java8 list对象取字段,java8 list去重

public class CollectionsTest { public static void main(String[] args) { List<String> list1 = new ArrayList<>(); list1.add("1"); list1.add("2"); list1.add("3"); list1.add("4"); list1.add("5"); List<String> list2 = new ArrayList<>(); list2.add("2"); list2.add("3"); list2.add("6"); list2.add("7"); // 交集 List<String> intersection = list1.stream().filter(item -> list2.contains(item)).collect(toList()); System.out.println("---交集 intersection---"); intersection.parallelStream().forEach(System.out::println); // 差集 (list1 - list2) List<String> reduce1 = list1.stream().filter(item -> !list2.contains(item)).collect(toList()); System.out.println("---差集 reduce1 (list1 - list2)---"); reduce1.parallelStream().forEach(System.out::println); // 差集 (list2 - list1) List<String> reduce2 = list2.stream().filter(item -> !list1.contains(item)).collect(toList()); System.out.println("---差集 reduce2 (list2 - list1)---"); reduce2.parallelStream().forEach(System.out::println); // 并集 List<String> listAll = list1.parallelStream().collect(toList()); List<String> listAll2 = list2.parallelStream().collect(toList()); listAll.addAll(listAll2); System.out.println("---并集 listAll---"); listAll.parallelStream().forEachOrdered(System.out::println); // 去重并集 List<String> listAllDistinct = listAll.stream().distinct().collect(toList()); System.out.println("---得到去重并集 listAllDistinct---"); listAllDistinct.parallelStream().forEachOrdered(System.out::println); }}