%a - Remote IP address
%A - Local IP address
%b - Bytes sent, excluding HTTP headers, or '-' if zero
%B - Bytes sent, excluding HTTP headers
%h - Remote host name (or IP address if enableLookups for the connector is false)
%H - Request protocol
%l - Remote logical username from identd (always returns '-')
%m - Request method (GET, POST, etc.)
%p - Local port on which this request was received
%q - Query string (prepended with a '?' if it exists)
%r - First line of the request (method and request URI)
%s - HTTP status code of the response
%S - User session ID
%t - Date and time, in Common Log Format
%u - Remote user that was authenticated (if any), else '-'
%U - Requested URL path
%v - Local server name
%D - Time taken to process the request, in millis
%T - Time taken to process the request, in seconds
%F - Time taken to commit the response, in millis
%I - Current request thread name (can compare later with stacktraces)
There is also support to write information incoming or outgoing headers, cookies, session or request attributes and special timestamp formats. It is modeled after the Apache HTTP Server log configuration syntax:
%{xxx}i for incoming headers
%{xxx}o for outgoing response headers
%{xxx}c for a specific cookie
%{xxx}r xxx is an attribute in the ServletRequest
%{xxx}s xxx is an attribute in the HttpSession
%{xxx}t xxx is an enhanced SimpleDateFormat pattern
上面最后一段的内容大概意思是我们还可以将cookie, 客户端请求中带的HTTP头(incoming header), 会话(session)或是ServletRequest中的数据都写到Tomcat的访问日志中
我们可以用下面的语法来引用。