【Python面向对象】（13）系统异常以及自定义异常

"""
捕获异常
"""


def test_div(num1, num2):
    """
    除法
    :param num1:
    :param num2:
    """
    return num1/num2


if __name__ == ‘__main__‘:
    # except后面无异常类型，则默认捕获Exception，则是捕获所有的异常
    try:
        rest1 = test_div(5, 0)
        print(rest1)  # 报错：ZeroDivisionError: division by zero
    except:
        print("报错啦")  # 输出：报错啦，除数不能为0

    # 捕获指定异常
    try:
        rest1 = test_div(5, 0)
        print(rest1)  # 报错：ZeroDivisionError: division by zero
    except ZeroDivisionError:
        print("报错啦，除数不能为0")  # 输出：报错啦，除数不能为0

    try:
        rest2 = test_div(5, ‘s‘)
        print(rest2)  # 报错：TypeError: unsupported operand type(s) for /: ‘int‘ and ‘str‘
    except TypeError:
        print("报错啦，请输入数字")  # 输出：报错啦，请输入数字

    # 捕获多个异常
    try:
        rest1 = test_div(5, 0)
        print(rest1)  # 报错：ZeroDivisionError: division by zero
    except (ZeroDivisionError, TypeError):
        print("报错啦，除数不能为0或者请输入数字")  # 输出：报错啦，除数不能为0或者请输入数字

"""
自定义异常
"""


class MyException(Exception):
    """我的异常类"""
    error_code = ""
    error_msg = ""

    def __init__(self, error_code=None, error_msg=None):
        self.error_code = self.error_code if self.error_code else error_code
        self.error_msg = self.error_msg if self.error_msg else error_msg

    def __str__(self):
        return "Error: {0} - {1}".format(self.error_code, self.error_msg)


class InvalidException(MyException):
    """当参数不合法时触发"""
    error_code = "400"
    error_msg = "两个必须为整数"


def divide(num1, num2):
    """除法"""
    # 两个数必须为整数
    if not isinstance(num1, int) or not isinstance(num2, int):
        raise InvalidException()
    # 除数不能为0
    if num2 == 0:
        raise MyException("401", "除数不能为0")
    return num1/num2


if __name__ == "__main__":
    try:
        res = divide(5, "s")
        print(res)
    except InvalidException as e:
        print(e)
    except MyException as e:
        print(e)