Java可选:如何处理长map()链

List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5);

List<Integer> result = numbers.stream()
        .map(x -> x * 2)
        .map(x -> x + 1)
        .map(x -> x - 3)
        .collect(Collectors.toList());

List<List<Integer>> numbers = Arrays.asList(
        Arrays.asList(1, 2, 3),
        Arrays.asList(4, 5, 6),
        Arrays.asList(7, 8, 9)
);

List<Integer> result = numbers.stream()
        .flatMap(Collection::stream)
        .map(x -> x * 2)
        .map(x -> x + 1)
        .map(x -> x - 3)
        .collect(Collectors.toList());

List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5);

Function<Integer, Integer> multiplyBy2 = x -> x * 2;
Function<Integer, Integer> add1 = x -> x + 1;
Function<Integer, Integer> subtract3 = x -> x - 3;

List<Integer> result = numbers.stream()
        .map(multiplyBy2)
        .map(add1)
        .map(subtract3)
        .collect(Collectors.toList());