(A)Log4j 的組成
1.Logger 負責 生成日志
2.Appender 定義輸出的地點和文件的屬性
3.Layout 定義了輸出的格式等
(B)
Log4j有5種級別
FATAL,ERROR,WARN,INFO,DEBUG(從高到低)
(C)
方法有
fatal(Object message)
error(...)
warn(...)
info(...)
debug(...)
log(Priority p, Object message) <參數1級別，2信息>只有大于等于他在文件中定義的級別的信息才會被輸出
(D)Appender組件
1.Console(控制臺)
2.File(文件)
3.GUI(GUI Component)
4.套接口服務器
5.NT的事件記錄器
6.UNIX Syslog守護進程
7.例子
/*************************
log4j.logger.testLogger = WARN,file,console
log4j.appender.file = org.apache.log4j.RollingFileAppender
log4j.appender.file.File = C:/log.txt
log4j.appender.console = org.apache.log4j.ConsoleAppender
**************************/
8.具體Page258
參考
##LOGGERS##
#configure root logger
log4j.rootLogger = INFO,console #根定義了INFO級別，輸出是控制臺
#define a logger named helloAppLogger
log4j.logger.helloappLogger=WARN,file #定義了一個helloappLogger繼承了rootLogger，級別為WARN，并且因為繼承了rootLogger,所以輸出為file 和 console(除非把子類的additivity 改為false
#define a second logger that is a child to helloAppLogger
log4j.logger.helloappLogger.childLogger=,file
##APPENDERS##
#define an appender named console ,which is set to be a ConsoleAppender
log4j.appender.console=org.apache.log4j.ConsoleAppender
#define an appender named file, which is set to be a RollingFileAppender
log4j.appender.file=org.apache.log4j.RollingFileAppender
log4j.appender.file.File=c:/logHello.html
#define a simpleLaout to console appender
log4j.appender.file.layout=org.apache.log4j.HTMLLayout
log4j.appender.console.layout=org.apache.log4j.PatternLayout
</script>