Question

public class Monitor extends Peripheral {
    public Monitor(){
        super();
    }
    public Monitor (String name,String maker, int age, int price,String type,int size,String res,String ports){
        super(name,maker,age,price);
        this.type = typel
        this.size = size;
        this.res = res;
        this.ports = ports;
    }
}

这是子类。我想创建它以便我可以创建一个监视器对象而不给它任何参数。这些是其父母的类别：

public class Product {
    protected String name, maker;
    protected int age,price;
    public Product(){}
    public Product(String name,String maker, int age, int price){
        this.name = name;
        this.maker = maker;
        this.age = age;
        this.price = price;
    }
}
public class Peripheral extends Product {
    //basically nothing here
    private static double discount = 0;
    public static void setDiscount(double disc){
        discount = disc;
    }
    public static double getDiscount(){
        return discount;
    }
}

编译器说：error：constructor类Peripheral中的Peripheral不能适用于给定的类型; 超（）; required：String，String，int，int 发现：没有参数

Answer 1

没有带外设参数的构造函数！

Peripheral(String name, String maker, int age, int price)

Answer 2

来自Peripheral的

Product does not inherit constructor，您需要明确声明：

public class Peripheral extends Product {

    public Peripheral(String name,String maker, int age, int price) {
        super(name,maker,age,price);
    } 

    //....
}

Answer 3

首先，你有一个拼写错误：

public Monitor (String name,String maker, int age, int price,String type,int 
size,String res,String ports){
    super(name,maker,age,price);
    this.type = typel <--- here(nasty semi-colons)

我认为您必须在监视器对象之前强制创建一个产品对象，因为您将缺少监视器试图获取的超级参数。

解决方法是，您可能想要创建另一个没有超级（params）的构造函数;这样就可以摆脱你所得到的错误。

所以代替你的构造函数，你应该做这样的事情：

public Monitor (String type,int size,String res,String ports){
    this.type = type;
    this.size = size;
    this.res = res;
    this.ports = ports;
}

希望这能解决你的问题！

创建空子类构造函数

3 个答案: