对象的Map聚合该怎么处理-Javalambda实现

import java.util.HashMap;
import java.util.Map;

public class StudentMapAggregation {

    public static void main(String[] args) {
        // 创建包含 Student 对象的 Map
        Map<Integer, Student> studentMap = new HashMap<>();

        // 添加第一个学生
        Student student1 = new Student(123, "John Doe", 90);
        studentMap.put(student1.getId(), student1);

        // 尝试添加具有相同 ID 的第二个学生
        Student student2 = new Student(123, "Jane Smith", 85);

        // 使用 lambda 合并两个学生对象
        studentMap.merge(student2.getId(), student2, (s1, s2) -> s1.combine(s2));

        // 获取合并后的学生对象
        Student mergedStudent = studentMap.get(123);

        // 打印合并后的学生信息
        System.out.println(mergedStudent);
    }
}

// Student 类
class Student {
    private int id;
    private String name;
    private int score;

    // 构造函数
    public Student(int id, String name, int score) {
        this.id = id;
        this.name = name;
        this.score = score;
    }

    // 获取 ID
    public int getId() {
        return id;
    }

    // 合并另一个学生对象
    public Student combine(Student other) {
        return new Student(id, name, (score + other.score) / 2);
    }

    @Override
    public String toString() {
        return "ID: " + id + ", Name: " + name + ", Score: " + score;
    }
}