Raise and Handle Exception Demo

import sys

class MyError(Exception):
	def __init__(self,value):
		self.value = value
	def __str__(self):
		return repr(self.value)

try:
	f = open('new.in')
	s = f.readline()
	f.close()
	i = int(s.strip()) 
	raise MyError(3*3) 
except IOError as e:
	print "I/O error({0}):{1}".format(e.errno , e.strerror)
except ValueError:
	print "Could not convert string to int"
except MyError as e:
	print "My errro occurred,value:",e.value
except:
	print "Unexpected error:",sys.exc_info[0]
	raise

参考 ： http://docs.python.org/2/tutorial/errors.html