Java 8在某个位置按属性对列表进行分组

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) {
        // 创建一个包含对象的列表
        List<Person> personList = Arrays.asList(
                new Person("Alice", 25),
                new Person("Bob", 30),
                new Person("Alice", 35),
                new Person("Bob", 40)
        );

        // 按姓名对列表进行分组
        Map<String, List<Person>> groupedByName = personList.stream()
                .collect(Collectors.groupingBy(Person::getName));

        // 输出分组结果
        for (Map.Entry<String, List<Person>> entry : groupedByName.entrySet()) {
            System.out.println("Name: " + entry.getKey());
            System.out.println("Persons: " + entry.getValue());
            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 +
                    '}';
        }
    }
}

Name: Alice
Persons: [Person{name='Alice', age=25}, Person{name='Alice', age=35}]

Name: Bob
Persons: [Person{name='Bob', age=30}, Person{name='Bob', age=40}]