只使用log4j，不涉及commons.logging
指定一个记录器
import org.apache.log4j.Logger;static Logger log = Logger.getLogger("blogjavabean");
log4j.properties
log4j.rootLogger=error, Consolelog4j.logger.blogjavabean = error,Consolelog4j.appender.Console=org.apache.log4j.ConsoleAppenderlog4j.appender.Console.layout = org.apache.log4j.SimpleLayout#FATAL 0#ERROR 3#WARN 4#INFO 6#DEBUG 7
