@Override
	public Token get(String userId) throws KankantuException {
		ShardedJedis jedis =  getConnection();
		
		// 获取token的JSON格式的字符串
		String key = prefix + userId + ":token";
		String value = jedis.get(key);
		if (null == value) {
			return null;
		}
		
		// 获取token对象的ttl
		Long expire = jedis.ttl(key);
		
		// 将JSON格式的字符串转换为JSON对象
		JSONObject jo = null;
		try {
			jo = new JSONObject(value);
		} catch (JSONException e1) {
			return null;
		}
//		jo = (JSONObject) JSONObject.stringToValue(value);
		if (null == jo) {
			return null;
		}
		
		// 将JSON对象转换为Token对象
		Token token = new Token();
		try {
			token.setExpire(jo.getString("expire"));
			token.setToken(jo.getString("token"));
			token.setUid(jo.getString("uid"));
			token.setUserId(jo.getString("user_id"));
			token.setUserName(jo.getString("user_name"));
		} catch (JSONException e) {
			throw new KankantuException("将JSONObject转换为Token对象的时候出现错误");
		}
		
		//将token的TTL设置为当前的真实值
		token.setExpire(String.valueOf(expire));
		
		returnConnection(jedis);
		return token;
	}