最近,在做一个项目时遇到的了一个问题,主线程无法捕获子线程中抛出的异常。
先看一个线程类的定义
''''' Created on Oct 27, 2015 @author: wujz ''' import threading class runScriptThread(threading.Thread): def __init__(self, funcName, *args): threading.Thread.__init__(self) self.args = args self.funcName = funcName def run(self): try: self.funcName(*(self.args)) except Exception as e: raise e
很简单,传入要调用的方法,并启用一个新的线程来运行这个方法。
在主线程中,启动这个线程类的一个对象时,这要声明一个对象然后启动就可以了,示例如下
import runScriptThread,traceback if __name__=='__main__': sth = 'hello world' try: aChildThread = runScriptThread(printSth, sth) aChildThread.start() aChildThread.join() except Exception as e: print(str(traceback.format_exc()))
但是这样的代码,main方法中无法捕获子线程中的异常,原因在于start()方法将为子线程开辟一条新的栈,main方法的栈因此无法捕获到这一异常。
解决方法很简单,就是通过设置一个线程是否异常退出的flag的成员变量,当线程异常退出时,对其作一标记。然后在主线程中检查改线程运行结束后该标志位的值,如果异常,再通过sys和traceback回溯异常信息,然后抛出即可。改写后的异常类:
''''' Created on Oct 27, 2015 @author: wujz ''' import threading,traceback,sys class runScriptThread(threading.Thread): #The timer class is derived from the class threading.Thread def __init__(self, funcName, *args): threading.Thread.__init__(self) self.args = args self.funcName = funcName self.exitcode = 0 self.exception = None self.exc_traceback = '' def run(self): #Overwrite run() method, put what you want the thread do here try: self._run() except Exception as e: self.exitcode = 1 # 如果线程异常退出,将该标志位设置为1,正常退出为0 self.exception = e self.exc_traceback = ''.join(traceback.format_exception(*sys.exc_info())) #在改成员变量中记录异常信息 def _run(self): try: self.funcName(*(self.args)) except Exception as e: raise e
改写后的主线程:
import runScriptThread,traceback if __name__=='__main__': sth = 'hello world' try: aChildThread = runScriptThread(printSth, sth) aChildThread.start() aChildThread.join() except Exception as e: print(aChildThread.exc_traceback)
以上全部为本篇文章的全部内容,希望对大家的学习有所帮助,也希望大家多多支持。