/**
* 根据名称获取参数
* @param string $name 参数名
* @return mixed
* @throws \InvalidArgumentException
*/
public function getArgument($name)
{
if (!$this->definition->hasArgument($name)) {
throw new \InvalidArgumentException(sprintf('The "%s" argument does not exist.', $name));
}
return isset($this->arguments[$name]) ? $this->arguments[$name] : $this->definition->getArgument($name)->getDefault();
}