The reason you are getting all that spam is because Log4J is set globally to DEBUG level. What you need to do is find out how log4j is configured (depends on the context, but there may be an initialisation servlet defined in web.xml).
Then, you need to set the default appender (look for root) to INFO level.
If you need DEBUG level logging for your classes, you can set loggers that are specific to your classes (i.e. excluding the Digester packages).