案例:
定义一个Student类:
package JiHe.MapJiHe;
import java.util.Objects;
public class Student {
private String name;
private int age;
//作为key的元素,必须重写hashCode方法和equals方法,以保证key唯一性
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Student student = (Student) o;
return age == student.age &&
Objects.equals(name, student.name);
}
@Override
public int hashCode() {
return Objects.hash(name, age);
}
@Override
public String toString() {
return "Student{" +
"name='" + name + '\'' +
", age=" + age +
'}';
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public