基本結構 目前（1.7），logback有3個模塊logback-core, logback-classic 和 logback-access.  logback-core是另外兩個模塊的基礎。logback-classic扩展了核心模塊，经典模块對log4j進行類显著改进並自身實現類slf4j-api。称为访问的第三个模块，集成了Servlet容器以提供HTTP访问日志功能。
Logger 确保所有的日誌記錄最终会有继承层次,root logger总是有一个指定的級別。默认情况下,这个级别是debug。任何logger都會繼承root logger。
Example 1 Logger name Assigned level Effective level root DEBUG DEBUG X none DEBUG X.Y none DEBUG X.Y.Z none DEBUG Example 2 Logger name Assigned level Effective level root ERROR ERROR X INFO INFO X.Y DEBUG DEBUG X.Y.Z WARN WARN Example 3 Logger name Assigned level Effective level root DEBUG DEBUG X INFO INFO X.Y none INFO X.Y.Z ERROR ERROR Example 4 Logger name Assigned level Effective level root DEBUG DEBUG X INFO INFO X.Y none INFO X.Y.Z none INFO

級別順序 TRACE < DEBUG < INFO <  WARN < ERROR 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
Appenders 和 Layouts
addAppender方法添加一个appender到给定的logger。 Logger Name Attached Appenders Additivity Flag Output Targets Comment root A1 not applicable A1 Since the root logger stands at the top of the logger hierarchy, the additivity flag does not apply to it. x A-x1, A-x2 true A1, A-x1, A-x2 Appenders of "x" and of root. x.y none true A1, A-x1, A-x2 Appenders of "x" and of root. x.y.z A-xyz1 true A1, A-x1, A-x2, A-xyz1 Appenders of "x.y.z", "x" and of root. security A-sec false A-sec No appender accumulation since the additivity flag is set to false. Only appender A-sec will be used. security.access none true A-sec Only appenders of "security" because the additivity flag in "security" is set to false.
通常，用户不仅希望定制输出目的地，而且希望定制输出格式。
For example, the PatternLayout with the conversion pattern "%-4relative [%thread] %-5level %logger{32} - %msg%n" will output something akin to:
例如，PatternLayout爲"%-4relative [%thread] %-5level %logger{32} - %msg%n"時，將會輸出類似信息： 176  [main] DEBUG manual.architecture.HelloWorld2 - Hello world.
第一个字段是程序運行以来经过的毫秒数。第二个是發起日志请求的线程。第三个字段是日志请求的级别。第四個与日誌请求相關的logger的名字。“-”后是請求的文本消息。

參數化 logger.debug("The new entry is "+entry+"."); logger.debug("The new entry is {}.", entry);logger.debug("The new entry is {}. It replaces {}.", entry, oldEntry); 後面兩個比第一個更高效。
內部調用 这是一个UML序列图，以info()爲例来显示其內部調用情況。
性能 暫缺