前言
Spring Boot 默认使用Logback,来打印日志，这里还想说的SLFJ(Simple Logging Facade for Java)，它们之间的关系，一张图，说明一切：
maven 配置
<!--use log4j2 property-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-log4j2</artifactId>
</dependency>
<!--flume log4j appender-->
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-flume-ng</artifactId>
<version>2.6</version>
</dependency>
log4j2.xml 配置
Log4j2 提供非常丰富的Appender,比如CassandraAppender，AsyncAppender，我们这里配置了简单的Flume Appnder,Failover Appender.
<?xml version="1.0" encoding="UTF-8"?>
<Configuration monitorInterval="60">
<Properties>
<Property name="source">api-web</Property>
<Property name="log-pattern">%d{yyyy-MM-dd HH:mm:ss.SSS} [%X{userId}] [%t] [%-5level] %c{1.}@%M%L - %m%n</Property>
<!--get product dynamic property-->
</Properties>
<Appenders>
<RollingFile name="RollingFile" fileName="logs/app.log"
filePattern="logs/$${date:yyyy-MM}/app-%d{MM-dd-yyyy}-%i.log.gz">
<PatternLayout>
<Pattern>${log-pattern}</Pattern>
</PatternLayout>
<Policies>
<TimeBasedTriggeringPolicy />
<SizeBasedTriggeringPolicy size="250 MB"/>
</Policies>
</RollingFile>
<Flume name="eventLogger" compress="false" type="avro" ignoreExceptions="false">
<Agent host="192.168.31.115" port="4444"/>
<Agent host="127.0.0.1" port="4444"/>
<PatternLayout>
<pattern>
<pattern>${log-pattern}</pattern>
</pattern>
</PatternLayout>
</Flume>
<Console name="Console-Appender" target="SYSTEM_OUT" ignoreExceptions="false">
<PatternLayout>
<pattern>${log-pattern}</pattern>
</PatternLayout>
</Console>
<!-- 主要Apeender失败的时候使用备用Appender-->
<Failover name="Failover" primary="eventLogger">
<Failovers>
<AppenderRef ref="RollingFile"/>
</Failovers>
</Failover>
</Appenders>
<Loggers>
<!--在需要同时打印文件和发送至flume的时候使用-->
<!--<Logger name="" level="info" additivity="false">-->
<!--<AppenderRef ref="RollingFile"/>-->
<!--</Logger>-->
<Root level="info">
<AppenderRef ref="Console-Appender"/>
<AppenderRef ref="Failover"/>
</Root>
</Loggers>
</Configuration>
总结
如果遇到识别不了log4j2.properties/xml，可以在application.properties,中指定 logging.config=classpath:log4j2.properties/xml
参考
https://springframework.guru/introducing-log4j-enterprise-class-logging/
http://logging.apache.org/log4j/2.x/manual/appenders.html
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持
