方法的重写

在子类中可以根据需要对从基类中继承来的方法进行重写
重写方法必须和被重写方法具有相同方法名称、参数列表和返回类型
重写方法不能使用比被重写方法更严格的访问权限
class Person {
    private String name;
    private int age;
    public void setName(String name) {
        this.name = name;
    }
    public void setAge(int age) {
    this.age = age;
    }
    public String getName() {
        return name;
    }
    public int getAge() {
    return age;    
    }
    public String getInfo() {
        return "Name:" + name + "\n" +"age: " + age;
    }
}

class Student extends Person {
    private String school;
    public String getSchool() {
        return school;
    }
    public void setSchool(String school)
        {this.school = school;}
    public String getInfo() {
        return "Name:" + getName + "\nage" +getAge() + "\nschool:"+school;
    }
}