python2 一些错误处理

python2各种问题

pip安装django出错：python2 -m pip install django

编码问题：Unicode Decode Error ascii codec can't decode byte...

原因：windows系统默认编码是gbk，而pip默认编码是utf8，故出错

解决方法： python27\Lib\site-packages下，新建一个 sitecustomize.py 文件，写入

import sys

sys.setdefaultencoding('gbk')

pip安装django出错：python2 -m pip install django

源码编译问题：IOError: [Errno 22] invalid mode ('wb') or filename

原因：pip默认下载最新版本，最新版本为django2.0，而源上只有django2.0 python3的whl文件，没有python2的whl文件。因此只能采用源码编译安装，而源码编译安装又出了这个错误

解决方法：指定下载较低版本的django，这里用django 1.11.4

查看django版本：https://pypi.python.org/pypi

pip指定版本号用“==”：

python2 -m pip install django==1.11.4

启动django出错：python2 manage.py runserver

RuntimeError: maximum recursion depth exceeded in cmp

django启动时出错，报错显示在python27/Lib/functool.py的第56行

解决办法：在python目录中的Lib下面找到functools将56行

convert = {

'__lt__': [('__gt__', lambda self, other: other < self),

('__le__', lambda self, other: not other < self),

('__ge__', lambda self, other: not self < other)],

'__le__': [('__ge__', lambda self, other: other <= self),

('__lt__', lambda self, other: not other <= self),

('__gt__', lambda self, other: not self <= other)],

'__gt__': [('__lt__', lambda self, other: other > self),

('__ge__', lambda self, other: not other > self),

('__le__', lambda self, other: not self > other)],

'__ge__': [('__le__', lambda self, other: other >= self),

('__gt__', lambda self, other: not other >= self),

('__lt__', lambda self, other: not self >= other)]

}

修改成：

convert = {

'__lt__': [('__gt__', lambda self, other: not (self < other or self == other)),

('__le__', lambda self, other: self < other or self == other),

('__ge__', lambda self, other: not self < other)],

'__le__': [('__ge__', lambda self, other: not self <= other or self == other),

('__lt__', lambda self, other: self <= other and not self == other),

('__gt__', lambda self, other: not self <= other)],

'__gt__': [('__lt__', lambda self, other: not (self > other or self == other)),

('__ge__', lambda self, other: self > other or self == other),

('__le__', lambda self, other: not self > other)],

'__ge__ ': [('__le__', lambda self, other: (not self >= other) or self == other),

('__gt__', lambda self, other: self >= other and not self == other),

('__lt__', lambda self, other: not self >= other)]

}

django连接postgresql出错：python2 manage.py runserver

django.db.utils.OperationalError:

FATAL: no pg_hba.conf entry for host "172.16.23.129", user "postgres", database "datamanager", SSL on
FATAL: no pg_hba.conf entry for host "172.16.23.129", user "postgres", database "datamanager", SSL off

PostgreSQ数据库为了安全，它不会监听除本地以外的所有连接请求，当用户通过JDBC访问是，会报一些如下的异常：

org.postgresql.util.PSQLException: FATAL: no pg_hba.conf entry for host

要解决这个问题，只需要在PostgreSQL数据库的安装目录下找到/data/pg_hba.conf,找到“# IPv4 local connections:”

在其下加上请求连接的机器IP

host all all 127.0.0.1/32 md5

32是子网掩码的网段；md5是密码验证方法，可以改（见文件pg_hba.conf上的说明）