Java：NoSuchElementException [英] Java: NoSuchElementException

问题描述

我开始只是在读取数据文件时进行练习。当我运行程序时，数据文件被读取，什么不是，但由于某种原因，我仍然得到一个NoSuchElementException，我的输出没有按照它应该的方式格式化。以下是发生的事情：

I'm beginning to do exercises with simply reading in a data file. When I run the program, the data file gets read and what not, but for some reason I still get a "NoSuchElementException" and my output is not formatted the way it is supposed to be. Here is what is going on:

我创建了一个如下所示的简单数据文件：

I created a simple data file that looks like this:

Barry Burd
Author
5000.00
Harriet Ritter
Captain
7000.00
Ryan Christman
CEO
10000.00

之后我写了一个简单的getter和setter程序（代码如下）。

After that I wrote a simple "getter" and "setter" program (code is below).

import static java.lang.System.out;

  //This class defines what it means to be an employee

public class Employee {

  private String name;
  private String jobTitle;

  public void setName(String nameIn) {
    name = nameIn;
  }

  public String getName() {
    return name;
  }

  public void setJobTitle(String jobTitleIn) {
    jobTitle = jobTitleIn;
  }

  public String getJobTitle() {
    return jobTitle;
  }

  /*The following method provides the method for writing a paycheck*/

  public void cutCheck(double amountPaid)   {
    out.printf("Pay to the order of %s ", name);
    out.printf("(%s) ***$", jobTitle);
    out.printf("%,.2f\n", amountPaid);
  }

}

足够简单。 然后我写了实际使用这个东西的程序（下面的代码）。

Easy enough. Then I wrote the program that actually uses this stuff (code below).

import java.util.Scanner;
import java.io.File;
import java.io.IOException;

public class DoPayroll {

  public static void main(String[] args) throws IOException {
    Scanner diskScanner = new Scanner(new File("EmployeeInfo.txt"));

    for (int empNum = 1; empNum <= 3; empNum++) {
      payOneEmployee(diskScanner);
    }
  }

  static void payOneEmployee(Scanner aScanner) {
    Employee anEmployee = new Employee();

    anEmployee.setName(aScanner.nextLine());
    anEmployee.setJobTitle(aScanner.nextLine());
    anEmployee.cutCheck(aScanner.nextDouble());
    aScanner.nextLine();
  }
}

这是我的输出：

Pay to the order of Exception in thread "main" java.util.NoSuchElementException: No line found
    at java.util.Scanner.nextLine(Scanner.java:1516)
    at DoPayroll.payOneEmployee(DoPayroll.java:25)
    at DoPayroll.main(DoPayroll.java:14)
 Barry Burd ( Author) ***$5,000.00
Pay to the order of  Harriet Ritter ( Captain) ***$7,000.00
Pay to the order of  Ryan Christman ( CEO) ***$10,000.00

编辑我发现了问题，但我不明白lol。显然，我必须在数据文件的末尾添加一个空行....为什么??

EDIT I found the problem but I don't understand it lol. Apparently, I had to add a blank line to the end of the data file....why??

推荐答案

我发现了问题，但我不明白它哈哈。显然，我必须在数据文件的末尾添加一个空行....为什么??

I found the problem but I don't understand it lol. Apparently, I had to add a blank line to the end of the data file....why??

因为你在告诉扫描器在输入文件中的工资之后将有一个回车符。但是，对于最后一个条目，没有回车符，因此它确定您发出了编程错误并抛出了未经检查的异常。

Because you are telling the Scanner that there will be a carriage return after the salary in the input file. However, for the last entry, there was no carriage return and so it determined that you had made a programming error and threw an unchecked exception.

您可以解决此问题您的代码如下：

You could solve the problem in your code like so:

static void payOneEmployee(Scanner aScanner) {
    Employee anEmployee = new Employee();

    anEmployee.setName(aScanner.nextLine());
    anEmployee.setJobTitle(aScanner.nextLine());
    anEmployee.cutCheck(aScanner.nextDouble());
    if (aScanner.hasNextLine()) {
        aScanner.nextLine();
    }
}

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