src/Foundation/DI.php
public function get($key, $default = null)
    {
        if (!isset($this->data[$key])) {
            $this->data[$key] = $default;
        }

        $this->recordHitTimes($key);

        if ($this->isFirstHit($key)) {
            $this->data[$key] = $this->initService($this->data[$key]);
        }

        return $this->data[$key];
    }
public function get($key, $default = null)
    {
        if (!isset($this->data[$key])) {
            $this->data[$key] = $default;
        }

        $this->recordHitTimes($key);

        if ($this->isFirstHit($key)) {
            $this->data[$key] = $this->initService($this->data[$key]);
        }

        return $this->data[$key];
    }
统一 getter

@param $key
@param null $default
@return mixed