Java合并两个List后并去掉重复项的两种做法

String[] arr1 = {"a", "b", "c", "d", "e", "f"};
List<String> listA = new ArrayList<>(Arrays.asList(arr1));
 
String[] arr2 = {"d", "e", "f", "g", "h"};
List<String> listB = new ArrayList<>(Arrays.asList(arr2));

List<String> collect = Stream.of(listA, listB)
                .flatMap(Collection::stream)
                .distinct()
                .collect(Collectors.toList());

String[] arr1 = {"a", "b", "c", "d", "e", "f"};
List<String> listA = new ArrayList<>(Arrays.asList(arr1));

String[] arr2 = {"d", "e", "f", "g", "h"};
 List<String> listB = new ArrayList<>(Arrays.asList(arr2));

Set<String> set = new HashSet<>(listA);
set.addAll(listB);
List<String> list = new ArrayList<>(set);
System.out.println(list);

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

public class MergeListExample {

    public static void main(String[] args) {
        List<String> list1 = new ArrayList<>();
        list1.add("A");
        list1.add("B");
        list1.add("C");
        list1.add("D");

        List<String> list2 = new ArrayList<>();
        list2.add("C");
        list2.add("D");
        list2.add("E");
        list2.add("F");

        List<String> mergedList = mergeLists(list1, list2);

        System.out.println("Merged list with duplicates: " + mergedList);

        List<String> distinctList = mergedList.stream().distinct().collect(Collectors.toList());

        System.out.println("Distinct merged list: " + distinctList);
    }

    private static List<String> mergeLists(List<String> list1, List<String> list2) {
        List<String> mergedList = new ArrayList<>(list1);
        mergedList.addAll(list2);
        Map<String, String> map = mergedList.stream()
                .collect(Collectors.toMap(s -> s, s -> s, (s1, s2) -> s1));
        return new ArrayList<>(map.values());
    }
}