PHP依赖倒置(Dependency Injection)代码实例
实现类：
<?php
classContainer
{
protected$setings=array();
publicfunctionset($abstract,$concrete=null)
{
if($concrete===null){
$concrete=$abstract;
}
$this->setings[$abstract]=$concrete;
}
publicfunctionget($abstract,$parameters=array())
{
if(!isset($this->setings[$abstract])){
returnnull;
}
return$this->build($this->setings[$abstract],$parameters);
}
publicfunctionbuild($concrete,$parameters)
{
if($concreteinstanceofClosure){
return$concrete($this,$parameters);
}
$reflector=newReflectionClass($concrete);
if(!$reflector->isInstantiable()){
thrownewException("Class{$concrete}isnotinstantiable");
}
$constructor=$reflector->getConstructor();
if(is_null($constructor)){
return$reflector->newInstance();
}
$parameters=$constructor->getParameters();
$dependencies=$this->getDependencies($parameters);
return$reflector->newInstanceArgs($dependencies);
}
publicfunctiongetDependencies($parameters)
{
$dependencies=array();
foreach($parametersas$parameter){
$dependency=$parameter->getClass();
if($dependency===null){
if($parameter->isDefaultValueAvailable()){
$dependencies[]=$parameter->getDefaultValue();
}else{
thrownewException("Cannotberesolveclassdependency{$parameter->name}");
}
}else{
$dependencies[]=$this->get($dependency->name);
}
}
return$dependencies;
}
}
实现实例：
<?php
require'container.php';
interfaceMyInterface{}
classFooimplementsMyInterface{}
classBarimplementsMyInterface{}
classBaz
{
publicfunction__construct(MyInterface$foo)
{
$this->foo=$foo;
}
}
$container=newContainer();
$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);