public void demo() {
        String str = "ABCDEFGfdsdgdgdgdH1f";
        List<String> list = new ArrayList<String>();
        String streee = "";
        int len = str.length();
        int sub = 3;
        if (len % sub != 0) {
            for (int i = 0; i < str.length() - (len % sub); i += 3) {
                streee = str.substring(i, i + 3);
                list.add(streee);
            }
            String tpm = str.substring(str.length() - (len % sub), str.length());
            list.add(tpm);
        } else {
            for (int i = 0; i < str.length(); i += 3) {
                streee = str.substring(i, i + 3);
                list.add(streee);
            }
        }
        for (String arr : list) {
            System.err.println(arr);
        }
    }