How to log stdout output in Tomcat?

Question

Is there a way to log all stdout output to the catalina.log file in Tomcat? (i.e. everything that gets printed to System.out.println())

The console window that opens when you run TOMCAT/bin/startup.bat displays output from stdout, but it's not saved to TOMCAT/logs/catalina.<date>.log.

My specific problem is that I have a console appender defined in log4j to output to the console. These log messages appear correctly in the Tomcat console window, but they are not written to catalina.log. I'm running Tomcat 5.5 on Windows. Thanks.

EDIT:

Here is my log4j.properties file. It is located at TOMCAT/webapps/app/WEB-INF/classes/log4j.properties:

log4j.rootCategory=DEBUG, console
log4j.appender.console=org.apache.log4j.ConsoleAppender
log4j.appender.console.layout=org.apache.log4j.PatternLayout
log4j.appender.console.layout.ConversionPattern=[%d{ABSOLUTE} %-5p %c{1}]: %m%n

Answer 1

I've come across similar questions before, and haven't found a way to do this by logging System.out in Windows unless you are running Tomcat as a Windows service. This seems to work by default in Unix since startup.sh points to catalina.sh which logs stdout to the catalina.out file like below

org.apache.catalina.startup.Bootstrap "$@" start >> "$CATALINA_BASE"/logs/catalina.out 2>&1 &

In log4j, ConsoleAppender by itself does not append to a File, only to System.out

However, I've modified your log4j properties to add a FileAppender and this config works, but of course this logs into a separate log file.

New config

# Set root logger level to DEBUG.
log4j.rootLogger=DEBUG, console, myFile

log4j.appender.console=org.apache.log4j.ConsoleAppender
log4j.appender.console.layout=org.apache.log4j.PatternLayout
log4j.appender.console.layout.ConversionPattern=[%d{ABSOLUTE} %-5p %c{1}]: %m%n




# myFile writes to file
log4j.appender.myFile=org.apache.log4j.RollingFileAppender
log4j.appender.myFile.File=logs/tomcatlog4j.log
log4j.appender.myFile.MaxFileSize=100KB
log4j.appender.myFile.layout=org.apache.log4j.PatternLayout
log4j.appender.myFile.layout.ConversionPattern==[%d{ABSOLUTE} %-5p %c{1}]: %m%n

Output

=[15:24:03,819 INFO A1]: In my.jsp =[15:24:03,975 INFO A1]: Out of my.jsp =[15:24:04,880 INFO A1]: In my.jsp =[15:24:04,880 INFO A1]: Out of my.jsp

also see

How to log exceptions from a specific package deployed in tomcat

log select events into a separate file

https://serverfault.com/questions/201178/tomcat-5-5-how-to-redirect-the-logging-output-to-one-file-per-web-application

Answer 2

Did you checked, whether the log4j.properties file can be found from your application? Maybe you can check, by setting a hardcoded file path like

-Dlog4j.configuration=file:///C:\Dev\log4j.properties

If the logs are written after these change, the relativ path to the log4j file is wrong.