Logging with specific label in log file for every user

Question

I have web application in Java (JSP + Servlets) and logging with log4j 1.2.17. When user login on site he take ID. I wanna see all his actions in log file with ID prefix like this:

01.05.2015 11:12:30 INFO [Roy] - login correct

But i don't want to pass ID in every calling method to logging events in that method. I want to save ID somewhere and take it when need.

Answer 1

What you probably want is a Mapped Diagnostic Context . This effectively gives you a stack of ThreadLocal to put data elements into that you can log later.

In java...

MDC.put('LOGIN_ID', 'Roy');

In your log pattern:

"%d %p [%X{LOGIN_ID}] %m