# 定义handler的输出格式formatter
formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
fh.setFormatter(formatter)
ch.setFormatter(formatter)
#定义一个filter
#filter = logging.Filter('mylogger.child1.child2')
#fh.addFilter(filter)
# 给logger添加handler
#logger.addFilter(filter)
logger.addHandler(fh)
logger.addHandler(ch)
#logger1.addFilter(filter)
logger1.addHandler(fh)
logger1.addHandler(ch)
logger2.addHandler(fh)
logger2.addHandler(ch)
#logger3.addFilter(filter)
logger3.addHandler(fh)
logger3.addHandler(ch)
#logger4.addFilter(filter)
logger4.addHandler(fh)
logger4.addHandler(ch)
logger5.addHandler(fh)
logger5.addHandler(ch)
# 记录一条日志
logger.debug('logger debug message')
logger.info('logger info message')
logger.warning('logger warning message')
logger.error('logger error message')
logger.critical('logger critical message')
logger1.debug('logger1 debug message')
logger1.info('logger1 info message')
logger1.warning('logger1 warning message')
logger1.error('logger1 error message')
logger1.critical('logger1 critical message')
logger2.debug('logger2 debug message')
logger2.info('logger2 info message')
logger2.warning('logger2 warning message')
logger2.error('logger2 error message')
logger2.critical('logger2 critical message')
logger3.debug('logger3 debug message')
logger3.info('logger3 info message')
logger3.warning('logger3 warning message')
logger3.error('logger3 error message')
logger3.critical('logger3 critical message')
logger4.debug('logger4 debug message')
logger4.info('logger4 info message')
logger4.warning('logger4 warning message')
logger4.error('logger4 error message')
logger4.critical('logger4 critical message')
logger5.debug('logger5 debug message')
logger5.info('logger5 info message')
logger5.warning('logger5 warning message')
logger5.error('logger5 error message')
logger5.critical('logger5 critical message')
输出：
2014-05-06 12:54:43,222 - root - WARNING - logger warning message
2014-05-06 12:54:43,223 - root - ERROR - logger error message
2014-05-06 12:54:43,224 - root - CRITICAL - logger critical message
2014-05-06 12:54:43,224 - mylogger - INFO - logger1 info message
2014-05-06 12:54:43,224 - mylogger - INFO - logger1 info message
2014-05-06 12:54:43,225 - mylogger - WARNING - logger1 warning message
2014-05-06 12:54:43,225 - mylogger - WARNING - logger1 warning message
2014-05-06 12:54:43,226 - mylogger - ERROR - logger1 error message
2014-05-06 12:54:43,226 - mylogger - ERROR - logger1 error message
2014-05-06 12:54:43,227 - mylogger - CRITICAL - logger1 critical message
2014-05-06 12:54:43,227 - mylogger - CRITICAL - logger1 critical message
2014-05-06 12:54:43,228 - mylogger - INFO - logger2 info message
2014-05-06 12:54:43,228 - mylogger - INFO - logger2 info message
2014-05-06 12:54:43,229 - mylogger - WARNING - logger2 warning message
2014-05-06 12:54:43,229 - mylogger - WARNING - logger2 warning message
2014-05-06 12:54:43,230 - mylogger - ERROR - logger2 error message
2014-05-06 12:54:43,230 - mylogger - ERROR - logger2 error message
2014-05-06 12:54:43,231 - mylogger - CRITICAL - logger2 critical message
2014-05-06 12:54:43,231 - mylogger - CRITICAL - logger2 critical message
2014-05-06 12:54:43,232 - mylogger.child1 - WARNING - logger3 warning message
2014-05-06 12:54:43,232 - mylogger.child1 - WARNING - logger3 warning message
2014-05-06 12:54:43,232 - mylogger.child1 - WARNING - logger3 warning message
2014-05-06 12:54:43,234 - mylogger.child1 - ERROR - logger3 error message
2014-05-06 12:54:43,234 - mylogger.child1 - ERROR - logger3 error message
2014-05-06 12:54:43,234 - mylogger.child1 - ERROR - logger3 error message
2014-05-06 12:54:43,235 - mylogger.child1 - CRITICAL - logger3 critical message
2014-05-06 12:54:43,235 - mylogger.child1 - CRITICAL - logger3 critical message
2014-05-06 12:54:43,235 - mylogger.child1 - CRITICAL - logger3 critical message
2014-05-06 12:54:43,237 - mylogger.child1.child2 - DEBUG - logger4 debug message
2014-05-06 12:54:43,237 - mylogger.child1.child2 - DEBUG - logger4 debug message
2014-05-06 12:54:43,237 - mylogger.child1.child2 - DEBUG - logger4 debug message
2014-05-06 12:54:43,237 - mylogger.child1.child2 - DEBUG - logger4 debug message
2014-05-06 12:54:43,239 - mylogger.child1.child2 - INFO - logger4 info message
2014-05-06 12:54:43,239 - mylogger.child1.child2 - INFO - logger4 info message
2014-05-06 12:54:43,239 - mylogger.child1.child2 - INFO - logger4 info message
2014-05-06 12:54:43,239 - mylogger.child1.child2 - INFO - logger4 info message
2014-05-06 12:54:43,240 - mylogger.child1.child2 - WARNING - logger4 warning message
2014-05-06 12:54:43,240 - mylogger.child1.child2 - WARNING - logger4 warning message
2014-05-06 12:54:43,240 - mylogger.child1.child2 - WARNING - logger4 warning message
2014-05-06 12:54:43,240 - mylogger.child1.child2 - WARNING - logger4 warning message
2014-05-06 12:54:43,242 - mylogger.child1.child2 - ERROR - logger4 error message
2014-05-06 12:54:43,242 - mylogger.child1.child2 - ERROR - logger4 error message
2014-05-06 12:54:43,242 - mylogger.child1.child2 - ERROR - logger4 error message
2014-05-06 12:54:43,242 - mylogger.child1.child2 - ERROR - logger4 error message
2014-05-06 12:54:43,243 - mylogger.child1.child2 - CRITICAL - logger4 critical message
2014-05-06 12:54:43,243 - mylogger.child1.child2 - CRITICAL - logger4 critical message
2014-05-06 12:54:43,243 - mylogger.child1.child2 - CRITICAL - logger4 critical message
2014-05-06 12:54:43,243 - mylogger.child1.child2 - CRITICAL - logger4 critical message
2014-05-06 12:54:43,244 - mylogger.child1.child2.child3 - DEBUG - logger5 debug message
2014-05-06 12:54:43,244 - mylogger.child1.child2.child3 - DEBUG - logger5 debug message
2014-05-06 12:54:43,244 - mylogger.child1.child2.child3 - DEBUG - logger5 debug message
2014-05-06 12:54:43,244 - mylogger.child1.child2.child3 - DEBUG - logger5 debug message
2014-05-06 12:54:43,244 - mylogger.child1.child2.child3 - DEBUG - logger5 debug message
2014-05-06 12:54:43,246 - mylogger.child1.child2.child3 - INFO - logger5 info message
2014-05-06 12:54:43,246 - mylogger.child1.child2.child3 - INFO - logger5 info message
2014-05-06 12:54:43,246 - mylogger.child1.child2.child3 - INFO - logger5 info message
2014-05-06 12:54:43,246 - mylogger.child1.child2.child3 - INFO - logger5 info message
2014-05-06 12:54:43,246 - mylogger.child1.child2.child3 - INFO - logger5 info message
2014-05-06 12:54:43,247 - mylogger.child1.child2.child3 - WARNING - logger5 warning message
2014-05-06 12:54:43,247 - mylogger.child1.child2.child3 - WARNING - logger5 warning message
2014-05-06 12:54:43,247 - mylogger.child1.child2.child3 - WARNING - logger5 warning message
2014-05-06 12:54:43,247 - mylogger.child1.child2.child3 - WARNING - logger5 warning message
2014-05-06 12:54:43,247 - mylogger.child1.child2.child3 - WARNING - logger5 warning message
2014-05-06 12:54:43,249 - mylogger.child1.child2.child3 - ERROR - logger5 error message
2014-05-06 12:54:43,249 - mylogger.child1.child2.child3 - ERROR - logger5 error message
2014-05-06 12:54:43,249 - mylogger.child1.child2.child3 - ERROR - logger5 error message
2014-05-06 12:54:43,249 - mylogger.child1.child2.child3 - ERROR - logger5 error message
2014-05-06 12:54:43,249 - mylogger.child1.child2.child3 - ERROR - logger5 error message
2014-05-06 12:54:43,250 - mylogger.child1.child2.child3 - CRITICAL - logger5 critical message
2014-05-06 12:54:43,250 - mylogger.child1.child2.child3 - CRITICAL - logger5 critical message
2014-05-06 12:54:43,250 - mylogger.child1.child2.child3 - CRITICAL - logger5 critical message
2014-05-06 12:54:43,250 - mylogger.child1.child2.child3 - CRITICAL - logger5 critical message
2014-05-06 12:54:43,250 - mylogger.child1.child2.child3 - CRITICAL - logger5 critical message
先简单介绍一下，logging库提供了多个组件：Logger、Handler、Filter、Formatter。Logger对象提供应用程序可直接使用的接口，Handler发送日志到适当的目的地，Filter提供了过滤日志信息的方法，Formatter指定日志显示格式。
Logger
Logger是一个树形层级结构，输出信息之前都要获得一个Logger（如果没有显示的获取则自动创建并使用root Logger，如第一个例子所示）。
logger = logging.getLogger()返回一个默认的Logger也即root Logger，并应用默认的日志级别、Handler和Formatter设置。
当然也可以通过Logger.setLevel(lel)指定最低的日志级别，可用的日志级别有logging.DEBUG、logging.INFO、logging.WARNING、logging.ERROR、logging.CRITICAL。
Logger.debug()、Logger.info()、Logger.warning()、Logger.error()、Logger.critical()输出不同级别的日志，只有日志等级大于或等于设置的日志级别的日志才会被输出。
我们看到程序中