log4j2配置详解
据网上博客整理，再加上自己一些理解。
参考：
https://www.cnblogs.com/sa-dan/p/6837225.html
https://www.jianshu.com/p/d13c2e50a89c
<?xml version="1.0" encoding="UTF-8"?>
<!--日志级别以及优先级排序: OFF > FATAL > ERROR > WARN > INFO > DEBUG > TRACE > ALL -->
<!--status="WARN" :用于设置log4j2自身内部日志的信息输出级别，默认是OFF-->
<!--monitorInterval="30" :间隔秒数,自动检测配置文件的变更和重新配置本身-->
<configuration status="warn" monitorInterval="60" strict="true">
<properties>
<!--自定义一些常量，之后使用${变量名}引用-->
<property name="logpath">./logs</property>
<property name="charset">UTF-8</property>
<!--自定义的输出格式-->
<property name="pattern">%-d{yyyy-MM-dd HH:mm:ss.SSS}@@%p@@%X{ip}@@%t %C@@%X{requestId} %M %m %n </property>
</properties>
<!--appenders:定义输出内容,输出格式,输出方式,日志保存策略等,常用其下三种标签[console,File,RollingFile]-->
<!--Appender可以理解为日志的输出目的地-->
<appenders>
<!--console :控制台输出的配置-->
<Console name="console" target="SYSTEM_OUT">
<PatternLayout pattern="${pattern}" charset="${charset}"/>
</Console>
<!--RollingRandomAccessFile性能比RollingFile提升官网宣称是20-200%-->
<RollingRandomAccessFile name="YZY.TRACE" immediateFlush="true" bufferSize="1024"
fileName="${logpath}/trace.log"
filePattern="${logpath}/trace.log.%d{yyyy-MM-dd}.gz">
<PatternLayout pattern="${pattern}" charset="${charset}"/>
<TimeBasedTriggeringPolicy/>
<DefaultRolloverStrategy>
<Delete basePath="${logpath}" maxDepth="2" followLinks="true">
<IfFileName glob="trace.log.*.gz"/>
<IfLastModified age="3d"/>
</Delete>
</DefaultRolloverStrategy>
</RollingRandomAccessFile>
<RollingRandomAccessFile name="YZY.SYSTEM" immediateFlush="true" bufferSize="4096"
fileName="${logpath}/system.log"
filePattern="${logpath}/system.log.%d{yyyy-MM-dd}.gz"
ignoreExceptions="false">
<!--引用上面自定义的输出格式-->
<PatternLayout pattern="${pattern}" charset="${charset}"/>
<Filters>
<!--ThresholdFilter :日志输出过滤-->
<!--level="info" :日志级别,onMatch="ACCEPT" :级别在info之上则接受,onMismatch="DENY" :级别在info之下则拒绝-->
<!--与logger、root中定义的日志级别相配合，相当于两个闸门，先判断logger、root的级别，符合了才会用到该filter中的level，此时再进行一次筛选-->
<ThresholdFilter level="TRACE" onMatch="ACCEPT" onMismatch="DENY"/>
<!--<ThresholdFilter level="DEBUG" onMatch="ACCEPT" onMismatch="DENY"/>-->
<!--<ThresholdFilter level="INFO" onMatch="ACCEPT" onMismatch="DENY"/>-->
</Filters>
<!-- Policies :日志滚动策略-->
<Policies>
<!--<TimeBasedTriggeringPolicy interval="1" modulate="true"/>-->
<CronTriggeringPolicy schedule="0 0 2 * * ?" evaluateOnStartup="true"/>
</Policies>
<!-- DefaultRolloverStrategy属性如不设置，则默认为最多同一文件夹下7个文件-->
<DefaultRolloverStrategy>
<Delete basePath="${logpath}" maxDepth="2" followLinks="true">
<IfFileName glob="system.log.*.gz"/>
<!--只保留7天，超过则删除-->
<IfLastModified age="7d"/>
</Delete>
</DefaultRolloverStrategy>
</RollingRandomAccessFile>
<RollingRandomAccessFile name="YZY.ERROR" immediateFlush="true" bufferSize="4096"
fileName="${logpath}/error.log"
filePattern="${logpath}/error.log.%d{yyyy-MM-dd}.gz"
ignoreExceptions="false">
<PatternLayout pattern="${pattern}" charset="${charset}"/>
<Filters>
<ThresholdFilter level="ERROR" onMatch="ACCEPT" onMismatch="DENY"/>
</Filters>
<TimeBasedTriggeringPolicy/>
<DefaultRolloverStrategy>
<Delete basePath="${logpath}" maxDepth="2" followLinks="true">
<IfFileName glob="error.log.*.gz"/>
<IfLastModified age="7d"/>
</Delete>
</DefaultRolloverStrategy>
</RollingRandomAccessFile>
<RollingRandomAccessFile name="YZY.AUDIT" immediateFlush="false" bufferSize="8192"
fileName="${logpath}/audit.log"
filePattern="${logpath}/audit.log.%d{yyyy-MM-dd}.gz"
ignoreExceptions="false">
<PatternLayout pattern="${pattern}" charset="${charset}"/>
<Filters>
<ThresholdFilter level="WARN" onMatch="ACCEPT" onMismatch="DENY"/>
</Filters>
<TimeBasedTriggeringPolicy/>
<DefaultRolloverStrategy>
<Delete basePath="${logpath}" maxDepth="2" followLinks="true">
<IfFileName glob="audit.log.*.gz"/>
<IfLastModified age="7d"/>
</Delete>
</DefaultRolloverStrategy>
</RollingRandomAccessFile>
<RollingRandomAccessFile name="YZY.POOL" immediateFlush="true" bufferSize="1024"
fileName="${logpath}/pool.log"
filePattern="${logpath}/pool.log.%d{yyyy-MM-dd}.gz"
ignoreExceptions="false">
<PatternLayout pattern="${pattern}" charset="${charset}"/>
<TimeBasedTriggeringPolicy/>
<DefaultRolloverStrategy>
<Delete basePath="${logpath}" maxDepth="2" followLinks="true">
<IfFileName glob="pool.log.*.gz"/>
<IfLastModified age="3d"/>
</Delete>
</DefaultRolloverStrategy>
</RollingRandomAccessFile>
<RollingRandomAccessFile name="YZY.MONITOR" immediateFlush="true" bufferSize="1024"
fileName="${logpath}/monitor.log"
filePattern="${logpath}/pool.log.%d{yyyy-MM-dd}.gz"
ignoreExceptions="false">
<PatternLayout pattern="${pattern}" charset="${charset}"/>
<TimeBasedTriggeringPolicy/>
<DefaultRolloverStrategy>
<Delete basePath="${logpath}" maxDepth="2" followLinks="true">
<IfFileName glob="pool.log.*.gz"/>
<IfLastModified age="3d"/>
</Delete>
</DefaultRolloverStrategy>
</RollingRandomAccessFile>
<RollingRandomAccessFile name="YZY.BIZ" immediateFlush="true"
fileName="${logpath}/biz.log"
filePattern="${logpath}/biz.log.%d{yyyy-MM-dd}.gz"
ignoreExceptions="false">
<PatternLayout pattern="${pattern}" charset="${charset}"/>
<TimeBasedTriggeringPolicy/>
<DefaultRolloverStrategy>
<Delete basePath="${logpath}" maxDepth="2" followLinks="true">
<IfFileName glob="biz.log.*.gz"/>
<IfLastModified age="7d"/>
</Delete>
</DefaultRolloverStrategy>
</RollingRandomAccessFile>
</appenders>
<!--然后定义logger，只有定义了logger并引入的appender，appender才会生效-->
<loggers>
<!--additivity="false"表示在该logger中输出的日志不会再延伸到父层logger。这里如果改为true，则会延伸到Root Logger，遵循Root Logger的配置也输出一次。-->
<Logger additivity="false" name="YZY.TRACE" level="INFO">
<AppenderRef ref="YZY.TRACE"/>
</Logger>
<Logger additivity="false" name="YZY.SYSTEM" level="INFO">
<AppenderRef ref="YZY.SYSTEM"/>
<AppenderRef ref="YZY.ERROR"/>
</Logger>
<Logger additivity="false" name="YZY.BIZ" level="INFO">
<AppenderRef ref="YZY.BIZ"/>
</Logger>
<!--Logger节点用来单独指定日志的形式，name为包路径,比如要为org.apache包下所有日志指定为INFO级别等。 -->
<Logger additivity="false" name="org.apache" level="INFO">
<AppenderRef ref="console"/>
</Logger>
<Logger additivity="false"
name="com.alibaba.dubbo.common.threadpool.monitor.MonitorPoolRunnable" level="INFO">
<AppenderRef ref="YZY.POOL"/>
</Logger>
<Logger additivity="false" name="com.alibaba.dubbo.monitor.dubbo.sfextend.SfMonitorExtend"
level="INFO">
<AppenderRef ref="YZY.MONITOR"/>
</Logger>
<!--针对,request以及reponse的信息配置输出级别,生产线请配置为error-->
<Logger additivity="true" name="com.alibaba.dubbo.rpc.protocol.rest.support" level="INFO">
<AppenderRef ref="console"/>
</Logger>
<!-- 在开发和测试环境启用,输出sql -->
<Logger additivity="true" name="com.YZY.mapper" level="DEBUG">
</Logger>
<!-- Root节点用来指定项目的根日志，如果没有单独指定Logger，那么就会默认使用该Root日志输出 -->
<Root level="DEBUG" includeLocation="true">
<AppenderRef ref="console"/>
<AppenderRef ref="YZY.SYSTEM"/>
<AppenderRef ref="YZY.ERROR"/>
<AppenderRef ref="YZY.AUDIT"/>
</Root>
</loggers>
</configuration>
public class TestLog {
public static void main(String[] args) {
Logger logger = LoggerFactory.getLogger("YZY.SYSTEM");
//Logger logger = LoggerFactory.getLogger(TestLog.class);
logger.trace("trace level");
logger.debug("debug level");
logger.info("info level");
logger.warn("warn level");
logger.error("error level");
}
}
RollingRandomAccessFile性能比RollingFile提高很多。
另https://www.cnblogs.com/sa-dan/p/6837225.html解释了
即可以在程序中使用Logger logger = LoggerFactory.getLogger("YZY.SYSTEM");来获取对应的logger，如果找到对应名称的logger，就不会使用root节点的logger。
LoggerFactory.getLogger(TestLog.class)底层实现也是调用的getLogger(clazz.getName());
如上代码，LoggerFactory.getLogger(TestLog.class)找不到对应的logger，会使用默认的root节点的配置。
