python使用笔记26--多线程

 1 def insert_db():
 2     time.sleep(3)
 3     print(‘insert_db over‘)
 4 
 5 start_time = time.time()
 6 for i in range(3): #串行的方式
 7     insert_db()
 8 end_time = time.time()
 9 print(‘串行的执行的时间‘,end_time - start_time )
10 
11 start_time2 = time.time()
12 #2、判断当前存活的线程个数为1个时
13 for i in range(3):
14     t = threading.Thread(target=insert_db)
15     t.start()
16 
17 while threading.activeCount()!=1:
18     pass
19 
20 end_time2 = time.time()
21 print(‘多线程执行的时间‘,end_time2 - start_time2)#只是主线程执行的时间，不计算子线程执行的时间

 1 def insert_db():
 2     time.sleep(3)
 3     print(‘insert_db over‘)
 4 start_time2 = time.time()
 5 #2、判断当前存活的线程个数为1个时
 6 for i in range(3):
 7     t = threading.Thread(target=insert_db)
 8     t.start()
 9 
10 end_time2 = time.time()
11 print(‘多线程执行的时间‘,end_time2 - start_time2)#只是主线程执行的时间，不计算子线程执行的时间

 1 threads = []
 2 start_time2 = time.time()
 3 #2、判断当前存活的线程个数为1个时
 4 for i in range(3):
 5     t = threading.Thread(target=insert_db)
 6     t.start()
 7     threads.append(t)
 8 
 9 for i in threads:
10     i.join()
11 end_time2 = time.time()
12 print(‘多线程执行的时间‘,end_time2 - start_time2)

 1 start_time2 = time.time()
 2 #2、判断当前存活的线程个数为1个时
 3 for i in range(3):
 4     t = threading.Thread(target=insert_db)
 5     t.start()
 6 
 7 while threading.activeCount()!=1:
 8     pass
 9 
10 end_time2 = time.time()
11 print(‘多线程执行的时间‘,end_time2 - start_time2)

 1 import threading
 2 import requests
 3 import hashlib
 4 import time
 5 def down_load(url):
 6     name = hashlib.md5(url.encode()).hexdigest()
 7     r = requests.get(url)
 8     with open(‘%s.jpg‘%name,‘wb‘) as fw:
 9         fw.write(r.content)
10 
11 l = [
12     ‘http://www.nnzhp.cn/wp-content/themes/QQ/images/logo.jpg‘,
13     ‘http://www.nnzhp.cn/wp-content/uploads/2016/12/2016aj5kn45fjk5-150x150.jpg‘,
14     ‘http://www.nnzhp.cn/wp-content/themes/QQ/images/thumbnail.png‘
15 ]
16 
17 for i in l:
18     t = threading.Thread(target=down_load,args=(i,))#args=(i,),一个参数的时候要加，
19     t.start()
20 
21 while threading.activeCount() != 1:
22     pass
23 
24 print(‘down_load over...‘)

1 case_result = []
2 def run_case(case_name):
3     print(‘run case over...‘)
4     case_result.append({case_name,‘success‘})

 1 #守护线程，一旦主线程死掉，不管守护线程有没有执行完成，全部都结束
 2 
 3 import threading
 4 import time
 5 
 6 def talk(name):
 7     print(‘正在和%s聊天‘%name)
 8     time.sleep(200)
 9 
10 
11 def shipin(name):
12     print(‘正在和%s视频‘ % name)
13     time.sleep(200)
14 
15 
16 print(‘qq聊天窗口‘)
17 t1 = threading.Thread(target=talk,args=[‘xxl‘])
18 t1.setDaemon(True)#设置线程为守护线程
19 t1.start()
20 
21 
22 t2 = threading.Thread(target=shipin,args=[‘lxy‘])
23 t2.setDaemon(True)#设置线程为守护线程
24 t2.start()
25 
26 
27 time.sleep(5)
28 print(‘结束‘)

 1 #线程锁
 2 #多个线程同时操作同一个数据的时候，会有问题
 3 import threading
 4 lock = threading.Lock()
 5 count = 0
 6 def test():
 7     global count
 8     lock.acquire(timeout=3000)#加锁，设置超时时间为3毫秒
 9     count += 1
10     print(count)
11     lock.release()#解锁
12 
13 for i in range(100):
14     t = threading.Thread(target=test)
15     t.start()