Java HashMap存储自定义数据类型

package Object_Oriented;

import java.util.Objects;

public class Person {
    private String name;
    private int age;

    public Person() {
    }

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Person person = (Person) o;
        return age == person.age && Objects.equals(name, person.name);
    }

    @Override
    public int hashCode() {
        return Objects.hash(name, age);
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

package Object_Oriented;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

/*
       自定义HashMap存储对象
       作为Key的对象必须重写hashmap和equals方法,Value则可以重复
 */
public class HashMap_Test {
    public static void main(String[] args) {
        show();
    }

    private static void show() {
        Map<Person,String> map =new HashMap<>();
        map.put(new Person("Lily",20),"America");
        map.put(new Person("Bill",20),"England");
        map.put(new Person("Leo",20),"China");
        map.put(new Person("Halley",20),"Greece");
        map.put(new Person("Lily",20),"America");
        Set<Map.Entry<Person,String>> set = map.entrySet();
        for (Map.Entry<Person, String> personStringEntry : set) {
            Person key = personStringEntry.getKey();
            String value = personStringEntry.getValue();
            System.out.println(key);
            System.out.println(value);
        }
    }
}