代码简单示意：利用log4j将一个类中不同业务日志记录到不同位置

下文代码中，除了指定rootlogger输出到控制台和文件logdemo.log中之外，还定义了一个指定目的的子logger，令其日志输出到logdemo2.log文件中，同时它不继承rootlogger的输出特性。

实验环境log4j-1.2.11

log4j.properties:
#category/logger
log4j.rootLogger=debug, stdout, file
log4j.logger.SpecialPurpose=debug,file2

#Succession
log4j.additivity.SpecialPurpose=false

#to console
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH\:mm\:ss} %p %c %m %n

#to file#
log4j.appender.file=org.apache.log4j.FileAppender
log4j.appender.file.File=logdemo.log
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %l %m%n

#to file2
log4j.appender.file2=org.apache.log4j.FileAppender
log4j.appender.file2.File=logdemo2.log
log4j.appender.file2.layout=org.apache.log4j.PatternLayout
log4j.appender.file2.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %l %m%n

java:
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.log4j.Logger;

public class Log4jTest {

private static Logger logger =Logger.getLogger(Log4jTest.class);
private static Log logger2 = LogFactory.getLog("SpecialPurpose");

public static void main(String[] args) {

logger.error("error");
logger.warn("warn");
logger.info("info");
logger.debug("debug");

logger2.error("error for SpecialPurpose...");
logger2.warn("warn for SpecialPurpose...");
logger2.info("info for SpecialPurpose...");
logger2.debug("debug for SpecialPurpose...");
}
}

logdemo.log和控制台文件信息：

2012-12-13 22:06:23 Log4jTest.main(Log4jTest.java:13) error
2012-12-13 22:06:23 Log4jTest.main(Log4jTest.java:14) warn
2012-12-13 22:06:23 Log4jTest.main(Log4jTest.java:15) info
2012-12-13 22:06:23 Log4jTest.main(Log4jTest.java:16) debug

logdemo2.log文件信息：

2012-12-13 22:06:23 Log4jTest.main(Log4jTest.java:18) error for SpecialPurpose...
2012-12-13 22:06:23 Log4jTest.main(Log4jTest.java:19) warn for SpecialPurpose...
2012-12-13 22:06:23 Log4jTest.main(Log4jTest.java:20) info for SpecialPurpose...
2012-12-13 22:06:23 Log4jTest.main(Log4jTest.java:21) debug for SpecialPurpose...