day12作业（toString()方法和equals()方法）

Posted 2021-12-30 linkedLP

//都可以直接Generate生成
//要点1：重写equals()方法，比较内容 【要会手写，体会过程】
//要点2：重写toString()方法，通过toString方法看到这个对象的成员变量的取值

public class Test 
    public static void main(String[] args) 
        Teacher teacher = new Teacher(28, 20000, new Student(21));
        System.out.println(teacher.toString());
        Teacher teacher1 = new Teacher(28, 20000, new Student(222));

        System.out.println(teacher.equals(teacher1));
    


class Teacher 
    int age;
    double money;
    Student s;

    //构造器
    public Teacher(int age, double money, Student s) 
        this.age = age;
        this.money = money;
        this.s = s;
    

    public Teacher() 
    

    //toString()方法
    @Override
    public String toString() 
        return "Teacher" +
                "age=" + age +
                ", money=" + money +
                ", s=" + s +
                ;
    

    /*//手写Teacher的equals方法
    @Override
    public boolean equals(Object o) 
        //自反性
        if (this == o) return true;

        //排它性
        //getClass 是程序运行中该类唯一的运行时对象,这个是很严格的,必须严格是这个类的对象
        if (o == null || this.getClass() != o.getClass()) 
            return false;   //表示该obj对象不是当前类的对象
        

        //对称性、传递性、一致性
        Teacher teacher = (Teacher) o;
        if (this.age != teacher.age) return false;
        if (Double.compare(this.money, money) != 0) return false;
        return s != null ? s.equals(teacher.s) : (teacher.s == null);

    */

    //Generate生成
    @Override
    public boolean equals(Object o) 
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        Teacher teacher = (Teacher) o;

        if (age != teacher.age) return false;
        if (Double.compare(teacher.money, money) != 0) return false;
        return s != null ? s.equals(teacher.s) : teacher.s == null;
    


class Student 
    int age;

    public Student(int age) 
        this.age = age;
    

    public Student() 
    

    @Override
    public String toString() 
        return "Student" +
                "age=" + age +
                ;
    

    @Override
    public boolean equals(Object o) 
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Student student = (Student) o;
        return this.age == student.age;