Question

我有一个试图从“concerts.txt”文件中读取信息的程序。我把它放在我的文件夹的根文件中，即使我100％肯定文件存在，它仍然返回“错误：找不到文件”异常。我已经尝试将它从源文件夹移动到根项目文件夹，以及放入文件的整个地址（“C：...”），似乎没有任何工作。我继续得到错误信息，似乎无论我做什么。此外，我尝试将try catch块移动到包含构造函数ConcertEvent的类中，所做的就是获取在ConcertEvent的所有三个实例中编写的数据的第一个实例。我不确定如何将其更改为获取正确数据的位置（concert1的名称应该是Maroon 5，concert2的名称应该是One Direction但是现在两个实例的名称都显示为Maroon 5）请帮助我！

另外，我附上了我应该从

读取的构造函数和.txt文件

public class ConcertDriver
{
    private static String name = null;
    private static char orderType = ' ';
    private static int numTicketsOrdered = 0;
    private static String bandName = null;
    private static double ticketPrice = 0;
    private static int showCapacity = 0;
    private static double amountOwed = 0;
    private static boolean answer = true;
    private static int response = 0;
    private static Scanner keyboard = new Scanner(System.in);

    public static void main(String[] args)

    {
        try
        {
            Scanner input = new Scanner(new File("concerts.txt"));
            ConcertEvent concert1 = new ConcertEvent(input);
            ConcertEvent concert2 = new ConcertEvent(input);
            ConcertEvent concert3 = new ConcertEvent(input);


            System.out.println("Redbird Concert Hall");
            System.out.println();
            System.out.println("Please choose your concert:");
            System.out.println("1. " + concert1.getBandName());
            System.out.println("2. " + concert2.getBandName());
            System.out.println("3. " + concert3.getBandName());
            System.out.println("4. Quit");
            System.out.println();
            response = keyboard.nextInt();
            while(answer)
            {
                switch(response)
                {
                    case 1:
                    {
                        manageSales(concert1);
                    }
                    case 2:
                    {
                        manageSales(concert2);
                    }
                    case 3:
                    {
                        manageSales(concert3);
                    }
                    case 4:
                    {
                        answer = false;
                        FileWriter output = new FileWriter(new File("report.txt"));
                        output.write(concert1.getBandName() + "\n");
                        output.write(concert1.getShowCapacity() + "\n");
                        output.write(concert1.getTotalTicketsSold() + "\n");
                        output.write(concert2.getBandName() + "\n");
                        output.write(concert2.getShowCapacity() + "\n");
                        output.write(concert2.getTotalTicketsSold() + "\n");
                        output.write(concert3.getBandName() + "\n");
                        output.write(concert3.getShowCapacity() + "\n");
                        output.write(concert3.getTotalTicketsSold() + "\n");
                    }
                    default:
                    {
                        System.out.println("Invalid option, please try again.");
                    }
                }               
            }
        }
        catch(Exception e)
        {
            System.out.println("Error: File Not Found");
        }
    }
    /*
     * Handles sales, and uses other private helper methods to confirm ticket amounts and calculate necessary data
     */
    private static void manageSales(ConcertEvent concert)
    {
        bandName = concert.getBandName();
        showCapacity = concert.getShowCapacity();
        ticketPrice = concert.getTicketPrice();

        System.out.println("There are " + showCapacity + " tickets remaining for " + bandName + ".");
        System.out.println();
        System.out.println("Enter your first and last name:");
        name = keyboard.nextLine();
        System.out.println();
        System.out.println("How is your order placed? B for box office or P for phone");
        orderType = keyboard.next().toUpperCase().charAt(0);
        ticketPrice = concert.getTicketPrice();
        if(orderType == 'P')
        {
            ticketPrice += 4; 
        }
        System.out.println();
        System.out.println("How many tickets would you like?");
        numTicketsOrdered = keyboard.nextInt();
        confirmAmount(numTicketsOrdered, concert);

    }
    /*
     * Checks to make sure that there is enough tickets available for sale
     */
    private static void confirmAmount(int numTickets, ConcertEvent concert)
    {
        if(numTickets > showCapacity)
        {
            System.out.println("You asked for " + numTicketsOrdered + " to "
                    + concert.getBandName() + ", but there are only "
                    + concert.getShowCapacity() + " tickets remaining.");
        }
        else    
        {
            amountOwed = ConcertCalculator.calculate(numTicketsOrdered, concert.getTicketPrice());
            printReceipt(bandName, name, numTicketsOrdered, amountOwed);
        }
    }
    /*
     * Prints receipt for purchase
     */
    private static void printReceipt(String bandName, String name, int numTickets, double amountOwed)
    {
        System.out.println("Concert: " + bandName);
        System.out.println("Name: " + name);
        System.out.println("Number tickets: " + numTickets);
        System.out.println("Amount owed: " + amountOwed);
    }
}




public ConcertEvent(Scanner input)
    {
        try
        {
        input = new Scanner(new File("concerts.txt"));
                bandName = input.nextLine();
                showCapacity = input.nextInt();
                ticketPrice = input.nextDouble();
                input.nextLine();
        }
        catch(Exception e)
        {
            System.out.println("Error: file not found");
        }

Maroon 5
15
40
One Direction
10
50
Pearl Jam
20
30

Answer 1

此：

Scanner input = new Scanner(new File("concerts.txt"));

将在用户目录中查找该文件，而不是在根目录中查找。您可以通过在代码中的某处放置System.out.println(System.getProperty("user.dir"));来找到用户的目录。如果要在特定位置获取文件，可能需要使用文件的完整路径。

或者，通过Class的getResourceAsStream(...)方法将这些资源作为资源通常更好。如果使用此方法，资源的路径（此处为文本文件）将相对于类文件的路径。

Answer 2

Here您可以看到如何使用类路径查看相对路径。

如果您知道文件的相对位置，那么您可以轻松地访问项目的根目录，并从那里到达您的文件。

在java中没有明显错误时显示错误

2 个答案: