使用collect()而不是filter()筛选流

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

class Person {
    private String name;
    private int age;

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }
}

public class StreamExample {
    public static void main(String[] args) {
        List<Person> people = Arrays.asList(
            new Person("Alice", 25),
            new Person("Bob", 17),
            new Person("Charlie", 30)
        );

        List<String> adultsNames = people.stream()
            .filter(person -> person.getAge() > 18)
            .map(Person::getName)
            .collect(Collectors.toList());

        System.out.println(adultsNames); // 输出: [Alice, Charlie]
    }
}

Map<String, Integer> nameToAgeMap = people.stream()
    .filter(person -> person.getAge() > 18)
    .collect(Collectors.toMap(Person::getName, Person::getAge));