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python 异常 反射

异常 反射

一、异常处理：

 1 AttributeError 试图访问一个对象没有的树形，比如foo.x，但是foo没有属性x
 2 IOError 输入/输出异常；基本上是无法打开文件
 3 ImportError 无法引入模块或包；基本上是路径问题或名称错误
 4 IndentationError 语法错误（的子类） ；代码没有正确对齐
 5 IndexError 下标索引超出序列边界，比如当x只有三个元素，却试图访问x[5]
 6 KeyError 试图访问字典里不存在的键
 7 KeyboardInterrupt Ctrl+C被按下
 8 NameError 使用一个还未被赋予对象的变量
 9 SyntaxError Python代码非法，代码不能编译(个人认为这是语法错误，写错了）
10 TypeError 传入对象类型与要求的不符合
11 UnboundLocalError 试图访问一个还未被设置的局部变量，基本上是由于另有一个同名的全局变量，
12 导致你以为正在访问它
13 ValueError 传入一个调用者不期望的值，即使值的类型是正确的
14 
15 常用异常
16 
17 常用异常
常用异常
 1 ArithmeticError
 2 AssertionError
 3 AttributeError
 4 BaseException
 5 BufferError
 6 BytesWarning
 7 DeprecationWarning
 8 EnvironmentError
 9 EOFError
10 Exception
11 FloatingPointError
12 FutureWarning
13 GeneratorExit
14 ImportError
15 ImportWarning
16 IndentationError
17 IndexError
18 IOError
19 KeyboardInterrupt
20 KeyError
21 LookupError
22 MemoryError
23 NameError
24 NotImplementedError
25 OSError
26 OverflowError
27 PendingDeprecationWarning
28 ReferenceError
29 RuntimeError
30 RuntimeWarning
31 StandardError
32 StopIteration
33 SyntaxError
34 SyntaxWarning
35 SystemError
36 SystemExit
37 TabError
38 TypeError
39 UnboundLocalError
40 UnicodeDecodeError
41 UnicodeEncodeError
42 UnicodeError
43 UnicodeTranslateError
44 UnicodeWarning
45 UserWarning
46 ValueError
47 Warning
48 ZeroDivisionError
49 
50 更多异常
51 
52 更多异常
更多异常
1  try:
2      intput = raw_input()
3      data = int(intput)
4  except Exception,e:  #e是Exception类的一个对象，调用__str__方法
5  print"请输入数字"
 1 #输出sb,输出A类的__str__方法
 2 
 3 class A:
 4     def __str__(self):
 5         return 'sb'
 6 obj = A()
 7 print obj
 8 
 9 #自定义错误异常
10 
11 class AlexError(Exception):
12     def __init__(self,msg=None):
13         self.message = msg
14     def __str__(self):
15         if self.message:
16             return self.message
17         else:
18             return 'alex error'
19 try:
20     raise AlexError('error')    #当有值时，输出值，否则输出alex erroer
21 except Exception,e:
22     print e
23 
24 自定义异常
自定义异常

 

二、反射：

 1 helpper.py    #模块
 2 -----------------------------------------------
 3 def dev():
 4     return "home dev"
 5 def index():
 6     return "home index"
 7 
 8 
 9 index.py     #模块
10 -----------------------------------------------
11 import helpper
12 
13 url = raw_input('url:')      #输入helpper/dev
14 
15 if url == "helpper/dev":
16     ret = helpper.dev()
17     print ret
18 elif url == "helpper/index":
19     ret = helpper.index()
20     print ret
21 
22 Example
Example
 1 helpper.py    #模块
 2 -----------------------------------------------
 3 def dev():
 4     return "home dev"
 5 def index():
 6     return "home index"
 7 
 8 
 9 index.py     #模块
10 -----------------------------------------------
11 import helpper
12 
13 url = raw_input('url:')  #输入helpper/dev
14 controller,action = url.split('/')
15 func = getattr(helpper,action)
16 ret = func()
17 print ret
18 
19 Example 进阶
Example 进阶
 1 helpper.py   #模块
 2 --------------------------------------------
 3 def dev():
 4     return "home dev"
 5 def index():
 6     return "home index"
 7 
 8 
 9 
10 index.py    #模块
11 ---------------------------------------------
12 controller,action = raw_input("url:").split('/')
13 model = __import__(controller)
14 
15 func = getattr(model,action)
16 ret = func()
17 print ret
18 
19 __import__和反射 getattr
__import__和反射 getattr

二、反射(2)：

 1 import sys
 2 
 3 class WebServer(object):
 4     def __init__(self,host,port):
 5         self.host = host
 6         self.port = port
 7     def start(self):
 8         print("Server is starting...")
 9     def stop(self):
10         print("Server is stopping...")
11     def restart(self):
12         self.stop()
13         self.start()
14 if __name__ == "__main__":
15     obj = WebServer('localhost','3306')
16     if sys.argv[1] == "start":
17         obj.start()
18 
19 example
example
 1 import sys
 2 
 3 class WebServer(object):
 4     def __init__(self,host,port):
 5         self.host = host
 6         self.port = port
 7     def start(self):
 8         print("Server is starting...")
 9     def stop(self):
10         print("Server is stopping...")
11     def restart(self):
12         self.stop()
13         self.start()
14 if __name__ == "__main__":
15     obj = WebServer('localhost','3306')
16     cmd_list = {
17         'start':obj.start,
18         'stop':obj.stop
19     }
20     if sys.argv[1] in cmd_list:
21         cmd_list[sys.argv[1]]()
22 
23 example 字典形式
example 字典形式
 1 import sys
 2 
 3 class WebServer(object):
 4     def __init__(self,host,port):
 5         self.host = host
 6         self.port = port
 7     def start(self):
 8         print("Server is starting...")
 9     def stop(self):
10         print("Server is stopping...")
11     def restart(self):
12         self.stop()
13         self.start()
14 if __name__ == "__main__":
15     obj = WebServer('localhost','3306')
16     if hasattr(obj,sys.argv[1]):
17         func = getattr(obj,sys.argv[1])  #获取obj.start 的内存地址
18         func()
19 
20 example 进阶hasattr  getattr
example 进阶hasattr getattr
 1 import sys
 2 
 3 class WebServer(object):
 4     def __init__(self,host,port):
 5         self.host = host
 6         self.port = port
 7     def start(self):
 8         print("Server is starting...")
 9     def stop(self):
10         print("Server is stopping...")
11     def restart(self):
12         self.stop()
13         self.start()
14 
15 def test_run(name):
16     print("running..",name)
17 
18 if __name__ == "__main__":
19     obj = WebServer('localhost','3306')
20     if hasattr(obj,sys.argv[1]):
21         func = getattr(obj,sys.argv[1])  #获取obj.start 的内存地址
22         func()
23     setattr(obj,"run",test_run)
24     obj.run('xxx')
25 
26 ----------------------------------------------------------------------
27 
28 #/usr/bin/env python
29 # -*- coding:utf-8 -*-
30 
31 import sys
32 
33 class WebServer(object):
34     def __init__(self,host,port):
35         self.host = host
36         self.port = port
37     def start(self):
38         print("Server is starting...")
39     def stop(self):
40         print("Server is stopping...")
41     def restart(self):
42         self.stop()
43         self.start()
44 
45 def test_run(self,name):
46     print("running..",name,self.host)
47 
48 if __name__ == "__main__":
49     obj = WebServer('localhost','3306')
50     if hasattr(obj,sys.argv[1]):
51         func = getattr(obj,sys.argv[1])  #获取obj.start 的内存地址
52         func()
53     setattr(obj,"run",test_run)
54     obj.run(obj,'xxx')
55 
56 setattr
setattr

三、设计模式：

 1 class SqlHelper:
 2 
 3     __static_instance = None
 4 
 5     def __init__(self):
 6         self.hostname = '0.0.0.0'
 7         self.port = 3306
 8         self.user = 'root'
 9         self.passd = '123'
10 
11     @classmethod
12     def instance(cls):
13         if cls.__static_instance:
14             return cls.__static_instance
15         else:
16             cls.__static_instance = SqlHelper()
17             return cls.__static_instance
18 
19     def fetch(self):
20         pass
21     def remove(self):
22         pass
23 
24 def add_user():
25     obj = SqlHelper.instance()
26     obj.fetch()
27 
28 def del_user():
29     obj = SqlHelper.instance()
30     obj.remove()
31 
32 print id(SqlHelper.instance())
33 print id(SqlHelper.instance())
34 
35 单例模式一
单例模式一
posted @ 2017-06-27 23:23  Meet~  阅读(237)  评论(0)    收藏  举报