Java去重合并List

之前写C#的项目，去重合并List很方便，使用list1.Union(list2).ToList()即可(Enumerable.Union)。并且，如果想要从list1里移除list2的item，也很方便，list2.Except(list1).ToList()

现在写Java的项目，它没有此类原生方法可以直接调用，操作起来，稍微多点步骤。

    public static void main(String[] args){        List<String> listA = Arrays.asList("Unicorn","Penguin","Koala","Hippo","Unicorn");        List<String> listB = Arrays.asList("Swan","Penguin","Ape");        //Merge lists and remove duplicated entries        Set<String> set = new LinkedHashSet<>();        set.addAll(listA);        set.addAll(listB);        System.out.println("Merge and remove duplicates: " + set);        //Intersection        List<String> intersection = new ArrayList<>(listA);        intersection.retainAll(listB);        System.out.println("Intersection of two lists: " + intersection);        //Concat        List<String> concat = new ArrayList<>(listA);        concat.addAll(listB);        System.out.println("Concat of two lists: " + concat);        //listA - listB        List<String> minus = new ArrayList<>(listA);        minus.removeAll(listB);        System.out.println("Remove items that are in listB from listA: " + minus);    }

程序输出：
Merge and remove duplicates: [Unicorn, Penguin, Koala, Hippo, Swan, Ape]
Intersection of two lists: [Penguin]
Concat of two lists: [Unicorn, Penguin, Koala, Hippo, Unicorn, Swan, Penguin, Ape]
Remove items that are in listB from listA: [Unicorn, Koala, Hippo, Unicorn]