问题:

I'm using java.util.logging for logging and tracing purposes. How can I within a Java application dynamically set the file to which the log should be written.

回答1:

The java.util.logging.FileHandler might do its job for you. The following code snippet shows a simple example how to do set the logging destination programmatically:

    Logger logger = Logger.getLogger("my.logger.name");
    try {
        FileHandler handler = new FileHandler("application.log", true);
        logger.addHandler(handler);
    } catch (IOException e) {
        throw new IllegalStateException("Could not add file handler.", e);
    }
    logger.info("Hello Logger!");

回答2:

Are you talking about JULog?

If so, the answer is "you can't". In order to change what file you're logging to (or change anything else in configuration) you need to know what underlying logging implementation you are using and the whole point of using JULog (quite arguable, btw, unless you're developing a library) is to not have ANY ties to logging implementations.

If selecting a file at runtime is a requirement you're likely going to be better off going with a concrete implementation like Log4j.