private static boolean procStringDefValue(boolean isCompFieldType,
            String defValue,
            ProcessResult result) {
        if (isCompFieldType) {
            TreeSet<String> valItemSet = new TreeSet<>();
            if (TStringUtils.isNotBlank(defValue)) {
                valItemSet.add(defValue);
            }
            valItemSet.comparator();
            result.setSuccResult(valItemSet);
        } else {
            result.setSuccResult(defValue);
        }
        return result.isSuccess();
    }
process string default value

@param isCompFieldType   the parameter if compound field type
@param defValue   the parameter default value
@param result process result
@return process result for default value of parameter
inlong-tubemq/tubemq-server/src/main/java/org/apache/inlong/tubemq/server/common/utils/WebParameterUtils.java