[PHP知识库]Yii2新增service层解决多个model互相耦合

service层的作用就是把这些需要多个model参与的复杂业务逻辑单独封装出来，这些model之间不再发生直接的依赖，而是在service层内协同完成逻辑。service层的第一个目的其实就是对model层进行解耦，从而达到低耦合高内聚的目的。

具体实现

定义服务层基类Service.php,位置/services/Service.php

<?php 

namespace api\services;
use yii\base\BaseObject;
use yii\base\InvalidConfigException;

class Service extends BaseObject
{
    public $childService;
    public $childServiceList;


    public function getChildService($childServiceName)
    {
        if (!isset($this->childServiceList[$childServiceName])) {
            $childService = $this->childService;
            if (isset($childService[$childServiceName])) {
                $service = $childService[$childServiceName];
                $this->childServiceList[$childServiceName] = \Yii::createObject($service);
            } else {
                throw new InvalidConfigException(
                'Child Service [' . $childServiceName . '] is not find in ' .
                get_called_class() . ', you must config it! '
                );
            }
        }
        return $this->childServiceList[$childServiceName];
    }

    public function __get($attr)
    {
        return $this->getChildService($attr);
    }
}

增加服务层子类，这里以订单服务为例，创建Order.php,位置/services/Order.php

<?php 

namespace api\services;

class Order extends Service
{
    public function test(){
        return 'test Service[order] success';
    }
}

项目主配置文件/config/main.php,增加components节点的配置

    'components' => [
        'service' => require('service.php'),
    ],

增加/config/service.php文件，内容如下

<?php

return [
    'class' => 'api\services\Service',
    'childService' => [
        'order' => 'api\services\Order',
        //其他服务子类...
    ],
];

调用服务方法

Yii::$app->service->order->test();