Question

有人知道如何在不使用全局变量的情况下在此代码中从threadOne向threadTwo发送变量（或获取变量）吗？如果没有，我将如何操作全局变量？只需在两个类之前定义它并在运行函数中使用全局定义吗？

import threading

print "Press Escape to Quit"

class threadOne(threading.Thread): #I don't understand this or the next line
    def run(self):
        setup()

    def setup():
        print 'hello world - this is threadOne'


class threadTwo(threading.Thread):
    def run(self):
        print 'ran'

threadOne().start()
threadTwo().start()

由于

Answer 1

您可以使用queues以线程安全的方式在线程之间发送消息。

def worker():
    while True:
        item = q.get()
        do_work(item)
        q.task_done()

q = Queue()
for i in range(num_worker_threads):
     t = Thread(target=worker)
     t.daemon = True
     t.start()

for item in source():
    q.put(item)

q.join()       # block until all tasks are done

Answer 2

在这里，您可以使用Lock。

import threading

print "Press Escape to Quit"

# Global variable
data = None

class threadOne(threading.Thread): #I don't understand this or the next line
    def run(self):
        self.setup()

    def setup(self):
        global data
        print 'hello world - this is threadOne'

        with lock:
            print "Thread one has lock"
            data = "Some value"


class threadTwo(threading.Thread):
    def run(self):
        global data
        print 'ran'
        print "Waiting"

        with lock:
            print "Thread two has lock"
            print data

lock = threading.Lock()

threadOne().start()
threadTwo().start()

使用全局变量data。

第一个线程获取锁并写入变量。

第二个线程等待数据并打印出来。

<强>更新

如果您有两个以上的线程需要传递消息，最好使用threading.Condition。

在类线程Python之间发送消息

2 个答案: