Question

我想在python3中创建一个线程类。我想在其中一个类函数中控制一个无限循环。我想在课外的主函数中启动或停止这个循环。假设这段代码：

import threading
from time import sleep
class my_thread(threading.Thread):
    """Thread class with a stop() method. The thread itself has to check
    regularly for the stopped() condition."""

    def __init__(self):
        super(my_thread, self).__init__()
        self._stop_event = threading.Event()

    def stop(self):
        print("stopping the thread")
        self._stop_event.set()

    def stopped(self):
        return(self._stop_event.is_set())

    def run(self):
        print("running the thread")
        print("start function startt()")
        self._stop_event.clear()
        self.startt()

    def startt(self):
        print("it is going to wait forever")
        while not self.stopped():
            #wait forever, this part is going to run again and again
            pass
        print("This line never executes")


if __name__+'__main__':
    thr=my_thread()
    thr.start()
    sleep(5)
    print("stopping the thread")
    thr.stop()
    # I cant start the thread and relative while loop again
    #thr.start()   
    print("Exiting the whole program")

但问题是我无法启动线程两次，所以我想要的是有两个函数用于启动和停止我的while循环。我不需要停止线程，但我需要控制它。这意味着我想在主程序中需要多次调用stop()和startt()函数。感谢

Answer 1

首先，在my_thread类中使用Queue进行由线程完成或调用的manage task（方法）

您可以使用LIFO队列，优先级队列，FIFO队列detail

第二，添加一个类方法，以便可以将新方法或任务添加到队列中

将以下代码添加到您的代码中：

from queue import Queue
# or
# from multiprocessing import Queue
class my_thread(threading.Thread):
    queue = Queue()

    @classmethod
    def add_task(cls,callable_task):
        cls.queue.put(callable_task)

    def startt(self):
        print("it is going to wait forever")
        while not self.stopped():
            #wait forever, this part is going to run again and again
            if not  self.queue.empty():
                  _m = self.queue.get()
                 # do what ever you want to do with _m

        print("This line never executes")

表示停止线程

 Class my_thread(Threading.Thread)
     stop_event = threading.Event()

     @classmethod
     def stop_thread(cls)
         cls.stop_event.set()

     def startt(self):
         print("it is going to wait forever")
         cls = self.__class__
         while not cls.stop_event.is_set():
             #wait forever, this part is going to run again and again
             if not  self.queue.empty():
                 _m = self.queue.get()
                 # do what ever you want to do with _m

         print("This line never executes")

现在请求停止therad

  my_thread.stop_thread()

<强> Exapmle

import threading
import time
class my_thread(threading.Thread):
    stop_event = threading.Event()

    @classmethod
    def stop_thread(cls):
        cls.stop_event.set()

    def run(self):
        print("running the thread")
        print("start function startt()")
        self.__class__.stop_event.clear()
        self.startt()

    def startt(self):
        print("it is going to wait forever")
        cls = self.__class__
        print cls.stop_event.is_set()
        while not cls.stop_event.is_set():
            pass

        print("This line never executes")

a = my_thread()
a.start()
time.sleep(0.5)
my_thread.stop_thread()
print "\n\n\n"
b = my_thread()
b.start()
time.sleep(0.5)
my_thread.stop_thread()

控制线程类python

1 个答案: