获取配置，支持a.b.c的层级调用.

@param      $key
@param null $default

@return mixed
545316
public function get($key, $default = null)
    {
        $result = $this->load($key);
        return Arr::get(static::$configs[$result[0]], $result[1], $default);
    }
52800
public static function get($key, $default=null) {
		if( !isset(static::$main) ) {
			return $default;
		}
		return isset(static::$main->$key) ? static::$main->$key : $default;
	}
213226
public static function get($key, $default = null)
    {
        if ( ! is_string($key)) {
            return $default;
        }
        $key = strtoupper($key);
        if ( ! strpos($key, '.')) {
            return isset(self::$config[$key]) ? self::$config[$key] : $default;
        } else {
            // 试图获取二维数组值
            $d = explode('.', $key);
            $d1 = array_shift($d);
            $d2 = implode('.', $d);

            return isset(self::$config[$d1][$d2]) ? self::$config[$d1][$d2] : $default;
        }
    }
774898
public function get(string $key, $default = null)
    {
        $result = $this->iterateConfig($key);

        return is_null($result) ? $default : $result;
    }
301436
public function getHeader($key, $default = NULL) {
        // 延时加载，提升性能
        if ($this->headers === NULL) {
            $this->headers = $this->getAllHeaders();
        }

        // 保持一致性，兼容多种格式的KEY输入，提高友好性 @dogstar 2019032
        if (stripos($key, 'HTTP_') !== FALSE) {
            $key = $this->formatHeaderKey($key);
        }

        return isset($this->headers[$key]) ? $this->headers[$key] : $default;
    }
296850
public function get(string $key, $default = null)
    {
        $value = Arr::get($this->items, $key);

        if (\is_null($value)) {
            return \value($default);
        }

        return $value;
    }
40132
public function get($key, $default = NULL)
    {
        if (array_key_exists($key, $this->attributes)) {
            return $this->attributes[$key];
        }

        return $default;
    }
863141
public function get($key, $default = null)
		{
			if (Arrays::exists($key, $this->attributes)) {
				return $this->attributes[$key];
			}

			return value($default);
		}
12538
public function get($key, $default = null)
    {
        $config = $this->config;

        foreach (explode('.', $key) as $k) {
            if (! isset($config[$k])) {
                return $default;
            }
            $config = $config[$k];
        }

        return $config;
    }
296045
public function get($key, $default = null)
    {
        $value = parent::get($key, $default);
        if (is_array($value)) {
            $value = array_shift($value);
        }
        return $value;
    }
1278076
public function get($key, $default = null)
    {
        list($baseKey, $searchKey) = $this->fetchKey($key);

        $value = $this->fetchValue($baseKey, $searchKey);

        return (! is_null($value)) ? $value : $default;
    }
436284
public function get($key, $default = null)
    {
        if (array_key_exists($key, $this->params)) {
            return $this->params[$key];
        }

        return $default;
    }
154572
public function get($key, $default = null) {
		$key = $this->getKey($key);
		$result = getConf($key);
		return $result === null ? $default : $result;
	}
329215
public function get($key, $default = NULL) {
    $value = parent::get($key);

    if (isset($value)) {
      return $value;
    }

    return $default;
  }
1169378
public function default($key, $default = null)
	{
		if($this->has($key))
			return $this->get($key);

		$this->put($key, $default);

		return $default;
	}
376862
public function get($key, $default = null)
    {
        if (isset($this->contents[$key])) {
            return $this->contents[$key];
        }
        return $default;
    }
1101921
public function get(string $key, $default = null)
	{
		[$file, $path] = $this->parseKey($key);

		if(!isset($this->configuration[$file]))
		{
			$this->load($file);
		}

		return $path === null ? $this->configuration[$file] : Arr::get($this->configuration[$file], $path, $default);
	}