private Logger logger = Logger.getLogger(Common.class.getName());

logger.error("2222");
logger.warn("1111");
logger.warn("info");

配置
log.dir=logs
log4j.rootLogger=INFO, stdout, info

log4j.appender.info=org.apache.log4j.RollingFileAppender
log4j.appender.info.layout=org.apache.log4j.PatternLayout
log4j.appender.info.Encoding=UTF-8
log4j.appender.info.layout.ConversionPattern=%p [%t] %d{yyyy-MM-dd HH:mm:ss} %F(Line %L): %m%n
log4j.appender.info.File=${log.dir}/info.log
log4j.appender.info.maxFileSize=5MB
log4j.appender.info.maxBackupIndex=10

log4j.appender.error=org.apache.log4j.RollingFileAppender
log4j.appender.error.layout=org.apache.log4j.PatternLayout
log4j.appender.error.Encoding=UTF-8
log4j.appender.error.layout.ConversionPattern=%p [%t] %d{yyyy-MM-dd HH:mm:ss} %F(Line %L): %m%n
log4j.appender.error.File=${log.dir}/error.log
log4j.appender.error.maxFileSize=5MB
log4j.appender.error.maxBackupIndex=10

怎样让 error 的日志 写到 error.log
info 的日志写到 info.log
debug 日志写到 debug.log
...