private void doCycleRetry(Request request) {
        Object cycleTriedTimesObject = request.getExtra(Request.CYCLE_TRIED_TIMES);
        if (cycleTriedTimesObject == null) {
            addRequest(SerializationUtils.clone(request).setPriority(0).putExtra(Request.CYCLE_TRIED_TIMES, 1));
        } else {
            int cycleTriedTimes = (Integer) cycleTriedTimesObject;
            cycleTriedTimes++;
            if (cycleTriedTimes < site.getCycleRetryTimes()) {
                addRequest(SerializationUtils.clone(request).setPriority(0).putExtra(Request.CYCLE_TRIED_TIMES, cycleTriedTimes));
            }
        }
        sleep(site.getRetrySleepTime());
    }
Process specific urls without url discovering.

@param urls urls to process
webmagic-core/src/main/java/us/codecraft/webmagic/Spider.java