Java，分隔符

Question

我有这个分隔符代码：(":|\\s+")。 我想要这样的标志：(":")，但如果我使用它，程序将无法工作 - 它会在第一个问题后停止。

谁能看到我哪里出错了？

import java.util.Scanner;
public class Salary
{
    public static void main(String[] args)
    {
        int hour1, hour2, minute1, minute2, salary; 
        double totaly, totSalary, totHours, totMinutes, totDecMinutes;

        salary = 190;       

        Scanner scan = new Scanner(System.in);

        scan.useDelimiter(":|\\s+"); 

        System.out.println("Write the time when you startet working."
            + "Use the format (hh:mm).");

        hour1 = scan.nextInt();
        minute1 = scan.nextInt();

        System.out.println("Write the time when you stopped working."
            + "Use the formatet (hh:mm).");

        hour2 = scan.nextInt();
        minute2 = scan.nextInt();

        // Counts the number of workinghours.
        totHours = (hour2 - hour1);

        // Counts the number om workingminutes, decimal number
        totMinutes = (minute2 - minute1);
        totDecMinutes = totMinutes/60;

        // Counts the salary: total hours.
        totaly = totHours + totDecMinutes;
        totSalary = totaly*salary;

        System.out.printf("Din lön för idag blir: %.2f kr.", totSalary);
    }
}

Answer 1

我认为（虽然不确定）换行符被解释为某种空格组合。上面使用的分隔符分隔 : 或一个或多个空格。如果我写了 2:34 然后单击 Enter 转到换行符，扫描仪将在 : 上定界，以 2 表示小时，然后在换行符上定界，以 34 表示分钟。我不确定换行符是如何转换为 ASCII 的，并且无论如何它会随操作系统而变化。

这就是为什么我更喜欢使用 Scanner.nextLine() 它从行的其余部分返回输入，不包括末尾的任何行分隔符。清理用户输入也更容易（参见下面的示例代码），因为如果之前的时间格式不正确，我可以反复要求用户提供时间。

public class Salary
{
public static void main(String[] args)
{
    int hour1, hour2, minute1, minute2, salary; 
    double totaly, totSalary, totHours, totMinutes, totDecMinutes;

    salary = 190;       

    Scanner scan = new Scanner(System.in);

    System.out.print("Write the time when you startet working."
            + "Use the format (hh:mm).\n>> ");
    while (true) {
        String s = scan.nextLine();
        String[] parsed = s.split(":");
        if (s.split(":").length == 2) {
            try {
                hour1 = Integer.parseInt(parsed[0]);
                minute1 = Integer.parseInt(parsed[1]);
                break;
            } catch (NumberFormatException e) {
            }
        }
        System.out.print("Invalid input. Try again\n>> ");
    }

    System.out.print("Write the time when you stopped working."
            + "Use the formatet (hh:mm).\n>> ");
    while (true) {
        String s = scan.nextLine();
        String[] parsed = s.split(":");
        if (s.split(":").length == 2) {
            try {
                hour2 = Integer.parseInt(parsed[0]);
                minute2 = Integer.parseInt(parsed[1]);
                break;
            } catch (NumberFormatException e) {
            }
        }
        System.out.print("Invalid input. Try again\n>> ");
    }

    // Counts the number of workinghours.
    totHours = (hour2 - hour1);

    // Counts the number om workingminutes, decimal number
    totMinutes = (minute2 - minute1);
    totDecMinutes = totMinutes/60.0;

    // Counts the salary: total hours.
    totaly = totHours + totDecMinutes;
    totSalary = totaly*salary;

    System.out.printf("Din lön för idag blir: %.2f kr.", totSalary);
}

}