操作方法：将Tomcat9配置为通过Log4j2进行日志记录

Question

如何将Tomcat9的内部日志记录（catalina和localhost）重定向到log4j2？

虽然Tomcat和Log4j的旧版本有很多指南，但我找不到任何关于Tomcat 9和Log4J2的“完整”指南；Apache Tomcat 9文档指向“替代日志框架提供的说明”，Apache Log4j文档说明（2.更正的jar名称）：

Log4j可以用作Apache Tomcat的日志记录框架。这种支持是通过在引导类路径中包含log4j-api、log4j-core和log4j-appserver JAR自动实现的。名为log4j2-tomcat.xml、log4j2-tomcat.json、log4j2-tomcat.yaml、log4j2-tomcat.yml或log4j2-tomcat.properties的文件也必须放在引导类路径中。最容易做到这一点的是：

1. 在catalina home中创建一组名为log4j2/lib和log4j2/conf的目录。
2. 将log4j-api-2.12.0.jar、log4j-core-2.12.0.jar和log4j-appserver-2.12.0.jar放置在log4j2/lib目录中。
3. 在log4j2/conf目录中创建一个名为log4j2-tomcat.xml、log4j2-tomcat.json、log4j2-tomcat.yaml、log4j2-tomcat.yml或log4j2-tomcat.properties的文件。
4. 在tomcat bin目录中创建或修改html" target="_blank">setenv.sh以包含classpath=$CATALINA_HOME/log4j2/lib/*:$CATALINA_HOME/log4j2/conf

但是要在log4j2-tomcat.*配置文件中放些什么呢？

Answer 1

我在Apache Tomcat7文档中找到了一个示例属性文件，但由于这是用于Log4J1.x的，所以我必须使其适应Log4j2属性文件语法。这就是结果：

# 'status' refers to log messages from Log4j2 itself
monitorInterval = 30
status = warn

property.loglevel.catalina = info
property.loglevel.localhost = info

property.layoutPattern.catalina = %d %-5p [%t] %-22.22c{1} %m%n
property.layoutPattern.localhost = %d %-5p [%t] %-30.30c{1} %m%n

# Roll-over the logs once per month using CronTriggerPolicy.

property.fileDatePattern.catalina = %d{yyyy-MM}
property.fileDatePattern.localhost = %d{yyyy-MM}

property.cronTriggerSchedule.catalina = 0 0 0 1 * ?
property.cronTriggerSchedule.localhost = 0 0 0 1 * ?

## Appenders

# N.B.: - No need to specify 'appenders = CATALINA, LOCALHOST, CONSOLE'
#         since these identifiers do not contain '.' characters.
#       - The sub-component identifiers 'policies' and 'cron' are arbitrarily
#         chosen; the actual type is specified via the 'type' attribute.
#       - 'DirectWriteRolloverStrategy' is used automatically since no 'fileName' specified.

appender.CATALINA.type = RollingFile
appender.CATALINA.name = RollingFile-CATALINA
appender.CATALINA.filePattern = ${sys:catalina.base}/logs/catalina.${fileDatePattern.catalina}.log
appender.CATALINA.layout.type = PatternLayout
appender.CATALINA.layout.pattern = ${layoutPattern.catalina}
appender.CATALINA.policies.type = Policies
appender.CATALINA.policies.cron.type = CronTriggeringPolicy
appender.CATALINA.policies.cron.schedule = ${cronTriggerSchedule.catalina}
appender.CATALINA.policies.cron.evaluateOnStartup = true
appender.CATALINA.filePermissions = rw-r-----
appender.CATALINA.fileOwner = tomcat
appender.CATALINA.fileGroup = adm

appender.LOCALHOST.type = RollingFile
appender.LOCALHOST.name = RollingFile-LOCALHOST
appender.LOCALHOST.filePattern = ${sys:catalina.base}/logs/localhost.${fileDatePattern.localhost}.log
appender.LOCALHOST.layout.type = PatternLayout
appender.LOCALHOST.layout.pattern = ${layoutPattern.localhost}
appender.LOCALHOST.policies.type = Policies
appender.LOCALHOST.policies.cron.type = CronTriggeringPolicy
appender.LOCALHOST.policies.cron.schedule = ${cronTriggerSchedule.localhost}
appender.LOCALHOST.policies.cron.evaluateOnStartup = true
appender.LOCALHOST.filePermissions = rw-r-----
appender.LOCALHOST.fileOwner = tomcat
appender.LOCALHOST.fileGroup = adm

# Uncomment if you want to keep logging to catalina.out after Log4j2 takes over.

#appender.CONSOLE.type = Console
#appender.CONSOLE.name = STDOUT
#appender.CONSOLE.layout.type = PatternLayout

## Configure which loggers log to which appenders

rootLogger.level = ${loglevel.catalina}
rootLogger.appenderRef.CATALINA.ref = RollingFile-CATALINA
#rootLogger.appenderRef.stdout.ref = STDOUT

# Here, the identifier does contain '.' characters, so we must specify the list.
loggers = org.apache.catalina.core.ContainerBase.[Catalina].[localhost]

logger.org.apache.catalina.core.ContainerBase.[Catalina].[localhost].name = LOCALHOST
logger.org.apache.catalina.core.ContainerBase.[Catalina].[localhost].level = ${loglevel.localhost}
logger.org.apache.catalina.core.ContainerBase.[Catalina].[localhost].appenderRef.LOCALHOST.ref = RollingFile-LOCALHOST

我使用Log4j2的主要原因是能够每月进行日志循环，但您可以轻松地根据自己的喜好调整所有内容，甚至无需重新启动Tomcat。