使用流的map的For键的for循环

import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

public class StreamExample {
    public static void main(String[] args) {
        List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5);

        List<Integer> doubledNumbers = numbers.stream()
                                           .map(n -> n * 2)
                                           .collect(Collectors.toList());

        System.out.println(doubledNumbers); // 输出: [2, 4, 6, 8, 10]
    }
}

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

List<Integer> doubledNumbers = numbers.stream()
                                       .filter(n -> n != null)
                                       .map(n -> n * 2)
                                       .collect(Collectors.toList());

List<Integer> doubledNumbers = numbers.stream()
                                       .map(n -> n * 2)
                                       .collect(Collectors.toList());