我想创建一个用于测试的选项列表。起初,我这样做:

ArrayList<String> places = new ArrayList<String>();
places.add("Buenos Aires");
places.add("Córdoba");
places.add("La Plata");

然后,我将代码重构如下:

ArrayList<String> places = new ArrayList<String>(
    Arrays.asList("Buenos Aires", "Córdoba", "La Plata"));

有更好的方法吗?


当前回答

有多种方法可以在一行中创建和初始化列表。

    //Using Double brace initialization
    List<String> list1 = new ArrayList<>() {{ add("A");  add("B"); }};
    
    //Immutable List
    List<String> list2 = List.of("A", "B");

    //Fixed size list. Can't add or remove element, though replacing the element is allowed.
    List<String> list3 = Arrays.asList("A", "B");

    //Modifiable list
    List<String> list4 = new ArrayList<>(Arrays.asList("A", "B"));

    //Using Java Stream
    List<String> list5 = Stream.of("A", "B").collect(Collectors.toList());

    //Thread safe List
    List<String> list6 = new CopyOnWriteArrayList<>(Arrays.asList("A", "B"));

其他回答

还有一种方法:

List<String> values = Stream.of("One", "Two").collect(Collectors.toList());

对我来说,Arrays.asList()是最好且方便的方法。我总是喜欢这样初始化。如果您是Java集合的初学者,那么我希望您参考ArrayList初始化

有多种方法可以在一行中创建和初始化列表。

    //Using Double brace initialization
    List<String> list1 = new ArrayList<>() {{ add("A");  add("B"); }};
    
    //Immutable List
    List<String> list2 = List.of("A", "B");

    //Fixed size list. Can't add or remove element, though replacing the element is allowed.
    List<String> list3 = Arrays.asList("A", "B");

    //Modifiable list
    List<String> list4 = new ArrayList<>(Arrays.asList("A", "B"));

    //Using Java Stream
    List<String> list5 = Stream.of("A", "B").collect(Collectors.toList());

    //Thread safe List
    List<String> list6 = new CopyOnWriteArrayList<>(Arrays.asList("A", "B"));
List<String> names = Arrays.asList("2","@2234","21","11");

您可以使用Cactoos中的粘滞列表:

List<String> names = new StickyList<>(
  "Scott Fitzgerald", "Fyodor Dostoyevsky"
);