HashSet作业练习

案例一

• 定义一个Employee类，该类包含private成员属性name，age

  1.创建三个Employee对象放入HashSet中

  2.当name与age相同时，被认为是相同的员工，不能添加到HshSet中

package com.JiHe_.Set_;

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

public class Employee_ {
    public static void main(String[] args) {
        HashSet hashSet = new HashSet();
        hashSet.add(new Employee("玥骋",21));//加入成功
        hashSet.add(new Employee("婉茹",20));//加入成功
        hashSet.add(new Employee("玥骋",21));//加入不成功
        System.out.println(hashSet);

    }
}
class Employee{
    private String name;
    private int age;
    public Employee(String name,int age){
        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 String toString() {
        return "Employee{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
    //如果name和age的值都相同则返回相同的hashcode哈希值
    //hashcode判断在哪个链表，equals判断两个对象是否相等，如果相等是绝对加不进去的

    @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);
    }
}

案例二

• 定义一个Employee类，该类包含：private成员属性name，sal，birthday（MyDate类型），其中birthday为MyDate类型(属性包括，year，month，day)。注意MyDate类型需要自己定义

  要求：

  1.创建三个Employee放入HashSet中，

  2.当name与birthday的值相同时，认为是相同元GG，不能添加到HashSet中

package com.JiHe_.Set_;

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

public class Employee_ {
    public static void main(String[] args) {
        HashSet hashSet = new HashSet();
        hashSet.add(new Employee("jack",new MyDate(2000,3,20)));
        hashSet.add(new Employee("join",new MyDate(2000,10,30)));
        hashSet.add(new Employee("jack",new MyDate(2000,3,20)));
        System.out.println(hashSet);
    }
}
/*
* 定义一个Employee类，该类包含：private成员属性name，sal，birthday（MyDate类型），其中birthday为MyDate类型(属性包括，year，month，day)。注意Mydata类型需要自己定义
要求：
1.创建三个Employee放入HashSet中，
2.当name与birthday的值相同时，认为是相同元GG，不能添加到HashSet中*/
class Employee{
    private String name;
    private MyDate birthday;

    public Employee(String name,MyDate birthday){
        this.name=name;
        this.birthday=birthday;
    }

    public String getName() {
        return name;
    }

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

    public MyDate getBirthday() {
        return birthday;
    }

    public void setBirthday(MyDate birthday) {
        this.birthday = birthday;
    }

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

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

    @Override
    public int hashCode() {
        return Objects.hash(name, birthday);
    }
}
class MyDate{
    private int year;
    private int month;
    private int day;

    public MyDate(int year, int month, int day) {
        this.year = year;
        this.month = month;
        this.day = day;
    }

    public int getYear() {
        return year;
    }

    public void setYear(int year) {
        this.year = year;
    }

    public int getMonth() {
        return month;
    }

    public void setMonth(int month) {
        this.month = month;
    }

    public int getDay() {
        return day;
    }

    public void setDay(int day) {
        this.day = day;
    }

    @Override
    public String toString() {
        return "MyDate{" +
                "year=" + year +
                ", month=" + month +
                ", day=" + day +
                '}';
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        MyDate myDate = (MyDate) o;
        return year == myDate.year && month == myDate.month && day == myDate.day;
    }

    @Override
    public int hashCode() {
        return Objects.hash(year, month, day);
    }
}