log4j:WARN Please initialize the log4j system properly 问题解决

在tomcat启动的时候，出现这个警告：

log4j:WARN No appenders could be found for logger (org.apache.commons.digester.Digester.sax).
log4j:WARN Please initialize the log4j system properly.

解决办法：

log4j.properties文件需要放到web-inf/class目录下面,在eclipse里面放到src目录下面，会自动拷贝到class目录下面去。

文件里面的内容如下即可：

# For JBoss: Avoid to setup Log4J outside $JBOSS_HOME/server/default/deploy/log4j.xml!
# For all other servers: Comment out the Log4J listener in web.xml to activate Log4J.
log4j.rootLogger=INFO, stdout, logfile

log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m%n

log4j.appender.logfile=org.apache.log4j.RollingFileAppender
log4j.appender.logfile.File=F:/dream/workspace/MyZhiNengTuanDemo/WebRoot/WEB-INF/znt.log
log4j.appender.logfile.MaxFileSize=512KB
# Keep three backup files.
log4j.appender.logfile.MaxBackupIndex=3
# Pattern to output: date priority [category] - message
log4j.appender.logfile.layout=org.apache.log4j.PatternLayout
log4j.appender.logfile.layout.ConversionPattern=%d %p [%c] - %m%n
 

log4j.properties文件路径：在eclipse目录下的文件中，可通过搜索找到

其中log4j.appender.logfile.File=F:/dream/workspace/MyZhiNengTuanDemo/WebRoot/WEB-INF/znt.log这句话中的路径可以选择自己项目下的WEB-INF目录下。