Arraylist不能添加元素

Question

为什么这不适合我？

public class Band {

    public void addMember(Musician musician) {      
    musicians.add(musician);
    System.out.println("Muscian: " + musician + "was successfully added");
    }
}

public static void main(String[] args) {

        Band Beatles = new Band("Beatles");
        Beatles.addMember("John Lennon");
}

public class Musician {


private String name;

    public Musician(String name, Instrument instrument) {
        this.name = name;
        Instrument Guitar = instrument;
    }

    public void play() {

    }
}

Answer 1

Beatles.addMember("John Lennon");

应该是

Beatles.addMember(new Musician("John Lennon", new Instrument(new Guitar()));

我怀疑，没有看到你的实际乐器类，根据你的评论，该行应该有效。

问题在于您将某些对象视为字符串。您需要首先从定义它的类中创建对象。