在java中创建一个存储字符串和整数的打印对象

Question

我有以下问题。五个班级互相交流。两个主题都做得很好。但是随着在我的主类 Event 中创建一个类（Ticket）的对象（从另一个类（UserInput）获取用户输入，在 costructor 中处理它），我现在无法显示结果。

主类事件与主方法

import java.util.ArrayList;

public class Event {

    
    private static String artistName;
    private static int artistSalary;
    private Language language;
    private static ArrayList<String> trackList;
    private InputReader inputReader;
    private Ticket ticket;
    private int amountOfTicketCategories;
    private static Object[] ticketList;
    private static int index;
    
    
    
    public Event() {
        
    }
    
    public Event(Artist artist, Ticket ticket) {
        artistName = artist.getArtistName();
        artistSalary = artist.getArtistSalary();
        trackList = artist.getArrayList();
        for (index = 0; index < amountOfTicketCategories; index++) {
        ticketList[index] = ticket.getTicket();
        ticketList[index].toString();
        }
    }
    
    public void chooseWhatToDefine() {
        language = new Language();
        language.whatToSpecify();
    }


    public void setTicketPrice(String ticketCategory, int ticketPrice) {
    
    }
    
    public void displayArtist(String artistName, int artistSalary) {
        language = new Language();
        language.displayArtistAndSalary(artistName, artistSalary);
    }
    
    public void displayTracklist(ArrayList<String> trackList) {
        language = new Language();
        language.displayTrackList(trackList);
    }
    
    public void displayTickets(Object[] ticketList) {
        language = new Language();
        language.displayTicket(ticketList);
    }           
                        
public static void main(String[] args) {

        Event event1 = new Event(new Artist(), new Ticket());
    
        event1.displayArtist(artistName, artistSalary);
        event1.displayTracklist(trackList);
        event1.displayTickets(ticketList);
    
}
}

带有构造函数的 Ticket 类使用来自 InputReader 类的用户输入初始化该类，并创建一个字符串和整数对象。

import java.util.Arrays;

public class Ticket {

    
    private static String ticketCategory;
    private static int ticketAmount;
    private static int ticketPrice;
    private InputReader inputReader;
    private int amountOfTicketCategories;
    private int index;
    private Ticket[] ticketList;
    
    public Ticket(String ticketCategory,int ticketAmount,int ticketPrice) {
        
    }
    
    public Ticket() {
    inputReader = new InputReader();
    inputReader.specifyTicketCategories();
    ticketList = new Ticket[amountOfTicketCategories];
    for (index = 0; index < amountOfTicketCategories; index++) {
    inputReader.specifyTicket(ticketCategory, ticketAmount, ticketPrice);
    ticketList[index] = new Ticket(ticketCategory, ticketAmount, ticketPrice);
    
    
}
    }
    
public String toString() {
    return("TicketCategory: " + ticketCategory + "Amount of Tickets: " + ticketAmount + "Ticket Price: " +ticketPrice);
}

public Object getTicket() {
    return ticketList[index];
}

public int getAmountOfTicketCategories() {
    amountOfTicketCategories = inputReader.specifyTicketCategories();
    return amountOfTicketCategories;

    
    
}
}

处理用户输入的 InptReader 类：

import java.util.ArrayList;
import java.util.Scanner;

public class InputReader {

    private  Scanner sc;
    private  Language language;
    private  ArrayList <String> tracks;
    
    
    
    
    
    public InputReader() {
        tracks = new ArrayList<String>();
        language = new Language();
        sc = new Scanner(System.in);
        
        

    }

    public int specifyTicketCategories() {
        language.defineAmountOfTicketCategories();
        return sc.nextInt();
    
        
    }
    
    public void specifyTicket(String ticketCategory, int ticketAmount, int ticketPrice) {
        language.specifyTicketCategory();
        ticketCategory = sc.next();
        language.specifyTicketAmount();
        ticketAmount = sc.nextInt();
        language.specifyTicketPrice();
        ticketPrice = sc.nextInt();
        
    }
    
    public int amountOfTickets() {
        return sc.nextInt();
    }
    
    public int ticketPrice() {
        return sc.nextInt();
    }
    
    
    public String readName() {
        language.specifyArtist();
        return sc.nextLine();

    }

    public int readInteger() {
        language.specifyArtistSalary();
        return sc.nextInt();

    }

    public void addTitle() {
        int anzahlSongs = 3;
        int index = 0;
        while (index < anzahlSongs) {
            language.specifyTrackList();
            tracks.add(sc.nextLine());
            index++;
        }
    

}
    public  ArrayList<String> getArray() {
        return tracks;
    }

}

由语言语句组成的语言类

import java.util.ArrayList;

public class Language {
    
    public Language () {
    
        
    }

    public void whatToSpecify() {
        System.out.println("What would you like to specify fist? For Artist press 1, for Ticket press 2");
    }
    
    public void specifyArtist() {
    System.out.println("Who is the artist? ");
}


public void specifyArtistSalary() {
    System.out.println("How much does the artist earn? ");
}

public void displayTicket(Object[] ticketList) {
    System.out.println("Ticketlist: " + ticketList);
}
    
public void displayArtistAndSalary(String artistName, int artistSalary) {
    System.out.println("Artist: " + artistName + " " + "Salary: " + artistSalary);
}

public void displayTrackList(ArrayList<String> trackList) {
    System.out.println("Tracklist: " + trackList);
}

public void specifyTicketCategory() {
    System.out.println("What is the ticket category? ");
}

public void specifyTicketAmount() {
    System.out.println("What ist the amount of tickets? ");
}

public void specifyTicketPrice() {
    System.out.println("What is the price for your ticket?");
}

public void specifyTrackList() {
    System.out.println("Add title: ");
}

public void defineAmountOfTicketCategories() {
    System.out.println("How many ticket categories you like to set up?");
}

public void line() {
    System.out.println("***********************************");
}

}

在主类中创建艺术家实例的艺术家类（与票证相同）但具有其他变量和参数。

import java.util.ArrayList;

public class Artist {

    private int artistSalary;
    private String artistName;
    private InputReader inputReader;
    ArrayList <String> trackList;
    
    
    

    public Artist() {
        
        
        inputReader = new InputReader();
        artistName =    inputReader.readName();
        artistSalary = inputReader.readInteger();
        inputReader.addTitle();
        trackList = inputReader.getArray();
        trackList.remove(2);
        
            
    }

    public String getArtistName() {
        return artistName;

    }

    public int getArtistSalary() {
        return artistSalary;
    }

                
    
    public ArrayList<String> getArrayList(){
        return trackList;
    }

}

控制台输出： 添加标题： 你好 添加标题： 你好 您喜欢设置多少个门票类别？ 5 艺术家：大卫薪水：5000 曲目列表：[，你好] 票务清单：空

Answer 1

首先，在 Ticket 类的构造函数中，您使用另一个构造函数（具有 3 个参数的构造函数），它的主体为空。

ticketList[index] = new Ticket(ticketCategory, ticketAmount, ticketPrice);

public Ticket(String ticketCategory,int ticketAmount,int ticketPrice) {
    //this is empty
}

这意味着您正在创建一个对象，其中没有任何内容（空变量）。

试试这个：

public Ticket(String ticketCategory,int ticketAmount,int ticketPrice) {
    this.ticketCategory = ticketCategory;
    this.ticketAmount = ticketAmount;
    this.ticketPrice = ticketPrice;
}

那么，您的 getTicket 方法是错误的。您永远不会在 Ticket 类中定义“索引”整数。

public Object getTicket() {
    return ticketList[index];
}

其中“索引”未定义。

ticketList 不应该在 Ticket class=> 每次创建 Ticket 实例时，它可能与之前的不一样。