函数装饰器

装饰器又称语法糖，以下代码是装饰器没有简写之前：

# __*__ coding: utf-8 __*__
__author__ = "David.z"
user_status = False
def login(func):
    def inner():#嵌套函数
        _username = "alex"  # 假装这个DB里存的用户信息
        _password = "abc123"  # 假装这是DB里存的用户密码
        global user_status

        if user_status == False:
            username = input("user:").strip()
            password = input("password:").strip()

            if username == _username and password == _password:
                print("welcome login...")
                user_status = True
            else:
                print("wrong username or password!")
        else:
            print("用户已登录，验证通过。。。")
        if user_status:
            func()
    return inner
def home():
    print("首页".center(15,"*"))
def america():
    print("欧美专区".center(15, "*"))
def japan():
    print("日韩专区".center(15,"*"))
def henan():
    print("河南专区".center(15,"*"))
henan = login(henan) #inner

print(henan) #打印出来看看是不是内存地址
henan() #加上()执行函数

以下代码是简写之后：

唯一区别就是在装饰的时候用@login

# __*__ coding: utf-8 __*__
__author__ = "David.z"
user_status = False
def login(func):
    def inner():#嵌套函数
        _username = "alex"  # 假装这个DB里存的用户信息
        _password = "abc123"  # 假装这是DB里存的用户密码
        global user_status

        if user_status == False:
            username = input("user:").strip()
            password = input("password:").strip()

            if username == _username and password == _password:
                print("welcome login...")
                user_status = True
            else:
                print("wrong username or password!")
        else:
            print("用户已登录，验证通过。。。")
        if user_status:
            func()
    return inner
def home():
    print("首页".center(15,"*"))
def america():
    print("欧美专区".center(15, "*"))
def japan():
    print("日韩专区".center(15,"*"))
@login
def henan():
    print("河南专区".center(15,"*"))
# henan = login(henan) #inner
#
# print(henan) #打印出来看看是不是内存地址
henan() #加上()执行函数

最后一点改变，现在是在调用函数里面加了参数调用，为了不影响其他函数的调用。需要在嵌套的函数里加入*args,**kwargs

# __*__ coding: utf-8 __*__
__author__ = "David.z"
user_status = False
def login(func):
    def inner(*args,**kwargs):#嵌套函数
        _username = "alex"  # 假装这个DB里存的用户信息
        _password = "abc123"  # 假装这是DB里存的用户密码
        global user_status

        if user_status == False:
            username = input("user:").strip()
            password = input("password:").strip()

            if username == _username and password == _password:
                print("welcome login...")
                user_status = True
            else:
                print("wrong username or password!")
        else:
            print("用户已登录，验证通过。。。")
        if user_status:
            func(*args,**kwargs)
    return inner
def home():
    print("首页".center(15,"*"))
def america():
    print("欧美专区".center(15, "*"))
@login
def japan():
    print("日韩专区".center(15,"*"))
@login
def henan(style):
    print("河南专区,--%s".center(15,"*")%style)
#henan = login(henan) #inner
#japan = login(japan)

print(henan) #打印出来看看是不是内存地址
henan("3P") #加上()执行函数
japan()

两层嵌套函数，并带入参数的装饰器：

# __*__ coding: utf-8 __*__
__author__ = "David.z"
user_status = False
def login(func2):
    def outer(func):
        def inner(*args, **kwargs):
            _username = "alex"  # 假装这个DB里存的用户信息
            _password = "abc123"  # 假装这是DB里存的用户密码
            global user_status
            if user_status == False:
                username = input("user:").strip()
                password = input("password:").strip()

                if username == _username and password == _password:
                    print("welcome login...")
                    user_status = True
                else:
                    print("wrong username or password!")
            else:
                print("用户已登录，验证通过。。。")
            if user_status:
                func(*args, **kwargs)

        return inner
    return outer
def home():
    print("首页".center(15,"*"))

def america():
    print("欧美专区".center(15, "*"))
@login("weixin")
def japan():
    print("日韩专区".center(15,"*"))
@login("qq")
def henan(style):
    print("河南专区，---%s".center(15,"*")%style)

henan("3P")
japan()