I'd like a very simple XML configuration file with a console and a file appender using log4j2.
(The Apache Website is killing me with much Information.)
24 Answers
<?xml version="1.0" encoding="UTF-8"?> <Configuration status="INFO"> <Appenders> <Console name="Console" target="SYSTEM_OUT"> <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n" /> </Console> <File name="MyFile" fileName="all.log" immediateFlush="false" append="false"> <PatternLayout pattern="%d{yyy-MM-dd HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/> </File> </Appenders> <Loggers> <Root level="debug"> <AppenderRef ref="Console" /> <AppenderRef ref="MyFile"/> </Root> </Loggers> </Configuration> Notes:
- Put the following content in your configuration file.
- Name the configuration file log4j2.xml
- Put the log4j2.xml in a folder which is in the class-path (i.e. your source folder "src")
- Use
Logger logger = LogManager.getLogger();to initialize your logger - I did set the immediateFlush="false" since this is better for SSD lifetime. If you need the log right away in your log-file remove the parameter or set it to true
Here is my simplistic log4j2.xml that prints to console and writes to a daily rolling file:
// java private static final Logger LOGGER = LogManager.getLogger(MyClass.class); // log4j2.xml <?xml version="1.0" encoding="UTF-8"?> <Configuration status="WARN"> <Properties> <Property name="logPath">target/cucumber-logs</Property> <Property name="rollingFileName">cucumber</Property> </Properties> <Appenders> <Console name="console" target="SYSTEM_OUT"> <PatternLayout pattern="[%highlight{%-5level}] %d{DEFAULT} %c{1}.%M() - %msg%n%throwable{short.lineNumber}" /> </Console> <RollingFile name="rollingFile" fileName="${logPath}/${rollingFileName}.log" filePattern="${logPath}/${rollingFileName}_%d{yyyy-MM-dd}.log"> <PatternLayout pattern="[%highlight{%-5level}] %d{DEFAULT} %c{1}.%M() - %msg%n%throwable{short.lineNumber}" /> <Policies> <!-- Causes a rollover if the log file is older than the current JVM's start time --> <OnStartupTriggeringPolicy /> <!-- Causes a rollover once the date/time pattern no longer applies to the active file --> <TimeBasedTriggeringPolicy interval="1" modulate="true" /> </Policies> </RollingFile> </Appenders> <Loggers> <Root level="DEBUG" additivity="false"> <AppenderRef ref="console" /> <AppenderRef ref="rollingFile" /> </Root> </Loggers> </Configuration> TimeBasedTriggeringPolicy
interval (integer) - How often a rollover should occur based on the most specific time unit in the date pattern. For example, with a date pattern with hours as the most specific item and and increment of 4 rollovers would occur every 4 hours. The default value is 1.
modulate (boolean) - Indicates whether the interval should be adjusted to cause the next rollover to occur on the interval boundary. For example, if the item is hours, the current hour is 3 am and the interval is 4 then the first rollover will occur at 4 am and then next ones will occur at 8 am, noon, 4pm, etc.
Output:
[INFO ] 2018-07-21 12:03:47,412 ScenarioHook.beforeScenario() - Browser=CHROME32_NOHEAD [INFO ] 2018-07-21 12:03:48,623 ScenarioHook.beforeScenario() - Screen Resolution (WxH)=1366x768 [DEBUG] 2018-07-21 12:03:52,125 HomePageNavigationSteps.I_Am_At_The_Home_Page() - Base URL= [DEBUG] 2018-07-21 12:03:52,700 NetIncomeProjectorSteps.I_Enter_My_Start_Balance() - Start Balance=348000 A new log file will be created daily with previous day automatically renamed to:
cucumber_yyyy-MM-dd.log
In a Maven project, you would put the log4j2.xml in src/main/resources or src/test/resources.
log4j2 has a very flexible configuration system (which IMHO is more a distraction than a help), you can even use JSON. See for a reference.
Personally, I just recently started using log4j2, but I'm tending toward the "strict XML" configuration (that is, using attributes instead of element names), which can be schema-validated.
Here is my simple example using autoconfiguration and strict mode, using a "Property" for setting the filename:
<?xml version="1.0" encoding="UTF-8"?> <Configuration monitorinterval="30" status="info" strict="true"> <Properties> <Property name="filename">log/CelsiusConverter.log</Property> </Properties> <Appenders> <Appender type="Console" name="Console"> <Layout type="PatternLayout" pattern="%d %p [%t] %m%n" /> </Appender> <Appender type="Console" name="FLOW"> <Layout type="PatternLayout" pattern="%C{1}.%M %m %ex%n" /> </Appender> <Appender type="File" name="File" fileName="${filename}"> <Layout type="PatternLayout" pattern="%d %p %C{1.} [%t] %m%n" /> </Appender> </Appenders> <Loggers> <Root level="debug"> <AppenderRef ref="File" /> <AppenderRef ref="Console" /> <!-- Use FLOW to trace down exact method sending the msg --> <!-- <AppenderRef ref="FLOW" /> --> </Root> </Loggers> </Configuration> There are excellent answers, but if you want to color your console logs you can use the pattern :
<PatternLayout pattern="%style{%date{DEFAULT}}{yellow} [%t] %highlight{%-5level}{FATAL=bg_red, ERROR=red, WARN=yellow, INFO=green} %logger{36} - %message\n"/> The full log4j2 file is:
<?xml version="1.0" encoding="UTF-8"?> <Configuration status="WARN"> <Properties> <Property name="APP_LOG_ROOT">/opt/test/log</Property> </Properties> <Appenders> <Console name="ConsoleAppender" target="SYSTEM_OUT"> <PatternLayout pattern="%style{%date{DEFAULT}}{yellow} [%t] %highlight{%-5level}{FATAL=bg_red, ERROR=red, WARN=yellow, INFO=green} %logger{36} - %message\n"/> </Console> <RollingFile name="XML_ROLLING_FILE_APPENDER" fileName="${APP_LOG_ROOT}/appName.log" filePattern="${APP_LOG_ROOT}/appName-%d{yyyy-MM-dd}-%i.log.gz"> <PatternLayout pattern="%d{DEFAULT} [%t] %-5level %logger{36} - %msg%n"/> <Policies> <SizeBasedTriggeringPolicy size="19500KB"/> </Policies> </RollingFile> </Appenders> <Loggers> <Root level="error"> <AppenderRef ref="ConsoleAppender"/> </Root> <Logger name="com.compName.projectName" level="debug"> <AppenderRef ref="XML_ROLLING_FILE_APPENDER"/> </Logger> </Loggers> </Configuration> And the logs will look like this: 
