Converting Strings to Zenkaku (全角) or Hankaku (半角) using Salesforce APEX

ZenkakuHankaku.cls

public class ZenkakuHankaku{
   /* The character list retrieved from a JavaScript library, can't find now though. :/ */
   public static String toZenkaku(String s) {
        if (String.isBlank(s)){
            return s;
        }
        String str = s.replace('\u0020', '\u3000').replace('\u0022', '\u201D').replace('\u0027', '\u2019').replace('\u00A5', '\uFFE5').replace('\uff61', '\u3002').replace('\uff62', '\u300c').replace('\uff63', '\u300d').replace('\uff64', '\u3001').replace('\uff65', '\u30fb').replace('\uff66', '\u30f2').replace('\uff67', '\u30a1').replace('\uff68', '\u30a3').replace('\uff69', '\u30a5').replace('\uff6a', '\u30a7').replace('\uff6b', '\u30a9').replace('\uff6c', '\u30e3').replace('\uff6d', '\u30e5').replace('\uff6e', '\u30e7').replace('\uff6f', '\u30c3').replace('\uff70', '\u30fc').replace('\uff71', '\u30a2').replace('\uff72', '\u30a4').replace('\uff73', '\u30a6').replace('\uff74', '\u30a8').replace('\uff75', '\u30aa').replace('\uff76', '\u30ab').replace('\uff77', '\u30ad').replace('\uff78', '\u30af').replace('\uff79', '\u30b1').replace('\uff7a', '\u30b3').replace('\uff7b', '\u30b5').replace('\uff7c', '\u30b7').replace('\uff7d', '\u30b9').replace('\uff7e', '\u30bb').replace('\uff7f', '\u30bd').replace('\uff80', '\u30bf').replace('\uff81', '\u30c1').replace('\uff82', '\u30c4').replace('\uff83', '\u30c6').replace('\uff84', '\u30c8').replace('\uff85', '\u30ca').replace('\uff86', '\u30cb').replace('\uff87', '\u30cc').replace('\uff88', '\u30cd').replace('\uff89', '\u30ce').replace('\uff8a', '\u30cf').replace('\uff8b', '\u30d2').replace('\uff8c', '\u30d5').replace('\uff8d', '\u30d8').replace('\uff8e', '\u30db').replace('\uff8f', '\u30de').replace('\uff90', '\u30df').replace('\uff91', '\u30e0').replace('\uff92', '\u30e1').replace('\uff93', '\u30e2').replace('\uff94', '\u30e4').replace('\uff95', '\u30e6').replace('\uff96', '\u30e8').replace('\uff97', '\u30e9').replace('\uff98', '\u30ea').replace('\uff99', '\u30eb').replace('\uff9a', '\u30ec').replace('\uff9b', '\u30ed').replace('\uff9c', '\u30ef').replace('\uff9d', '\u30f3').replace('\uff9e', '\u3099').replace('\uff9f', '\u309a');
        List<Integer> chars = new List<Integer>();
        for (Integer sint: str.getChars()){
            chars.add(sint >= 32 && sint <= 127 ? sint + 65248 : sint); // ascii characters
        }
        return String.fromCharArray(chars);
    }

    public static String toHankaku(String s) {
        if (String.isBlank(s)){
            return s;
        }
        String str = s.replace('\u3000', '\u0020').replace('\u201D', '\u0022').replace('\u2019', '\u0027').replace('\uFFE5', '\u00A5').replace('\u3002', '\uff61').replace('\u300c', '\uff62').replace('\u300d', '\uff63').replace('\u3001', '\uff64').replace('\u30fb', '\uff65').replace('\u30f2', '\uff66').replace('\u30a1', '\uff67').replace('\u30a3', '\uff68').replace('\u30a5', '\uff69').replace('\u30a7', '\uff6a').replace('\u30a9', '\uff6b').replace('\u30e3', '\uff6c').replace('\u30e5', '\uff6d').replace('\u30e7', '\uff6e').replace('\u30c3', '\uff6f').replace('\u30fc', '\uff70').replace('\u30a2', '\uff71').replace('\u30a4', '\uff72').replace('\u30a6', '\uff73').replace('\u30a8', '\uff74').replace('\u30aa', '\uff75').replace('\u30ab', '\uff76').replace('\u30ad', '\uff77').replace('\u30af', '\uff78').replace('\u30b1', '\uff79').replace('\u30b3', '\uff7a').replace('\u30b5', '\uff7b').replace('\u30b7', '\uff7c').replace('\u30b9', '\uff7d').replace('\u30bb', '\uff7e').replace('\u30bd', '\uff7f').replace('\u30bf', '\uff80').replace('\u30c1', '\uff81').replace('\u30c4', '\uff82').replace('\u30c6', '\uff83').replace('\u30c8', '\uff84').replace('\u30ca', '\uff85').replace('\u30cb', '\uff86').replace('\u30cc', '\uff87').replace('\u30cd', '\uff88').replace('\u30ce', '\uff89').replace('\u30cf', '\uff8a').replace('\u30d2', '\uff8b').replace('\u30d5', '\uff8c').replace('\u30d8', '\uff8d').replace('\u30db', '\uff8e').replace('\u30de', '\uff8f').replace('\u30df', '\uff90').replace('\u30e0', '\uff91').replace('\u30e1', '\uff92').replace('\u30e2', '\uff93').replace('\u30e4', '\uff94').replace('\u30e6', '\uff95').replace('\u30e8', '\uff96').replace('\u30e9', '\uff97').replace('\u30ea', '\uff98').replace('\u30eb', '\uff99').replace('\u30ec', '\uff9a').replace('\u30ed', '\uff9b').replace('\u30ef', '\uff9c').replace('\u30f3', '\uff9d').replace('\u3099', '\uff9e').replace('\u309a', '\uff9f');
        List<Integer> chars = new List<Integer>();
        for (Integer sint: str.getChars()){
            chars.add(sint >= 65248+32 && sint <= 65248+127 ? sint - 65248 : sint); // ascii characters
        }
        return String.fromCharArray(chars);
    }
}