开发笔记:用代码写代理给代码找代练！

from abc import abstractmethod,ABCMeta
class Subject(metaclass=ABCMeta):
@abstractmethod
def get_content(self):
pass
class RealSubject(Subject):
def __init__(self,filename):
self.filename = filename
print("读取%s文件内容" % filename)
f = open(filename)
self.content = f.read()
f.close()
def get_content(self):
return self.content
def set_content(self, content):
f = open(self.filename, \'w\')
f.write(content)
f.close()
class ProxyA(Subject):
def __init__(self, filename):
self.subj = RealSubject(filename)
def get_content(self):
return self.subj.get_content()
class ProxyB(Subject):
\'\'\'虚代理\'\'\'
def __init__(self, filename):
self.filename = filename
self.subj = None
def get_content(self):
if not self.subj: #if True 如果为空的时候，就去读取文本
self.subj = RealSubject(self.filename)
return self.subj.get_content()
class ProxyC(Subject):
\'\'\'保护代理\'\'\'
def __init__(self, filename):
self.subj = RealSubject(filename)
def get_content(self):
return self.get_content()
def set_content(self):
raise PermissionError
# 写一个set_content
b = ProxyB("abc.txt")
print(b.get_content())