python学习之反射

发布时间：2019-07-17 10:08:44编辑：auto阅读（1447）

python学习反射




实例1

脚本内容如下：

#coding: utf8 class myClass(object):     def fax(self):         print 'faxing....'     def copy(self):         print 'copying...' def printing():     print 'printing....' m = myClass() if hasattr(m,'fax'):          #判断myClass类中是否有fax方法     func = getattr(m,'fax')    #返回内存对象     func()                #调用 setattr(m,'print2',printing) m.print2() try:     #delattr(m,'copy')     #print name     #print dfdf     #print tttt     print m except AttributeError,e:     print 'something wrong..',e except Exception,e:     print e finally:     print '-----------' #else: #    print "print nothing wrong ...."

执行脚本结果如下：


faxing....

printing....

<__main__.myClass object at 0x028211D0>

-----------




实例2

脚本内容如下：

#/usr/bin/env python #coding: utf8 import sys class WebServer(object):      def __init__(self,host,port):          self.host = host          self.port = port      def start(self):          print "Server is starting..."      def stop(self):         print "Server is stopping..."      def restart(self):         self.stop()         self.start() if __name__ == "__main__":      server = WebServer('localhost',80)      #print sys.argv[1]      cmd_dic = {         'start':server.start,         'stop':server.stop,         'restart':server.restart,      }     #if sys.argv[1] == 'start':      if sys.argv[1] in cmd_dic:         cmd_dic[sys.argv[1]]()

执行脚本结果如下：


D:\Python学习\脚本学习>python 反射01.py start

Server is starting...




修改上面的脚本如下：

#/usr/bin/env python #coding: utf8 import sys class WebServer(object):      def __init__(self,host,port):          self.host = host          self.port = port      def start(self):          print "Server is starting..."      def stop(self):         print "Server is stopping..."      def restart(self):         self.stop()         self.start() if __name__ == "__main__":      server = WebServer('localhost',80)      if hasattr(server,sys.argv[1]):          func = getattr(server,sys.argv[1])   ##获取server.start的内存地址          func()     ##相当于server.start()

执行脚本结果如下：


D:\Python学习\脚本学习>python 反射02.py start

Server is starting...




D:\Python学习\脚本学习>python 反射02.py stop

Server is stopping...




修改上面的脚本如下：


#/usr/bin/env python #coding: utf8 import sys class WebServer(object):      def __init__(self,host,port):          self.host = host          self.port = port      def start(self):          print "Server is starting..."      def stop(self):         print "Server is stopping..."      def restart(self):         self.stop()         self.start() def test_run(name):     print "running...",name if __name__ == "__main__":      server = WebServer('localhost',80)      if hasattr(server,sys.argv[1]):          func = getattr(server,sys.argv[1])   ##获取server.start的内存地址          func()     ##相当于server.start()      setattr(server,'run',test_run)  ##test_run以run身份绑定到server实例中      server.run('peng')       ##类似执行test_run('peng')

执行脚本结果如下：


D:\Python学习\脚本学习>python 反射03.py start

Server is starting...

running... peng




修改上面的脚本如下：

#/usr/bin/env python #coding: utf8 import sys class WebServer(object):      def __init__(self,host,port):          self.host = host          self.port = port      def start(self):          print "Server is starting..."      def stop(self):         print "Server is stopping..."      def restart(self):         self.stop()         self.start() def test_run(self,name):     print "running...",name,self.host if __name__ == "__main__":      server = WebServer('localhost',80)      if hasattr(server,sys.argv[1]):          func = getattr(server,sys.argv[1])   ##获取server.start的内存地址          func()     ##相当于server.start()      setattr(server,'run',test_run)  ##test_run以run身份绑定到server实例中      server.run(server,'peng')       ##类似执行test_run('peng')

执行脚本结果如下：


D:\Python学习\脚本学习>python 反射04.py start

Server is starting...

running... peng localhost




修改上面的脚本如下：

#/usr/bin/env python #coding: utf8 import sys class WebServer(object):      def __init__(self,host,port):          self.host = host          self.port = port      def start(self):          print "Server is starting..."      def stop(self):         print "Server is stopping..."      def restart(self):         self.stop()         self.start() def test_run(self,name):     print "running...",name,self.host if __name__ == "__main__":      server = WebServer('localhost',80)      if hasattr(server,sys.argv[1]):          func = getattr(server,sys.argv[1])   ##获取server.start的内存地址          func()     ##相当于server.start()      delattr(WebServer,'start')      print server.restart()      #setattr(server,'run',test_run)  ##test_run以run身份绑定到server实例中      #server.run(server,'peng')       ##类似执行test_run('peng')

执行脚本结果如下：


D:\Python学习\脚本学习>python 反射05.py restart

Server is stopping...    ---》执行的是func(）的调用

Server is starting...    ---》执行的是func(）的调用

Server is stopping...    ---》执行的是server.restart(）的调用

Traceback (most recent call last):

  File "反射05.py", line 31, in <module>

    print server.restart()

  File "反射05.py", line 19, in restart

    self.start()

AttributeError: 'WebServer' object has no attribute 'start' ---》执行的是server.restart(）的调用,此时start已经删除，所以报了“'WebServer' object has no attribute 'start'”错误！！！