java Map分组

Map<String, List<SaicDnHead>> groupMap = saicDnHeadList.stream()
				.collect(Collectors.groupingBy(o -> o.getAddress() + "_" + o.getCityName() + "_" + o.getConsigneePickup()+"_"+ o.getOrderType().toLowerCase() , Collectors.toList()));
		groupMap.forEach((key, value) -> {});