用log4j输出日志

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

 

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