java子类继承父类重写tostring和重写equals方法-蒲公英云

java子类继承父类重写tostring和重写equals方法

以你之姓@ 2023-05-21 10:26 114阅读 0赞

用学生的输出为例子，子类继承父类，然后在子类中新定义一个属性并可以给父类属性赋值，以及重写tostring和重写equals方法。
在这里插入图片描述
demo测试

package Student;
public class demo {
    public static void main(String[] args) {
    // TODO Auto-generated method stub
    Undergraduate s1 = new Undergraduate("张三", 30, "专科");
    Undergraduate s2 = new Undergraduate("张三", 30, "本科");
    Undergraduate s3 = new Undergraduate("张三", 30, "本科");
    System.out.println(s1.equals(s2));
    System.out.println(s3.equals(s2));
    System.out.println(s1);
    System.out.println(s2);
    System.out.println(s3);
    }
}

父类定义属性

package Student;
public class Student {
    public String name;
    public int age;
    public Student() {
    // TODO Auto-generated constructor stub
    }
    public Student(String name, int age) {
    this.name = name;
    this.age = age;
    }
    public void show() {
    System.out.println(name + "," + age);
    }
}

子类定义新属性，重写函数

package Student;
public class Undergraduate extends Student {
    public String degrre;
    public Undergraduate(String name, int age, String degrre) {
    super(name, age);
    this.degrre = degrre;
    }
    @Override
    public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + ((degrre == null) ? 0 : degrre.hashCode());
    return result;
    }
    @Override
    public boolean equals(Object obj) {
    if (this == obj)
        return true;
    if (obj == null)
        return false;
    if (getClass() != obj.getClass())
        return false;
    Undergraduate other = (Undergraduate) obj;
    if (degrre == null) {
        if (other.degrre != null)
        return false;
    } else if (!degrre.equals(other.degrre))
        return false;
    return true;
    }
    @Override
    public String toString() {
    return "degrre=" + degrre + ", name=" + name + ", age=" + age + "";
    }
    public void show() {
    System.out.println(name + "," + degrre + "," + age);
    }
}