Day 30 process&thread_2

进程和线程_2

1、继承类创建线程

 import threading,time

 class Mythread(threading.Thread):       #建立类，继承threading.Thread
     def __init__(self):
         threading.Thread.__init__(self)     #继承父类的__init__功能

     def run(self):          #run为python 自带，后面实例化后，start（）自动调用run（）功能
         print("{name} start to read in the {time}.".format(name=self,time = time.ctime()))

 l = []
 for i in range(6):
     t = Mythread()
     t.start()                       #相当于t.run()
     l.append(t)
     t.join()

 # for j in l:
 #     j.join()

 print("All is end...{time}".format(time=time.ctime()))

2、互斥锁

 import threading
 import time

 lock = threading.Lock()         #引用互斥锁，使用前先定义

 def sub():
     global num
     lock.acquire()              #lock.aquire() 引用锁后，只有运行到release（）才能让其它单位继续引用
     temp = num
     time.sleep(0.1)
     num = temp - 1
     lock.release()              #释放锁
     time.sleep(2)

 num = 100
 l = []
 for i in range(100):
     t = threading.Thread(target=sub,args=())
     t.start()
     l.append(t)

 for t in l:
     t.join()

 print(num)

3、递归锁和死锁

import threading,time

Rlock = threading.RLock()  #Rlock引入Lock和counter变量，每进行一次acquire，counter计数一次，release则减少一次，直到归0，其它线程才可以获得资源。

class Th(threading.Thread):
    def __init__(self):
        threading.Thread.__init__(self)

    def run(self):
        self.foo()
        self.bar()

    def foo(self):
        Rlock.acquire()
        print("I am %s GET LOCKA.....%s" %(self.name,time.ctime()))
        Rlock.acquire()
        print("I am %s GET LOCKB.....%s" %(self.name,time.ctime()))
        Rlock.release()
        Rlock.release()

    def bar(self):
        Rlock.acquire()
        print("I am %s GET LOCKA.....%s" %(self.name,time.ctime()))
        time.sleep(1)
        Rlock.acquire()
        print("I am %s GET LOCKB.....%s" %(self.name,time.ctime()))
        Rlock.release()
        Rlock.release()

for i in range(10):
    t = Th()
    t.start()