What is the difference between log4j. rootLogger and log4j. rootCategory in log4j. properties?

Address: http://blog.csdn.net/caolaosanahnu/article/details/7553999

The following is written in the official log4j API, which is sufficient to explain the difference between logger and category:

public class Category
   
   

    
    

      extends java.lang.Object 
    
    
    

      implements AppenderAttachable 
    
   
   

This class has been deprecated and replaced byLoggerSubclass. It will be kept around to preserve backward compatibility until mid 2003.

LoggerIs a subclass of Category, I. e. it extends Category. In other words, a loggerIsA category. thus, all operations that can be performed med on a category can be performed med on a logger. internally, whenever log4j is asked to produce a Category object, it will instead produce a Logger object. log4j 1.2 willNeverProduce Category objects but onlyLoggerInstances. In order to preserve backward compatibility, methods that previusly accepted category objects still continue to accept category objects.

For example, the following are all legal and will work as expected.

       // Deprecated form:       Category cat = Category.getInstance("foo.bar")       // Preferred form for retrieving loggers:       Logger logger = Logger.getLogger("foo.bar")   

The first form is deprecated and shoshould be avoided.

There is absolutely no need for new client code to use or refer toCategoryClass.Whenever possible, please avoid referring to it or using it.

See the short manual for an introduction on this class.

See the document entitled preparing for log4j 1.3 for a more detailed discussion.

Author:

Ceki gülc U, Anders Kristensen

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