在 log4j2 中按类名过滤

Question

I am using log4j2 and I don't know how I can filter by class name. I have tried with RegexFilter but it only filters the text message. In old log4j was enough with tag 'filter'

<filter class="aaaa.bbbb.cccc.ClassName">

Somebody knows how to do now?

Thank you in advance!

Update:

Ok, I did it! I need to define a logger and set the class name in attribute 'name':

<loggers>
    <logger name="aaaa.bbbb.cccc.ClassName" additivity="false" level="info">
        <appender-ref ref="RollingFile" />
    </logger>
    <root level="error">
        <appender-ref ref="RollingFile" />
    </root>
</loggers>

Answer 1

This works automatically in Log4j if you follow the naming convention for loggers. In your code, declare loggers with their class name:

Logger logger = LogManager.getLogger(MyClass.class);

The logger is automatically assigned the name fully.qualified.class.name.of.MyClass . Now, in your configuration you can use this fully qualified name (or the package name or the first part of the package ) to do filtering and routing .

---

Filtering

The below example shows how to filter log events based on the package of the class doing the logging: all DEBUG and TRACE level log events by classes in package com.other.company will be ignored, and for classes in package com.another.project only ERROR and FATAL logging will be included.

<Configuration status="warn">
  <Appenders>
    <File name="MyFile" fileName="logs/my.log">
      <PatternLayout pattern="%d %p %c{1.} [%t] %m%n" />
    </File>
  </Appenders>
  <Loggers>

    <!-- drops all DEBUG and TRACE logging done by any class in this package -->
    <Logger name="com.other.company" level="INFO" />

    <!-- log only ERROR and FATAL logging by classes in this package -->
    <Logger name="com.another.project" level="ERROR" />

    <!-- by default, all log events are written to MyFile -->
    <Root level="trace">
      <AppenderRef ref="MyFile"/>
    </Root>
  </Loggers>
</Configuration>

---

Routing

The below example shows how to route log events to separate log files based on the package of the class doing the logging: all logging by classes in package com.other.company will not be written to my.log by only to other.log .

<Configuration status="warn">
  <Appenders>
    <File name="MyFile" fileName="logs/my.log">
      <PatternLayout pattern="%d %p %c{1.} [%t] %m%n" />
    </File>
    <File name="OtherFile" fileName="logs/other.log">
      <PatternLayout pattern="%d %p %c{1.} [%t] %m%n" />
    </File>
  </Appenders>
  <Loggers>
    <!-- all logging from this package and subpackages goes to OtherFile -->
    <!-- Note: set additivity=false or logging will also go to the root logger -->
    <Logger name="com.other.company" additivity="false">
      <AppenderRef ref="OtherFile"/>
    </Logger>
    <Root level="trace">
      <AppenderRef ref="MyFile"/>
    </Root>
  </Loggers>
</Configuration>