如何将字符串args [0]转换为char

Question

How do you convert from string to char if, for example, the string is entered as an argument in command line (not using scanner). Eg how would you convert "abcd" to char?

String input = args[0]
String [] part = input.split(""); 

//splits string into 2 parts (action and characters to encode)
String action = part[0];
// action is what is done to letter i.e. decrypt or encrypt
String plainText = part[1];
char [] letters = plainText.toCharArray();

Answer 1

If you want to convert a String with more than 2 characters to a char array:

String hello = "Hello";
char[] char_array = hello.toCharArray();

Otherwise if you only need one specific char, use hello.charAt(0) .

Please notice that you only can store one single 16bit Unicode character inside a char datatype. That's the reason why you need an array for more than 2 characters.