If You have no access to plugin for instance outside of controller You can get params from servicelocator like this
//from POST
$foo = $this->serviceLocator->get('request')->getPost('foo');
//from GET
$foo = $this->serviceLocator->get('request')->getQuery()->foo;
//from route
$foo = $this->serviceLocator->get('application')->getMvcEvent()->getRouteMatch()->getParam('foo');