java - 验证扫描仪仅允许字符

Question

这是我的第一个问题。我正在参加在线编码类(class)，它的说明中肯定存在一些漏洞。我们的任务是获取 2 个仅包含一个字符的不同输入，并将它们转换为 ASCII 值。我很沮丧，我正在努力解决如何验证输入仅允许一个字符，而不是数字或符号等内容，然后在出现此类错误时退出程序。这是我的代码。

import java.io.*;
import java.util.*;
public class AndrewBrutonMod4TopSecret
{
    public static void main(String args[])
    {
        Scanner kaReader = new Scanner(System.in);
        System.out.println("Enter the first initial of your first name:");
        String i1 = kaReader.next();
        System.out.println("Enter the first initial of your last name:");
        String i2 = kaReader.next();
        char a = i1.charAt(0);
        char b = i2.charAt(0);
        char a1 = Character.toUpperCase(a);
        char b1 = Character.toUpperCase(b);
        int c = (int)a;
        int d = (int)b;
        System.out.println("Initials: "+a1+" "+b1);
        System.out.println("Encrypted Initials: "+c+" "+d);
    }
}

有什么想法吗？

Answer 1

I'm struggling with how I'm supposed to validate the inputs to only allow one character, and not something such as a number or symbol

您可以使用 isAlphabetic() 方法

Java 文档:

Determines if the specified character (Unicode code point) is an alphabet. A character is considered to be alphabetic if its general category type, provided by getType(codePoint), is any of the following:

UPPERCASE_LETTER

LOWERCASE_LETTER

TITLECASE_LETTER

MODIFIER_LETTER

OTHER_LETTER

LETTER_NUMBER

or it has contributory property Other_Alphabetic as defined by the Unicode Standard.

private static boolean isValidChar(char ch) {
    return Character.isAlphabetic(ch);
}

and then exit the program if such an error arises

例如

if (!isValidChar(a))
    System.exit(-1);