Python面向对象(约束,异常处理,md5加密)(五)

1. 类的约束

1. 写一个父类. 父类中的某个方法要抛出一个异常 NotImplementedError

class Base:
    def login(self):
        raise NotImplementedError("没有实现登录")

class Person(Base):
    def login(self):
        print("正常使用")

class SpecialPerson(Base):
    def denglu(self):
        print("非正常")

def func(obj):
    obj.login()

p1 = Person()
p2 = SpecialPerson()
func(p1)
func(p2)

2. 抽象类和抽象方法

from abc import ABCMeta, abstractmethod

class Base(metaclass = ABCMeta):

@abstractmethod

def fangfa(self):

pass

from abc import ABCMeta,abstractmethod
class Animal(metaclass = ABCMeta):
    @abstractmethod
    def chi(self):pass
    def run(self):
        print("能跑")

class Cat(Animal):
    def chi(self):
        print("吃鱼")
    def dong(self):
        print("guyong")

c = Cat()
c.chi()
c.dong()
c.run()

2. 异常处理.

　try except raise finally

try:

代码

except 异常类:

除了错, 如何处理异常

except 异常类:

除了错, 如何处理异常

except 异常类:

除了错, 如何处理异常

else:

当程序不出错

finally:

不管出不出错, 都要执行

raise 异常类("信息")

如何自己定义异常

class 类(Exception):

pass

堆栈

import traceback

traceback.format_exc()

import traceback
class GenderException(Exception):
    pass

class Person:
    def __init__(self,name,gender):
        self.name = name
        self.gender = gender

    def xizao(self):
        print(f"{self.name}在洗澡")

def zaotang(ren):
    if ren.gender == "男":
        ren.xizao()
    else:
        raise GenderException("性别不对,去对门看看")

try:
    p1 = Person("tom","男")
    p2 = Person("jerry","mouse")
    zaotang(p1)
    zaotang(p2)
except GenderException:
    ret = traceback.format_exc()
    print(ret)

3. MD5加密

import hashlib

obj = hashlib.md5(b‘盐‘)

obj.update(b"要加密的内容")

print(obj.hexdigest())

import hashlib
def my_md5(c):
    obj = hashlib.md5(b"safgd")
    obj.update(c.encode("utf-8"))
    return obj.hexdigest()

print(my_md5("1996"))

4. 日志处理 

等级:

critical: 50

error:40

warning:30

info:20

debug:10

import logging

logging.basicConfig(filename=‘x1.txt‘, # 把日志信息写入的文件名
                    format=‘%(asctime)s - %(name)s - %(levelname)s -%(module)s: %(message)s‘,
                    datefmt=‘%Y-%m-%d %H:%M:%S‘, # 时间的格式
                    level=20) # 当前配置表示 10以上的分数会被写入日件

logging.critical("高")
logging.error("很高")
logging.warning("一般")
logging.info("较低")
logging.debug("最低")
logging.log(500,"自己定")

file_handler = logging.FileHandler(‘l1.log‘, ‘a‘, encoding=‘utf-8‘) # 创建文件
file_handler.setFormatter(logging.Formatter(
    fmt="%(asctime)s - %(name)s - %(levelname)s -%(module)s: %(message)s")) # 设置日志文件的格式
logger1 = logging.Logger(‘腾讯qq‘, level=40) # 创建一个日志文件处理对象
logger1.addHandler(file_handler) # 把文件添加到日志

logger1.error("运行出错了")

file_handler2 = logging.FileHandler(‘l2.log‘, ‘a‘, encoding=‘utf-8‘)
file_handler2.setFormatter(logging.Formatter(
    fmt="%(asctime)s - %(name)s -%(levelname)s -%(module)s: %(message)s"))
logger2 = logging.Logger(‘百度贴吧‘, level=logging.DEBUG)
logger2.addHandler(file_handler2)

logger2.debug("有点小问题")

原文地址：https://www.cnblogs.com/fu-1111/p/10158722.html