实现类：
<?php
class Container
{
protected $setings = array();
public function set($abstract, $concrete = null)
{
if ($concrete === null) {
$concrete = $abstract;
}
$this->setings[$abstract] = $concrete;
}
public function get($abstract, $parameters = array())
{
if (!isset($this->setings[$abstract])) {
return null;
}
return $this->build($this->setings[$abstract], $parameters);
}
public function build($concrete, $parameters)
{
if ($concrete instanceof Closure) {
return $concrete($this, $parameters);
}
$reflector = new ReflectionClass($concrete);
if (!$reflector->isInstantiable()) {
throw new Exception("Class {$concrete} is not instantiable");
}
$constructor = $reflector->getConstructor();
if (is_null($constructor)) {
return $reflector->newInstance();
}
$parameters = $constructor->getParameters();
$dependencies = $this->getDependencies($parameters);
return $reflector->newInstanceArgs($dependencies);
}
public function getDependencies($parameters)
{
$dependencies = array();
foreach ($parameters as $parameter) {
$dependency = $parameter->getClass();
if ($dependency === null) {
if ($parameter->isDefaultValueAvailable()) {
$dependencies[] = $parameter->getDefaultValue();
} else {
throw new Exception("Can not be resolve class dependency {$parameter->name}");
}
} else {
$dependencies[] = $this->get($dependency->name);
}
}
return $dependencies;
}
}
实现实例：
<?php
require 'container.php';
interface MyInterface{}
class Foo implements MyInterface{}
class Bar implements MyInterface{}
class Baz
{
public function __construct(MyInterface $foo)
{
$this->foo = $foo;
}
}
$container = new Container();
$container->set('Baz', 'Baz');
$container->set('MyInterface', 'Foo');
$baz = $container->get('Baz');
print_r($baz);
$container->set('MyInterface', 'Bar');
$baz = $container->get('Baz');
print_r($baz);