要点，下载相应的jar包tomcat-juli-adapters.jar、tomcat-juli.jar、log4j-1.2.15.jar，配置Log4j

1.tomcat目录的lib下，添加log4j.properties、tomcat-juli-adapters.jar、log4j-1.2.15.jar

2.tomcat目录的bin下，添加tomcat-juli.jar(替换)

3.tomcat目录的conf下，编辑context.xml，Context增加属性swallowOutput="true"

4.tomcat目录的conf下，删除文件logging.properties

5.完成

附简单配置，即同时输出到控制台、文件

log4j.appender.console_out=org.apache.log4j.ConsoleAppender
log4j.appender.console_out.layout=org.apache.log4j.PatternLayout
log4j.appender.console_out.layout.ConversionPattern=[TomcatLog4j_Console] [%-5p] [%d{yyyy-MM-dd HH:mm:ss,SSS}] %c - %m%n


log4j.appender.root_out=org.apache.log4j.DailyRollingFileAppender
log4j.appender.root_out.File=${catalina.home}/logs/log4j
log4j.appender.root_out.DatePattern=‘-‘yyyy-MM-dd‘.log‘
log4j.appender.root_out.layout=org.apache.log4j.PatternLayout
log4j.appender.root_out.layout.ConversionPattern=[TomcatLog4j_Root] [%-5p] [%d{yyyy-MM-dd HH:mm:ss,SSS}] %c - %m%n


log4j.rootLogger=INFO,root_out,console_out

Tomcat6改用Log4j日志