使用lambda表達式對兩個list並集、去重並集、交集、差集處理

import java.util.ArrayList;
import java.util.List;
import static java.util.stream.Collectors.toList;
public class Code {
    public static void main(String[] args) throws ParseException {
        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");
        new Code().quchongjiaoji(list1,list2);
    }

    // 交集
    public void jiaoji(List<String> list1,List<String> list2){
    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)
    public void chaji(List<String> list1,List<String> 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)
    public void chajito(List<String> list1,List<String> list2){
    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);
    }

    // 並集
    public void binji(List<String> list1,List<String> list2){
    List<String> listAll = list1.parallelStream().collect(toList());
    List<String> listAll2 = list2.parallelStream().collect(toList());
    listAll.addAll(listAll2);
    System.out.println("---並集 listAll---");
    listAll.parallelStream().forEachOrdered(System.out :: println);
    }

    // 去重並集
    public void quchongjiaoji(List<String> list1,List<String> list2){
     List<String> listAll = list1.parallelStream().collect(toList());
     List<String> listAll2 = list2.parallelStream().collect(toList());
     listAll.addAll(listAll2);
     List<String> listAllDistinct = listAll.stream().distinct().collect(toList());
     System.out.println("---得到去重並集 listAllDistinct---");
     listAllDistinct.parallelStream().forEachOrdered(System.out::println);
    }
    }