List 集合转String 逗号拼接

public String listToString(List<String> list) {
   StringBuilder sb = new StringBuilder();
   for (int i = 0; i < list.size(); i++) {
      if (i == list.size() - 1) {
         sb.append(list.get(i));
      } else {
         sb.append(list.get(i));
         sb.append(",");
      }
   }
   return sb.toString();
}