jdk 8 交集 差集

import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;

public class Test {

    public static void main(String[] args) {
        List<String> list1 = new ArrayList<String>();
        list1.add("1");
        list1.add("2");
        list1.add("3");
        list1.add("5");
        list1.add("6");

        List<String> list2 = new ArrayList<String>();
        list2.add("2");
        list2.add("3");
        list2.add("7");
        list2.add("8");

        // 交集  2，3
        List<String> intersection = list1.stream().filter(item -> list2.contains(item)).collect(Collectors.toList());
        System.out.println("---交集 intersection---");
        intersection.parallelStream().forEach(System.out :: println);

        // 差集 (list1 - list2)
//        List<WmSoDetail> chajiDetails = wmSoDetailList.stream()
//            .filter(item -> !upWmSoDetailList.stream()
//                .map(e -> e.getJobId())
//                .collect(Collectors.toList())
//                .contains(item.getJobId()))
//            .collect(Collectors.toList());
        List<String> reduce1 = list1.stream().filter(item -> !list2.contains(item)).collect(Collectors.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(Collectors.toList());
        System.out.println("---差集 reduce2 (list2 - list1)---");
        reduce2.parallelStream().forEach(System.out :: println);

        // 并集 123562378
        List<String> listAll = list1.parallelStream().collect(Collectors.toList());
        List<String> listAll2 = list2.parallelStream().collect(Collectors.toList());
        listAll.addAll(listAll2);
        System.out.println("---并集 listAll---");
        listAll.parallelStream().forEachOrdered(System.out :: println);

        // 去重并集    1235678
        List<String> listAllDistinct = listAll.stream().distinct().collect(Collectors.toList());
        System.out.println("---得到去重并集 listAllDistinct---");
        listAllDistinct.parallelStream().forEachOrdered(System.out :: println);

        System.out.println("---原来的List1---");
        list1.parallelStream().forEachOrdered(System.out :: println);
        System.out.println("---原来的List2---");
        list2.parallelStream().forEachOrdered(System.out :: println);

    }
}

 

list1:12356
list2:2378


---交集 intersection---
3
2
---差集 reduce1 (list1 - list2)---
5
6
1
---差集 reduce2 (list2 - list1)---
8
7
---并集 listAll---
1
2
3
5
6
2
3
7
8
---得到去重并集 listAllDistinct---
1
2
3
5
6
7
8
---原来的List1---
1
2
3
5
6
---原来的List2---
2
3
7
8

 

来源：https://blog.csdn.net/Dhjie_king/article/details/103169427