使用扫描仪从 CSV 文件中读取数据会引发异常

Question

我最近才开始使用 Java，所以请多多包涵。我正在尝试通过从格式为

的 csv 文件中读取数据来创建对象 Product 的数组

Name,Price,Stock

但每次我尝试使用 Load() 函数时，它总是在 Product 构造函数行中给我一个错误。

  private Product[] product = new Product[100];

  public Product[] Load() throws FileNotFoundException {
    int  counter = 0;
    boolean end = false;

    Scanner scanner = new Scanner(new File("products.csv"));
    scanner.useDelimiter(",");

    while (!end) {
        if (scanner.hasNext()) {
            product[counter] = new Product(scanner.next(), scanner.nextFloat(), scanner.nextInt());
            counter++;
        }
        else {
            end = true;
        }

    }

    scanner.close();
    return product;
}

错误消息是java.util.scanner.next(unknown source)，scanner.nextFloat() 和 scanner.nextInt()

的错误相同

Exception in thread "main" java.util.InputMismatchException
at java.util.Scanner.throwFor(Unknown Source)
at java.util.Scanner.next(Unknown Source)
at java.util.Scanner.nextInt(Unknown Source)
at java.util.Scanner.nextInt(Unknown Source)
at ScoutShop.CSVReader.Load(CSVReader.java:20)
at ScoutShop.Main.main(Main.java:11)

Answer 1

生成的java类也应该是products.csv的同一个位置。

或者尝试将 products.csv 放在根目录或 `C:\products.csv 中并执行（看看会发生什么）：

 Scanner scanner = new Scanner(new File("C:\\products.csv"));

Answer 2

检查Java Docs 中的new File(String path) 知道您必须为尝试读取的文件指定确切的文件路径

检查此答案以通过Scheintod 解析CSV Parsing errors 的CSV

private Product[] product = new Product[100];
public Product[] load() throws FileNotFoundException {
    int  counter = 0;
    Scanner scanner = new Scanner(new File("products.csv"));
    scanner.useDelimiter(",");
    // try the following while loop without use of if-else statements to 
    // avoid complexity in case of up scaling/maintaining your application 
    while(scanner.hasNext()){
         // System.out.print(scanner.next()+"|");
         product[counter] = new Product(scanner.next(), scanner.nextFloat(), 
         scanner.nextInt());
         counter++;
    }
    scanner.close();
    return product;
}