Yii2配置基本概念

$config = [    'class' => 'yii\db\Connection',    'dsn' => 'mysql:host=127.0.0.1;dbname=demo',   
 'username' => 'root',    'password' => '',    'charset' => 'utf8',
];$db = Yii::createObject($config);

Yii::configure($object, $config);

class Person
{    private $strategy = null;    public function __construct(TravelStrategy $travel)
    {
        $this->strategy = $travel;
    }    /**
     * 设置旅行的方式.
     */
    public function setTravelStrategy(TravelStrategy $travel)
    {
        $this->strategy = $travel;
    }    /**
     * 旅行.
     */
    public function travel()
    {        //这里实现了“委托”，委托给$this->strategy来实现旅行的具体方式
        return $this->strategy->travelAlgorithm();
    }
}

class Test{
    public function run($argument)
    {
        // 乘坐火车旅行
        $person = new Person(new TrainStrategy());        $person->travel();        // 改骑自行车
        $person->setTravelStrategy(new BicycleStrategy());        $person->travel();
    }
}

$person = new Person(new TrainStrategy());

class Person extends Component{    private $strategy = null;    /**
     * 旅行.
     */
    public function setTravelStrategy($travel)
    {        if (!($travel instanceof TravelStrategy)) {
            $travel = Yii::createObject($travel);
        }
        $this->strategy = $travel;
    }    /**
     * 旅行.
     */
    public function travel()
    {        
        return $this->strategy->travelAlgorithm();
    }
}

//用配置创建对象并初始化，选择火车出行
$person = Yii::createObject([    'class' => Person::class,
    'travelStrategy' => [        'class' => TrainStrategy::class
    ]
]);
$person->travel();//用配置重新初始化对象，改骑自行车
$person = Yii::configure($person, [    'travelStrategy' => [        'class' => BicycleStrategy::class
    ]
]);
$person->travel();

[    'class' => 'ClassName',    'propertyName' => 'propertyValue',    'on eventName' => $eventHandler,    'as behaviorName' => $behaviorConfig,
]

[    'class' => 'app\components\SearchEngine',    'apiKey' => 'xxxxxxxx',    'on search' => function ($event) {
        Yii::info("搜索的关键词： " . $event->keyword);
    },    'as indexer' => [        'class' => 'app\components\IndexerBehavior',
        // ... 初始化属性值 ...
    ],
]

public function __construct($config = []){
    if (!empty($config)) {
        Yii::configure($this, $config);
    }    $this->init();
}

// $object就是即将被配置的对象实例，$properties是配置数组public static function configure($object, $properties){
    //遍历每个参数，将其设置为属性，这里可能调用setter等方法
    foreach ($properties as $name => $value) {        $object->$name = $value;
    }    return $object;
}

$config = [    'id' => 'basic',    'basePath' => dirname(__DIR__),    'extensions' => require(__DIR__ . '/../vendor/yiisoft/extensions.php'),    'components' => [        'cache' => [            'class' => 'yii\caching\FileCache',
        ],        'mailer' => [            'class' => 'yii\swiftmailer\Mailer',
        ],        'log' => [            'class' => 'yii\log\Dispatcher',            'traceLevel' => YII_DEBUG ? 3 : 0,            'targets' => [
                [                    'class' => 'yii\log\FileTarget',
                ],
            ],
        ],        'db' => [            'class' => 'yii\db\Connection',            'dsn' => 'mysql:host=localhost;dbname=stay2',            'username' => 'root',            'password' => '',            'charset' => 'utf8',
        ],
    ],
];

(new yii\web\Application($config))->run();

$config = [    'id' => 'basic',    'basePath' => dirname(__DIR__),    'extensions' => require __DIR__ . '/../vendor/yiisoft/extensions.php',    'container' => [        'definitions' => [            'yii\widgets\LinkPager' => ['maxButtonCount' => 5]
        ],        'singletons' => [            // 依赖注入容器单例配置
        ]
    ]
];

return [    'id' => 'basic',    'basePath' => dirname(__DIR__),    'extensions' => require(__DIR__ . '/../vendor/yiisoft/extensions.php'),    'components' => require(__DIR__ . '/components.php'),
];

鉴于 components 配置也很复杂，上述代码把它们存储在单独的 components.php 文件中，并且包含在 web.php 里。 components.php 的内容如下：

return [    'cache' => [        'class' => 'yii\caching\FileCache',
    ],    'mailer' => [        'class' => 'yii\swiftmailer\Mailer',
    ],    'log' => [        'class' => 'yii\log\Dispatcher',        'traceLevel' => YII_DEBUG ? 3 : 0,        'targets' => [
            [                'class' => 'yii\log\FileTarget',
            ],
        ],
    ],    'db' => [        'class' => 'yii\db\Connection',        'dsn' => 'mysql:host=localhost;dbname=stay2',        'username' => 'root',        'password' => '',        'charset' => 'utf8',
    ],
];

$config = require('path/to/web.php');(new yii\web\Application($config))->run();

\Yii::$container->set('yii\widgets\LinkPager', [    'maxButtonCount' => 5,
]);

defined('YII_ENV') or define('YII_ENV', 'dev');

$config = [...];if (YII_ENV_DEV) {
    // 根据 `dev` 环境进行的配置调整
    $config['bootstrap'][] = 'debug';
    $config['modules']['debug'] = 'yii\debug\Module';
}return $config;