log4j配置及使用

一、使用方法：

1、将log4j.properties放到你创建项目的src中

2、引入log4j.jar

import org.apache.log4j.*;
public class log4jTest {
     static Logger logger = null;
     public static void test(){
         logger=Logger.getLogger(log4jTest.class.getName());
         logger.info("info");
         logger.error("error");
     }

     public static void main(String args[]){
         test();
     }

}

二、log4j.properties文件配置

log4j.rootCategory=INFO, dest1, FILE, ROLLING_FILE

#log4j.logger.cn=DEBUG,dest1

####################
# Console Appender
####################
log4j.appender.dest1=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.Threshold=DEBUG
log4j.appender.dest1.layout=org.apache.log4j.PatternLayout
log4j.appender.dest1.layout.ConversionPattern=%-5p - %m [%l] %n

####################
# File Appender
####################
log4j.appender.FILE=org.apache.log4j.FileAppender
log4j.appender.FILE.File=C:\\log4jTestFile.log
log4j.appender.FILE.Append=true
log4j.appender.FILE.layout=org.apache.log4j.PatternLayout
log4j.appender.FILE.layout.ConversionPattern=[log4jTest] %d -%-4r [%t] %c %x%n %-5p - %m [%l] %n

####################
# Rolling File Appender
####################
log4j.appender.ROLLING_FILE=org.apache.log4j.RollingFileAppender
log4j.appender.ROLLING_FILE.File=C:\\log4jTestRolling.log
log4j.appender.ROLLING_FILE.Append=true
log4j.appender.ROLLING_FILE.MaxFileSize=10KB
log4j.appender.ROLLING_FILE.MaxBackupIndex=1
log4j.appender.ROLLING_FILE.layout=org.apache.log4j.PatternLayout
log4j.appender.ROLLING_FILE.layout.ConversionPattern=[log4jTest]%d -%-4r [%t] %c %x%n %-5p - %m [%l] %n

####################
# Socket Appender
####################
#log4j.appender.SOCKET=org.apache.log4j.net.SocketAppender
#log4j.appender.SOCKET.RemoteHost=localhost
#log4j.appender.SOCKET.Port=4445
#log4j.appender.SOCKET.LocationInfo=true
## Set up for Log Facter 5
#log4j.appender.SOCKET.layout=org.apache.log4j.PatternLayout
#log4j.appender.SOCKET.layout.ConversionPattern=[start]%d{DATE}[DATE]%n%p[PRIORITY]%n%x[NDC]%n%t[TH#READ]%n%c[CATEGORY]%n%m[MESSAGE]%n%n

当项目改变时我们只需要将上面的红色处更改即可（更改文件存放路径及写入日志的名称）