private void setExtrasInItem(Jedis jedis,Request request, Task task) {
        if (!request.getExtras().isEmpty()) {
            String field = DigestUtils.sha1Hex(request.getUrl());
            String value = JSON.toJSONString(request);
            jedis.hset(getItemKey(task), field, value);
        }
    }
the redis scheduler with priority
@author sai
Created by sai on 16-5-27.
webmagic-extension/src/main/java/us/codecraft/webmagic/scheduler/RedisPriorityScheduler.java