Question

所以这是我的代码：

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

public class Main {
public static void main(String[] args){

    ArrayList<Employee> ArrEmployee = new ArrayList<Employee>(); //  array for employee objects

        try {
            Scanner txtIn = new Scanner(new File("payroll.txt"));
            PrintWriter txtOut = new PrintWriter("payrollError.txt");


            while (txtIn.hasNext()) { // looping through the payroll.txt file and creating Employee objects from its data
                try{
                long EmployeeNumber = txtIn.nextLong();
                String EmployeeName = txtIn.next();
                String LastName = txtIn.next();
                double HoursWorked = txtIn.nextDouble();
                double HourlyWage = txtIn.nextDouble();
                if (HourlyWage > 10.35){ 
                    throw new InputMismatchException(); // throws exception if the hourly wage is less than 10.35$
                }
                else
                    ArrEmployee.add(new Employee(EmployeeNumber,EmployeeName,LastName,HoursWorked,HourlyWage)); // creates Employee objects according to the input payroll.txt
                }
                catch (InputMismatchException n) { // catching long,strings and doubles in the payroll.txt that aren't valid
                    txtOut.println(Employee.EmployeeNumber + " " + Employee.EmployeeName + " " + Employee.LastName + " " + Employee.HoursWorked + " " + Employee.HourlyWage);
                    System.out.println("lol");
                      }
                txtOut.close();
            }

        } catch (FileNotFoundException e) {
            System.out.println("File payroll.txt was not found.");

            }

          }

        }

我试图输出到名为payrollError.txt的.txt文件，但出于某种原因，while循环无限地继续......

我似乎无法在班级找到问题，我们将不胜感激。

这是来自payroll.txt的代码：

31718 PHILLIP LENNOX 55.0 20.00
11528 NANCY TROOPER 40.0 10.45
16783 JOHN CONNAUGHT 30.5 10.00
10538 PETER DUNCAN 45.0 10.75
21O15 JAMES HAROLD 32.0 10.50
61326 HARRY KUHN 25.0 12.30
82465 MICHELLE BENOIT 50.0 18.50
31816 DANIELLE RAYMOND 35.5 15.25
73745 JACK O'TOOLE 28.0 11.50
81514 VICTORIA HALL 48.5 17.50
71854 ALI MOHUMAD 35.0 10.75
92012 ALLAN MARS 36.0 15.00
52853 MICHAEL BOONE 60.5 17.50
41714 JULIE HART 25.0 10.50
58342 MIKE HEINZ 28.2 16.85
62080 PIETRO SULA 32.5 11.50
21638 MICHEL RAE 40.5 12.50
52726 MITCHELL HACKETT 23,7 12.05

基本上它应该像线一样循环遍历这些（long，string，string，double，double），找到任何无效的值，就像写为23,7而不是23.7的double并将其输出到我的文件payrollError.txt。

我的员工课程：

public class Employee {

     public static long EmployeeNumber;
     public static String EmployeeName;
     public static String LastName;
     public static double HoursWorked;
     public static double HourlyWage;

    public Employee(long EmployeeNumber, String EmployeeName, String LastName, double HoursWorked, double HourlyWage ){

        this.EmployeeNumber = EmployeeNumber;
        this.EmployeeName = EmployeeName;
        this.LastName = LastName;
        this.HoursWorked = HoursWorked;
        this.HourlyWage = HourlyWage;
    }
}

Answer 1

请勿关闭while循环体中的输出。另外，请遵循Java变量命名约定。而不是显示“大声笑”尝试并输出您正在写的消息。如果您无法初始化Employee，则很难看到现有方法如何获取已读取的值。最后，您需要close() PrintWriter（或使用以下try-with-resources为您执行此操作）。像

这样的东西

List<Employee> al = new ArrayList<>();
try (PrintWriter txtOut = new PrintWriter("payrollError.txt")) {
    Scanner txtIn = new Scanner(new File("payroll.txt"));
    while (txtIn.hasNext()) {
        long employeeNumber;
        String employeeName;
        String lastName;
        double hoursWorked;
        double hourlyWage;

        try {
            employeeNumber = txtIn.nextLong();
            employeeName = txtIn.next();
            lastName = txtIn.next();
            hoursWorked = txtIn.nextDouble();
            hourlyWage = txtIn.nextDouble();
            if (hourlyWage > 10.35) {
                throw new InputMismatchException();
            } else {
                al.add(new Employee(employeeNumber, employeeName,
                                lastName, hoursWorked, hourlyWage));
            }
        } catch (InputMismatchException n) {
            String msg = employeeNumber + " " + employeeName + " "
                    + lastName + " " + hoursWorked + " " + hourlyWage;
            txtOut.println(msg);
            System.out.println(msg);
        }
        // txtOut.close(); // <-- this is inside the loop.
    }
} catch (FileNotFoundException e) {
    System.out.println("File payroll.txt was not found.");
}

您的static课程中的字段不能为Employee！（我会使它们小写以遵循Java命名约定;否则它们看起来像类名称）

 private /* static */ long EmployeeNumber;
 private /* static */ String EmployeeName;
 private /* static */ String LastName;
 private /* static */ double HoursWorked;
 private /* static */ double HourlyWage;

制作字段private是封装的一个例子。

Answer 2

使用文件流时最好使用缓冲的读写器。

使用以下代码修改代码：

public class Main {
    public static void main(String[] args) {
        ArrayList<Employee> ArrEmployee = new ArrayList<Employee>();
        FileReader bfr = null;
        try {
            bfr = new FileReader(new File("payroll.txt"));
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        BufferedReader br = new BufferedReader(bfr);
        String EmployeeName = "no data";
        FileWriter bfw = null;
        try {
            bfw = new FileWriter("payroolError.txt");
        } catch (IOException e) {
            e.printStackTrace();
        }
        BufferedWriter txtOut = new BufferedWriter(bfw);

    try {
        while (br.read() != -1) {
            String temp = br.readLine();
            Pattern p = Pattern.compile(" ");
            String[] items = p.split(temp);
            try {
                int EmployeeNumber = Integer.parseInt(items[0]);
                EmployeeName = items[1];
                String LastName = items[2];
                double HoursWorked = Double.parseDouble(items[3]);
                double HourlyWage = Double.parseDouble(items[4]);
                if (HourlyWage > 10.35) {
                    throw new InputMismatchException();
                } else {
                    ArrEmployee
                            .add(new Employee(EmployeeNumber, EmployeeName,
                                    LastName, HoursWorked, HourlyWage));
                }
            } catch (NumberFormatException n) {
                txtOut.write(EmployeeName);
            } catch (InputMismatchException n) {
                txtOut.write(EmployeeName);
            }
        }
    } catch (IOException e) {
        e.printStackTrace();
    }

}}

在Java中将输出循环到.txt文件

2 个答案: