Yii ServiceLocator.php

　　public function getComponents($returnDefinitions = true)
    {
        return $returnDefinitions ? $this->_definitions : $this->_components;
    }

    /**
     * Registers a set of component definitions in this locator.
     *
     * This is the bulk version of [[set()]]. The parameter should be an array
     * whose keys are component IDs and values the corresponding component definitions.
     *
     * For more details on how to specify component IDs and definitions, please refer to [[set()]].
     *
     * If a component definition with the same ID already exists, it will be overwritten.
     *
     * The following is an example for registering two component definitions:
     *
     * ```php
     * [
     *     'db' => [
     *         'class' => 'yii\db\Connection',
     *         'dsn' => 'sqlite:path/to/file.db',
     *     ],
     *     'cache' => [
     *         'class' => 'yii\caching\DbCache',
     *         'db' => 'db',
     *     ],
     * ]
     * ```
     *
     * @param array $components component definitions or instances
     */
    public function setComponents($components)
    {
        foreach ($components as $id => $component) {
            $this->set($id, $component);
        }
    }

配置文件中的componets数组都到了这里