java构造函数无法设置从其他类获取的数据

Question

说来话长，我不知道如何将jet数据jetid和currentLocation加载到j。感谢您的帮助。如果我把事情提到错误的地方，我先道歉。多谢各位

public class Corporation {

    public Jet[] jets = new Jet[14];



    public Corporation()//RUN A CONSTRUCTOR TO CREATE 14 NEW JETS, IN DIFFERENT LOCATIONS
    {
        //create 14 new jets


        for(int i =0; i < jets.length; i++)
        {
            //make a new jet here
            Jet j = new Jet();
            j.jetid = 
        }

    }

}

第二个类是我试图从中提取的jetid和currentLocation是：

public class Jet {

    public int jetid;
    public Delivery deliveryArray[];
    public String currentLocation; //where it's currently sitting 

    public Jet()
    {
        int random = (int)(Math.random()*10000);

        this.jetid = random;
        this.currentLocation = setCurrentLocation();
        System.out.println("NEW JET IS ONLINE WITH JET ID: " + this.jetid + " AT LOCATION " + this.currentLocation);

    }

    private String setCurrentLocation() 
    {
        //set up a random # that determines which city the plane is based in
        double random = (Math.random());
        String location = " ";

        if(random < .1 && random > 0)
            location = "PHX";

        else if(random > .1 && random < .2)
            location = "SAN";

        else if(random > .2 && random <.3)
            location = "LAX";

        else if(random > .3 && random < .4)
            location = "POR";

        else if(random > .4 && random < .5)
            location = "SEA";

        else if(random > .5 && random <.6)
            location = "SAF";
        else
            location = "DAL";


        return location;
    }

}

Answer 1

谢谢大家的意见。抛开其他问题不谈，我在发布这个问题后不久就解决了这个代码：

Jet j = new Jet();
jets[i]=j;

从那时起，我就能够解决所有其他问题。再次感谢大家的投入

Answer 2

您需要将变量传递给jet类构造函数

Jet jet = new Jet(string _jetID, string _currentLocation)

Answer 3

Corporate对象将有一个数组，其中包含对Jet对象的14个引用

public class Corporation {

  private Jet[] jets = new Jet[14];

  // Constructor
  // RUN A CONSTRUCTOR TO CREATE 14 NEW JETS, IN DIFFERENT LOCATIONS
  public Corporation() { 

    //create 14 new jets
    for (int i =0; i < jets.length; i++)
    {
        //make a new jet here
        Jet j = new Jet();
        //save the reference to array
        jets[i] = j;
        // more Jet intialization
        j.id = ...
    }
  }

  // accessor
  public Jet [] getJets() {
    ...
  }

} 

Answer 4

您可能希望通过构造函数传递内容：

public Jet(int jetid, String currentLocation)
{
    this.jetid = jetid;
    this.currentLocation = currentLocation;
}

现在，您可以在公司课程中编写以下内容：

    for(int i =0; i < jets.length; i++)
    {
        //make a new jet here
        int randomId = (int)(Math.random()*10000);
        String randomLocation = randomLocation();
        jets[i] = new Jet(randomId, randomLocation);
    }

那randomLocation只是Jet类中旧的setCurrentLocation方法。您应该重命名它并将其移动到您的Corporation类中，因为Corporation现在负责创建随机位置。或者，您可以将其重命名，并将其保留在Jet中，并将其公开为静态，您可以只在两行代码中实现它：

public static String randomLocation() {
    // "DAL" is twice as likely as the others:
    String[] array = {"ABC", "DEF", "DAL", "DAL"};
    return array[new Random().nextInt(array.length)];
}

然后按如下方式调用它：

String randomLocation = Jet.randomLocation();

Answer 5

我想，我不确定你的构造器会出现什么错误：

public Corporation()//RUN A CONSTRUCTOR TO CREATE 14 NEW JETS, IN DIFFERENT LOCATIONS
{
    //create 14 new jets


    for(int i =0; i < jets.length; i++)
    {
        //make a new jet here
        Jet j = new Jet();
        j.jetid = 
    }

}

如果在Corporate类中声明了一个局部j[]，则应该是以下内容

public Corporation()//RUN A CONSTRUCTOR TO CREATE 14 NEW JETS, IN DIFFERENT LOCATIONS
{
    //create 14 new jets


    for(int i =0; i < jets.length; i++)
    {
        //make a new jet here
        Jet j[i] = new Jet();
        //j.jetid = no need to set this
    }

}

另一个错误是j.jetid =。但是您不需要设置它，因为它已经在Jet构造函数中设置为this.jetid = random;。每次在Jet j[i] = new Jet();中实例化新的Jet时发生

Answer 6

该代码似乎创建了14架飞机，所有这些飞机都初始化了自己的数据（例如，它们已经拥有jetId和当前位置）。数据已经存在，公司不需要设置

如果你想让公司创建它，那么创建一个新的构造函数Jet（int-jetId，String-currentLocation），然后你就可以将数据传入