Using a category hierarchy, it is possible to control which log statements are output at arbitrary granularity, thus reducing the volume of logged output and minimizing the cost of logging.

• 通过使用类别层次结构,它可以控制以任意间隔输出哪些日志语句,这样就减少了日志记录输出量,并将日志记录的开销降到最低。