Question

我正在尝试使用扫描程序从CSV文件中读取，但是当我尝试读取最后一个双数并且我的CSV文件中有多行时，我收到了一个InputMismatchException。我认为这是因为它正在读取\ n作为双重的一部分。如何让它忽略换行符？

CSV文件

P1,25,30
P2,10,10

爪哇

public static ArrayList<MarkEntry> readCSV(File file) {
    ArrayList<MarkEntry> entries = new ArrayList<>();
    try
    {
        Scanner in = new Scanner(file).useDelimiter(",");
        while (in.hasNext())
        {
            String title = in.next();
            double mark = in.nextDouble();
            double outOf = in.nextDouble(); //Program Crashes here
            entries.add(new MarkEntry(title, mark, outOf));
        }
    } catch (FileNotFoundException e)
    {
        System.out.println("File: " + file + " not found");
    }

    return entries;
}

Answer 1

    while (in.hasNext())
    {
        String[] inputLine = in.nextLine().split(",");
        //check that the line contains 3 comma seperated values
        if(inputLine.length == 3)
        {
            String title = inputLine[0]; //first on should be P1, p2 etc
            //catch the exception if we are unable to parse the two expected doubls
            try
            {
                double mark = Double.parseDouble(inputLine[1]);
                double outOf = Double.parseDouble(inputLine[2]); //Program Crashes here
                //if we got here then we have valid inputs for adding a MarkEntry
                entries.add(new MarkEntry(title, mark, outOf));
            }catch(NumberFormatException er)
            {
                //print stack trace or something
            }
        }

    }

使用Scanner从文件读取时的InputMismatchException

1 个答案: