python 多线程串行和并行的实例

2024-03-31 17:01:55

如下所示：

#coding=utf-8
import threading
import time
import cx_Oracle
from pprint import pprint
import csv
table_name = "dbtest.csv"
f = open(table_name + ".csv", "w")

def exp01():
  conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
  cursor = conn.cursor()
  owner = "system"
  writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
  tname = threading.current_thread()
  print tname
  exportOracleSql = "select 'exp01' from dual"
  print exportOracleSql
  x = cursor.execute(exportOracleSql)
  time.sleep(1000)
  cursor.close()
  conn.close()

def exp02():
  conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
  cursor = conn.cursor()
  owner = "system"
  writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
  tname = threading.current_thread()
  print tname
  exportOracleSql = "select 'exp02' from dual"
  print exportOracleSql
  x = cursor.execute(exportOracleSql)
  time.sleep(1000)
  cursor.close()
  conn.close()

def exp03():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp03' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

def exp04():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp04' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

def exp05():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp05' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

def exp06():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp06' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

def exp07():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp07' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

def exp08():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp08' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

def exp09():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp09' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

def exp10():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp10' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

def exp11():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp11' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

def exp12():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp12' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

def exp13():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp13' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

def exp14():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp14' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

threads = []
t1 = threading.Thread(target=exp01,name='exp01')
threads.append(t1)
t2 = threading.Thread(target=exp02,name='exp02')
threads.append(t2)
t2 = threading.Thread(target=exp03,name='exp03')
threads.append(t2)
t2 = threading.Thread(target=exp04,name='exp04')
threads.append(t2)
t2 = threading.Thread(target=exp05,name='exp05')
threads.append(t2)
t2 = threading.Thread(target=exp06,name='exp06')
threads.append(t2)
t2 = threading.Thread(target=exp07,name='exp07')
threads.append(t2)
t2 = threading.Thread(target=exp08,name='exp08')
threads.append(t2)
t2 = threading.Thread(target=exp09,name='exp09')
threads.append(t2)
t2 = threading.Thread(target=exp10,name='exp10')
threads.append(t2)
t2 = threading.Thread(target=exp11,name='exp11')
threads.append(t2)
t2 = threading.Thread(target=exp12,name='exp12')
threads.append(t2)
t2 = threading.Thread(target=exp13,name='exp13')
threads.append(t2)
t2 = threading.Thread(target=exp14,name='exp14')
threads.append(t2)

if __name__ == '__main__':
  for t in threads:
    #t.setDaemon(True)
    t.start()
    #t.run()
    #t.start()
    # print '3333333'
    print threading.current_thread()
    # print t.is_alive()
    # print '3333333'
  t.join()
  print "all over "

输出:
C:\Python27\python.exe C:/Users/TLCB/PycharmProjects/untitled/mycompany/thread/p7.py
<_MainThread(MainThread, started 156528)>
<_MainThread(MainThread, started 156528)>
<_MainThread(MainThread, started 156528)>
<_MainThread(MainThread, started 156528)>
<_MainThread(MainThread, started 156528)>
<_MainThread(MainThread, started 156528)>
<_MainThread(MainThread, started 156528)>
<_MainThread(MainThread, started 156528)>
<_MainThread(MainThread, started 156528)>
<_MainThread(MainThread, started 156528)>
<_MainThread(MainThread, started 156528)>
<_MainThread(MainThread, started 156528)>
<_MainThread(MainThread, started 156528)>
<_MainThread(MainThread, started 156528)>
<Thread(exp01, started 155004)>
select 'exp01' from dual
<Thread(exp12, started 155744)>
 select 'exp12' from dual<Thread(exp02, started 155000)>

select 'exp02' from dual
<Thread(exp08, started 155728)>
select 'exp08' from dual
<Thread(exp06, started 155752)>
select 'exp06' from dual
<Thread(exp03, started 154816)>
select 'exp03' from dual
<Thread(exp09, started 156544)>
select 'exp09' from dual
<Thread(exp11, started 155760)>
select 'exp11' from dual
<Thread(exp04, started 154112)>
select 'exp04' from dual
<Thread(exp10, started 155764)><Thread(exp05, started 154640)>

select 'exp10' from dualselect 'exp05' from dual

<Thread(exp07, started 155188)>
select 'exp07' from dual
<Thread(exp13, started 154600)>
select 'exp13' from dual
<Thread(exp14, started 155804)>
select 'exp14' from dual

  	SID	SERIAL#	USERNAME	PREV_SQL_ID
1	9	1179	TEST	01tjnxmmurdw7
2	10	75	TEST	g5ph474nsjvwv
3	12	907	TEST	87mdhpgj9k5tz
4	419	1303	TEST	4g8r4bkf8aq3n
5	420	655	TEST	1rx9mjdvp1udx
6	421	1955	TEST	928r7khrtn4jd
7	424	51	TEST	d6sgjjwpm74qz
8	839	3	TEST	a1hg7hrwgrdqk
9	840	43	TEST	fqjuj4qp5hmf0
10	841	111	TEST	2jzx0889h3k5n
11	1252	145	TEST	awtzfbx7dhn88
12	1253	7	TEST	55tzs9gdmcd4p
13	1254	9	TEST	4v01fvb5sj7k4
14	1255	265	TEST	39bcsfjr5y62b

此时是并发执行

改变join的位置:
#coding=utf-8
import threading
import time
import cx_Oracle
from pprint import pprint
import csv
table_name = "dbtest.csv"
f = open(table_name + ".csv", "w")

def exp01():
  conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
  cursor = conn.cursor()
  owner = "system"
  writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
  tname = threading.current_thread()
  print tname
  exportOracleSql = "select 'exp01' from dual"
  print exportOracleSql
  x = cursor.execute(exportOracleSql)
  time.sleep(1000)
  cursor.close()
  conn.close()

def exp02():
  conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
  cursor = conn.cursor()
  owner = "system"
  writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
  tname = threading.current_thread()
  print tname
  exportOracleSql = "select 'exp02' from dual"
  print exportOracleSql
  x = cursor.execute(exportOracleSql)
  time.sleep(1000)
  cursor.close()
  conn.close()

def exp03():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp03' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

def exp04():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp04' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

def exp05():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp05' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

def exp06():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp06' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

def exp07():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp07' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

def exp08():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp08' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

def exp09():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp09' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

def exp10():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp10' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

def exp11():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp11' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

def exp12():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp12' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

def exp13():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp13' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

def exp14():
    conn = cx_Oracle.connect('test/test@192.168.137.2/serv')
    cursor = conn.cursor()
    owner = "system"
    writer = csv.writer(f, lineterminator="\n", quoting=csv.QUOTE_NONNUMERIC)
    tname = threading.current_thread()
    print tname
    exportOracleSql = "select 'exp14' from dual"
    print exportOracleSql
    x = cursor.execute(exportOracleSql)
    time.sleep(1000)
    cursor.close()
    conn.close()

threads = []
t1 = threading.Thread(target=exp01,name='exp01')
threads.append(t1)
t2 = threading.Thread(target=exp02,name='exp02')
threads.append(t2)
t2 = threading.Thread(target=exp03,name='exp03')
threads.append(t2)
t2 = threading.Thread(target=exp04,name='exp04')
threads.append(t2)
t2 = threading.Thread(target=exp05,name='exp05')
threads.append(t2)
t2 = threading.Thread(target=exp06,name='exp06')
threads.append(t2)
t2 = threading.Thread(target=exp07,name='exp07')
threads.append(t2)
t2 = threading.Thread(target=exp08,name='exp08')
threads.append(t2)
t2 = threading.Thread(target=exp09,name='exp09')
threads.append(t2)
t2 = threading.Thread(target=exp10,name='exp10')
threads.append(t2)
t2 = threading.Thread(target=exp11,name='exp11')
threads.append(t2)
t2 = threading.Thread(target=exp12,name='exp12')
threads.append(t2)
t2 = threading.Thread(target=exp13,name='exp13')
threads.append(t2)
t2 = threading.Thread(target=exp14,name='exp14')
threads.append(t2)

if __name__ == '__main__':
  for t in threads:
    #t.setDaemon(True)
    t.start()
    #t.run()
    #t.start()
    # print '3333333'
    print threading.current_thread()
    # print t.is_alive()
    # print '3333333'
    t.join()
  print "all over "

C:\Python27\python.exe C:/Users/TLCB/PycharmProjects/untitled/mycompany/thread/p7.py
<_MainThread(MainThread, started 154776)>
<Thread(exp01, started 156240)>
select 'exp01' from dual

此时变成串行,数据库连接也只有一个:

  	SID	SERIAL#	USERNAME	PREV_SQL_ID
1	421	1957	TEST	928r7khrtn4jd

以上这篇python 多线程串行和并行的实例就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持我们。

python爬虫爬取微博评论案例详解

前几天,杨超越编程大赛火了,大家都在报名参加,而我也是其中的一员. 在我们的项目中,我负责的是数据爬取这块,我主要是把对于杨超越的每一条评论的相关信息. 数据格式:{"name":评论人姓名,"comment_time":评论时间,"comment_info":评论内容,"comment_url":评论人的主页} 以上就是我们需要的信息. 爬虫前的分析: 以上是杨超越的微博主页,这是我们首先需要获取到的内容. 因为我们需要等
python3 requests中使用ip代理池随机生成ip的实例

啥也不说了,直接上代码吧! # encoding:utf-8 import requests # 导入requests模块用于访问测试自己的ip import random pro = ['1.119.129.2:8080', '115.174.66.148', '113.200.214.164'] # 在(http://www.xicidaili.com/wt/)上面收集的ip用于测试 # 没有使用字典的原因是因为字典中的键是唯一的 http 和https 只能存在一个所以不建议使用字典
详解python多线程之间的同步(一)

引言: 线程之间经常需要协同工作,通过某种技术,让一个线程访问某些数据时,其它线程不能访问这些数据,直到该线程完成对数据的操作.这些技术包括临界区(Critical Section),互斥量(Mutex),信号量(Semaphore),事件Event等. Event threading库中的event对象通过使用内部一个flag标记,通过flag的True或者False的变化来进行操作. 名称含义 set( )
Python多线程同步---文件读写控制方法

1.实现文件读写的文件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_ti
python多线程+代理池爬取天天基金网、股票数据过程解析

简介提到爬虫,大部分人都会想到使用Scrapy工具,但是仅仅停留在会使用的阶段.为了增加对爬虫机制的理解,我们可以手动实现多线程的爬虫过程,同时,引入IP代理池进行基本的反爬操作. 本次使用天天基金网进行爬虫,该网站具有反爬机制,同时数量足够大,多线程效果较为明显. 技术路线 IP代理池多线程爬虫与反爬编写思路首先,开始分析天天基金网的一些数据.经过抓包分析,可知: ./fundcode_search.js包含所有基金的数据,同时,该地址具有反爬机制,多次访问将会失败的情况. 同时,经
对Python多线程读写文件加锁的实例详解

Python的多线程在io方面比单线程还是有优势,但是在多线程开发时,少不了对文件的读写操作.在管理多个线程对同一文件的读写操作时,就少不了文件锁了. 使用fcntl 在linux下,python的标准库有现成的文件锁,来自于fcntl模块.这个模块提供了unix系统fcntl()和ioctl()的接口. 对于文件锁的操作,主要需要使用 fcntl.flock(fd, operation)这个函数. 其中,参数 fd 表示文件描述符:参数 operation 指定要进行的锁操作,该参数的取值有如
python批量爬取下载抖音视频

本文实例为大家分享了python批量爬取下载抖音视频的具体代码,供大家参考,具体内容如下 import os import requests import re import sys import asyncio import aiohttp headers = { 'user-agent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 11_0 like Mac OS X) AppleWebKit/604.1.38 (KHTML, like Gecko) ' 'Ve
python 多线程串行和并行的实例

如下所示: #coding=utf-8 import threading import time import cx_Oracle from pprint import pprint import csv table_name = "dbtest.csv" f = open(table_name + ".csv", "w") def exp01(): conn = cx_Oracle.connect('test/test@192.168.137.
Python多线程threading和multiprocessing模块实例解析

本文研究的主要是Python多线程threading和multiprocessing模块的相关内容,具体介绍如下. 线程是一个进程的实体,是由表示程序运行状态的寄存器(如程序计数器.栈指针)以及堆栈组成,它是比进程更小的单位. 线程是程序中的一个执行流.一个执行流是由CPU运行程序代码并操作程序的数据所形成的.因此,线程被认为是以CPU为主体的行为. 线程不包含进程地址空间中的代码和数据,线程是计算过程在某一时刻的状态.所以,系统在产生一个线程或各个线程之间切换时,负担要比进程小得多. 线程是一
Python多线程获取返回值代码实例

这篇文章主要介绍了Python多线程获取返回值代码实例,文中通过示例代码介绍的非常详细,对大家的学习或者工作具有一定的参考学习价值,需要的朋友可以参考下在使用多线程的时候难免想要获取其操作完的返回值进行其他操作,下面的方法以作参考: 一,首先重写threading类,使其满足调用特定的方法获取其返回值 import threading class MyThread(threading.Thread): """重写多线程,使其能够返回值""" d
JavaScript异步操作中串行和并行

目录 1.前言 2.es5方式 3.异步函数串行执行 4.异步函数并行执行 5.异步函数串行执行和并行执行结合 6.es6方式 7.async 和await 结合promise all 1.前言本文写一下js中es5和es6针对异步函数,串行执行和并行执行的方案.已经串行和并行结合使用的例子. 2.es5方式在es6出来之前,社区nodejs中针对回调地狱,已经有了promise方案.假如多个异步函数,执行循序怎么安排,如何才能更快的执行完所有异步函数,再执行下一步呢?这里就出现了js的串行
Python多线程及其基本使用方法实例分析

本文实例讲述了Python多线程及其基本使用方法.分享给大家供大家参考,具体如下: 学习Python的多线程(Multi-threading),至少应该要有进程与线程的基本概念,可以参考:http://www.ruanyifeng.com/blog/2013/04/processes_and_threads.html. 1.Python中的多线程执行一个程序,即在操作系统中开启了一个进程,在某一时刻,一个CPU内核只能进行一个进程的任务,现在的计算机所说的多进程/多任务其实是通过加快CPU的执
python多线程threading.Lock锁用法实例

本文实例讲述了python多线程threading.Lock锁的用法实例,分享给大家供大家参考.具体分析如下: python的锁可以独立提取出来复制代码代码如下: mutex = threading.Lock() #锁的使用 #创建锁 mutex = threading.Lock() #锁定 mutex.acquire([timeout]) #释放 mutex.release() 锁定方法acquire可以有一个超时时间的可选参数timeout.如果设定了timeout,则在超时后通过返回值
Python多线程通信queue队列用法实例分析

本文实例讲述了Python多线程通信queue队列用法.分享给大家供大家参考,具体如下: queue: 什么是队列:是一种特殊的结构,类似于列表.不过就像排队一样,队列中的元素一旦取出,那么就会从队列中删除. 线程之间的通信可以使用队列queue来进行线程如何使用queue.Queue[还有其他类型的对象下面讲]来通信: 1.创建一个Queue对象:对象=queue.Queue(x),x是队列容量,x可以不填,默认没有容量限制, 2.get()可以使线程从队列中获取一个元素,如果队列为空,ge
Python多线程thread及模块使用实例

多线程类似于同时执行多个不同程序,多线程运行有如下优点: 使用线程可以把占据长时间的程序中的任务放到后台去处理. 用户界面可以更加吸引人,这样比如用户点击了一个按钮去触发某些事件的处理,可以弹出一个进度条来显示处理的进度程序的运行速度可能加快在一些等待的任务实现上如用户输入.文件读写和网络收发数据等,线程就比较有用了.在这种情况下我们可以释放一些珍贵的资源如内存占用等等. 线程在执行过程中与进程还是有区别的.每个独立的线程有一个程序运行的入口.顺序执行序列和程序的出口.但是线程不能够独立执行
Python多线程中阻塞(join)与锁(Lock)使用误区解析

关于阻塞主线程 join的错误用法 Thread.join() 作用为阻塞主线程,即在子线程未返回的时候,主线程等待其返回然后再继续执行. join不能与start在循环里连用以下为错误代码,代码创建了5个线程,然后用一个循环激活线程,激活之后令其阻塞主线程. threads = [Thread() for i in range(5)] for thread in threads: thread.start() thread.join() 执行过程: 1. 第一次循环中,主线程通过start函

python 多线程串行和并行的实例

相关推荐

随机推荐