java日志框架 (四) 日志相关

1. 输出等级

This rule is at the heart of logback. It assumes that levels are ordered as follows: 

TRACE < DEBUG < INFO <  WARN < ERROR.

In a more graphic way, here is how the selection rule works. In the following table, the vertical header shows the level of the logging request, designated by p, while the horizontal header shows effective level of the logger, designated by q. The intersection of the rows (level request) and columns (effective level) is the boolean resulting from the basic selection rule.

level of  request p	effective level q
	TRACE	DEBUG	INFO	WARN	ERROR	OFF
TRACE	YES	NO	NO	NO	NO	NO
DEBUG	YES	YES	NO	NO	NO	NO
INFO	YES	YES	YES	NO	NO	NO
WARN	YES	YES	YES	YES	NO	NO
ERROR	YES	YES	YES	YES	YES	NO