使用log4j2分离系统日志与业务日志

　　前一篇文章介绍了log4j2 扩展日志级别,支持将系统日志与业务处理日志拆分，现在介绍一下通过日志级别将系统日志与业务日志分类，要达到这个目的很容易，只需要配置一下log4j的xml文件：

<?xml version="1.0" encoding="UTF-8"?>
<configuration status="OFF">
    <Properties>
        <property name="log_pattern">%m%n</property> 
        <property name="basePath">/data/logs/</property>
        <property name="system-msg">${basePath}/system.log</property>
        <property name="business-a-msg">${basePath}/service_a.log</property>
        <property name="business-b-msg">${basePath}/service_b.log</property>
        <property name="rollingfile_system-msg">${basePath}/system%d{yyyy-MM-dd}.log</property>
        <property name="rollingfile_business-a-msg">${basePath}/service_a%d{yyyy-MM-dd}.log</property>
        <property name="rollingfile_business-b-msg">${basePath}/service_b%d{yyyy-MM-dd}.log</property>
    </Properties>
    <appenders>
    <Console name="console" target="SYSTEM_OUT">
        <ThresholdFilter level="debug" onMatch="ACCEPT" onMismatch="ACCEPT" />
            <PatternLayout pattern="${log_pattern}" />
    </Console>
        <RollingFile name="appender_system-msg" filename="${system-msg}" filePattern="${rollingfile_system-msg}" append="true">
            <Filters>
                <ThresholdFilter level="business" onMatch="NEUTRAL" onMismatch="ACCEPT"/>
             </Filters>
            <PatternLayout>
                <Pattern>%d{yyyy-MM-dd HH:mm:ss} %-5level %class{36} %L %M - %msg%xEx%n</Pattern>
            </PatternLayout>
            <Policies>
                <TimeBasedTriggeringPolicy />
            </Policies>
        </RollingFile>
        <RollingFile name="appender_business-a-msg" filename="${business-a-msg}" filePattern="${rollingfile_business-a-msg}" append="true">
             <ThresholdFilter level="business" onMatch="ACCEPT" onMismatch="DENY"/>
             <PatternLayout>
                <Pattern>${log_pattern}</Pattern>
            </PatternLayout>
            <Policies>
                <TimeBasedTriggeringPolicy />
            </Policies>
        </RollingFile>
        <RollingFile name="appender_business-b-msg" filename="${business-b-msg}" filePattern="${rollingfile_business-b-msg}" append="true">
             <ThresholdFilter level="business" onMatch="ACCEPT" onMismatch="DENY"/>
            <PatternLayout>
                <Pattern>${log_pattern}</Pattern>
            </PatternLayout>
            <Policies>
                <TimeBasedTriggeringPolicy />
            </Policies>
        </RollingFile>
    </appenders>
    <loggers>
            <AsyncLogger name="com.jessezeng" level="info" additivity="true"  includeLocation="true">
                <AppenderRef ref="appender_system-msg" />
            </AsyncLogger>
            <AsyncLogger name="com.jessezeng.service.a.ServiceAImpl" level="info" additivity="true"  includeLocation="true">
                <AppenderRef ref="appender_business-a-msg" />
            </AsyncLogger>
            <AsyncLogger name="com.jessezeng.service.b.ServiceBImpl" level="info" additivity="true"  includeLocation="true">
                <AppenderRef ref="appender_business-b-msg" />
            </AsyncLogger>
            <Root level="info">
                <AppenderRef ref="console" />
            </Root>
    </loggers>
</configuration>

通过上面的配置就可以达到我们想要的目的，主要用到了log4j2日志级别过滤，可参考另一篇文章 log4j2按日志级别输出到指定文件。