Java代码挂在扫描器hasNextLine上

Question

首先，我是java新手，正在尝试完成学校关于创建自动售货机的作业。我的程序接收两个文件作为cli参数，一个是产品，另一个是钱。

 (while (moneyTemp.hasNextLine());)

import java.util.Scanner;
import java.io.File;
import java.io.FileNotFoundException;

public class VendingMachine
{
    static Scanner input = new Scanner (System.in);

    public static void main(String[] args) 
    {
        try
        {
            Scanner productTempFile = new Scanner(new File(args[0]));
            Scanner moneyTemp = new Scanner(new File(args[1]));
            int numProducts = 0; //Number of products to be loaded to the machines
            int numMoney = 0;   //Number of money objects to be loaded in the machine

            while (productTempFile.hasNextLine()) //This block will get the number of products
            {
                numProducts++;
                productTempFile.nextLine();
            }
            productTempFile.close();


            Product[] invArray = new Product[numProducts];
            Scanner myFile = new Scanner(new File(args[0]));

            for(int i = 0; i < numProducts; i++)  //This block populates the array of products
            {
                String inputLine = myFile.nextLine();                               
                String[] lineArray = inputLine.split(",");

                invArray[i] = new Product(lineArray[0], Double.valueOf(lineArray[1]), lineArray[2], lineArray[3],
                        Double.valueOf(lineArray[4]), Integer.valueOf(lineArray[5]));
            } 

            myFile.close();

            System.out.println("I'm here");

            while (moneyTemp.hasNextLine()); //This block gets the number of different money items
            {
                numMoney++;
                moneyTemp.nextLine();               
            }

下面是我提供的ie Arg[1]的第二个文件，它的格式与第一个相同，工作。

PaperCurrency,100 Dollar Bill,100.0,medium,paper,0
PaperCurrency,50 Dollar Bill,50.0,medium,paper,0
PaperCurrency,20 Dollar Bill,20.0,medium,paper,0
PaperCurrency,10 Dollar Bill,10.0,medium,paper,4
PaperCurrency,5 Dollar Bill,5.0,medium,paper,8
PaperCurrency,1 Dollar Bill,100.0,medium,paper,16
CoinCurrency,50 Cent Piece,0.5,large,metal,10
CoinCurrency,Quarter,0.25,medium,metal,20
CoinCurrency,Dime,0.1,small,metal,30
CoinCurrency,Nickel,0.05,small,metal,40
CoinCurrency,Penny,0.01,small,metal,50

任何帮助都将不胜感激。谢谢

Answer 1

从行中删除分号

 while (moneyTemp.hasNextLine());

分号使while循环完成它的主体而不做任何事情意味着它像while(){}，当while条件为true时，什么也不做，并且由于您的条件为hasnextline()，它会一次又一次地检查相同的行，导致无限循环。