网上很多说的是 FileHandler.maxDays 但试了无效，后使用AsyncFileHandler.maxDays 可行，顾记录下供同学们少走弯路。
本人从 tomcat-8.5.100 下载
修改：tomcat8.5\conf\logging.properties
AsyncFileHandler.maxDays 属性设置天数
天数从0开始的，因此此处保留最近为8天的日志
1catalina.org.apache.juli.AsyncFileHandler.level = FINE
1catalina.org.apache.juli.AsyncFileHandler.directory = ${catalina.base}/logs
1catalina.org.apache.juli.AsyncFileHandler.prefix = catalina.
1catalina.org.apache.juli.AsyncFileHandler.encoding = UTF-8
1catalina.org.apache.juli.AsyncFileHandler.maxDays = 7
2localhost.org.apache.juli.AsyncFileHandler.level = FINE
2localhost.org.apache.juli.AsyncFileHandler.directory = ${catalina.base}/logs
2localhost.org.apache.juli.AsyncFileHandler.prefix = localhost.
2localhost.org.apache.juli.AsyncFileHandler.encoding = UTF-8
2localhost.org.apache.juli.AsyncFileHandler.maxDays = 7
3manager.org.apache.juli.AsyncFileHandler.level = FINE
3manager.org.apache.juli.AsyncFileHandler.directory = ${catalina.base}/logs
3manager.org.apache.juli.AsyncFileHandler.prefix = manager.
3manager.org.apache.juli.AsyncFileHandler.encoding = UTF-8
3manager.org.apache.juli.AsyncFileHandler.maxDays = 7
4host-manager.org.apache.juli.AsyncFileHandler.level = FINE
4host-manager.org.apache.juli.AsyncFileHandler.directory = ${catalina.base}/logs
4host-manager.org.apache.juli.AsyncFileHandler.prefix = host-manager.
4host-manager.org.apache.juli.AsyncFileHandler.encoding = UTF-8
4host-manager.org.apache.juli.AsyncFileHandler.maxDays = 7
可根据java版本下载所需的 Tomcat
