关于HashSet的equals和hashcode的重写

Posted 2021-02-06 shijinglu2018

关于HashSet的equals和hashcode的重写：
package Test;

import java.util.HashSet;
import java.util.Set;

public class HashSetTest {

    public static void main(String[] args) {
        Set hs = new HashSet();
        hs.add(new Student("张三"));
        hs.add(new Student("lisi"));
        hs.add(new Student("张三"));
        hs.add(new Student("lisi"));

        hs.stream().forEach(x -> System.out.println(x));
    }
}

class Student {
    String name;

    public Student(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

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

    @Override public String toString() {
        return name;
    }

    @Override public int hashCode() {
        return getName().hashCode();
    }

    @Override public boolean equals(Object obj) {
        if (obj instanceof Student && this.name.equals(((Student) obj).getName())) {
            return true;
        }
        return false;
    }
}

//说明：equals（桶中定位）和hashcode(散列分桶)要一起重写