HashSet最佳实践

Set接口实现类——HashSet

定义一个Employee类，该类包含：private成员属性name,age。要求：

1. 创建3个Employee放入HashSet中
2. 当name和age的值相同时，认为是相同员工，不能添加到HashSet集合中

import java.util.HashSet;
import java.util.Objects;

public class HashSetExercise {
    public static void main(String[] args) {
        HashSet hashSet = new HashSet();

        hashSet.add(new Employee("test1",1));
        hashSet.add(new Employee("test2",2));
        hashSet.add(new Employee("test1",1));

        System.out.println("hashSet = " + hashSet);
    }
}

//创建Employee对象
class Employee{
    private String name;
    private int age;

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

    //如果name和age值相同，则返回相同的hash值


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

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