HashMap,你是怎么做到的Key重复？

public class Student {

private Integer id;

private String name;

//get和set省略

public Student(Integer id, String name) {

this.id = id;

this.name = name;

}

@Override

public boolean equals(Object o) {

if (this == o) return true;

if (o == null || getClass() != o.getClass()) return false;

Student student = (Student) o;

return Objects.equals(id, student.id) &&

Objects.equals(name, student.name);

}

}

复制代码

Test

public class Test {

public static void main(String[] args) {

Student student1 = new Student(1,“小朱”);

Student student2 = new Student(2,“大牛”);

HashMap<Student,String> hashMap = new HashMap<>();

hashMap.put(student1,“菜鸡”);

hashMap.put(student2,“大神”);

//这个方法