List newList = list.stream().collect( Collectors.collectingAndThen( Collectors.toCollection(() -> new TreeSet<>(Comparator.comparing( o -> o.getProductName() + ";" + o.getManufactureName() +";"+ o.getShopSign() +";"+ o.getSpecComment() +";"+ o.getProductTypeCode() +";"+ o.getWeight() +";"+ o.getWarehouseCode() +";"+ o.getPackCode() )) ), ArrayList::new));
//根据多个属性分组 Map<String, List<String>> groupBy = voList.stream().collect(Collectors.groupingBy(CountDefaultOrderVo::getProviderCode, Collectors.mapping(CountDefaultOrderVo::getPackCode, Collectors.toList()))); //根据某一个属性分组 Map<Integer, List<TestStreamModel>> map = list.stream().collect(Collectors.groupingBy(t -> t.getGrade()));
List list = new ArrayList(); list.add("1"); List collect = list.stream().filter(x -> { if (!("0.5".equals(x) || "1".equals(x))) { return true; } return false; }).collect(Collectors.toList());
Map result1 = list.stream().collect(Collectors.toMap(对象::属性1, 对象::属性2));
map.entrySet().stream().map(e -> new Person(e.getKey(),e.getValue())).collect(Collectors.toList());
map.forEach((k, v) -> System.out.println("key:value = " + k + ":" + v));
原文：https://www.cnblogs.com/cnndevelop/p/13231415.html