+its default value, the default layout path can be represented as the path alias `@app/views/layouts`.
+
+该属性需要配置成一个目录或 路径 [别名](concept-aliases.md)。
+You may configure it as a directory or a path [alias](concept-aliases.md).
+
+
+#### [[yii\base\Application::runtimePath|runtimePath]] <a name="runtimePath"></a>
+
+该属性指定临时文件如日志文件、缓存文件等保存路径，默认值为带别名的 `@app/runtime`。
+This property specifies the path where temporary files, such as log files, cache files, can be generated.
+The default value is the directory represented by the alias `@app/runtime`.
+
+可以配置该属性为一个目录或者路径 [别名](concept-aliases.md)，注意应用运行时有对该路径的写入权限，
+以及终端用户不能访问改路径因为临时文件可能包含一些敏感信息。
+You may configure it as a directory or a path [alias](concept-aliases.md). Note that the runtime path must
+be writable by the process running the application. And the path should be protected from being accessed
+by end users because the temporary files under it may contain sensitive information.
+
+为了简化访问该路径，Yii预定义别名 `@runtime` 代表该路径。
+To simplify accessing to this path, Yii has predefined a path alias named `@runtime` for it.
+
+
+#### [[yii\base\Application::viewPath|viewPath]] <a name="viewPath"></a>
+
+该路径指定视图文件的根目录，默认值为带别名的 `@app/views`，可以配置它为一个目录或者路径 [别名](concept-aliases.md).
+This property specifies the root directory where view files are located. The default value is the directory
+represented by the alias `@app/views`. You may configure it as a directory or a path [alias](concept-aliases.md).
+
+
+#### [[yii\base\Application::vendorPath|vendorPath]] <a name="vendorPath"></a>
+
+该属性指定 [Composer](http://getcomposer.org) 管理的供应商路径，该路径包含应用使用的包括Yii框架在内的所有第三方库。
+默认值为带别名的 `@app/vendor` 。
+This property specifies the vendor directory managed by [Composer](http://getcomposer.org). It contains
+all third party libraries used by your application, including the Yii framework. The default value is
+the directory represented by the alias `@app/vendor`.
+
+可以配置它为一个目录或者路径 [别名](concept-aliases.md)，当你修改时，务必修改对应的 Composer 配置。
+You may configure this property as a directory or a path [alias](concept-aliases.md). When you modify
+this property, make sure you also adjust the Composer configuration accordingly.
+
+为了简化访问该路径，Yii预定义别名 `@vendor` 代表该路径。
+To simplify accessing to this path, Yii has predefined a path alias named `@vendor` for it.
+
+
+#### [[yii\console\Application::enableCoreCommands|enableCoreCommands]] <a name="enableCoreCommands"></a>
+
+该属性仅 [[yii\console\Application|console applications]] 控制台应用支持， 用来指定是否启用Yii中的核心命令，默认值为 `true`。
+This property is supported by [[yii\console\Application|console applications]] only. It specifies
+whether the core commands included in the Yii release should be enabled. The default value is `true`.
+
+
+## Application Events <a name="application-events"></a>
+
+应用在处理请求过程中会触发事件，可以在配置文件配置事件处理代码，如下所示：
+An application triggers several events during the lifecycle of handling an request. You may attach event
+handlers to these events in application configurations like the following,
+
+```php
+[
+    'on beforeRequest' => function ($event) {
+        // ...
+    },
+]
+```
+
+`on eventName` 语法的用法在 [Configurations](concept-configurations.md#configuration-format) 一节有详细描述.
+The use of the `on eventName` syntax is described in the [Configurations](concept-configurations.md#configuration-format)
+section.
+
+另外，在应用主体实例化后，你可以在[引导启动](runtime-bootstrapping.md) 阶段附加事件处理代码，例如：
+Alternatively, you may attach event handlers during the [bootstrapping process](runtime-bootstrapping.md) process
+after the application instance is created. For example,
+
+```php
+\Yii::$app->on(\yii\base\Application::EVENT_BEFORE_REQUEST, function ($event) {
+    // ...
+});
+```
+
+### [[yii\base\Application::EVENT_BEFORE_REQUEST|EVENT_BEFORE_REQUEST]] <a name="beforeRequest"></a>
+
+该事件在应用处理请求*before*之前，实际的事件名为 `beforeRequest`。
+This event is triggered *before* an application handles a request. The actual event name is `beforeRequest`.
+
+在事件触发前，应用主体已经实例化并配置好了，所以通过事件机制将你的代码嵌入到请求处理过程中非常不错。
+例如在事件处理中根据某些参数动态设置[[yii\base\Application::language]]语言属性。 
+When this event is triggered, the application instance has been configured and initialized. So it is a good place
+to insert your custom code via the event mechanism to intercept the request handling process. For example,
+in the event handler, you may dynamically set the [[yii\base\Application::language]] property based on some parameters.
+
+
+### [[yii\base\Application::EVENT_BEFORE_REQUEST|EVENT_AFTER_REQUEST]] <a name="afterRequest"></a>
+
+该事件在应用处理请求*after*之后但在返回响应*before*之前触发，实际的事件名为`afterRequest`。
+This event is triggered *after* an application finishes handling a request but *before* sending the response.
+The actual event name is `afterRequest`.
+
+该事件触发时，请求已经被处理完，可以做一些请求后处理或自定义响应。 
+When this event is triggered, the request handling is completed and you may take this chance to do some postprocessing
+of the request or customize the response.
+
+注意 [[yii\web\Response|response]] 组件在发送响应给终端用户时也会触发一些事件，这些事件都在本事件*after*之后触发。
+Note that the [[yii\web\Response|response]] component also triggers some events while it is sending out
+response content to end users. Those events are triggered *after* this event.
+
+
+### [[yii\base\Application::EVENT_BEFORE_REQUEST|EVENT_BEFORE_ACTION]] <a name="beforeAction"></a>
+
+该事件在每个 [控制器动作](structure-controllers.md) 运行*before*之前会被触发，实际的事件名为 `beforeAction`.
+
+事件的参数为一个 [[yii\base\ActionEvent]] 实例，
+事件处理中可以设置[[yii\base\ActionEvent::isValid]] 为 `false` 停止运行后续动作，例如：
+The event parameter is an instance of [[yii\base\ActionEvent]]. An event handler may set
+the [[yii\base\ActionEvent::isValid]] property to be `false` to stop running the action.
+For example,
+
+```php
+[
+    'on beforeAction' => function ($event) {
+        if (some condition) {
+            $event->isValid = false;
+        } else {
+        }
+    },
+]
+```
+
+注意 [模块](structure-modules.md) 和 [控制器](structure-controllers.md) 都会触发 `beforeAction` 事件。
+应用主体对象首先触发该事件，然后模块触发（如果存在模块），最后控制器触发。
+任何一个事件处理中设置 [[yii\base\ActionEvent::isValid]] 设置为 `false` 会停止触发后面的事件。
+Note that the same `beforeAction` event is also triggered by [modules](structure-modules.md)
+and [controllers](structure-controllers.md). Application objects are the first ones
+triggering this event, followed by modules (if any), and finally controllers. If an event handler
+sets [[yii\base\ActionEvent::isValid]] to be `false`, all the following events will NOT be triggered.
+
+
+### [[yii\base\Application::EVENT_BEFORE_REQUEST|EVENT_AFTER_ACTION]] <a name="afterAction"></a>
+
+该事件在每个 [控制器动作](structure-controllers.md) 运行*after*之后会被触发，实际的事件名为 `afterAction`.
+This event is triggered *after* running every [controller action](structure-controllers.md).
+The actual event name is `afterAction`.
+
+该事件的参数为 [[yii\base\ActionEvent]] 实例，通过[[yii\base\ActionEvent::result]]属性，事件处理可以访问和修改动作的结果。例如：
+The event parameter is an instance of [[yii\base\ActionEvent]]. Through
+the [[yii\base\ActionEvent::result]] property, an event handler may access or modify the action result.
+For example,
+
+```php
+[
+    'on afterAction' => function ($event) {
+        if (some condition) {
+            // 修改 $event->result
+        } else {
+        }
+    },
+]
+```
+
+注意 [模块](structure-modules.md) 和 [控制器](structure-controllers.md) 都会触发 `afterAction` 事件。
+这些对象的触发顺序和 `beforeAction` 相反，也就是说，控制器最先触发，然后是模块（如果有模块），最后为应用主体。Note that the same `afterAction` event is also triggered by [modules](structure-modules.md)
+and [controllers](structure-controllers.md). These objects trigger this event in the reverse order
+as for that of `beforeAction`. That is, controllers are the first objects triggering this event,
+followed by modules (if any), and finally applications.
+
+
+## 应用主体生命周期 <a name="application-lifecycle"></a>
+## Application Lifecycle <a name="application-lifecycle"></a>
+
+当运行 [入口脚本](structure-entry-scripts.md) 处理请求时，应用主体会经历以下生命周期:
+When an [entry script](structure-entry-scripts.md) is being executed to handle a request,
+an application will undergo the following lifecycle:
+
+1. 入口脚本加载应用主体配置数组。
+2. 入口脚本创建一个应用主体实例：
+  * 调用 [[yii\base\Application::preInit()|preInit()]] 配置几个高级别应用主体属性，比如[[yii\base\Application::basePath|basePath]]。
+  * 注册 [[yii\base\Application::errorHandler|error handler]] 错误处理方法.
+  * 配置应用主体属性.
+  * 调用 [[yii\base\Application::init()|init()]] 初始化，该函数会调用 [[yii\base\Application::bootstrap()|bootstrap()]] 运行引导启动组件.
+3. 入口脚本调用 [[yii\base\Application::run()]] 运行应用主体:
+  * 触发 [[yii\base\Application::EVENT_BEFORE_REQUEST|EVENT_BEFORE_REQUEST]] 事件。
+  * 处理请求：解析请求 [路由](runtime-routing.md) 和相关参数；创建路由指定的模块、控制器和动作对应的类，并运行动作。
+  * 触发 [[yii\base\Application::EVENT_AFTER_REQUEST|EVENT_AFTER_REQUEST]] 事件。
+  * 发送响应到终端用户.
+4. 入口脚本接收应用主体传来的退出状态并完成请求的处理。
+1. The entry script loads the application configuration as an array.
+2. The entry script creates a new instance of the application:
+  * [[yii\base\Application::preInit()|preInit()]] is called, which configures some high priority
+    application properties, such as [[yii\base\Application::basePath|basePath]].
+  * Register the [[yii\base\Application::errorHandler|error handler]].
+  * Configure application properties.
+  * [[yii\base\Application::init()|init()]] is called which further calls
+    [[yii\base\Application::bootstrap()|bootstrap()]] to run bootstrapping components.
+3. The entry script calls [[yii\base\Application::run()]] to run the application:
+  * Trigger the [[yii\base\Application::EVENT_BEFORE_REQUEST|EVENT_BEFORE_REQUEST]] event.
+  * Handle the request: resolve the request into a [route](runtime-routing.md) and the associated parameters;
+    create the module, controller and action objects as specified by the route; and run the action.
+  * Trigger the [[yii\base\Application::EVENT_AFTER_REQUEST|EVENT_AFTER_REQUEST]] event.
+  * Send response to the end user.
+4. The entry script receives the exit status from the application and completes the request processing.