【Java stream流 list之间取交集，差集，并集和去重】

 List intersection = list1.stream()
 			.filter(item -> list2.contains(item)).collect(Collectors.toList());

 List reduce1 = list1.stream()
 			.filter(item -> !list2.contains(item)).collect(Collectors.toList()); 

list1.addAll(listA2);

List listAllDistinct = list1.stream()
			.distinct().collect(Collectors.toList());