How to set different logging levels for console-writing and file-writing in java

Question

I'm working on a spring boot application. I need WARN and above level logs to be written in file whereas INFO and above to be displayed in the console. How can I configure this in the application.properties file?

If logback.xml is necessary for this(or similar file for log4j), can you help me configure this using either of them??

Answer 1

Here is a sample logback.xml for writing each level log to a unique file and all above INFO to console.

I guess things are self explanatory. If you don't think so, you my friend should spend some time with the official documentation.

Hope it helps. Cheers.

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

    <property name="DEV_HOME" value="logs" />

    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
        <layout class="ch.qos.logback.classic.PatternLayout">
            <Pattern>
                %d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg%n
            </Pattern>
        </layout>
    </appender>



    <appender name="FILE-ERROR"
              class="ch.qos.logback.core.rolling.RollingFileAppender">
        <file>${DEV_HOME}/error.log</file>
        <filter class="ch.qos.logback.classic.filter.LevelFilter">
            <level>ERROR</level>
            <onMatch>ACCEPT</onMatch>
            <onMismatch>DENY</onMismatch>
        </filter>
        <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
            <Pattern>
                %d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg%n
            </Pattern>
        </encoder>

        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <!-- rollover daily -->
            <fileNamePattern>${DEV_HOME}/archived/error.%d{yyyy-MM-dd}.%i.log
            </fileNamePattern>
            <timeBasedFileNamingAndTriggeringPolicy
                    class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
                <maxFileSize>10MB</maxFileSize>
            </timeBasedFileNamingAndTriggeringPolicy>
        </rollingPolicy>

    </appender>



    <appender name="FILE-INFO"
              class="ch.qos.logback.core.rolling.RollingFileAppender">
        <file>${DEV_HOME}/info.log</file>
        <filter class="ch.qos.logback.classic.filter.LevelFilter">
            <level>INFO</level>
            <onMatch>ACCEPT</onMatch>
            <onMismatch>DENY</onMismatch>
        </filter>
        <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
            <Pattern>
                %d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg%n
            </Pattern>
        </encoder>

        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <!-- rollover daily -->
            <fileNamePattern>${DEV_HOME}/archived/info.%d{yyyy-MM-dd}.%i.log
            </fileNamePattern>
            <timeBasedFileNamingAndTriggeringPolicy
                    class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
                <maxFileSize>10MB</maxFileSize>
            </timeBasedFileNamingAndTriggeringPolicy>
        </rollingPolicy>

    </appender>



    <appender name="FILE-FATAL"
              class="ch.qos.logback.core.rolling.RollingFileAppender">
        <file>${DEV_HOME}/fatal.log</file>
        <filter class="ch.qos.logback.classic.filter.LevelFilter">
            <level>FATAL</level>
            <onMatch>ACCEPT</onMatch>
            <onMismatch>DENY</onMismatch>
        </filter>
        <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
            <Pattern>
                %d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg%n
            </Pattern>
        </encoder>

        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <!-- rollover daily -->
            <fileNamePattern>${DEV_HOME}/archived/fatal.%d{yyyy-MM-dd}.%i.log
            </fileNamePattern>
            <timeBasedFileNamingAndTriggeringPolicy
                    class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
                <maxFileSize>10MB</maxFileSize>
            </timeBasedFileNamingAndTriggeringPolicy>
        </rollingPolicy>

    </appender>


    <appender name="FILE-WARN"
              class="ch.qos.logback.core.rolling.RollingFileAppender">
        <file>${DEV_HOME}/warn.log</file>
        <filter class="ch.qos.logback.classic.filter.LevelFilter">
            <level>WARN</level>
            <onMatch>ACCEPT</onMatch>
            <onMismatch>DENY</onMismatch>
        </filter>
        <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
            <Pattern>
                %d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg%n
            </Pattern>
        </encoder>

        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <!-- rollover daily -->
            <fileNamePattern>${DEV_HOME}/archived/warn.%d{yyyy-MM-dd}.%i.log
            </fileNamePattern>
            <timeBasedFileNamingAndTriggeringPolicy
                    class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
                <maxFileSize>10MB</maxFileSize>
            </timeBasedFileNamingAndTriggeringPolicy>
        </rollingPolicy>

    </appender>


    <!-- Send logs to both console and file audit -->

    <logger name="com.vaidiksanatansewa.guruji" level="fatal"
            additivity="false">

        <appender-ref ref="FILE-FATAL" />
    </logger>


    <logger name="com.vaidiksanatansewa.guruji" level="error"
            additivity="false">

        <appender-ref ref="FILE-ERROR" />
    </logger>


    <logger name="com.vaidiksanatansewa.guruji" level="warn"
            additivity="false">

        <appender-ref ref="FILE-WARN" />
    </logger>


    <logger name="com.vaidiksanatansewa.guruji" level="info"
            additivity="false">

        <appender-ref ref="FILE-INFO" />
    </logger>

    <root level="INFO">
        <appender-ref ref="STDOUT" />
    </root>




</configuration>