1 log4j has three main components:
-
loggers: Responsible for capturing logging information.
-
appenders: Responsible for publishing logging information to various preferred destinations.
-
layouts: Responsible for formatting logging information in different styles.
2,level:
It uses multiple levels, namely ALL, TRACE, DEBUG, INFO, WARN, ERROR and FATAL.,
3.jar包
log4j common-logging
4、新建配置文件:log4j.properties
#FATAL 0
#ERROR 3
#WARN 4
#INFO 6
#DEBUG 7
#配置输出等级与媒介(配置根root)
log4j.rootLogger=ERROR, A1, A2,A3
#控制台配置
log4j.appender.A1=org.apache.log4j.ConsoleAppender
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern=%-d{yyyy-MM-dd HH:mm:ss} [%c]-[%p] %m%n
#日志输出到文件
log4j.appender.A2=org.apache.log4j.RollingFileAppender
#日志输出路径
log4j.appender.A2.File=F:/Log4jTest.log
#日志文件最大值(到达最大值是会重新建一个,把之前的内容存到log.1日志文档中)
log4j.appender.A2.MaxFileSize=20KB
#最多纪录文件数
log4j.appender.A2.MaxBackupIndex=1
#输出布局
log4j.appender.A2.layout=org.apache.log4j.PatternLayout
log4j.appender.A2.layout.ConversionPattern=%-d{yyyy-MM-dd HH:mm:ss} [%c]-[%p] %m%n
#日志输出到文件
log4j.appender.A3=org.apache.log4j.RollingFileAppender
#日志输出路径
log4j.appender.A3.File=H:/Log4jTest.log
#日志文件最大值
log4j.appender.A3.MaxFileSize=20KB
#最多纪录文件数
log4j.appender.A3.MaxBackupIndex=1
#输出日志布局
log4j.appender.A3.layout=org.apache.log4j.PatternLayout
log4j.appender.A3.layout.ConversionPattern=%-d{yyyy-MM-dd HH:mm:ss} [%c]-[%p] %m%n
该配置文件配置了log输出的目的地:console(A1)和file(A2,A3)
若直接配置文件放到src目录下则无需显示加下列的加载配置文件
加载log4j.properties:PropertyConfigurator.configure("/log4j.properties");
加载log4j.xml: DOMConfigurator.configure("lib//log4j.xml");
或者参考log4j.xml:http://xinklabi.iteye.com/blog/2124572