Question

我有一个叫做制造商的类，在其中我有一系列汽车。在我的主类中，我声明了一个Manufacturer对象数组。汽车具有模型，价格等属性。如何访问我在Car类中声明的getter方法？假设我的数组已填充。

public class Main
{
    public static void main(String[] args)
    {
        Manufacturer[] objManufacturer = new Manufacturer[10];
        System.out.println(objManufacturer[0].getManufacturer());
        // how do a print out the year of the first car in the first manufacturer?

    }
}

汽车类

public class Car
{

    private int year;           // year of the car
    private String model;       // model of the car
    private double price;       // price of the car
    private int kmTravelled;    // the KM travelled by the car
    private String extras;      // extra information about the car


    public Car()
    {

    }

    // Parameterized constructor
    public Car(int year, String model, double price,int kmTravelled, String extras )
    {
        this.year = year;
        this.model = model;
        this.price = price;
        this.kmTravelled = kmTravelled;       
        this.extras = extras;
    }

    // getter method for Year
    public int getYear()
    {
        return year;
    }                   
}

类制造商

public class Manufacturer
{
    private String manufacturerName;    // manufacturer of the car
    private Car[] cars;                 // an array to store the cars
    private int numOfCars;
    //default constructor initialize car array size to 10
    //and the current numOfCar to 0
    public Manufacturer()
    {
        numOfCars = 0;
        cars = new Car[10];
    }

    // getter methods for manufacturer
    public String getManufacturerName()
    {
        return manufacturerName;
    }

    public void setManufacturer(String aManufacturer)
    {
        manufacturerName = aManufacturer;
    }
}

Answer 1

objManufacturer [0] .getCars（）[0] .getYear（）

在manufacterer类中为数组创建getter方法后：

public getCars（）{return cars; }

Answer 2

首先，你没有有效的制定者和吸气剂。

public class Manufacturer{

    private String manufacturerName;    // manufacturer of the car
    private Car[] cars;                 // an array to store the cars
    private int numOfCars;
    //default constructor initialize car array size to 10
    //and the current numOfCar to 0

    public Manufacturer(){
        numOfCars = 0;
        cars = new Car[10];
    }

    // getter methods for manufacturer
    public String getManufacturerName(){
        return manufacturerName;
    }

    public void setManufacturerName(String aManufacturer){
        manufacturerName = aManufacturer;
    }


    public Car[] getCars(){
        return cars;
    }

    public void setCars(Car[] cars){
        this.cars = cars;
    }

}

主要方法：

 public static void main(String[] args){

        Manufacturer[] objManufacturer = new Manufacturer[10];
        //Assuming that you have populated data properly
        System.out.println(objManufacturer[0].getCars()[0].getYear());
        //Gives year of first car of first manufacturer         

    }

Answer 3

首先，你没有在你的Car类中定义getter和setter，所以这样做：

public class Car
{

    private int year;           // year of the car
    private String model;       // model of the car
    private double price;       // price of the car
    private int kmTravelled;    // the KM travelled by the car
    private String extras;      // extra information about the car


    public Car()
    {

    }

    // Parameterized constructor
    public Car(int year, String model, double price,int kmTravelled, String extras )
    {
        this.year = year;
        this.model = model;
        this.price = price;
        this.kmTravelled = kmTravelled;       
        this.extras = extras;
    }

    // getter method for Year
    public int getYear()
    {
        return year;
    }

    public String getModel() {
        return model;
    }

    public void setModel(String model) {
        this.model = model;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    public int getKmTravelled() {
        return kmTravelled;
    }

    public void setKmTravelled(int kmTravelled) {
        this.kmTravelled = kmTravelled;
    }

    public String getExtras() {
        return extras;
    }

    public void setExtras(String extras) {
        this.extras = extras;
    }

    public void setYear(int year) {
        this.year = year;
    } 


}

然后您必须在制造商中创建 addCars 和 getNumOfCars ：

public class Manufacturer
{
    private String manufacturerName;    // manufacturer of the car
    private Car[] cars;                 // an array to store the cars
    private int numOfCars;
    //default constructor initialize car array size to 10
    //and the current numOfCar to 0
    public Manufacturer()
    {
        numOfCars = 0;
        cars = new Car[10];
    }

    // getter methods for manufacturer
    public String getManufacturerName()
    {
        return manufacturerName;
    }

    public void setManufacturer(String aManufacturer)
    {
        manufacturerName = aManufacturer;
    }

    public Manufacturer getManufacturer() {
        return this;
    }

    public Car[] getCars() {
        return cars;
    }

    public void addCar(Car car){
        cars[numOfCars] = car;
        numOfCars++;
    }


    public int getNumOfCars() {
      return numOfCars;
    }
}

然后你可以从你的主要课程中获取：

public class Main {

    public static void main(String[] args) throws ParseException, IOException, InterruptedException {

        Manufacturer[] objManufacturer = new Manufacturer[10];
        Manufacturer obj1 = new Manufacturer();
        objManufacturer[0] = obj1;
        System.out.println(objManufacturer[0].getManufacturer());
        Car car1 = new Car(2014, "Gol", 20000, 0, null);
        obj1.addCar(car1);

        int numOfCars = obj1.getNumOfCars();
        Car[] cars = obj1.getCars();
        for (int i = 0; i < numOfCars; i++) {
           Car car = cars[i];
           System.out.println(car.getModel());
        }

    }

}

就是这样！

访问getter变量

3 个答案: