简述 container —— 反射机制实现

new User(
    new \Database\MysqlDrive(new \Database\Connection),
    new Builder(),
    new Relations(),
    new Event(new Listener()),
    new Auth(),
    ...
)

stop？我好像有点写不完，我只想获取一个用户名而已！！！Copy

<?php

namespace Container\Foo;

use Container\Bar\BarA;
use Container\Bar\BarB;
use Container\Bar\BarC;
use Container\Bar\BarD;

class Foo
{
    private $barA;
    private $barB;
    private $barC;
    private $barD;

    public function __construct(BarA $barA, BarB $barB, BarC $barC, BarD $barD)
    {

        $this->barA = $barA;
        $this->barB = $barB;
        $this->barC = $barC;
        $this->barD = $barD;
    }

    public function allBarName()
    {
        return $this->barA->name().'/'.$this->barB->name().'/'.$this->barC->name().'/'.$this->barD->name();
    }
}
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<?php

namespace Container\Bar;

class BarA
{
    public function name()
    {
        return '彼得·帕克';
    }
}
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$foo = new \Container\Foo\Foo(
    new \Container\Bar\BarA(),
    new \Container\Bar\BarB(),
    new \Container\Bar\BarC(),
    new \Container\Bar\BarD()
);

echo $foo->allBarName(); // 彼得·帕克/托尼·屎大颗/巴里·艾伦/布鲁斯·韦恩
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<?php

namespace Container;

class Container
{
    public static function make($class)
    {
        $reflection = new \ReflectionClass($class);

        $constructor = $reflection->getConstructor();
        $parameters = $constructor->getParameters();

        $instances = [];

        foreach ($parameters as $parameter) {
            $className =  $parameter->getClass()->getName();
            $instances[] = new $className;
        }

        //... 将数组拆封成参数传递给方法, 类似于 call_user_func_array()
        return new $class(...$instances);
    }
}Copy

$foo = \Container\Container::make(\Container\Foo\Foo::class);
echo $foo->allBarName(); // 彼得·帕克/托尼·屎大颗/巴里·艾伦/布鲁斯·韦恩Copy