java - 从不同的类打印 toString

Question

我已经尝试解决这个问题有一段时间了，我搜索了各种问题，但我认为我没有更接近。

我有一个父类(super class)车辆，它提供了车辆的各种详细信息。然后我有了继承自 Vehicle 的 Car 类。

我正在尝试从我的 Car 类打印 toString，该类覆盖了 Vehicle 类。

基本上我想打印出每辆车的信息。

这是我的主要内容

    public static void main(String []args)

    {

        Car Ford = new Car(Red, 4, true);

        //Ford = Ford.;   Tried various things here to no avail, kept getting nullfalse in output

        Car Honda = new Car(Blue, 4, false);


        System.out.println(Ford.vehicleDetails);

        System.out.println("Honda");

    }

}

这是我的车辆类别

public class Vehicle

{

// Variables

private String vehicleColour;

private int numberOfWheels;

String vehicleDetails;

// Constructor

public Vehicle(String vehicleColour, int numberOfWheels)

{

}

// Getters

public String getVehicleColour()

{
    return vehicleColour;
}

public int getNumberOfWheels()

{
    return numberOfWheels;
}



// Setters

public void setVehicleColour(String vehicleColour)

{
    this.vehicleColour = vehicleColour;
}


public void setNumberOfWheels(int numberOfWheels)

{
    this.numberOfWheels = numberOfWheels;
}


// Constructor

public Vehicle ()

{

}


// toString method super

public String toString() {

    String vehicleDetails = (getVehicleColour() + "" + getNumberOfWheels());

    return vehicleDetails;

}

}

这是我的汽车类(class)

    public class Car extends Vehicle

{

    // Variables

    private boolean convertible;

    Car vehicleDetails;

    // Getter

    public boolean getConvertible()

    {
        return convertible;
    }

    // Setter

    public void setConvertible(boolean convertible)

    {
        this.convertible = convertible;
    }

    // Constructor

    public Car(String vehicleColour, int numberOfWheels, boolean convertible) {


    }


        // toString method override

        @Override
        public String toString() {

        return super.toString() + convertible;

        }

    }

我希望我的输出类似于“福特是红色，有4轮子，是一辆敞篷车”，并带有粗体文本分别来自车辆和汽车类别。

如何让粗体文本显示在输出中？现在我只得到默认值，例如 null、0 和 false。

我很感激任何意见，我知道我可能正在做一些非常愚蠢的事情，这些事情非常明显，但我只是看不到它。

谢谢。

Answer 1

I want my output to be something like "The Ford is red, has 4 wheels and is a convertible"

对于您的上述要求，简单的解决方案:

System.out.println("The Ford is "+ Ford.toString() );

如果您打算从 Ford.toString 获取整个输出，那么在创建 Ford 对象时，您还需要传递汽车名称!如下所示，并对其构造函数进行必要的更改!

Car Ford = new Car("Ford","Red", 4, true);

然而，Car 和 Vehicle 类中的构造函数已创建，但没有为它们的局部变量赋值!因此 .toString() 没有显示任何内容!

所需的更改是:

在主类

System.out.println("The Ford is "+ Ford.toString() );

汽车类

//change in the constructor
public Car(String vehicleColour, int numberOfWheels, boolean convertible) {

    setNumberOfWheels(numberOfWheels);
    setVehicleColour(vehicleColour);
    setConvertible(convertible);

}

I am trying to print the toString from my Car class, which overides the Vehicle class.

//change in toString()


    @Override
    public String toString() {
        if(convertible){
             return super.toString() +"and is a convertible" ;
        }else{
             return super.toString() +"and is not a convertible" ;
        }


    }

车辆类别

//change the constructor
public Vehicle(String vehicleColour, int numberOfWheels)

{
        setNumberOfWheels(this.numberOfWheels);
        setVehicleColour(this.vehicleColour);

}

Basically I want to print out the information about each car.

//change the toString()
public String toString() {

    String vehicleDetails = (getVehicleColour() + ", has "  +getNumberOfWheels()+" wheels");

    return vehicleDetails;

}