第一步：pom依赖：需要在spring-boot-starter中进行依赖排除配置，因为spring-boot-starter中默认集成了log4j，两者会有冲突。

	<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>

第二步：进行日志的配置：

<?xml version="1.0" encoding="UTF-8"?>
<Configuration monitorInterval="180" packages="">
    <properties>
    	<property name="prjname">${project.name}</property>
        <property name="logdir">logs</property>
        <property name="PATTERN"> %date{YYYY-MM-dd HH:mm:ss,SSS} %level [%thread][%file:%line] - %msg%n%throwable</property>
    </properties>
    <Appenders>
        <Console name="Console" target="SYSTEM_OUT">
            <PatternLayout pattern="${PATTERN}"/>
        </Console>

        <RollingFile name="ErrorAppender" fileName="${logdir}/${prjname}_error.log"
            filePattern="${logdir}/$${date:yyyy-MM-dd}/${prjname}_error.%d{yyyy-MM-dd-HH}.log" append="true">
            <PatternLayout pattern="${PATTERN}"/>
            <ThresholdFilter level="ERROR" onMatch="ACCEPT" onMismatch="DENY"/>
            <Policies>
                <TimeBasedTriggeringPolicy interval="1" modulate="true" />
            </Policies>
        </RollingFile>

        <RollingFile name="DebugAppender" fileName="${logdir}/${prjname}_info.log"
            filePattern="${logdir}/$${date:yyyy-MM-dd}/${prjname}_info.%d{yyyy-MM-dd-HH}.log" append="true">
            <PatternLayout pattern="${PATTERN}"/>
            <ThresholdFilter level="DEBUG" onMatch="ACCEPT" onMismatch="DENY"/>
            <Policies>
                <TimeBasedTriggeringPolicy interval="1" modulate="true" />
            </Policies>
        </RollingFile>
        
        <!--异步appender-->
         <Async name="AsyncAppender" includeLocation="true">
            <AppenderRef ref="ErrorAppender"/>
            <AppenderRef ref="DebugAppender"/>
        </Async>
    </Appenders>
    
    <Loggers>
        <logger name="org.springframework" level="INFO">
        </logger>
        <logger name="org.mybatis" level="INFO">
        </logger>
        <logger name="springfox" level="INFO">
        </logger>
		<logger name="org.apache.http" level="INFO">
        </logger>
        <logger name="com.netflix.discovery" level="INFO">
        </logger>

        <Root level="INFO" includeLocation="true">
            <AppenderRef ref="AsyncAppender"/>
            <AppenderRef ref="Console"/>
        </Root>
    </Loggers>
</Configuration>

第三步：在application.yml配置日志：

logging: 
  config: classpath:log4j2-dev.xml

第四步：在代码中使用：

	private static final org.slf4j.Logger log = org.slf4j.LoggerFactory.getLogger(DiscoveryServer.class);

关于日志配置文件的详细解释，可以参考此文章：
https://www.cnblogs.com/keeya/p/10101547.html