log4j ERROR Category option "1." not a decimal integer

g4j: Setting property [conversionPattern] to [%d{dd MMM yyyy HH:mm:ss.SSS} [%p] [%t] [%c{1.}] - %m%n].
log4j:ERROR Category option "1." not a decimal integer.
java.lang.NumberFormatException: For input string: "1."
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Integer.parseInt(Integer.java:580)
at java.lang.Integer.parseInt(Integer.java:615)
………
log4j: Adding appender named [stdout] to category [root].

Solution1

Solution2

解决方案：
log4j.properties 的配置文件有问题
log4j.appender.stdout.layout.ConversionPattern = %d{ABSOLUTE} %5p %c{ 1 }:%L - %m%n
去除 1 前后的空格即可。