public static void main(String[] args) throws Exception {
    byte[] bytes = FileUtils.readFileToByteArray(
        new File("data.txt"));
    DataTable config = new XlsReader(                ┓
        new File("config.xls")).read().getTable(0);  ┛①
    MessageParser parser =　
        new MessageParser(bytes, config);
    parser.parse();
}

private static class MessageParser {
...
    private DataTable config;

    public MessageParser(byte[] bytes, DataTable config) {
        this.bytes = new ByteArray(bytes);
        this.config = config;
    }

    public void parse() throws Exception {
        while (index < bytes.getLength() - 1) {
            Map<String, Object> record =
                new HashMap<String, Object>();
            for (int i = 0; i < config.getRowSize(); i++) {      ┓
                DataRow row = config.getRow(i);                  ｜
                String name =                           ┓       ｜
                    (String) row.getValue("データ名称");  ┛③      ｜
                int length =                              ┓     ｜
                    ((BigDecimal) row.getValue("バイト数"))  ｜    ｜
                    .intValue();                          ┛④   ｜
                String value = getString(length);    ―⑤         ｜
                record.put(name, value);      ―⑥                ｜
            }                                                    ┛②

            System.out.println(record);
        }
    }
...
}