Can't generate the log file with slf4j? - maven

Question

I have a standard maven project and my maven settings:
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.25</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-simple</artifactId>
<version>1.6.4</version>
</dependency>
Under my "resources" directory, I have the two files:
1. boot.properties:
logging.config=classpath:log4j2.xml
log4j2.xml
log
info
error
<Appenders>
<Console name="CONSOLE" target="SYSTEM_OUT">
<ThresholdFilter level="INFO" onMatch="ACCEPT" onMismatch="DENY"/>
<PatternLayout pattern="%d{yyyy-MM-dd 'at' HH:mm:ss.SSS} [%t] %-5level %class{36} [%L] [%M] - %msg%xEx%n" />
</Console>
<RollingRandomAccessFile name="INFO-LOG" fileName="${LOG_HOME}/${INFO_FILE_NAME}.log" filePattern="${LOG_HOME}/${INFO_FILE_NAME}_%d{yyyy-MM-dd}_%i.log">
<ThresholdFilter level="INFO" onMatch="ACCEPT" onMismatch="DENY"/>
<PatternLayout pattern="%d{yyyy-MM-dd 'at' HH:mm:ss.SSS} [%t] %-5level %class{36} [%L] [%M] - %msg%xEx%n" />
<Policies>
<TimeBasedTriggeringPolicy modulate="true" interval="1" />
<SizeBasedTriggeringPolicy size="512000 KB" />
</Policies>
<DefaultRolloverStrategy max="20" />
</RollingRandomAccessFile>
<RollingRandomAccessFile name="ERROR-LOG" fileName="${LOG_HOME}/${ERROR_FILE_NAME}.log" filePattern="${LOG_HOME}/${ERROR_FILE_NAME}_%d{yyyy-MM-dd}_%i.log">
<ThresholdFilter level="ERROR" onMatch="ACCEPT" onMismatch="DENY"/>
<PatternLayout pattern="%d{yyyy-MM-dd 'at' HH:mm:ss.SSS} [%t] %-5level %class{36} [%L] [%M] - %msg%xEx%n" />
<Policies>
<TimeBasedTriggeringPolicy modulate="true" interval="1" />
<SizeBasedTriggeringPolicy size="512000 KB" />
</Policies>
<DefaultRolloverStrategy max="20" />
</RollingRandomAccessFile>
</Appenders>
<Loggers>
<Root level="INFO" includeLocation="true">
<appender-ref ref="CONSOLE" />
<appender-ref ref="INFO-LOG" />
<appender-ref ref="ERROR-LOG" />
</Root>
</Loggers>
My problem is that, when I run my application, I didn't see the "log" directory and log files generated in the root directory.

Answer 1

Slf4J doesn't provide any actual logging implementation.
It looks like you need an slf4j binding for log4j2. slf4j-simple can't read log4j2.xml
From this tutorial start off with the following dependencies
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-api</artifactId>
<version>2.7</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.7</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-slf4j-impl</artifactId>
<version>2.7</version>
</dependency>

Answer 2

I think problem is due to access privilege in root folder.
Logger is not able to create a log folder in root directory.
You can check it yourself by trying to create a directory in root folder.
You can users path instead of root directory in log4j2.xml.