Log4j2 - 闘うITエンジニアの覚え書き

https://logging.apache.org/log4j/2.x/maven-artifacts.html

Gradleの場合の例 †

dependencies {
  compile group: 'org.apache.logging.log4j', name: 'log4j-api', version: '2.11.0'
  compile group: 'org.apache.logging.log4j', name: 'log4j-core', version: '2.11.0'
}

classpatnが通っているディレクトリに log4j2.xml または log4j2.json を配置する。

log4j2.xml

<?xml version="1.0" encoding="UTF-8"?>
<Configuration>
  <Appenders>
    <Console name="Console" target="SYSTEM_OUT">
      <PatternLayout pattern="%d{DEFAULT_MICROS} %-5level %c{1}.%M %msg%n"/>
    </Console>
  </Appenders>
  <Loggers>
    <Root level="debug">
      <AppenderRef ref="Console"/>
    </Root>
  </Loggers>
</Configuration>

https://logging.apache.org/log4j/2.x/manual/layouts.html#PatternLayout

https://logging.apache.org/log4j/2.x/manual/configuration.html

package net.magata;

import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.LogManager;
 
public class Example {

  // Loggerの取り方が jog4j 1系と違うので注意
  static final Logger logger = LogManager.getLogger(Example.class.getName());
 
  public static void main(String[] args){
        logger.info("START");

        logger.trace("Trace Message");
        logger.debug("Debug Message");
        logger.info("Info Message");
        logger.warn("Warn Message");
        logger.error("Error Message");
        logger.fatal("Fatal Message");

        logger.info("END");
  }
}

結果 †

2018-04-16 21:41:50,235000 INFO  Example.main START
2018-04-16 21:41:50,238000 DEBUG Example.main Debug Message
2018-04-16 21:41:50,239000 INFO  Example.main Info Message
2018-04-16 21:41:50,239000 WARN  Example.main Warn Message
2018-04-16 21:41:50,239000 ERROR Example.main Error Message
2018-04-16 21:41:50,244000 FATAL Example.main Fatal Message
2018-04-16 21:41:50,244000 INFO  Example.main END