每隔一个固定时间去执行一次命令——作业update

对数据库的操作会用到每隔一段时间对数据库填写一行数据，如何操作，

这是隔5秒执行一次

import time
def sleeptime (hour,min,sec):
    return hour*3600 + min *60 + sec;
second = sleeptime(0,0,5);
while 1==1:
    time.sleep(second);

print（'down'）

# 程序功能：指定一个或者同时多个固定的延迟（例如，5mins, 1hour,1 day, 1 week）,程序按照这个指定的延迟定时循环执行某个work
from datetime import date, time, datetime, timedelta
def work():
  print "hello world."
def runTask(func, day=0, hour=0, min=0, second=0):
  # Init time

  now = datetime.now()

  strnow = now.strftime('%Y-%m-%d %H:%M:%S')

  print "now:",strnow

  # First next run time

  period = timedelta(days=day, hours=hour, minutes=min, seconds=second)

  next_time = now + period

  strnext_time = next_time.strftime('%Y-%m-%d %H:%M:%S')

  print "next run:",strnext_time

  while True:

      # Get system current time

      iter_now = datetime.now()

      iter_now_time = iter_now.strftime('%Y-%m-%d %H:%M:%S')

      if str(iter_now_time) == str(strnext_time):

          # Get every start work time

          print "start work: %s" % iter_now_time

          # Call task func

          func()

          print "task done."

          # Get next iteration time

          iter_time = iter_now + period

          strnext_time = iter_time.strftime('%Y-%m-%d %H:%M:%S')

          print "next_iter: %s" % strnext_time

          # Continue next iteration

          continue

 

# runTask(work, min=0.5)

runTask(work, day=1, hour=2, min=1)