先说一下按日期产生，不解释，大家都懂，这种方法的缺点就是很吃硬盘空间
log4j.rootLogger=INFO,logfile,stdoutlog4j.logger.java.sql=DEBUG,sqllog#log4j.additivity.java.sql=false#velocity print outlog4j.logger.org.apache.velocity=ERROR,velocityfilelog4j.additivity.org.apache.velocity=falselog4j.logger.org.springframework.web.servlet.mvc.annotation=false#app print outlog4j.logger.com.hundsun.network=DEBUGlog4j.logger.com.hundsun.network.melody.common.profiler=DEBUG,profilerlog4j.additivity.com.hundsun.network.melody.common.profiler=false#standout log appender #log4j.appender.stdout=org.apache.log4j.ConsoleAppenderlog4j.appender.stdout.layout=org.apache.log4j.PatternLayoutlog4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m%n#common log appender #log4j.appender.logfile=org.apache.log4j.DailyRollingFileAppenderlog4j.appender.logfile.File=/WEB-INF/log/app.loglog4j.appender.logfile.append=truelog4j.appender.logfile.encoding=GB18030log4j.appender.logfile.layout=org.apache.log4j.PatternLayoutlog4j.appender.logfile.layout.ConversionPattern=%d %p [%c] - %m%n#error log appender #log4j.appender.errorfile=org.apache.log4j.DailyRollingFileAppenderlog4j.appender.errorfile.File=/WEB-INF/log/error.loglog4j.appender.errorfile.Threshold=ERRORlog4j.appender.errorfile.append=truelog4j.appender.errorfile.encoding=GB18030log4j.appender.errorfile.layout=org.apache.log4j.PatternLayoutlog4j.appender.errorfile.layout.ConversionPattern=%d %p [%c] - %m%n#sql log appender #log4j.appender.sqllog=org.apache.log4j.DailyRollingFileAppenderlog4j.appender.sqllog.File=/WEB-INF/log/sql.loglog4j.appender.sqllog.append=truelog4j.appender.sqllog.encoding=GB18030log4j.appender.sqllog.layout=org.apache.log4j.PatternLayoutlog4j.appender.sqllog.layout.ConversionPattern=%d %p [%c] - %m%n#velocity log appender #log4j.appender.velocityfile=org.apache.log4j.DailyRollingFileAppenderlog4j.appender.velocityfile.File=/WEB-INF/log/velocity.loglog4j.appender.velocityfile.append=truelog4j.appender.velocityfile.encoding=GB18030log4j.appender.velocityfile.layout=org.apache.log4j.PatternLayoutlog4j.appender.velocityfile.layout.ConversionPattern=%d %p [%c] - %m%n#profile appender #log4j.appender.profiler=org.apache.log4j.DailyRollingFileAppenderlog4j.appender.profiler.File=/WEB-INF/log/profler.loglog4j.appender.profiler.append=truelog4j.appender.profiler.encoding=GB18030log4j.appender.profiler.layout=org.apache.log4j.PatternLayoutlog4j.appender.profiler.layout.ConversionPattern=%d %p [%c] - %m%n于是我们来解决一下这个问题，把日志的大小限在10240Ｋ,一共只许生成30个，循环覆盖
log4j.rootLogger=INFO,logfile,stdout,errorfilelog4j.logger.java.sql=@log.level@,sqlloglog4j.additivity.java.sql=false#velocity print outlog4j.logger.org.apache.velocity=ERROR,velocityfilelog4j.additivity.org.apache.velocity=false#app print outlog4j.logger.com.hundsun.network=DEBUGlog4j.logger.com.hundsun.network.melody.common.profiler=@log.level@,profilerlog4j.additivity.com.hundsun.network.melody.common.profiler=false#standout log appender #log4j.appender.stdout=org.apache.log4j.ConsoleAppenderlog4j.appender.stdout.layout=org.apache.log4j.PatternLayoutlog4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m%n#common log appender #log4j.appender.logfile=org.apache.log4j.RollingFileAppenderlog4j.appender.logfile.File=/WEB-INF/log/app.loglog4j.appender.logfile.append=truelog4j.appender.logfile.encoding=GB18030log4j.appender.logfile.layout=org.apache.log4j.PatternLayoutlog4j.appender.logfile.layout.ConversionPattern=%d %p [%c] - %m%nlog4j.appender.logfile.MaxFileSize=10240KBlog4j.appender.logfile.MaxBackupIndex=30#error log appender #log4j.appender.errorfile=org.apache.log4j.RollingFileAppenderlog4j.appender.errorfile.File=/WEB-INF/log/error.loglog4j.appender.errorfile.Threshold=ERRORlog4j.appender.errorfile.append=truelog4j.appender.errorfile.encoding=GB18030log4j.appender.errorfile.layout=org.apache.log4j.PatternLayoutlog4j.appender.errorfile.layout.ConversionPattern=%d %p [%c] - %m%nlog4j.appender.errorfile.MaxFileSize=10240KBlog4j.appender.errorfile.MaxBackupIndex=30#sql log appender #log4j.appender.sqllog=org.apache.log4j.RollingFileAppenderlog4j.appender.sqllog.File=/WEB-INF/log/sql.loglog4j.appender.sqllog.append=truelog4j.appender.sqllog.encoding=GB18030log4j.appender.sqllog.layout=org.apache.log4j.PatternLayoutlog4j.appender.sqllog.layout.ConversionPattern=%d %p [%c] - %m%nlog4j.appender.sqllog.MaxFileSize=10240KBlog4j.appender.sqllog.MaxBackupIndex=30#velocity log appender #log4j.appender.velocityfile=org.apache.log4j.RollingFileAppenderlog4j.appender.velocityfile.File=/WEB-INF/log/velocity.loglog4j.appender.velocityfile.append=truelog4j.appender.velocityfile.encoding=GB18030log4j.appender.velocityfile.layout=org.apache.log4j.PatternLayoutlog4j.appender.velocityfile.layout.ConversionPattern=%d %p [%c] - %m%nlog4j.appender.velocityfile.MaxFileSize=10240KBlog4j.appender.velocityfile.MaxBackupIndex=30#profile appender #log4j.appender.profiler=org.apache.log4j.RollingFileAppenderlog4j.appender.profiler.File=/WEB-INF/log/profler.loglog4j.appender.profiler.append=truelog4j.appender.profiler.encoding=GB18030log4j.appender.profiler.layout=org.apache.log4j.PatternLayoutlog4j.appender.profiler.layout.ConversionPattern=%d %p [%c] - %m%nlog4j.appender.profiler.MaxFileSize=10240KBlog4j.appender.profiler.MaxBackupIndex=30