java - 线程中出现异常 "main"java.util.InputMismatchException 错误消息

Question

我尝试了很多不同的方法来让它发挥作用。我很抱歉问了一个蹩脚的问题，我完全是新手。当我从 inFile 请求信息时，它是否需要按照数据的顺序排列？

这是 inData.txt :

10.20  \\\length
5.35   \\\width
15.6   \\\radius
Randy Gill   \\\first last name
31 \\\age
18500 \\\bank account balance
3.5 \\\ interest rate
A \\char 'a'

我应该打印矩形、圆形的尺寸。姓名及银行账户信息。感谢您的帮助!

import java.util.*;
import java.io.*;


public class ProgrammingExercise3_1   
{
   public static void main(String[] args) throws FileNotFoundException
   {

      double rectWidth;
      double rectLength;
      double radius;
      int age;
      double begBal;
      char A;
      String name;
      double rate;

      Scanner inFile = new Scanner(new FileReader("C:\\Users\\sierr_000\\Desktop\\Sam School\\IT-145\\Exercises\\Ch 3\\inData.txt"));

      PrintWriter outFile = new PrintWriter("C:\\Users\\sierr_000\\Desktop\\Sam School\\IT-145\\Exercises\\Ch 3\\outData.out");

      rectWidth = inFile.nextDouble();
      rectLength = inFile.nextDouble();

      outFile.println("Rectangle: ");
      outFile.println("Length = " + rectLength + ", width = " + rectWidth + ", area = "
                     + (rectWidth*rectLength) + ", perimeter = " + (2 * (rectWidth + rectLength)));

      radius = inFile.nextDouble();

      outFile.println("Circle: ");
      outFile.println("Radius = " + radius + ", area = " + (radius*3.1416) + "Circumfrence = " + (2*3.1416*radius));

      name = inFile.next();
      age = inFile.nextInt();

      outFile.println("Name: " + name + ", age: " + age);

      begBal = inFile.nextDouble();
      rate = inFile.nextDouble();

      outFile.printf("Beginning Balance: %.2f %n" , begBal + "interest rate: %.2f" , rate);
      outFile.println("The character that comes after A in the ASCII is B");      




      inFile.close();
      outFile.close();

   }
}

Answer 1

你有一个良好的开端!我发现您的代码有 2 个问题导致了问题。

name 变量应该这样分配:

name = inFile.next()+" "+inFile.next();

name = inFile.next() 只会获取“Randy”并弄乱 age 变量。

接下来，这一行引起了问题:

outFile.printf("Beginning Balance: %.2f %n" , begBal + "interest rate: %.2f" , rate);

我将其分成一系列 outFile.print 和 outFile.printf 语句。

  outFile.print("Beginning Balance: ");
  outFile.printf("%.2f %n", begBal);
  outFile.print("interest rate: ");
  outFile.printf("%.2f", rate);

在这两个问题之后，一切似乎都正常了。我希望这有帮助!