Java 接口(interface)和对象

Question

在这里，我尝试使用名为“Measurable”的接口(interface)以及一种名为 getMeasure 的方法。问题是，我试图通过访问界面中的方法来获取程序中所有人的平均高度。问题之一我由于某种原因无法访问getMeasure方法，最后得到数组中所有人的平均高度。我该如何解决这个问题？

class Main {
    public static void main(String args[]) {
        Person[] people = new Person[4];
        people[0] = new Person("Larry", 65);
        people[1] = new Person("Susan", 45);
        people[2] = new Person("Joe", -45);
        people[3] = new Person("", 0);
        double averageHeight = average(people);
    }

    public static double average(Person[] objects)
    {
        if (objects.length == 0) { return 0; }
        double sum = 0;
        for (Person obj : objects)
        {
            double measure = obj.getMeasure();
            sum = sum + measure;
        }
        double result = sum / objects.length;
        return result;
    }
}



interface Measurable {
    double getMeasure();
}

public class Person {
    private String name;
    private Integer height;



    public Person(String name, Integer height)
    {
        this.name = name;
        this.height = height;
    }


    public double getMeasure() {
        return height;
    }
}

Answer 1

Person类应该实现Measurable :

public class Person implements Measurable {
    ...
}

那么如果你想让你的average函数可重用(我想这是您想要的结果)，您应该替换 Person实例 Measurable :

public static double average(Measurable[] objects) {
    ...
    for (Measurable obj : objects){
        ...
    }
}

这样你就可以有不同的Measurable计算平均值的实现。