Log4j layout ConversionPattern符号说明

PATTERN FORMATS GLOSSARY
%n - newline
%m - your log message
%p - message priority (FATAL, ERROR, WARN, INFO, DEBUG or custom)
%r - millisecs since program started running
%% - percent sign in output

SOME MORE CLUTTER IN YOUR LOG
%c - name of your category (logger), %c{2} will outputs last two components
%t - name of current thread
%x - Nested Diagnostic Context (NDC) (you supply it)

SLOW PERFORMANCE FORMATS
%d - date and time, also %d{ISO8601}, %d{DATE}, %d{ABSOLUTE},
%d{HH:mm:ss,SSS}, %d{dd MMM yyyy HH:mm:ss,SSS} and so on
%l - Shortcut for %F%L%C%M
%F - Java source file name
%L - Java source line number
%C - Java class name, %C{1} will output the last one component
%M - Java method name

FORMAT MODIFIERS
%-any_letter_above - Left-justify in min. width (default is right-justify)
%20any_letter_above - 20 char. min. width (pad with spaces if reqd.)
%.30any_letter_above- 30 char. max. width (truncate beginning if reqd.)
%-10.10r - Example. Left-justify time elapsed within 10-wide field.
Truncate from beginning if wider than 10 characters.