Python之异常学习

系统异常处理

#异常方法
def divide():
    b = 0;
    a = 2;
    c = a / b;
#异常处理
try:
    divide();
except Exception as e:
    print(e)
else:
    #若发生异常，下面代码则不执行！
    print("I con't excuted!")
finally:
    print('I was had excuted!');

结果

division by zero
I was had excuted!

自定义异常

class MyError(Exception):
    #构造方法,可以赋多个值
    def __init__(self, cold, message):
        self.cold = cold;
        self.message = message;
    #相当于Java的toString( )方法
    def __str__(self):
        return 'cold:'+self.cold + '  message:'+self.message;

try:
    print('I will raise an error')
    raise MyError('500', 'System error');
except MyError as e:
    print(e.cold);
    print(e.message);
    print('end!');
    print(e);

结果

I will raise an error
500
System error
end!
cold:500 message:System error