Python多线程同步---文件读写控制方法

Python  /  管理员 发布于 7年前   245

1、实现文件读写的文件ltz_schedule_times.py

#! /usr/bin/env python#coding=utf-8import osdef 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_timesdef WriteTimes(schedule_times): if schedule_times <= 10:  fp = open('schedule_times.txt', 'a+')#10以内追加进去 else:  fp = open('schedule_times.txt', 'w')#10以外重新写入  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、不加锁对文件进行多线程读写。

file_lock.py

#! /usr/bin/env python#coding=utf-8from threading import Threadimport threadingimport timefrom ltz_schedule_times import *#1、不加锁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()

得到结果：

0write schedule_times start!write schedule_times finish!tmp: tmp: tmp: tmp:  [[[['1''1''1''1']]]]111 1write 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!

文件写入结果：

以上结果可以看出，不加锁多线程读写文件会出现错误。

2.2、加锁对文件进行多线程读写。

file_lock.py

#! /usr/bin/env python#coding=utf-8from threading import Threadimport threadingimport timefrom ltz_schedule_times import *#2、加锁mu = threading.Lock() #1、创建一个锁def lock_test(): #time.sleep(0.1)  if mu.acquire(True): #2、获取锁状态，一个线程有锁时，别的线程只能在外面等着  schedule_times = ReadTimes()  print schedule_times  schedule_times = schedule_times + 1  WriteTimes(schedule_times)  mu.release() #3、释放锁  if __name__ == '__main__': for i in range(5):  Thread(target = lock_test, args=()).start()

结果：

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

文件写入结果：

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