[英]python thread exception cause stop the process
in below code if i change one of the url to something invalid the whole process will stop and i couldn't exit form terminal using ctrl+c . 在下面的代码中,如果我将其中一个url更改为无效的内容,整个过程将停止,我无法使用ctrl + c退出表单终端。 so my question is how should i handle exception in my main thread run method and if an error happen trigger it and go to the next list element without fail the whole process: 所以我的问题是我应该如何处理我的主线程运行方法中的异常,如果发生错误触发它并且在没有失败的情况下转到下一个列表元素:
#!/usr/bin/env python
import Queue
import threading
import urllib2
import time
hosts = ["http://yahoo.com", "http://google.com", "http://amazon.com","http://apple.com"]
queue = Queue.Queue()
class ThreadUrl(threading.Thread):
"""Threaded Url Grab"""
def __init__(self, queue):
threading.Thread.__init__(self)
self.queue = queue
def run(self):
while True:
#grabs host from queue
host = self.queue.get()
#grabs urls of hosts and prints first 1024 bytes of page
url = urllib2.urlopen(host)
print "connected"
#signals to queue job is done
self.queue.task_done()
start = time.time()
def main():
#spawn a pool of threads, and pass them queue instance
for i in range(5):
t = ThreadUrl(queue)
t.setDaemon(True)
t.start()
#populate queue with data
for host in hosts:
queue.put(host)
#wait on the queue until everything has been processed
queue.join()
main()
print "Elapsed Time: %s" % (time.time() - start)
use a finally
block to make sure the thread always signals even when there is an error. 使用finally
块确保即使出现错误,线程也始终发出信号。
def run(self):
while True:
#grabs host from queue
host = self.queue.get()
#grabs urls of hosts and prints first 1024 bytes of page
try:
url = urllib2.urlopen(host)
print "connected"
except urllib2.URLError:
print "couldn't connect to %s" % host
finally:
#signals to queue job is done
self.queue.task_done()
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