重写JAVA中的hashCode()方法

▪️测试56.java

import java.util.*;

public class Test56 {
    public static void main(String[] args) {
        Set<Hare56> hare = new HashSet<Hare56>();
        Hare56 h1 = new Hare56();
        Hare56 h2 = new Hare56();
        Hare56 h3 = new Hare56();
        h1.name = "野うさぎ";
        h2.name = "野うさぎ２";
        h3.name = "野うさぎ３";
        h1.item = "にんじん";
        h2.item = "にんじん";
        h3.item = "にんじん";
        h1.item2 = "レタス";
        h2.item2 = "レタス";
        h3.item2 = "レタス";
        hare.add(h1);
        hare.add(h2);
        hare.add(h3);
        System.out.println(hare.size());
        hare.remove(h2);
        System.out.println(hare.size());

    }

}

Hare56.java的原文是：

public class Hare56 {
    public String name;
    public int hp;
    public String item;
    public String item2;

    public boolean equals(Object o) {
        if (this.name == o && this.item == o && this.item2 == o) {
            return true;
        }
        return false;
    }

    public int hashCode() {
        int result = 35;
        result = result * 31 + name.hashCode();
        result = result * 31 + item.hashCode();
        result = result * 31 + item2.hashCode();
        return result;
    }

}

▪️Test56.java 的执行结果是
3
2