课后一道作业题，没看明白 求解

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先定义好学生类，然后定义测试类。将多个学生对象存放在map集合中。
Map<String,Student> map=new HashMap<>();

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

class Student {
  public String name;
  public int number;

  public Student(String name, int number) {
    this.name = name;
    this.number = number;
  }

  @Override
  public String toString() {
    return "Student [name=" + name + ", number=" + number + "]";
  }

}

public class Main {
  public static void main(String[] args) {
    Map<Integer, Student> map1 = new HashMap<>();
    int num = 100;
    map1.put(num, new Student("张三",num++));
    map1.put(num, new Student("李四",num++));
    map1.put(num, new Student("王五",num++));
    for (Student stu : map1.values()) {
      System.out.println(stu);
    }
  }
}

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