JAVA:泛型扩展了两个子类

class Parent<T> {
    private T data;

    public Parent(T data) {
        this.data = data;
    }

    public T getData() {
        return data;
    }
}

class ChildA extends Parent<String> {
    public ChildA(String data) {
        super(data);
    }
}

class ChildB extends Parent<Integer> {
    public ChildB(Integer data) {
        super(data);
    }
}

public class Main {
    public static void main(String[] args) {
        ChildA childA = new ChildA("Hello");
        ChildB childB = new ChildB(123);

        System.out.println(childA.getData());  // 输出：Hello
        System.out.println(childB.getData());  // 输出：123
    }
}