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What is dependency injection? This article will take you to understand dependency injection in PHP, introduce the reasons for dependency injection, and the application of dependency injection. I hope it will be helpful to you!
1. What is Dependency Injection (DI)
II , The reason why dependency injection appears
<?php class container { private $adapter; public function __construct() { $this->adapter = new adapter(); } }
3. Simple dependencies Injection
<?php class container { private $adapter; public function __construct(adapter $adapter) { $this->adapter = $adapter; } }
<?php class container { public $instance = []; public function __set($name, $value) { $this->instance[$name] = $value; } } $container = new container(); $container->adapter = new adapter();
5. Application of Dependency Injection
<?php class container { public $instance = []; public function __set($name, $value) { $this->instance[$name] = $value; } } class adapter { public $name = '我是调度器'; } $container = new container(); $container->adapter = new adapter(); class autofelix { private $container; public function __construct(container $container) { $this->container = $container; } public function who($class) { return $this->container->instance[$class]->name; } } $autofelix = new autofelix($container); $who = $autofelix->who('adapter'); var_dump($who); //我是调度器
6. High-level optimization
In the above application, we directly inject the instantiated objects into the container.<?php $container = new container(); $container->adapter = new adapter(); //高阶优化 $container = new container(); $container->adapter = function () { return new adapter(); };
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