Java 抛出 InputMismatchException

Question

我开始学习 Java，并且正在根据书本做一些练习。在执行此操作时，我遇到了以下错误:线程“main”java.util.InputMismatchException 中出现异常。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。代码如下:

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 因此您需要显式设置 Locale 允许使用点作为小数点分隔符，例如 Locale.US 。因此，要修复您的代码，您只需在 for 循环之前将其添加到代码中即可:

diskScanner.useLocale(Locale.US);