如何在Java中定义字符串的结尾？

Question

I have a string that a user inputs their name in [Last, First Middle] format and I need to change it to [First Middle Last] format.

I've defined the last name as LFM.substring(0, commaSpace) . commaSpace being the name for the ", " in the input of the LFM (Last, First Middle) user input.

Then I needed to define firstMiddle . My question to you is, how could I define the end of the string LFM so I can have firstMiddle be LFM.substring(commaSpace, (end of string) ); ? That way I can just print firstMiddle + last .

ALL OF MY CURRENT CODE:

(IT'S REALLY MESSY, SORRY)

    System.out.println();

    System.out.println("This program will separate and convert a name in [Last, First, Middle] format to [First Middle Last].");

    System.out.println();

    System.out.print("Please enter a name in [Last, First Middle] format.  ");

    Scanner userInput = new Scanner(System.in);

    String lineSeparator = System.getProperty("line.separator"); 

    String LFM, first, middle, last, firstMiddle;
    int commaSpace, end, lastLength;

    userInput.useDelimiter(lineSeparator);

    LFM = userInput.nextLine(); 

    commaSpace = LFM.indexOf(","); 

    last = LFM.substring(0, commaSpace);

    lastLength = last.length();

    firstMiddle = LFM.substring(commaSpace, //?);

    first = LFM.substring(commaSpace + firstMiddle.length());

    System.out.println(firstMiddle + (" ") + last);

Answer 1

Use replaceAll or replaceFirst functions since it accepts regex as first argument.

string.replaceAll("^(\\w+),\\s*(\\w+)\\s+(\\w+)$", "$2 $3 $1");

DEMO