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Thread 是threading模块中最重要的类之一,可以使用它来创建线程。有两种方式来创建线程:一种是通过继承Thread类,重写它的run方法;另一种是创建一个threading.Thread对象,在它的初始化函数(__init__)中将可调用对象作为参数传入.
Thread模块是比较底层的模块,Threading模块是对Thread做了一些包装的,可以更加方便的被使用。
另外在工作时,有时需要让多条命令并发的执行, 而不是顺序执行.
有关线程的详细介绍,请参考官方文档 https://docs.python.org/2/library/threading.html
- #!/usr/bin/python
- # encoding=utf-8
- # Filename: thread-extends-class.py
- # 直接从Thread继承,创建一个新的class,把线程执行的代码放到这个新的 class里
- import threading
- import time
-
- class ThreadImpl(threading.Thread):
- def __init__(self, num):
- threading.Thread.__init__(self)
- self._num = num
-
- def run(self):
- global total, mutex
-
- # 打印线程名
- print threading.currentThread().getName()
-
- for x in xrange(0, int(self._num)):
- # 取得锁
- mutex.acquire()
- total = total + 1
- # 释放锁
- mutex.release()
-
- if __name__ == '__main__':
- #定义全局变量
- global total, mutex
- total = 0
- # 创建锁
- mutex = threading.Lock()
-
- #定义线程池
- threads = []
- # 创建线程对象
- for x in xrange(0, 40):
- threads.append(ThreadImpl(100))
- # 启动线程
- for t in threads:
- t.start()
- # 等待子线程结束
- for t in threads:
- t.join()
-
- # 打印执行结果
- print total
- #!/usr/bin/python
- # encoding=utf-8
- # Filename: thread-function.py
- # 创建线程要执行的函数,把这个函数传递进Thread对象里,让它来执行
-
- import threading
- import time
-
- def threadFunc(num):
- global total, mutex
-
- # 打印线程名
- print threading.currentThread().getName()
-
- for x in xrange(0, int(num)):
- # 取得锁
- mutex.acquire()
- total = total + 1
- # 释放锁
- mutex.release()
-
- def main(num):
- #定义全局变量
- global total, mutex
- total = 0
- # 创建锁
- mutex = threading.Lock()
-
- #定义线程池
- threads = []
- # 先创建线程对象
- for x in xrange(0, num):
- threads.append(threading.Thread(target=threadFunc, args=(100,)))
- # 启动所有线程
- for t in threads:
- t.start()
- # 主线程中等待所有子线程退出
- for t in threads:
- t.join()
-
- # 打印执行结果
- print total
-
-
- if __name__ == '__main__':
- # 创建40个线程
- main(40)
- #!/usr/bin/python
- # encoding=utf-8
- # Filename: put_files_hdfs.py
- # 让多条命令并发执行,如让多条scp,ftp,hdfs上传命令并发执行,提高程序运行效率
- import datetime
- import os
- import threading
-
- def execCmd(cmd):
- try:
- print "命令%s开始运行%s" % (cmd,datetime.datetime.now())
- os.system(cmd)
- print "命令%s结束运行%s" % (cmd,datetime.datetime.now())
- except Exception, e:
- print '%s\t 运行失败,失败原因\r\n%s' % (cmd,e)
-
- if __name__ == '__main__':
- # 需要执行的命令列表
- cmds = ['ls /root',
- 'pwd',]
-
- #线程池
- threads = []
-
- print "程序开始运行%s" % datetime.datetime.now()
-
- for cmd in cmds:
- th = threading.Thread(target=execCmd, args=(cmd,))
- th.start()
- threads.append(th)
-
- # 等待线程运行完毕
- for th in threads:
- th.join()
-
- print "程序结束运行%s" % datetime.datetime.now()
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