Question

我是Java编程的新手，我想在运行时动态创建Java中的对象，我已经检查了表单并尝试了一些代码，但似乎没有什么工作。

这是我的代码..非常感谢所有帮助：）

   import java.util.Scanner;

   public class Main{
   public static void main(String[] args){
   String carName;
   String carType;
   String engineType;
   int limit;

  Scanner in = new Scanner(System.in);
  System.out.print("Enter the number of Cars you want to add - ");
  limit = in.nextInt();

    for(int i = 0; i <limit; i++){

    Cars cars[i] = new Cars();

    System.out.print("Enter the number of Car Name - ");
    carName = in.nextLine();

    System.out.print("Enter the number of Car Type - ");
    carType = in.nextLine();

    System.out.print("Enter the Engine Type - ");
    engineType = in.nextLine();

    cars[i].setCarName(carName);
    cars[i].setCarType(carType);
    cars[i].setEngineeSize(engineType);
    String a = cars[i].getCarName();
    String b = cars[i].getCarType();
    String c = cars[i].getEngineeSize();
    System.out.println(a,b,c);

  } 
  }
  }

汽车类看起来像这样......

    public class Cars{
    public String carName;
    public String carType;
    public String engineeSize;

    public void Cars(){
    System.out.println("The Cars constructor was created ! :-) ");
    }

    public void setCarName(String cn){
    this.carName = cn;
    }

    public void setCarType(String ct){
    this.carType = ct;

    }

    public void setEngineeSize(String es){
    this.engineeSize = es;

    }

    public String getCarName(){
    return this.carName;
    }



    public String getCarType(){
    return this.carType;
    }

    public String getEngineeSize(){
    return this.engineeSize;
    }


    }

Answer 1

你走在正确的轨道上，虽然有一些错误和不必要的位。

汽车类

你的汽车课程大多都很好，（虽然在我看来Car会更有意义）但是你的构造函数没有意义，你有public void Cars()，void意思是“这个方法什么都不返回“，但你想返回一个Cars对象，这意味着你的构造函数需要变成：

public Cars()
{
    System.out.println("The Cars constructor was created ! :-) ");
}

您的主要班级

您也非常接近，主要问题是创建cars数组limit次：

for(int i = 0; i < limit; i++)
{
    Cars cars[i] = new Cars();
    //Other code
}

数组需要在for循环之外进行。

以下是修订后的Main课程，评论应该很好地解释我的所作所为以及为什么。

import java.util.Scanner;

public class Main{

public static void main(String[] args){
    //The strings here were unnecessary
    int limit;

    Scanner in = new Scanner(System.in);

    System.out.print("Enter the number of Cars you want to add - ");
    limit = in.nextInt();
    in.nextLine(); //nextInt leaves a newLine, this will clear it, it's a little strange, but it makes sense seeing as integers can't have newlines at the end

    //Make an array of Cars, the length of this array is limit
    Cars[] cars = new Cars[limit];

    //Iterate over array cars
    for(int i = 0; i < limit; i++)
    {
        //Read all the properties into strings
        System.out.println("Enter the number of Car Name - ");
        String carName = in.nextLine();

        System.out.println("Enter the number of Car Type - ");
        String carType = in.nextLine();

        System.out.println("Enter the Engine Type - ");
        String engineType = in.nextLine();

        //Set the object at current position to be a new Cars
        cars[i] = new Cars();

        //Adjust the properties of the Cars at this position
        cars[i].setCarName(carName);
        cars[i].setCarType(carType);
        cars[i].setEngineeSize(engineType);

        //We still have the variables from the scanner, so we don;t need to read them from the Cars object
        System.out.println(carName+carType+engineType);
    } 
    in.close(); //We don't need the scanner anymore
   }
}

完成打字并意识到这个问题是两年了：）

在循环中动态创建对象

1 个答案: