1 
     bim = $bim; 18     } 19  20     public function doSth() 21     { 22         $this->bim->doSth(); 23         echo __METHOD__.PHP_EOL; 24     } 25 } 26  27 class Bar2 extends Bar 28 { 29     protected $bim; 30  31     public function doSth() 32     { 33         $this->bim->doSth(); 34         echo __METHOD__.PHP_EOL; 35     } 36 } 37  38 class Foo 39 { 40     private $bar; 41  42     public function __construct(Bar $bar) 43     { 44         $this->bar = $bar; 45     } 46  47     public function doSth() 48     { 49         $this->bar->doSth(); 50         echo __METHOD__.PHP_EOL; 51     } 52 } 53  54 class Container 55 { 56     private $s = []; 57  58     public function __set($k, $c) 59     { 60         $this->s[$k] = $c; 61     } 62  63     public function __get($k) 64     { 65         return $this->s[$k]($this); 66     } 67 } 68  69 class Container2 70 { 71     private $s = []; 72  73     public function __set($k, $c) 74     { 75         $this->s[$k] = $c; 76     } 77  78     public function __get($k) 79     { 80         if (!$this->s[$k]) { 81             return false; 82         }     83         return $this->build($this->s[$k]); 84     } 85  86     public function build($className) 87     { 88         if ($className instanceof Closure) { 89             return $className($this); 90         } 91  92         try { 93             $reflector = new ReflectionClass($className); 94         } catch (\ReflectionException $e) { 95             echo $className.'类反射异常'.PHP_EOL; 96             echo $e->getMessage(); 97         } 98          99         #检查类是否可实例化, 排除抽象类abstract和对象接口interface100         if (!$reflector->isInstantiable()) {101             throw new Exception("Can't instantiate this.");102         }103 104         $constructor = $reflector->getConstructor();105         106         #如果没有构造函数， 直接实例化并返回107         if (is_null($constructor)) {108             return new $className;109         }110 111         $parameters = $constructor->getParameters();112 113         #递归解析构造函数的参数114         $dependencies = $this->getDependencies($parameters);115 116         #创建一个类的新实例,给出的参数将传递到类的构造函数.117         return $reflector->newInstanceArgs($dependencies);118     }119 120     public function getDependencies($parameters)121     {122         $dependencies = [];123 124         foreach ($parameters as $parameter) {125             $dependency = $parameter->getClass();126 127             if (is_null($dependency)) {128                 $dependencies[] = $this->resolveNonClass($parameter);129             } else {130                 #是一个类，递归解析131                 $className = lcfirst($dependency->name);132                 #先取出容器中绑定的类 否则自动绑定133                 if ($this->s[$className]) {134                     $dependencies[] = $this->$className;                    135                 } else {136                     $dependencies[] = $this->build($dependency->name);                                        137                 }138             }139         }140 141         return $dependencies;142     }143 144     public function resolveNonClass($parameter)145     {146         // 有默认值则返回默认值147         if ($parameter->isDefaultValueAvailable()) {148             return $parameter->getDefaultValue();149         }150         throw new Exception('I have no idea what to do here.');151     }152 }153 154 // 依赖注入模式155 //$foo = new Foo(new Bar(new Bim()));156 157 #di模式158 // $c = new Container();159 // $c->bim = function() {160 //     return new Bim();161 // };162 // $c->bar = function($c) {163 //     return new Bar($c->bim);164 // };165 // $c->foo = function($c) {166 //     return new Foo($c->bar);167 // };168 169 #实现了自动绑定170 #1向di中注册类171 $c = new Container2();172 $c->bim = 'Bim';173 #$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174 $c->foo = 'Foo';175 // $c->bar = 'Bar';176 // $c->foo = function ($c) {177 //     return new Foo($c->bar);178 // };179 // 从容器中取得Foo180 $foo = $c->foo;181 $foo->doSth();

参考:https://segmentfault.com/a/1190000002424023