本文例項為大家分享了python多執行緒同步之檔案讀寫控制的具體程式碼，供大家參考，具體內容如下

1、實現檔案讀寫的檔案ltz_schedule_times.py

#! /usr/bin/env python
#coding=utf-8
import os

def ReadTimes():
  res = []
  if os.path.exists('schedule_times.txt'):
    fp = open('schedule_times.txt','r')
  else:
    os.system('touch schedule_times.txt')
    fp = open('schedule_times.txt','r')
  try:
    line = fp.read()
    if line == None or len(line)==0:
      fp.close()
      return 0
    tmp = line.split()
    print 'tmp: ',tmp
    schedule_times = int(tmp[-1])
  finally:
    fp.close()
  #print schedule_times
  return schedule_times

def WriteTimes(schedule_times):
  if schedule_times <= 10:
    fp = open('schedule_times.txt','a+')#10以內追加進去
  else:
    fp = open('schedule_times.txt','w')#10以外重新寫入
    schedule_times = 1
  print 'write schedule_times start!'
  try:

    fp.write(str(schedule_times)+'\n')
  finally:
    fp.close()
    print 'write schedule_times finish!'

if __name__ == '__main__':

  schedule_times = ReadTimes()
  #if schedule_times > 10:
  #  schedule_times = 0
  print schedule_times
  schedule_times = schedule_times + 1
  WriteTimes(schedule_times)

2.1、不加鎖對檔案進行多執行緒讀寫。file_lock.py

#! /usr/bin/env python
#coding=utf-8

from threading import Thread
import threading
import time
from ltz_schedule_times import *

#1、不加鎖
def lock_test():
  time.sleep(0.1) 
  schedule_times = ReadTimes()
  print schedule_times
  schedule_times = schedule_times + 1
  WriteTimes(schedule_times)


if __name__ == '__main__':

  for i in range(5):
    Thread(target = lock_test,args=()).start()

得到結果：

0
write schedule_times start!
write schedule_times finish!
tmp: tmp: tmp: tmp:   [[[['1''1''1''1']]]]


11

1
 1
write schedule_times start!write schedule_times start!

write schedule_times start!write schedule_times start!

write schedule_times finish!
write schedule_times finish!
write schedule_times finish!write schedule_times finish!

檔案寫入結果：

以上結果可以看出，不加鎖多執行緒讀寫檔案會出現錯誤。

2.2、加鎖對檔案進行多執行緒讀寫。file_lock.py

#! /usr/bin/env python
#coding=utf-8

from threading import Thread
import threading
import time
from ltz_schedule_times import *

#2、加鎖
mu = threading.Lock() #1、建立一個鎖
def lock_test():
  #time.sleep(0.1) 
  if mu.acquire(True): #2、獲取鎖狀態，一個執行緒有鎖時，別的執行緒只能在外面等著
    schedule_times = ReadTimes()
    print schedule_times
    schedule_times = schedule_times + 1
    WriteTimes(schedule_times)
    mu.release() #3、釋放鎖   

if __name__ == '__main__':

  for i in range(5):
    Thread(target = lock_test,args=()).start()

結果：

0
write schedule_times start!
write schedule_times finish!
tmp: ['1']
1
write schedule_times start!
write schedule_times finish!
tmp: ['1','2']
2
write schedule_times start!
write schedule_times finish!
tmp: ['1','2','3']
3
write schedule_times start!
write schedule_times finish!
tmp: ['1','3','4']
4
write schedule_times start!
write schedule_times finish!

檔案寫入結果：

達到讀寫效果。

以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支援我們。