讲清楚容器（IOC）一段代码就够了

<?php

interface log
{
    public function write();
}

// 文件记录日志
class FileLog implements Log
{
    public function write(){
        echo 'file log write...';
    }
}

// 数据库记录日志
class DatabaseLog implements Log
{
    public function write(){
        echo 'database log write...';
    }
}

class User
{
    protected $log;
    public function __construct(Log $log)
    {
        $this->log = $log;
    }
    public function login()
    {
        // 登录成功，记录登录日志
        echo 'login success...';
        $this->log->write();
    }
}

class Ioc
{
    public $binding = [];

    public function bind($abstract, $concrete)
    {
        //这里为什么要返回一个closure呢？因为bind的时候还不需要创建User对象，所以采用closure等make的时候再创建FileLog;
        $this->binding[$abstract]['concrete'] = function ($ioc) use ($concrete) {
            return $ioc->build($concrete);
        };


    }

    public function make($abstract)
    {
        // 根据key获取binding的值
        $concrete = $this->binding[$abstract]['concrete'];
        //Log = function($ioc) use ($concrete){$this->build(User)}
        return $concrete($this);
    }

    // 创建对象
    public function build($concrete) {
        $reflector = new ReflectionClass($concrete);// User
        $constructor = $reflector->getConstructor();//
        if(is_null($constructor)) {
            return $reflector->newInstance();
        }else {
            $dependencies = $constructor->getParameters();// Log
            $instances = $this->getDependencies($dependencies);
            return $reflector->newInstanceArgs($instances);
        }
    }

    // 获取参数的依赖
    protected function getDependencies($paramters) {
        $dependencies = [];
        foreach ($paramters as $paramter) {
            $dependencies[] = $this->make($paramter->getClass()->name);
        }
        return $dependencies;
    }

}

//实例化IoC容器
$ioc = new Ioc();
$ioc->bind('log','FileLog');
$ioc->bind('user','User');
$user = $ioc->make('user');
$user->login();

原文链接：http://leechan.online/detail/26.html