AppEngine-Log4j和日志级别

Question

I want to use Log4j for my logging on AppEngine. I configured the logger like this:

.level = INFO
log4j.rootLogger=DEBUG, stdout 
log4j.appender.stdout=org.apache.log4j.ConsoleAppender 
log4j.appender.stdout.Target=System.out 
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout 
log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %t %c{1}:%M:%L - %m%n 

But the logger then logs everything to INFO and the real log level is just shown inline like this: (Log level error)

Is there a way to get the real log levels to work with log4j so that filtering on log levels works on the appengine UI?

Edit: More detailed example:

So I log an error like this:

import org.apache.log4j.Logger;
private static Logger logger = Logger.getLogger(PingServlet.class);

logger.error("Database was successfully pinged.");

And on the Appengine-UI, it shows up as an INFO (the green I). Only the loggin text indicates the correct log level:

Answer 1

The GAE Java documentation states that everything you write to stdout is logged as INFO and to stderr is WARNING [1]. Your root logger is writing everything to stdout.

I'm not a log4j expert, so I don't know of a way for a logger to write to both stdout and stderr. One workaround is to use two loggers, one for INFO and another one for WARNING.

[1] https://cloud.google.com/appengine/docs/java/requests#Java_Logging