java8 集合求差集、并集、交集

@Test
    public void test1(){
        List<Integer> list1=new ArrayList<>();
        list1.add(1);
        list1.add(2);
        list1.add(3);

        List<Integer> list2=new ArrayList<>();
        list2.add(3);
        list2.add(4);
        list2.add(5);

        System.out.println("====求交集===");

        List<Integer> list=list1.stream().filter(t->list2.contains(t)).collect(Collectors.toList());
        list.stream().forEach(System.out::println);




        System.out.println("====求差集===");
        list=list1.stream().filter(t-> !list2.contains(t)).collect(Collectors.toList());
        list.stream().forEach(System.out::println);


        System.out.println("====求并集===");

        list.addAll(list1);
        list.addAll(list2);
        list=list.stream().distinct().collect(Collectors.toList());
        list.stream().forEach(System.out::println);
    }

原文：https://www.cnblogs.com/sword-successful/archive/2017/12/05/7989035.html