import java.util.HashMap;

import java.util.Map;

public class HashMapOver {

    public static void main(String[] args) {

        Map<Person, Integer> map = new HashMap<Person, Integer>();

        Person p = new Person("zhangsan", 12);

        System.out.println(map.size());

        map.put(p, 1);

        System.out.println(p.hashCode());

        p.setName("lisi"); // 因为p.name参与了hash值的计算，修改了之后hash值发生了变化，所以下面删除不掉

        map.remove(p);

        System.out.println(p.hashCode());

        System.out.println(map.size());

    }

}

class Person {

    private String name;

    private int age;

    public Person(String name, int age) {

        super();

        this.name = name;

        this.age = 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;

    }

    @Override

    public boolean equals(Object obj) {

        // TODO Auto-generated method stub

        return super.equals(obj);

    }

    @Override

    public int hashCode() {

        return name.hashCode() * 123;

    }

}