1、Logger 完成日誌信息的處理
定義輸出的層次和決定信息是否輸出
DEBUG<INFO<WARN<ERROR
2、Appender 設置日誌信息的去向
常用的:
org.apache.log4j.ConsoleAppender(控制檯)
org.apache.log4j.FileAppender(文件)
org.apache.log4j.DailyRollingFileAppener(每天產生一個日誌文件)
org.apache.log4j.RollingFileAppender(文件大小到達指定尺寸的時候產生一個新的文件)
org.apache.log4j.WriterAppender(將日誌訊息以串流格式發送到任意指定的地方)
org.apache.log4j.JdbcAppender(將日誌訊息保存到數據庫中)
3、Layout 設置日誌信息的輸出樣式
layout有以下幾種:
org.apache.log4j.HTMLLayout(以HTML表格形式佈局)
org.apache.log4j.SimpleLayout(包含日誌訊息的級別和訊息字符串)
org.apache.log4j.TTCCLayout(包含日誌產生的時間、執行緒、類別等訊息)
org.apache.log4j.PatterLayout(可以靈活地指定佈局格式)
4、配置文件 log4j.properties或log4j.xml
- log4j.properties實例:
- log4j.logger.com.jjm.util=INFO, A1,A2
- log4j.logger.com.jjm.dao=DEBUG, A1
- 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-%M]%m%n
- log4j.appender.A2=org.apache.log4j.RollingFileAppender
- log4j.appender.A2.File=sshdemo.log
- log4j.appender.A2.MaxFileSize=500KB
- log4j.appender.A2.MaxBackupIndex=1
- log4j.appender.A2.layout=org.apache.log4j.PatternLayout
- log4j.appender.A2.layout.ConversionPattern=[%d{yyyy-MM-dd HH:mm:ss}][%C-%M]%m%n
log4j.xml實例:
- <?xml version="1.0" encoding="UTF-8" ?>
- <!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
- <log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
- <appender name="A1" class="org.apache.log4j.RollingFileAppender">
- <param name="File" value="sshdemo2.log" />
- <param name="MaxFileSize" value="1MB" />
- <param name="MaxBackupIndex" value="10" />
- <layout class="org.apache.log4j.PatternLayout">
- <param name="ConversionPattern" value="[%d{yyyy-MM-dd HH:mm:ss}][%C-%M]%m%n" />
- </layout>
- </appender>
- <appender name="A2" class="org.apache.log4j.ConsoleAppender">
- <layout class="org.apache.log4j.PatternLayout">
- <param name="ConversionPattern" value="[%d{yyyy-MM-dd HH:mm:ss}][%C-%M]%m%n" />
- </layout>
- </appender>
- <logger name="com.jjm.dao">
- <level value="DEBUG" />
- <appender-ref ref="A1" />
- </logger>
- <root>
- <priority value="DEBUG" />
- <appender-ref ref="A2" />
- </root>
- </log4j:configuration>