import os , string , datetime ;

str = '/home/aaa/tmp/tomcat/';

b = (datetime.datetime.now()).second + 5;

while 1 :

    a = datetime.datetime.now();

    if a.second == b :

    files = os.listdir(str);

        for file in files :

            os.remove(str+file);

        b = (a + datetime.timedelta(seconds=5)).second;

import os , string , datetime , pymongo;

conn = pymongo.Connection("127.0.0.1",27017);

db = conn.nn;

coll = db.nn_res;

b = (datetime.datetime.now()).second + 5;

while 1:

    a = datetime.datetime.now();

    if a.second == b :

        curr = coll.find().sort("update_time",1).limit(1);

        for tmp in curr :

            coll.remove(tmp);

        b = (a + datetime.timedelta(seconds=5)).second;