如何读取文本文件并将其存储/打印到控制台只有小写字母且没有空格？

Question

I am trying to take in a text file (UTF-8) and store/print it with the following constraints (see example below):

1. Only letters, no special characters (az)
2. If the letter is uppercase, convert to lower case
3. No spaces or lines between letters

I first tried using scanner to read until the end of the file. I converted the string read to a char array but could not make it lowercase correctly (see commented out code). I have tried using BufferedReader, but can't get the correct changes. I tried reading in by character and using the character class to set a lowercase restriction (see code below).

public static void OpenPlainText(File plainTextFile)
{
    try
    {
        Scanner scanner = new Scanner(plainTextFile);
        BufferedReader br = new BufferedReader(new InputStreamReader
                 (new FileInputStream (plainTextFile), Charset.forName("UTF-8")));
        StorePlainText(scanner, br);
        scanner.close();
        br.close();
    }
    catch (Exception e)
    {
        e.printStackTrace();
    }
}

public static void StorePlainText(Scanner scanner, BufferedReader br) throws IOException
{
    /*String str = "";
    while (scanner.hasNext())
    {
        str += scanner.next();
    }
        str.toCharArray();
        str.toLowerCase();
        System.out.println(str);*/
    int c;
    while ((c = br.read()) != -1)
    {
        char character = (char) c;
        if (Character.isLetter(character))
        {
            if (Character.isUpperCase(character))
            {
                Character.toLowerCase(character);
                System.out.print(character);
            }
        }
    }
}

Ex. Text File

Art of Computer Programming, Volume 1, Fascicle 1, The: MMIX -- A RISC Computer for the New Millennium

This multivolume work on the analysis of algorithms has long been recognized as the definitive description of classical computer science.

Ex. Store/Print

artofcomputerprogrammingvolumefasciclethemmixarisccomputerforthenewmillenniumthismultivolumeworkontheanalysisofalgorithmshaslongbeenrecognizedasthedefinitivedescriptionofclassicalcomputerscience

Answer 1

Character.toLowerCase returns the lower case character it does not convert the one you pass in.

while ((c = br.read()) != -1)
{
    char character = (char) c;
    if (Character.isLetter(character))
    {
        if (Character.isUpperCase(character))
        {
            character = Character.toLowerCase(character);
            System.out.print(character);
        }
    }
}