又是我们需要开启debug来排查故障，只需在项目目录下创建文件 WEB-INF/classes/log4j.properties 内容如下

log4j.rootLogger=debug,console,file		
			

重新启动tomcat将进入Debug模式，你将看到大量的调试信息。

			
1) log4j.properties: Add the console to the root logger
log4j.rootLogger = INFO, CATALINA, CONSOLE

2) log4j.properties: Change the DailyRollingFileAppender to:
log4j.appender.CATALINA=org.apache.log4j.rolling.RollingFileAppender
log4j.appender.CATALINA.RollingPolicy=org.apache.log4j.rolling.TimeBasedRollingPolicy
log4j.appender.CATALINA.RollingPolicy.FileNamePattern=${catalina.base}/logs/catalina.%d{yyyy-MM-dd}.log