Java8获取两个集合的交集、差集、并集

Java8获取两个集合的交集、差集、并集

/**
 * @author nanfengxiangbei
 * @date 2022/6/10 14:17
 */
public class CollectionsTest {

    public static void main(String[] args) {
        List<String> list1 = new ArrayList<>();
        list1.add("ACCOUNT1");
        list1.add("ACCOUNT2");
        list1.add("ACCOUNT3");
        list1.add("ACCOUNT4");
        list1.add("ACCOUNT5");

        List<String> list2 = new ArrayList<>();
        list2.add("ACC1");
        list2.add("ACCOUNT2");
        list2.add("ACCOUNT3");
        list2.add("ACCOUNT6");
        list2.add("ACCOUNT7");

        // 交集
        List<String> intersection = list1.stream().filter(list2::contains).collect(toList());
        System.out.println("---交集 intersection--->" + intersection);

        // 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);

        // 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);

        // 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);

        // 去重并集
        List<String> listAllDistinct = listAll.stream().distinct().collect(toList());
        System.out.println("---得到去重并集 listAllDistinct--->" + listAllDistinct);
    }
}