CharacterConverter.java

package ru.kovan.converter;

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.StandardOpenOption;
import java.util.HashMap;
import java.util.Map;
import java.util.function.Function;

/**
 * @author Kovan
 */
public class Application {

    private static final String[] APP_HEADER = new String[]{
            "******************************************",
            "*  CharacterConverter by [Kovan]",
            "*  VK page: [https://vk.com/itskovan]",
            "*  Enjoy! ;)",
            "******************************************"
    };
    private static final Map<Character, Character> CHARACTER_MAP = new HashMap<Character, Character>() {
        {
            //Letters
            put('a', 'ａ');
            put('b', 'ｂ');
            put('c', 'ｃ');
            put('d', 'ｄ');
            put('e', 'ｅ');
            put('f', 'ｆ');
            put('h', 'ｈ');
            put('i', 'ｉ');
            put('j', 'ｊ');
            put('k', 'ｋ');
            put('l', 'ｌ');
            put('m', 'ｍ');
            put('n', 'ｎ');
            put('o', 'ｏ');
            put('p', 'ｐ');
            put('q', 'ｑ');
            put('r', 'ｒ');
            put('s', 'ｓ');
            put('t', 'ｔ');
            put('u', 'ｕ');
            put('v', 'ｖ');
            put('w', 'ｗ');
            put('x', 'ｘ');
            put('y', 'ｙ');
            put('z', 'ｚ');
            put('g', 'ｇ');
            //Numbers
            put('0', '０');
            put('1', '１');
            put('2', '２');
            put('3', '３');
            put('4', '４');
            put('5', '５');
            put('6', '６');
            put('7', '７');
            put('8', '８');
            put('9', '９');
        }

    };

    private static final String DELIMITER = "=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-";

    private static File file;

    public static void main(String[] args) throws IOException {
        for (String s : APP_HEADER) System.out.println(s);
        loadFile();
        startup();
    }

    private static void loadFile() throws IOException {
        System.out.println("Загрузка файла...");
        file = new File("translated.txt");
        if (!file.exists()) file.createNewFile();
    }

    private static String[] getInfo(String translated) {
        return new String[]{
                DELIMITER,
                translated,
                DELIMITER
        };
    }

    private static void save(String translated) {
        try {
            for (String s : getInfo(translated)) {
                Files.write(file.toPath(), s.concat("\n").getBytes(Charset.forName("UTF-8")), StandardOpenOption.APPEND);
            }
        } catch (IOException ex) {
            System.out.println("Cannot save dump.");
            ex.printStackTrace();
        }
    }


    public static void startup() throws IOException {
        String text = translate(readString("Введите текст", (s) -> s));
        save(text);
        System.out.println("Переведенный текст сохранен в файл translated.txt");
        startup();
    }

    public static String translate(String s) {
        StringBuilder builder = new StringBuilder();

        int incompatible = 0;

        for (char ch : s.toCharArray()) {
            boolean upper = Character.isUpperCase(ch);
            Character translated = CHARACTER_MAP.get(upper ? Character.toLowerCase(ch) : ch);
            if (translated == null) {
                translated = ch;
                if (ch != ' ') incompatible++;
            }
            builder.append(upper ? Character.toUpperCase(translated) : translated);
        }
        System.out.println("Текст успешно переведен! Несовместимых символов найдено: " + incompatible);
        return builder.toString();
    }

    private static <T> T readString(String msg, Function<String, T> function) throws IOException {
        System.out.println(msg);
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        String line;
        while (((line = reader.readLine())) != null) {
            if (line.trim().isEmpty()) continue;
            if (function.apply(line) == null) return readString(msg, function);
            else return function.apply(line);
        }
        return null;
    }
}