* @return the parameter value as a String, or defaultValue if not found
     */
    public String getAsString(final String key, final String defaultValue) {
        final String value = getAsString(key);
        if (value != null) {
            return value;
        }
        return defaultValue;
    }

    /**

            defaultDataMap.put(fessConfig.getIndexFieldExpires(), documentExpires);
        }
        // segment
        defaultDataMap.put(fessConfig.getIndexFieldSegment(), initParamMap.getAsString(Constants.SESSION_ID));
        // created
        defaultDataMap.put(fessConfig.getIndexFieldCreated(), systemHelper.getCurrentTime());
        // boost