slf4j简单配置（满足日常）

SLF4j的功能就是充当一个门面，有点类似于jdbc，用class.forName的方式加载当前pom文件中引入的实现类。可以看看这个blog的分析，省的自己看源码了（https://blog.csdn.net/u010644448/article/details/50298275）

springBoot不用引入依赖，logback和slf4j的jar被依赖传递过来了。只需要配置一个logback.xml文件即可。

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <property name="warContextName" value="gateway"/>
    <contextName>${warContextName}</contextName>>
    <appender name="logfile_error" class="ch.qos.logback.core.rolling.RollingFileAppender">
        <filter class="ch.qos.logback.classic.filter.LevelFilter">
            <level>ERROR</level>
<!--            匹配的日志写入文件-->
            <onMatch>ACCEPT</onMatch>
<!--            不匹配的不写入文件-->
            <onMismatch>DENY</onMismatch>
        </filter>
<!--        谨慎模式  多个fileAppender同时向同一个文件中写日志时 不会出错具体百度吧-->
        <Prudent>true</Prudent>
<!--        按时间段进行写入策略 其他的还有按文件大小的策略-->
        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <FileNamePattern>
<!--                文件名称-->
                logs/error/${HOSTNAME}.${CONTEXT_NAME}.%d{yyyy-MM-dd-HH}.error.log
            </FileNamePattern>
        </rollingPolicy>
        <encoder>
            <Pattern>
<!--                文件中记录日志的格式-->
                %d{HH:mm:ss.SSS} [%thread] %.-1level %logger{32} - %msg %n
            </Pattern>
        </encoder>
    </appender>
    <appender name="logfile_info" class="ch.qos.logback.core.rolling.RollingFileAppender">
        <filter class="ch.qos.logback.classic.filter.LevelFilter">
            <level>INFO</level>
            <onMatch>ACCEPT</onMatch>
            <onMismatch>DENY</onMismatch>
        </filter>
        <Prudent>true</Prudent>
        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <FileNamePattern>
                logs/info/${HOSTNAME}.${CONTEXT_NAME}.%d{yyyy-MM-dd-HH}.info.log
            </FileNamePattern>
        </rollingPolicy>
        <encoder>
            <Pattern>
                %d{HH:mm:ss.SSS} [%thread] %.-1level %logger{32} - %msg %n
            </Pattern>
        </encoder>
    </appender>

    <appender name="logfile_debug" class="ch.qos.logback.classic.AsyncAppender">
        <queueSize>512</queueSize>
        <appender name="_logfile_debug" class="ch.qos.logback.core.rolling.RollingFileAppender">
            <filter class="ch.qos.logback.classic.filter.ThresholdFilter">
                <level>DEBUG</level>
            </filter>
            <Prudent>true</Prudent>
            <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
                <FileNamePattern>
                    logs/debug/${HOSTNAME}.${CONTEXT_NAME}.%d{yyyy-MM-dd-HH}-%i.debug.log
                </FileNamePattern>
                <timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
                    <maxFileSize>800MB</maxFileSize>
                </timeBasedFileNamingAndTriggeringPolicy>
            </rollingPolicy>
            <encoder>
                <Pattern>
                    %d{HH:mm:ss.SSS} [%thread] %.-1level %logger{32} - %msg %n
                </Pattern>
            </encoder>
        </appender>
    </appender>
<!--控制台输出的格式-->
    <appender name="logfile_console" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
            <Pattern>
                <pattern>%-4relative [%thread] %-5level %logger{35} - %msg %n</pattern>
            </Pattern>
        </encoder>
        <filter class="ch.qos.logback.classic.filter.LevelFilter">
            <level>DEBUG</level>
            <onMatch>ACCEPT</onMatch>
            <onMismatch>ACCEPT</onMismatch>
        </filter>
    </appender>

<!--    对具体包进行日志的输出设置-->
    <logger name="com.mpt.slf4jdemo" level="DEBUG"/>
<!--    <logger name="ht" level="DEBUG" />-->
    <logger name="root" level="INFO">
        <appender-ref ref="logfile_error"/>
        <appender-ref ref="logfile_debug"/>
        <appender-ref ref="logfile_info"/>
        <appender-ref ref="logfile_console"/>
    </logger>
</configuration>