pom.xml中
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.25</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.7.25</version>
</dependency>
log4j.properties (位于classpath下)
### set log levels ###
log4j.rootLogger = DEBUG, stdout, D, E
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
log4j.appender.D = org.apache.log4j.RollingFileAppender
log4j.appender.D.File =${catalina.home}/logs/a9.log
log4j.appender.D.Append = true
log4j.appender.D.Threshold = DEBUG
log4j.appender.D.MaxFileSize = 50000KB
log4j.appender.D.layout = org.apache.log4j.PatternLayout
log4j.appender.D.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss} [ %t:%r ] - [ %p ] %m%n
log4j.appender.E = org.apache.log4j.RollingFileAppender
log4j.appender.E.File = ${catalina.home}/logs/a9.log
log4j.appender.E.Append = true
log4j.appender.E.Threshold = ERROR
log4j.appender.E.MaxFileSize = 50000KB
log4j.appender.E.layout = org.apache.log4j.PatternLayout
log4j.appender.E.layout.ConversionPattern =%-d{yyyy-MM-dd HH\:mm\:ss} [ %l\:%c\:%t\:%r ] - [ %p ] %m%n
${catalina.home}
是java -Dcatalina.home=xxx,由tomcat执行时传入，该变量可以直接获取到tomcat的安装位置
