commons-logging和apache-log4j的结合使用

1.添加2个工具相关的jar包到工程
http://apache.etoak.com/logging/log4j/1.2.15/apache-log4j-1.2.15.zip
http://labs.renren.com/apache-mirror/commons/logging/binaries/commons-logging-1.1.1-bin.zip
2.为log4j编写配置文件，使用默认的文件名，如:log4j.xml或log4j.properties，因为log4j会自动去找这2个文件。放在classes目录下。
3.在代码中使用：
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

Log log = LogFactory.getLog("name");
log.info(obj);

////////////////////////////////////////////////////////////////////////////

///log4j.properties
## LOGGERS ##
#configure root logger
log4j.rootLogger=INFO,console
#define a logger named helloAppLogger
log4j.logger.helloappLogger=WARN
#define a second logger that is a child to helloAppLogger
log4j.logger.helloappLogger.childLogger=,file
## APPENDERS ##
# define an appender named console, which is set to be a ConsoleAppender
log4j.appender.console=org.apache.log4j.ConsoleAppender
# define an appender named file, which is set to be a RollingFileAppender
log4j.appender.file=org.apache.log4j.RollingFileAppender
log4j.appender.file.File=log.txt
## LAYOUTS ##
# assign a SimpleLayout to console appender
log4j.appender.console.layout=org.apache.log4j.PatternLayout
log4j.appender.console.layout.ConversionPattern=%d %c %p - %m%n
# assign a PatternLayout to file appender
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d %c %p - %m%n