Java基础 8.7

1.面向对象练习

package com.logic.homework;

//编写Doctor类{name, age,job, gender, sal}相应的getter()和setter0)方法，5个参数的构造器，
//重写父类(Object)的equals()方法:
//public boolean equals(Object obj)，并判断测试类中创建的两个对象是否相等
//相等就是判断属性是否相同
public class Doctor {
    //属性
    private String name;
    private int age;
    private String job;
    private char gender;
    private double sal;

    public Doctor(String name, int age, String job, char gender, double sal) {
        this.name = name;
        this.age = age;
        this.job = job;
        this.gender = gender;
        this.sal = sal;
    }

    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;
    }

    public String getJob() {
        return job;
    }

    public void setJob(String job) {
        this.job = job;
    }

    public char getGender() {
        return gender;
    }

    public void setGender(char gender) {
        this.gender = gender;
    }

    public double getSal() {
        return sal;
    }

    public void setSal(double sal) {
        this.sal = sal;
    }

    //方法
    public boolean equals(Object obj) {
        //判断两个比较对象是否相同
        if (this == obj) {
            return true;
        }
        //判断obj是否为Doctor或其子类
        //过关斩将校验方法
        if (!(obj instanceof Doctor)) {
            return false;
        }
        //向下转型 因为obj为Doctor或其子类

        Doctor doctor = (Doctor) obj;
        return this.name.equals(doctor.name) && this.age == doctor.age
                && this.job.equals(doctor.job) && this.gender == doctor.gender
                && this.sal == doctor.sal;
    }
}

package com.logic.homework;

public class Homework10 {
    public static void main(String[] args) {
        Doctor doctor1 = new Doctor("logic", 20, "BOSS", '男', 200000);
        Doctor doctor2 = new Doctor("logic", 20, "BOSS", '男', 200000);

        System.out.println(doctor1.equals(doctor2));
    }
}

2.equals和==的比较

==

概念：比较运算符

用于基本数据类型：可以，比较数值大小

用于引用类型：可以，判断对象是否相等

equals

概念：Object类方法（Java类都可以使用equals）

用于基本数据类型：不可以

用于引用类型：可以，默认判断对象是否相等 但是子类往往重写该方法，比较对象的属性是否相等（比如String Integer）