How would I robustly log binary or XML using slf4j/log4j/java.util.logging?

Question

After doing logging for many years I have now reached a point where I need to be able to postprocess the log files with the long term goal of using the log files as a "transport medium" allowing me to persist objects et. al. so I can replay the backend requests. In order to do so I need to persist objects into a loggable form.

The recommended way to do this by Sun, is to use java.beans.XMLEncoder to create an XML snippet which is quite agreeable with me, but the problem is that it is sent to an UTF-8 encoded OutputStream including an UTF-8 header, and OutputStreams are byte oriented. Log files are character oriented (strings) and logfiles are typically encoded in the default encoding for that platform. Our XML may include any Unicode character.

I need a robust way of handling this, with preferation to an approach which generates humanly readable files.

I have thought about converting the XML OuptutStream to a String, removing the unusable header, and flattening to ASCII (with any non-ASCII character encoded as a numeric entity). I have also thought about using XML transformations but I have a gut feeling that this will require more resources than I want a logger to do.

Suggestions?

Answer 1

More a hint than a real answer: maybe have a look at this thread on the logback-dev mailing list and especially the messages from Joern Huxhorn (which is the author of Lilith). More generally, I think that you should look at logback, the "successor" of log4j from the same author, Ceki Gülcü. This is where things happen in my opinion.