Java抛出InputMismatchException

Question

我开始学习Java，我正在从我的书中做一些练习。在执行此操作时，我遇到了以下错误：Exception in thread "main" java.util.InputMismatchException。我正在编写一个简单的程序，它从.txt文件中获取数据并将其返回到控制台。下面是代码：

Employee.java

import static java.lang.System.out;

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;
    }

    public void cutCheck(double amountPaid){
        out.printf("Pay an employee %s ", name);
        out.printf("(%s) ***$", jobTitle);
        out.printf("%,.2f", amountPaid);
    }
}

DoPayroll.java

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

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();
    }
}

EmployeeInfo.txt

John
Manager
15000.00
Alice
Secretary
8000.00
Bob
Engineer
12000.00
**an empty line**

编译器中的错误日志：

Exception in thread "main" java.util.InputMismatchException
    at java.util.Scanner.throwFor(Scanner.java:864)
    at java.util.Scanner.next(Scanner.java:1485)
    at java.util.Scanner.nextDouble(Scanner.java:2413)
    at DoPayroll.payOneEmployee(DoPayroll.java:19)
    at DoPayroll.main(DoPayroll.java:11)

Answer 1

您的问题是由于Scanner使用当前的Locale来解析Double，所以您需要显式地设置一个允许使用点作为小数分隔符的Locale，例如Locale.US。因此，要修复代码，只需在for循环之前将其添加到代码中：

diskScanner.useLocale(Locale.US);