（一）在Python中创建一个线程对象
类继承threading.Thread
在__init__里调用threading.Thread.__init__(self, name = threadname)
threadname为线程名字，这样就实现了一个空线程
重写run()方法：需要做的事情
getName() 获得线程对象名称
setName() 设置线程对象名称
start() 启动线程
线程的状态：
runable 运行
sleeping 等待
dead 销毁（run方法执行完成或执行时抛出异常）
jion(t) 等待另某一线程结束后再运行
参数t为可选，单位为秒，为等待时间
setDaemon(bool) 子线程是否随主线程一起结束，必须在start()之前调用，默认为False
True 子线程随主线程一起结束
False 子线程不随主线程一起结束
currentThread() 获取当前正在运行的线程的引用
enumerate() 获取当前所有活动对象的一个列表
activeCount() 获取一个线程对象的状态
1 表示runnable
例子一：
import threading
import time
class MyThread(threading.Thread):
def __init__(self, threadname):
threading.Thread.__init__(self, name = threadname)
def run(self):
for i in range(10):
print self.getName(), i
time.sleep(1)
if __name__ == '__main__':
t1 = MyThread('MyThread')
print t1.getName(), t1.isDaemon() # False
#t1.setDaemon(True)
#print t1.getName(), t1.isDaemon() # True
t1.start()
print 'Main thread exit'
print 'CurrentThread', threading.currentThread()
print 'Enumrate', threading.enumerate()
print 'ActiveCount', threading.activeCount()
print 'IsAlive', t1.isAlive()
###############################################################################
# Console:
# MyThread False
# MyThread 0
# Main thread exit
# CurrentThread <_MainThread(MainThread, started)>
# Enumrate [<MyThread(MyThread, started)>, <_MainThread(MainThread, started)>]
# ActiveCount 2
# IsAlive True
# MyThread 1
# MyThread 2
# MyThread 3
# MyThread 4
# MyThread 5
# MyThread 6
# MyThread 7
# MyThread 8
# MyThread 9
###############################################################################
（二）线程同步
同步机制
“锁” threading.RLock
acquire() 获取锁方法，进入locked状态，其他进程试图获得这个锁将变为blocked状态
release() 释放锁方法，进入unlocked状态
修改共享数据代码放置在acquire()和release()之间
“条件变量” threading.Condition
wait() 线程释放锁，进入blocked状态
notify() 唤醒blocked状态的线程
notifyAll() 唤醒所有的blocked状态的线程
保证每一个wait()方法调用都有一个相对应的notify()调用，也可以调用notifyAll()方法以防万一
例子二：
import threading
import time
myLock = threading.RLock()
class MyThread(threading.Thread):
def __init__(self, threadname):
threading.Thread.__init__(self, name = threadname)
def run(self):
print self.getName()
myLock.acquire()
self.add()
myLock.release()
def add(self):
global shareData
shareData += 1
print 'shareData = ', shareData, 'time = ', time.ctime()
if __name__ == '__main__':
shareData = 0
for i in range(10):
t1 = MyThread('MyThread %d' % i)
t1.start()
time.sleep(1)
###############################################################################
# Console:
#MyThread 0
#shareData = 1 time = Wed Jan 16 23:16:35 2008
#MyThread 1
#shareData = 2 time = Wed Jan 16 23:16:36 2008
#MyThread 2
#shareData = 3 time = Wed Jan 16 23:16:37 2008
#MyThread 3
#shareData = 4 time = Wed Jan 16 23:16:38 2008
#MyThread 4
#shareData = 5 time = Wed Jan 16 23:16:39 2008
#MyThread 5
#shareData = 6 time = Wed Jan 16 23:16:40 2008
#MyThread 6
#shareData = 7 time = Wed Jan 16 23:16:41 2008
#MyThread 7
#shareData = 8 time = Wed Jan 16 23:16:42 2008
#MyThread 8
#shareData = 9 time = Wed Jan 16 23:16:43 2008
#MyThread 9
#shareData = 10 time = Wed Jan 16 23:16:44 2008
###############################################################################
例三：
from Queue import Queue
import threading
import random
import time
#Producer thread
class Producer(threading.Thread):
def __init__(self, threadname, queue):
threading.Thread.__init__(self, name = threadname)
self.sharedata = queue
def run(self):
for i in range(20):
print self.getName(), 'adding', i, 'to queue'
self.sharedata.put(i)
time.sleep(random.randrange(10)/10.0)
print self.getName(), 'Finished'
#Consumer thread
class Consumer(threading.Thread):
def __init__(self, threadname, queue):
threading.Thread.__init__(self, name = threadname)
self.sharedata = queue
def run(self):
for i in range(20):
print self.getName(), 'got a value: ', self.sharedata.get()
time.sleep(random.randrange(10)/10.0)
print self.getName(), 'Finished'
#Main thread
def main():
queue = Queue()
producer = Producer('Producer', queue)
consumer = Consumer('Consumer', queue)
print 'Starting threads ...'
producer.start()
consumer.start()
producer.join()
consumer.join()
print 'All threads have terminated.'
if __name__ == '__main__':
main()
###############################################################################
#Starting threads ...
#Producer adding 0 to queue
#Consumer got a value: 0
#Producer Finished
#Producer adding 1 to queue
#Consumer got a value: 1
#Consumer got a value: Producer Finished
#Producer adding 2 to queue
#2
#Consumer got a value: Producer Finished
#Producer adding 3 to queue
#3
#Consumer got a value: Producer Finished
#Producer adding 4 to queue
#4
#Consumer got a value: Producer Finished
#Producer adding 5 to queue
#5
#Consumer got a value: Producer Finished
#Producer adding 6 to queue
#6
#Producer Finished
#Producer adding 7 to queue
#Consumer got a value: 7
#Producer Finished
#Producer adding 8 to queue
#Producer Finished
#Producer adding 9 to queue
#Consumer got a value: 8
#Consumer got a value: 9
#Producer Finished
#Producer adding 10 to queue
#Producer Finished
#Producer adding 11 to queue
#Producer Finished
#Producer adding 12 to queue
#Consumer got a value: 10
#Consumer got a value: 11
#Producer Finished
#Producer adding 13 to queue
#Consumer got a value: 12
#Producer Finished
#Producer adding 14 to queue
#Consumer got a value: 13
#Producer Finished
#Producer adding 15 to queue
#Consumer got a value: 14
#Consumer got a value: 15
#Consumer got a value: Producer Finished
#Producer adding 16 to queue
#16
#Consumer got a value: Producer Finished
#Producer adding 17 to queue
#17
#Producer Finished
#Producer adding 18 to queue
#Consumer got a value: 18
#Consumer got a value: Producer Finished
#Producer adding 19 to queue
#19
#Consumer Finished
#Producer Finished
#All threads have terminated.
###############################################################################
