学步园

public class A{<br /> private Logger logger;<br /> public PeriodicSendEmail(){<br /> //设置日志<br /> PropertyConfigurator.configure("log4j.properties");<br /> logger =Logger.getLogger("PeriodicSendEmail");<br /> }</p> <p> public void f() {<br /> logger.info("输出日志");</p> <p> }</p> <p>}<br />

用的包是log4j-1.2.15.jar

log4j.properties文件如下：

log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{MM-dd HH/:mm/:ss.SSS} %-5p [%F/:%L]%x %m%n

log4j.appender.fileout=org.apache.log4j.RollingFileAppender
log4j.appender.fileout.File=application.log
log4j.appender.fileout.MaxFileSize=10000KB
log4j.appender.fileout.MaxBackupIndex=10
log4j.appender.fileout.layout=org.apache.log4j.PatternLayout
log4j.appender.fileout.layout.ConversionPattern=%d{MM-dd HH:mm:ss.SSS}[%24F:%-3L:%-5p]%x %m%n

log4j.rootCategory=INFO, stdout, fileout
edu.pku.dblab.topicclassifier=DEBUG,stdout

最后，日志输出到application.log当中。

如果对日志工具加以封装，就有如下的代码：

package com.waleking.httpclient;</p> <p>import org.apache.log4j.Logger;<br /> import org.apache.log4j.PropertyConfigurator;</p> <p>public class CLogger {<br /> private static Logger logger; </p> <p> private static void initialize(){<br /> //设置日志<br /> PropertyConfigurator.configure("log4j.properties");<br /> logger =Logger.getLogger("PaperDownloader");<br /> }</p> <p> public CLogger(){<br /> if(logger==null){<br /> initialize();<br /> }<br /> }</p> <p> /*<br /> * 写日志<br /> */<br /> public static void writeLog(String message) {<br /> if(logger==null){<br /> initialize();<br /> }<br /> logger.info(message);<br /> }<br /> }