20220727-Java中方法重写override

目录

• 代码示例
• 注意事项

代码示例

public class OverrideExercise {
    public static void main(String[] args) {
        Person jack = new Person("jack", 18);
        System.out.println(jack.say());
        Student smith = new Student("smith", 18, 1, 99);
        System.out.println(smith.say());
    }
}
class Person {
    private String name;
    private int age;
    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }
    public String say() {
        return "name=" + name + ",age=" + age;
    }
}
class Student extends Person {
    private int id;
    private double score;
    public Student(String name, int age, int id, double score) {
        super(name, age);
        this.id = id;
        this.score = score;
    }
    @Override
    public String say() {
        return super.say() + ",id=" + id + ",score=" + score;
    }
}

注意事项

1. 方法重写override存在于父类与子类中
2. 方法名保持一致
3. 方法形参列表保持一致
4. 子类方法的返回值应与父类方法返回值一致或者为其子类
   • 父类返回值若为Object，则子类返回值可以为Object或者其他Object子类
5. 子类方法的修饰符应与父类方法修饰符一致或者比其更大
   • 父类方法修饰符若为protected，则子类方法修饰符可以为protected或者public