What is right way to supply initialization for log4j2 in a Spring MVC Webapp using Java Config and no web.xml?

Question

I have a Spring MVC Web App (4.0) with log4j2. This webapp uses no web.xml and takes care of configuration through Java Config. Log4j2 configuration needs to take plac

Answer 1

I believe you can reconfigure log4j2 to a new config file during runtime like this.

     LoggerContext context = (LoggerContext)LogManager.getContext(false);
     context.setConfigLocation(URI.create("path to file"));
     context.reconfigure();

Could just add this to your onStartup.

Answer 2

I haven’t tested it but the following should be worth a try; replace your servletContext.setAttribute(…) call in the onStartup(…) method with the following Log4jConfigurer call:

Log4jConfigurer.initLogging("file:///path/to/log4j2.xml")

This is basically what happens under the hood when you use log4jConfigLocation in the <context-param> of a web.xml file (via Log4jWebConfigurer, see code).

I’m only wondering if this will also work with log4j2, although I wouldn’t expect the <context-param> way to work with it either. Did you also use log4j2 when you were still using the web.xml file?

Answer 3

Probably this is a little too late, but you can do the following to set the log4j2 configuration to an external path:

public class ApplicationInitializer implements WebApplicationInitializer {
    @Override
    public void onStartup(ServletContext servletContext)
        throws ServletException {
        servletContext.setInitParameter(Log4jWebSupport.LOG4J_CONFIG_LOCATION, "file:///path/to/log4j2.xml");