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1. 認識執行緒同步現象：

在https://blog.csdn.net/weixin_41827162/article/details/84104421執行緒非同步中，

將方法1中：

建多個執行緒，同時執行多個執行緒，由新到舊逐個釋放執行緒

改成：

建立一個執行緒，執行一個執行緒，釋放一個執行緒

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#!/usr/bin/python3
# 執行緒非同步
 
import threading
import time
 
exitFlag = 0
 
 
class myThread(threading.Thread):
    def __init__(self, thread_id, name, counter):
        threading.Thread.__init__(self)
        self.thread_id = thread_id
        self.name = name
        self.counter = counter
        pass
 
    def run(self):
        print("開始執行緒=" + self.name)
        run_def(self.name, self.counter, 5)
        print("退出執行緒=" + self.name)
        pass
    pass
 
 
def run_def(thread_name, delay, counter):
    while counter:
        if exitFlag:
            thread_name.exit()
            pass
        time.sleep(delay)
        # time.sleep(0)
        list(thread_name)
        counter -= 1
        pass
    pass
 
 
def list(thread_name):
    print("\n執行執行緒=" + thread_name)
    pass
 
 
threads = []  # 儲存線上執行緒
 
# 建立執行緒
for this_t in range(1, 10):
    t = myThread(this_t, "Thread-" + str(this_t), 0.1)
    t.start()
    t.join()  # 執行緒同步，執行緒非同步
    threads.append(t)
    pass
 
# 終止執行緒
# for t in threads:
#     t.join()
#     pass
 
print("程式完成！！")
 

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2. 真正的執行緒同步：

#!/usr/bin/python3

# 執行緒同步

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("開啟執行緒： " + self.name)
        # 獲取鎖，用於執行緒同步
        threadLock.acquire()
        print_time(self.name, self.counter, 3)
        # 釋放鎖，開啟下一個執行緒
        threadLock.release()


def print_time(threadName, delay, counter):
    while counter:
        time.sleep(0)
        print("%s: %s" % (threadName, time.ctime(time.time())))
        counter -= 1


threadLock = threading.Lock()
threads = []


for cal in range(1, 100):
    that = myThread(cal, "Thread-" + str(cal), cal).start()
    print("建立了執行緒=" + str(cal))
    threads.append(that)
    pass

print("退出主執行緒")
 

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