如何使用扫描仪使该 switch 语句起作用？

我正在尝试编写一个程序，将字母表中的任何字母（大写或小写）转换为拼音字母表。例如，如果我输入“A”或“a”，我的程序会给我（将其更改为）“Alpha”。 我对此和 switch 语句做了很多研究，但我总是陷入困境。我意识到我不能在扫描仪中使用“char”。但是，当我将“char”更改为“String”时，我的 switch 语句会混乱（特别是改为大写在我的代码中带有下划线。我看不到我的错误。这是我到目前为止所做的：

import java.util.Scanner;
public class PhoneticTranslate {
public static void main(String[] args) {


char letter;
String phonetic;

Scanner kb = new Scanner(System.in);


System.out.print("Please enter a letter: ");
letter = kb.next();

switch(Character.toUpperCase(letter))
{
case 'A':
    phonetic = "Alpha";
break;
case 'B':
    phonetic = "Bravo";
    break;
case 'C':
    phonetic = "Charlie";
    break;
case 'D': 
    phonetic = "Delta";
    break;
case 'E':
    phonetic = "Echo";
    break;
case 'F':
    phonetic = "Foxtrot";
    break;
case 'G':
    phonetic = "Golf";
    break;
case 'H':
    phonetic = "Hotel";
    break;
case 'I':
    phonetic = "India";
    break;
case 'J':
    phonetic = "Juliet";
case 'K':
    phonetic = "Kilo";
    break;
case 'L':
    phonetic = "Lima";
    break;
case 'M':
    phonetic = "Mike";
    break;
case 'N':
    phonetic = "November";
    break;
case 'O':
    phonetic = "Oscar";
    break;
case 'P':
    phonetic = "Papa";
    break;
case 'Q':
    phonetic = "Quebec";
    break;
case 'R':
    phonetic = "Romeo";
    break;
case 'S':
    phonetic = "Sierra";
    break;
case 'T':
    phonetic = "Tango";
    break;
case 'U':
    phonetic = "Uniform";
    break;
case 'V':
    phonetic = "Victor";
    break;
case 'W':
    phonetic = "Whiskey";
    break;
case 'X':
    phonetic = "X-Ray";
    break;
case 'Y':
    phonetic = "Yankee";
    break;
case 'Z':
    phonetic = "Zulu";
    break;


}

}
}

您需要使用 charAt。Scanner.next()方法返回String not char所以你需要转换String to char

letter = kb.next().charAt(0);