python2 線程基礎

1，感謝菜鳥教程，

線程基礎：導入，創建函數，創建線和運行

import thread
import time

# 為線程定義一個函數
def print_time(threadName, delay):
    count = 0
    while count < 5:
        time.sleep(delay)
        count += 1
        print "%s: %s" % (threadName, time.ctime(time.time()))


# 創建兩個線程
try:
    thread.start_new_thread(print_time, ("Thread-1", 2,))    #函數名和它的兩個參數
    thread.start_new_thread(print_time, ("Thread-2", 5,))
except:
    print "Error: unable to start thread"

while 1:
    pass
#兩個線程會同時分別進行，一個每五秒打印一次，一個每2秒打印一次

2，threading

import threading
import time

exitFlag = 0

class myThread(threading.Thread):  # 繼承父類 threading.Thread
    def __init__(self, threadID, name, counter):
        threading.Thread.__init__(self)
        self.threadID = threadID
        self.name = name
        self.counter = counter

    def run(self):  # 把要執行的代碼寫到 run 函數里面 線程在創建后會直接運行 run 函數，所以基本可以理解為threading中，function run里的函數會自動運行
        print "Starting " + self.name
        print_time(self.name, self.counter, 5)
        print "Exiting " + self.name

def print_time(threadName, delay, counter):    #這個是單獨的一個函數
    while counter:
        if exitFlag:
            (threading.Thread).exit()
        time.sleep(delay)
        print "%s: %s" % (threadName, time.ctime(time.time()))
        counter -= 1

    # 創建新線程
thread1 = myThread(1, "Thread-1", 1)
thread2 = myThread(2, "Thread-2", 2)

# 開啟線程
thread1.start()
thread2.start()

print "Exiting Main Thread"

3，線程鎖

import threading
import time
 
class myThread (threading.Thread):
    def __init__(self, threadID, name, counter):
        threading.Thread.__init__(self)
        self.threadID = threadID
        self.name = name
        self.counter = counter
    def run(self):
        print "Starting " + self.name
       # 上鎖
        threadLock.acquire()
        print_time(self.name, self.counter, 3)
        # 釋放鎖
         threadLock.release()
 
def print_time(threadName, delay, counter):
    while counter:
        time.sleep(delay)
        print "%s: %s" % (threadName, time.ctime(time.time()))
        counter -= 1
 
threadLock = threading.Lock()    #這個應該是實例化一個方法或者對象
threads = []
 
# 創建新線程
 thread1 = myThread(1, "Thread-1", 1)
thread2 = myThread(2, "Thread-2", 2)
 
# 開啟新線程
 thread1.start()
thread2.start()
 
# 添加線程到線程列表，注意此處，兩個線程添加到一個列表，所以先執行第一個，執行完成以后再執行第二個
 threads.append(thread1)
threads.append(thread2)
 
# 等待所有線程完成，結果是兩個線程依次執行
 for t in threads:
    t.join()
print "Exiting Main Thread"

4，多個線程之間的同步用隊列

import Queue
import threading
import time

exitFlag = 0


class myThread(threading.Thread):
    def __init__(self, threadID, name, q):
        threading.Thread.__init__(self)
        self.threadID = threadID
        self.name = name
        self.q = q

    def run(self):
        print "Starting " + self.name
        process_data(self.name, self.q)
        print "Exiting " + self.name


def process_data(threadName, q):    #實際上就是單個線程輪換着對隊列進行某個操作，
    while not exitFlag:
        queueLock.acquire()
        if not workQueue.empty():
            data = q.get()
            queueLock.release()
            print "%s processing %s" % (threadName, data)
        else:
            queueLock.release()
        time.sleep(1)


threadList = ["Thread-1", "Thread-2", "Thread-3"]
nameList = ["One", "Two", "Three", "Four", "Five"]
queueLock = threading.Lock()
workQueue = Queue.Queue(10)
threads = []
threadID = 1

# for循環創建新線程
for tName in threadList:
    thread = myThread(threadID, tName, workQueue)
    thread.start()
    threads.append(thread)
    threadID += 1

# 填充隊列
queueLock.acquire()
for word in nameList:
    workQueue.put(word)
queueLock.release()

# 等待隊列清空
while not workQueue.empty():
    pass

# 通知線程是時候退出
exitFlag = 1

# 等待所有線程完成
for t in threads:
    t.join()
print "Exiting Main Thread"
#實際上就是開三個線程清空了一個隊列，線程輪流參與，實現線程之間的同步