导入依赖

<dependency>
    <groupId>log4j</groupId>
    <artifactId>log4j</artifactId>
    <version>1.2.17</version>
</dependency>

<!--log4j2-->
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.17.2</version>
</dependency>
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-api</artifactId>
    <version>2.17.2</version>
</dependency>

！！！注意，屏蔽内部日志部分必须添加上，因为其自带的是logback的依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
    <exclusions>
        <!--屏蔽内置日志-->
        <exclusion>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-logging</artifactId>
        </exclusion>
    </exclusions>
</dependency>

添加配置文件

<?xml version="1.0" encoding="UTF-8"?>

<Configuration status="WARN">
    <Properties>
        <Property name="patternLayout">%date{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</Property>
        <!--生成日志保存位置-->
        <Property name="logdir">D:/home/demo</Property>
    </Properties>

    <Appenders>
        <Console name="Console" target="SYSTEM_OUT">
            <PatternLayout pattern="${patternLayout}"/>

<!--            <ThresholdFilter level="INFO" onMatch="ACCEPT" onMismatch="DENY"/>-->
            <!--控制台将会打印执行sql及结果-->
            <!--<ThresholdFilter level="TRACE"/>-->
            <ThresholdFilter level="DEBUG"/>
        </Console>

        <RollingFile name="InfoLogger"
                     fileName="D:/home/demo/debug/log.log"
                     filePattern="D:/home/demo/debug/log_%d{yyyy-MM-dd}.log" append="true">
            <PatternLayout pattern="${patternLayout}"/>
            <ThresholdFilter level="INFO" onMatch="ACCEPT" onMismatch="DENY"/>
            <Policies>
                <!--根据时间来滚动 -->
                <TimeBasedTriggeringPolicy modulate="true" interval="1"/>
            </Policies>
            <!-- 日志保留策略，配置只保留七天 -->
            <DefaultRolloverStrategy>
                <Delete basePath="${logDir}/debug/" maxDepth="1">
                    <IfFileName glob="log_*.log"/>
                    <IfLastModified age="7d"/>
                </Delete>
            </DefaultRolloverStrategy>
        </RollingFile>

        <!-- sql：保存sql相关日志 -->
        <RollingFile name="sql"
                     fileName="${logdir}/sql/sql.log"
                     filePattern="${logdir}/sql/sql_%d{yyyy-MM-dd}.log" append="true">
            <PatternLayout pattern="${patternLayout}"/>
            <Policies>
                <TimeBasedTriggeringPolicy modulate="true" interval="1"/>
            </Policies>
            <DefaultRolloverStrategy>
                <Delete basePath="${logDir}/sql/" maxDepth="1">
                    <IfFileName glob="sql_*.log"/>
                    <IfLastModified age="7d"/>
                </Delete>
            </DefaultRolloverStrategy>
        </RollingFile>

    </Appenders>

    <Loggers>
        <!-- 开启mybatis的sql日志, name和mybatis-config.xml的logPrefix一致 . 级别为debug或trace-->

        <Logger name="com.example.demo.mybatis.plus.dao" level="TRACE" additivity="false">
            <AppenderRef ref="Console"/>
            <AppenderRef ref="sql"/>
        </Logger>

        <Root level="debug">
            <AppenderRef ref="Console"/>
            <AppenderRef ref="InfoLogger"/>
        </Root>

    </Loggers>

</Configuration>

配置文件名字及位置如下图: log4j2.xml

application.yml配置文件

# 日志配置
logging:
  config: classpath:log4j2.xml
  level:
  	# 查询接口路径
    com.example.demo.mybatis.plus.dao: DEBUG

常见问题及解决

① 常见问题
问题原因是没有排除spring-boot中自带的日志。

11:34:08.938 [Thread-1] DEBUG org.springframework.boot.devtools.restart.classloader.RestartClassLoader - Created RestartClassLoader org.springframework.boot.devtools.restart.classloader.RestartClassLoader@21253577
Logging system failed to initialize using configuration from 'classpath:log4j2.xml'
java.lang.IllegalStateException: Logback configuration error detected: 
ERROR in ch.qos.logback.core.joran.spi.Interpreter@4:17 - no applicable action for [Properties], current ElementPath  is [[Configuration][Properties]]

② 解决方案
依赖中添加org.springframework.boot，屏蔽内置日志。