将字符串转换为数组并转换为Java

Question

Okay so if I have a strings(can be anything) that I need to put into an array(letter by letter), then convert the letters of that array to numbers using this switch statement:

public static char[] convert(char c)
{
    switch(c)
    {
        case 'A' :
        case 'B' :
        case 'C' :
            return new char[]{'2'};
        case 'D' :
        case 'E' :
        case 'F' :
            return new char[]{'3'};
        case 'G' :
        case 'H' :
        case 'I' :
            return new char[]{'4'};
        case 'J' :
        case 'K' :
        case 'L' :
            return new char[]{'5'};
        case 'M' :
        case 'N' :
        case 'O' :
            return new char[]{'6'};
        case 'P' :
        case 'R' :
        case 'S' :
            return new char[]{'7'};
        case 'T' :
        case 'U' :
        case 'V' :
            return new char[]{'8'};
        default:
            return new char[]{'9'};
    }
}

finally after converting it I need to change the converted array back into a string.

how would i approach without importing anything but scanner

For example using the word = words.next(); (the string is BBCNEWS)

Answer 1

//get the input from standard in or wherever it is
Scanner scanner = new Scanner(System.in);

while(scanner.hasNext()){
    String output = "";
    String word = scanner.nextLine();
    char[] wordChars = word.toCharArray();

    for(char wordChar: wordChars){
        output = output.concat(new String(convert(wordChar)));
    }
    //do something with the output
}