php 自动绑定di容器实现

 <?php

 class Bim

 {

     public function doSth()

     {

         echo __METHOD__.PHP_EOL;

     }

 }

 class Bar

 {

     protected $bim;

     public function __construct(Bim $bim)

     {

         $this->bim = $bim;

     }

     public function doSth()

     {

         $this->bim->doSth();

         echo __METHOD__.PHP_EOL;

     }

 }

 class Bar2 extends Bar

 {

     protected $bim;

     public function doSth()

     {

         $this->bim->doSth();

         echo __METHOD__.PHP_EOL;

     }

 }

 class Foo

 {

     private $bar;

     public function __construct(Bar $bar)

     {

         $this->bar = $bar;

     }

     public function doSth()

     {

         $this->bar->doSth();

         echo __METHOD__.PHP_EOL;

     }

 }

 class Container

 {

     private $s = [];

     public function __set($k, $c)

     {

         $this->s[$k] = $c;

     }

     public function __get($k)

     {

         return $this->s[$k]($this);

     }

 }

 class Container2

 {

     private $s = [];

     public function __set($k, $c)

     {

         $this->s[$k] = $c;

     }

     public function __get($k)

     {

         if (!$this->s[$k]) {

             return false;

         }

         return $this->build($this->s[$k]);

     }

     public function build($className)

     {

         if ($className instanceof Closure) {

             return $className($this);

         }

         try {

             $reflector = new ReflectionClass($className);

         } catch (\ReflectionException $e) {

             echo $className.'类反射异常'.PHP_EOL;

             echo $e->getMessage();

         }

         #检查类是否可实例化, 排除抽象类abstract和对象接口interface

         if (!$reflector->isInstantiable()) {

             throw new Exception("Can't instantiate this.");

         }

         $constructor = $reflector->getConstructor();

         #如果没有构造函数， 直接实例化并返回

         if (is_null($constructor)) {

             return new $className;

         }

         $parameters = $constructor->getParameters();

         #递归解析构造函数的参数

         $dependencies = $this->getDependencies($parameters);

         #创建一个类的新实例,给出的参数将传递到类的构造函数.

         return $reflector->newInstanceArgs($dependencies);

     }

     public function getDependencies($parameters)

     {

         $dependencies = [];

         foreach ($parameters as $parameter) {

             $dependency = $parameter->getClass();

             if (is_null($dependency)) {

                 $dependencies[] = $this->resolveNonClass($parameter);

             } else {

                 #是一个类，递归解析

                 $className = lcfirst($dependency->name);

                 #先取出容器中绑定的类 否则自动绑定

                 if ($this->s[$className]) {

                     $dependencies[] = $this->$className;

                 } else {

                     $dependencies[] = $this->build($dependency->name);

                 }

             }

         }

         return $dependencies;

     }

     public function resolveNonClass($parameter)

     {

         // 有默认值则返回默认值

         if ($parameter->isDefaultValueAvailable()) {

             return $parameter->getDefaultValue();

         }

         throw new Exception('I have no idea what to do here.');

     }

 }

 // 依赖注入模式

 //$foo = new Foo(new Bar(new Bim()));

 #di模式

 // $c = new Container();

 // $c->bim = function() {

 //     return new Bim();

 // };

 // $c->bar = function($c) {

 //     return new Bar($c->bim);

 // };

 // $c->foo = function($c) {

 //     return new Foo($c->bar);

 // };

 #实现了自动绑定

 #1向di中注册类

 $c = new Container2();

 $c->bim = 'Bim';

 #$c->bar = 'Bar2'; #实现了自动绑定 如果没有注册类的化就按自动加载去寻找类

 $c->foo = 'Foo';

 // $c->bar = 'Bar';

 // $c->foo = function ($c) {

 //     return new Foo($c->bar);

 // };

 // 从容器中取得Foo

 $foo = $c->foo;

 $foo->doSth();