StringBuilder 문자열 합치기

// procedure processed comma separate
StringBuilder cd_items = new StringBuilder();
StringBuilder qtys = new StringBuilder();

for( Map.Entry<String, Object> entry : ((Map<String, Object>)formData.get("orderL")).entrySet() ){
   cd_items.append(",").append(entry.getKey());
   qtys.append(",").append(entry.getValue().toString());
}