private String genColumns(Iterator<String> fieldNames) {
        if (fieldNames != null && fieldNames.hasNext()) {
            StringBuilder sb = new StringBuilder();
            while (fieldNames.hasNext()) {
                String item = fieldNames.next();
                sb.append("`").append(item.trim()
                        .replace("`", "")).append("`,");
            }
            if (enableBatchDelete()) {
                sb.append(DORIS_DELETE_SIGN);
            } else {
                sb.deleteCharAt(sb.lastIndexOf(","));
            }
            return sb.toString();
        }
        return null;
    }
A builder used to set parameters to the output format's configuration in a fluent way.

@return builder
inlong-sort/sort-flink/sort-flink-v1.13/sort-connectors/doris/src/main/java/org/apache/inlong/sort/doris/table/DorisDynamicSchemaOutputFormat.java