扫描器类和线程“main”java.util.InputMismatchException错误中的一个异常

Question

public class PolynomialTest {

public static void main(String[] args) throws IOException {

Scanner fileData = new Scanner(new File("operations.txt"));
Polynomial math = new Polynomial();
int coeff = fileData.nextInt();
int expo = fileData.nextInt();

while (fileData.hasNext()) {

    Scanner nextTerm = new Scanner(fileData.nextLine());

    if (nextTerm.next().equalsIgnoreCase("insert")) {

        math.insert(coeff, expo);
        System.out.println("The term (" + coeff + ", " + expo
                + ") has been added to the list in its proper place");
        System.out.println("The list is now: " + math.toString());

    } else if (nextTerm.next().equalsIgnoreCase("delete")) {

        math.delete(coeff, expo);
        System.out.println("The following term has been removed ("
                + coeff + ", " + expo + ")");
        System.out.println("The list is now: " + math.toString());

    } else if (nextTerm.next().equalsIgnoreCase("reverse")) {

        math.reverse();
        System.out
                .println("The list was reversed in order and the list is now: "
                        + math.toString());

    } else if (nextTerm.next().equalsIgnoreCase("product")) {

        System.out.println("The product of the polynomial is: "
                + math.product());

    } else {

        System.out.println("Not a recognized input method");

    }
    nextTerm.close();
}
PrintWriter save = new PrintWriter("operations.txt");
save.close();
fileData.close();

Answer 1

InputMismatchException由扫描程序引发，以指示检索到的令牌与预期类型的模式不匹配，或者令牌超出了预期类型的范围。

int coeff = fileData.nextInt();
int expo = fileData.nextInt();

尝试将上面的内容更改为下面的内容。（如果在两个单独的行中有前两个整数输入，否则请尝试在使用filedata.nextline().split（“”）读取它们后解析它们）

int coeff  = Integer.parseInt(fileData.nextLine());
int expo = Integer.parseInt(fileData.nextLine());

如果同一行中有2个整数

    String s[] = fileData.nextLine().split(" ");
    int coeff   = Integer.parseInt(s[0]);
    int expo  = Integer.parseInt(s[1]);