使用commons-logging的笔记

commons-logging是Jarkata封装了多种Java Log，如：Log4j、JDK Log、LogKit、NoOpLog、SimpleLog。

Eclipse下可以使用Log4E插件，快速插入Logger对象，设置Log4E的模版为commons-logging模版就可以了。并同时把commons-logging和log4j的jar包至于工程的classpath中。

在一个类MyClass的代码编辑页面，右键选择Log4E，选择declare logger，即在源代码基础上添加如下几段代码，如下：

import  org.apache.commons.logging.Log;
import  org.apache.commons.logging.LogFactory;

/** */ /**
 * Logger for this class
 */
private   static   final  Log logger  =  LogFactory.getLog(MyClass. class );

需要在src目录下添加log4j.xml文件，如下：

<? xml version="1.0" encoding="UTF-8"  ?>
<! DOCTYPE log4j:configuration SYSTEM "log4j.dtd" >

< log4j:configuration >

     <!-- config console="STDOUT"/ -->
     < appender  name ="STDOUT"  class ="org.apache.log4j.ConsoleAppender" >
         < layout  class ="org.apache.log4j.PatternLayout" >
             < param  name ="ConversionPattern"  value ="%d{HH:mm:ss.SSS} %-5p [%t] - %m "   />
         </ layout >
     </ appender >

     <!-- config debug="DEBUG"/ -->
     < appender  name ="DEBUG_LOG"  class ="org.apache.log4j.RollingFileAppender" >
         < param  name ="File"  value ="log/debug.log"   />
         < param  name ="Append"  value ="true"   />
         < param  name ="MaxFileSize"  value ="5000KB"   />
         < param  name ="MaxBackupIndex"  value ="2"   />
         < layout  class ="org.apache.log4j.PatternLayout" >
             < param  name ="ConversionPattern"  value ="%d{HH:mm:ss.SSS} %c -- %m "   />
         </ layout >
         < filter  class ="org.apache.log4j.varia.LevelRangeFilter" >
             < param  name ="LevelMin"  value ="DEBUG"   />
             < param  name ="LevelMax"  value ="DEBUG"   />
         </ filter >
     </ appender >
    
     <!-- config info="INFO"/ -->
     < appender  name ="INFO_LOG"  class ="org.apache.log4j.RollingFileAppender" >
         < param  name ="File"  value ="log/denet.log"   />
         < param  name ="Append"  value ="true"   />
         < param  name ="MaxFileSize"  value ="5000KB"   />
         < param  name ="MaxBackupIndex"  value ="2"   />
         < layout  class ="org.apache.log4j.PatternLayout" >
             < param  name ="ConversionPattern"  value ="%d{ISO8601} %c -- %m "   />
         </ layout >
         < filter  class ="org.apache.log4j.varia.LevelRangeFilter" >
             < param  name ="LevelMin"  value ="INFO"   />
             < param  name ="LevelMax"  value ="INFO"   />
         </ filter >
     </ appender >
    
     <!-- config error="ERROR"/ -->
     < appender  name ="ERROR_LOG"  class ="org.apache.log4j.RollingFileAppender" >
         < param  name ="File"  value ="log/error.log"   />
         < param  name ="Append"  value ="true"   />
         < param  name ="MaxFileSize"  value ="500KB"   />
         < param  name ="MaxBackupIndex"  value ="2"   />
         < layout  class ="org.apache.log4j.PatternLayout" >
             < param  name ="ConversionPattern"  value ="%d{ISO8601} %l -- %m "   />
         </ layout >
         < filter  class ="org.apache.log4j.varia.LevelRangeFilter" >
             < param  name ="LevelMin"  value ="ERROR"   />
             < param  name ="LevelMax"  value ="ERROR"   />
         </ filter >
     </ appender >
    
     <!-- config error="ERROR"/ -->
     < appender  name ="FATAL_LOG"  class ="org.apache.log4j.RollingFileAppender" >
         < param  name ="File"  value ="log/fatal.log"   />
         < param  name ="Append"  value ="true"   />
         < param  name ="MaxFileSize"  value ="5000KB"   />
         < param  name ="MaxBackupIndex"  value ="2"   />
         < layout  class ="org.apache.log4j.PatternLayout" >
             < param  name ="ConversionPattern"  value ="%d{ISO8601} %l -- %m "   />
         </ layout >
         < filter  class ="org.apache.log4j.varia.LevelRangeFilter" >
             < param  name ="LevelMin"  value ="FATAL"   />
             < param  name ="LevelMax"  value ="FATAL"   />
         </ filter >
     </ appender >
    
     <!--  
    <appender name="TASK_RUNNING" class="org.apache.log4j.RollingFileAppender">
        <param name="File" value="log/task_running.log" />
        <param name="Append" value="true" />
        <param name="MaxFileSize" value="5000KB" />
        <param name="MaxBackupIndex" value="3" />
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%d{yyyy:MM:dd HH:mm:ss.SSS} [%t] - %m " />
        </layout>
    </appender>

    <appender name="MONITOR" class="org.apache.log4j.RollingFileAppender">
        <param name="File" value="log/monitor.log" />
        <param name="Append" value="true" />
        <param name="MaxFileSize" value="5000KB" />
        <param name="MaxBackupIndex" value="3" />
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%d{yyyy:MM:dd HH:mm:ss.SSS} %c - %m " />
        </layout>
    </appender>

    <appender name="MONITOR_DAO" class="org.apache.log4j.RollingFileAppender">
        <param name="File" value="log/monitor_dao.log" />
        <param name="Append" value="true" />
        <param name="MaxFileSize" value="5000KB" />
        <param name="MaxBackupIndex" value="3" />
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%d{yyyy:MM:dd HH:mm:ss.SSS} %c - %m " />
        </layout>
    </appender>

    <logger name="monitor.general" additivity="true">
        <level value="DEBUG" />
        <appender-ref ref="MONITOR" />
    </logger>

    <logger name="monitor.dao" additivity="true">
        <level value="DEBUG" />
        <appender-ref ref="MONITOR_DAO" />
    </logger>

    <logger name="monitor.task" additivity="true">
        <level value="DEBUG" />
        <appender-ref ref="TASK_RUNNING" />
    </logger>
     -->

     < root >
         < priority  value ="DEBUG"   />
         < appender-ref  ref ="STDOUT"   />
         <!-- config ref,you can select what you want to show/ -->
         <!--  
        <appender-ref ref="INFO_LOG" />
        <appender-ref ref="ERROR_LOG" />
        <appender-ref ref="FATAL_LOG" />
         -->
     </ root >

</ log4j:configuration >


<!--
    
    Log4J Configuration Quick Reference:
    ====================================
    
    
    Priority order is DEBUG < INFO < WARN < ERROR < FATAL
    
    
    PatternLayout conversion characters:
    
    %c   Category of the logging event
    %C   Fully qualified class name of the caller
    %d   Date of the logging event  (example: %d{HH:mm:ss,SSS} )
    %F   File name where the logging request was issued (caution: extremely slow)
    %l   Location information of the caller (caution: extremely slow)
    %L   Line number from where the logging request was issued (caution: extremely slow)
    %m   Application-supplied message
    %M   Method name from where the logging request was issued (caution: extremely slow)
    %n   Line separator
    %p   Priority of the logging event
    %r   Number of milliseconds since the start of the application
    %t   Name of the thread that generated the logging event
    %x   Nested diagnotic context associated with the thread
    %%   A single percent sign
    
    Format modifiers examples:
    
    %20c     Left pad with spaces if category is less than 20 characters long
    %-20c    Right pad with spaces if category is less than 20 characters long
    %.30c    Truncate from the beginning if category is more than 30 chars long
    %20.30c  Left pad 20 chars + truncate from beginning if more than 30 chars
    %-20.30c Right pad 20 chars + truncate from beginning if more than 30 chars
    
    Examples:  "%r [%t] %-5p %c %x - %m "
    "%-6r [%15.15t] %-5p %30.30c %x - %m "  
    
-->

大功告成！