#all logger output level is 'ERROR' and output position is stdout
#so only write our project's DEBUG log and ERROR log of the others
log4j.rootLogger=ERROR, stdout ,R
#log4j.appender is set output postion
#log4j.logger is set some package(some package your want output logger specially)=[output level],[...output position]
#log4j.logger.org.springframework=OFF
#log4j.logger.org.apache.commons=OFF
#log4j.logger.org.apache.struts=OFF
#log4j.logger.org.hibernate=OFF
#log4j.logger.org.logicalcobwebs=OFF
#only write our project's log(DEBUG)
log4j.logger.com.diantu=DEBUG
#in the console
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
#config stdout position output contain INFO level and up
log4j.appender.stdout.Threshold=DEBUG
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=[%-5p] %l:%t - %m %n
#in the daily files
log4j.appender.R=org.apache.log4j.DailyRollingFileAppender
log4j.appender.R.Threshold=DEBUG
log4j.appender.R.File=${root.path}/log/EMR.log
log4j.appender.R.DatePattern='.'yyyy-MM-dd'.log'
log4j.appender.R.layout=org.apache.log4j.PatternLayout
log4j.appender.R.layout.ConversionPattern=%d [%-5p] %l:%t - %m %n
log4j.logger.com.statestr=DEBUG
原理就是 指定 默认的 Log level 为 ERROR，然后指定我们要输入的日志的 包 的log level 为 DEBUG, 这样就能实现输入我们指定包的 DEBUG 基本的 log 和 其它所有代码的 ERROR 级别的 log.
方便调试。