How to add uuid to log4j for logging into file?

问题

I have this log4j2.xml file:

<?xml version="1.0" encoding="UTF-8"?>
<Configuration xmlns="http://logging.apache.org/log4j/2.0/config">
<Appenders>
    <File name="FILE" fileName="logfile.log" append="true">
        <PatternLayout pattern="%p | [%t] %l | message : %m%n"/>
    </File>
    <Console name="STDOUT" target="SYSTEM_OUT">
        <PatternLayout pattern="%p | [%t] %l | message : %m%n"/>
    </Console>
</Appenders>
</Configuration>

And my goal is to add in the RestEndpoint a unique id with uuid, but i dont know how to add to the xml file...or i have to configure it not in an xml file?

回答1:

In your application, put the uuid in the ThreadContext:

ThreadContext.put("myUuid", new UUID());

I assume you know where the entry points in your application are where to put and remove these.

In configuration, extract the UUID from the ThreadContext with the %X pattern converter: (also added Loggers to your configuration)

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="warn">
<Appenders>
    <File name="FILE" fileName="logfile.log" append="true">
        <PatternLayout pattern="%p | [%t] %l | id: %X{myUuid} | message : %m%n"/>
    </File>
    <Console name="STDOUT" target="SYSTEM_OUT">
        <PatternLayout pattern="%p | [%t] %l | id: %X{myUuid} | message : %m%n"/>
    </Console>
</Appenders>

<Loggers>
  <Root level ="trace">
    <AppenderRef ref="STDOUT" />
    <AppenderRef ref="FILE" />
  </Root>
</Loggers>
</Configuration>

回答2:

Feel like there is another solution, which is easier, if what you need is just a unique id for each log record. Check UUID in Log4j doc
The only update is to change the layout in xml file is to add %u{"RANDOM"}.

sample xml configuration

<PatternLayout>
    <pattern>%d{DATE} [%p] UUID:%u{"RANDOM"} (%t) %c: %m%n</pattern>
</PatternLayout>

来源：https://stackoverflow.com/questions/43999342/how-to-add-uuid-to-log4j-for-logging-into-file