Java8 GroupBy并将结果转换为列表

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

public class GroupByExample {
    public static void main(String[] args) {
        // 创建一个包含Person对象的集合
        List<Person> persons = Arrays.asList(
                new Person("Alice", 20),
                new Person("Bob", 25),
                new Person("Alice", 30),
                new Person("Bob", 35)
        );

        // 按照name属性进行分组，并将每个分组的结果转换为一个列表
        Map<String, List<Person>> groups = persons.stream()
                .collect(Collectors.groupingBy(Person::getName));

        // 输出每个分组的结果
        for (Map.Entry<String, List<Person>> entry : groups.entrySet()) {
            String name = entry.getKey();
            List<Person> group = entry.getValue();
            System.out.println("Group: " + name);
            for (Person person : group) {
                System.out.println(person);
            }
            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 +
                    '}';
        }
    }
}