for循环的问题，接受和利用输入

Question

我正在尝试创建一个程序来接收商品代码并检查它们在“Stock.txt”文件中是否有效，该文件的格式如下：

ItemCode,ItemName,Quantity,Price

其中的内容：

jmpr,Jumper,30,13.99
tsrt,T-Shirt,12,4.99
shs,Shoes,9,14.99
trsrs,Trousers,3,9.99
jkt,Jacket,0,19.99
scks,Socks,11,3.99
muwear,Male Underwear,4,4.99
fuwear,Female Underwear,8,6.99
hat,Hat,0,7.99
txdo,Tuxedo,3,99.99

我要求一个或多个项目代码用空格分隔，然后他们希望购买的数量也用空格分隔，然后我将 Stock.txt 文件的内容存储到 ArrayList 并扫描到检查项目代码是否存在，以及该项目代码的对应数量是否小于或等于 Stock.txt 文件中的数量，如果是，它将被添加到我稍后将使用的 String shoppingCart上。如果数量大于当前库存量，同样如果项目代码错误我退出程序。

我遇到的问题是，当我运行程序时，它会询问项目代码，然后是数量，然后它会在程序结束时进入打印语句，但是当输入 1 时，它会询问项目代码和数量再次，而不是打印出“采购..”，我不知道出了什么问题，它不在循环之内，任何帮助都会让我开心。

*抱歉，如果我将代码取出并将其放在自己的类中，因为我在其他文件中将其用作方法。

import java.io.*;
import java.util.*;
public class Items
{
    public static Scanner userInput = new Scanner(System.in);
    public static File stockFile    = new File("Stock.txt");
    public static void main() throws IOException
    {
        boolean valid = true;
        String shoppingCart = "";
        List<String[]> contents = new ArrayList<>();
        Scanner searchStockFile = new Scanner(stockFile);
        while(searchStockFile.hasNextLine())
        {
            String[] current = searchStockFile.nextLine().split(",");
            contents.add(current);
        }
        System.out.println("\n----------Add Items----------");
        System.out.print("Enter Item Codes: ");
        String itemCodes = userInput.nextLine();
        String itemCodesArray[] = itemCodes.split(" ");

        System.out.print("Enter Item Quantities: ");
        String quantities = userInput.nextLine();
        String quantityArray[] = quantities.split(" ");
        int[] quantityIntArray = new int[quantityArray.length];
        for(int i = 0; i < quantityArray.length; i++)
            quantityIntArray[i] = Integer.parseInt(quantityArray[i]);

        for(int i = 0; i < itemCodesArray.length; i++)
        {
            for(String[] elements : contents)
            {
                try
                {
                    if(itemCodesArray[i].equals(elements[0]) && Integer.parseInt(elements[2]) >= quantityIntArray[i])
                        shoppingCart += itemCodesArray[i] + "," + elements[1] + "," + elements[2] + "," + quantityIntArray[i] + "," + elements[3] + ".";

                    else if(itemCodesArray[i].equals(elements[0]) && Integer.parseInt(elements[2]) < quantityIntArray[i])
                    {
                        System.out.println("The quantity of Item Code - " + itemCodesArray[i] + " - exceeds the current stock.");
                        valid = false;
                    }
                }
                catch(Exception e)
                {
                    System.out.println("The Item code you entered does not exist.");
                    valid = false;
                }
                if(!valid)
                    System.exit(0);
            }
        }

        System.out.println("\n----------Purchase/Hire Items----------");
        System.out.print("1. Purchase Item\n2. Quit\nEnter Option Number: ");
        String PH = userInput.nextLine();
        if(PH.equals("1"))
            System.out.println("Purchasing..)";
        else if(PH.equals("2"))
            System.out.println("Quitting..)";
        else
            System.out.println("Invalid Option chosen.\nPlease choose Options 1 or 2.");
    }
}

Answer 1

如果购买，您需要在用户输入后循环返回，检查此

 boolean valid = true;
    String shoppingCart = "";
    List<String[]> contents = new ArrayList<>();
    Scanner searchStockFile = new Scanner(stockFile);
    while (searchStockFile.hasNextLine()) {
        String[] current = searchStockFile.nextLine().split(",");
        contents.add(current);
    }
    String PH = "1";
    do {
        System.out.println("\n----------Add Items----------");
        System.out.print("Enter Item Codes: ");
        String itemCodes = userInput.nextLine();
        String itemCodesArray[] = itemCodes.split(" ");

        System.out.print("Enter Item Quantities: ");
        String quantities = userInput.nextLine();
        String quantityArray[] = quantities.split(" ");
        int[] quantityIntArray = new int[quantityArray.length];
        for (int i = 0; i < quantityArray.length; i++) {
            quantityIntArray[i] = Integer.parseInt(quantityArray[i]);
        }

        for (int i = 0; i < itemCodesArray.length; i++) {
            for (String[] elements : contents) {
                try {
                    if (itemCodesArray[i].equals(elements[0]) && Integer.parseInt(elements[2]) >= quantityIntArray[i]) {
                        shoppingCart += itemCodesArray[i] + "," + elements[1] + "," + elements[2] + "," + quantityIntArray[i] + "," + elements[3] + ".";
                    } else if (itemCodesArray[i].equals(elements[0]) && Integer.parseInt(elements[2]) < quantityIntArray[i]) {
                        System.out.println("The quantity of Item Code - " + itemCodesArray[i] + " - exceeds the current stock.");
                        valid = false;
                    }
                } catch (Exception e) {
                    System.out.println("The Item code you entered does not exist.");
                    valid = false;
                }
                if (!valid) {
                    System.exit(0);
                }
            }
        }

        while (true) {
            System.out.println("\n----------Purchase/Hire Items----------");
            System.out.print("1. Purchase Item\n2. Quit\nEnter Option Number: ");
            PH = userInput.nextLine();
            if (PH.equals("1")) {
                System.out.println("Purchasing..");
                break;
            } else if (PH.equals("2")) {
                System.out.println("Quitting..");
                System.exit(0);
            } else {
                System.out.println("Invalid Option chosen.\nPlease choose Options 1 or 2.");
            }
        }
    } while (PH.equals("1"));