java面向对象3

子类使用extends继承父类

子类可以直接把父类的方法拿来用，也可以重写父类的某些方法，也可以有自己的方法。（不可以调用父类的私有成员）

Java只允许单继承，不允许多继承。

public class ExtendsTest01 {
    public static void main(String[] args) {
        Person p=new Person();
        p.setName("xiaoming");
        p.eat();
        Person p1=new Student();
        p1.setName("xiaozhang");
        p1.eat();
    }

}

class Person{
    private String name;
    private int 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;
    }
    
    public void eat() {
        System.out.println(name+" is eating!");
    }
}

class Student extends Person{
    private int num;
    private String name;

    public int getNum() {
        return num;
    }

    public void setNum(int num) {
        this.num = num;
    }
    
    public String getName() {
        return name;
    }

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

    public void Study() {
        System.out.println(num+" is studying!");
    }
    public void eat() {
        System.out.println(name+" is studying!");
    }
}

如果要在子类中调用被重写的父类方法，那么加一个super就可以了