面向对象oop知识

面向对象知识点属性

class Request(object):
    def __init__(self, req, xx):
        self._request = req
        self.xx = xx


obj = Request(1, 2)
print(obj.xx)
print(obj._request)

获取对象中的成员时，本质上会调用 __getattribute__方法，默认我们不定义就用父类中的

class Request(object):
    def __init__(self, req, xx):
        self._request = req
        self.xx = xx

    def __getattribute__(self, item):
        print("执行__getattribute__", item)
        return super().__getattribute__(item)


obj = Request(1, 2)
print(obj.xx)
print(obj._request)
# int(obj.v1) # 报错
# 注意：如果不是对象中的成员，就会报错。

不过想要访问对象中不存在成员，则可以通过定义 __getattr__实现。

• 先执行自己的 __getattribute__

• 再执行父类的__getattribute__

  • 是自己对象，直接获取并返回

  • 不是自己对象，调用__getattr__

class Request(object):
    def __init__(self, req, xx):
        self._request = req
        self.xx = xx

    def __getattribute__(self, item):
        print("执行__getattribute__", item)
        return super().__getattribute__(item)

    def __getattr__(self, item):
        print("__getattr__", item)
        return 999


obj = Request(1, 2)
print(obj.xx)
print(obj._request)
print(obj.v1)

对象封装

class HttpRequest(object):
    def __init__(self):
        pass
    
    def v1(self):
        print("v1")
        
    def v2(self):
        print("v1")

class Request(object):
    def __init__(self,req, xx):
        self._request = req
        self.xx = xx

request = HttpRequest()
request.v1()
request.v2()

request = Request(request,111)
request._request.v1()
request._request.v2()

class HttpRequest(object):
    def __init__(self):
        pass
    
    def v1(self):
        print("v1")
        
    def v2(self):
        print("v1")

class Request(object):
    def __init__(self,req, xx):
        self._request = req
        self.xx = xx
        
    def __getattr__(self, attr):
        try:
            return getattr(self._request, attr)
        except AttributeError:
            return self.__getattribute__(attr)
        
request = HttpRequest()
request.v1()
request.v2()

request = Request(request,111)
request.v1()
request.v2()