Java面向对象编程中封装继承多态的应用

public class Student {
    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) {
        if (age > 0) {
            this.age = age;
        }
    }
}

public class Person {
    protected String name;
    protected int age;

    public void eat() {
        System.out.println(name + "正在吃饭");
    }
}

public class Student extends Person {
    private String studentId;

    public void study() {
        System.out.println(name + "正在学习");
    }
}

public class Person {
    public void eat() {
        System.out.println("人需要吃饭");
    }
}

public class Student extends Person {
    @Override
    public void eat() {
        System.out.println("学生在食堂吃饭");
    }
}

public class Teacher extends Person {
    @Override
    public void eat() {
        System.out.println("老师在教工餐厅吃饭");
    }
}

Person p1 = new Student();
Person p2 = new Teacher();
p1.eat(); // 输出：学生在食堂吃饭
p2.eat(); // 输出：老师在教工餐厅吃饭