Java 8 streams:条件收集器

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

public class Main {
    public static void main(String[] args) {
        List<Person> persons = Arrays.asList(
                new Person("Alice", 20),
                new Person("Bob", 25),
                new Person("Charlie", 30),
                new Person("David", 35)
        );

        Map<Boolean, List<Person>> partitionedPersons = persons.stream()
                .collect(Collectors.partitioningBy(person -> person.getAge() > 25));

        System.out.println("年龄大于25岁的人员：");
        partitionedPersons.get(true).forEach(System.out::println);

        System.out.println("年龄不大于25岁的人员：");
        partitionedPersons.get(false).forEach(System.out::println);
    }

    static 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;
        }

        @Override
        public String toString() {
            return "Person{" +
                    "name='" + name + '\'' +
                    ", age=" + age +
                    '}';
        }
    }
}