Java8 判断一个集合的元素哪些不在另外一个集合

     List dataList = Arrays.asList(data);   //集合1
     List dataList1 = Arrays.asList(data1);  //集合2


     List list2 = (List) dataList1.stream().filter(item -> !dataList.contains(item)).collect(Collectors.toList());

     System.out.println("数量 :" + list2.size());
     list2.forEach(x -> System.out.println(x));