吃了没日志的亏，以前总以为日志没用，以后要重视起来了，很多错误服务器不会显示，但是页面上就是出错，这个时候就要显示日志了。
日志的代码如下，创建日志文件，文件名为log4j.properties，把这个文件放在resources下。
# Set root category priority to INFO and its only appender to CONSOLE.
#log4j.rootCategory=INFO, CONSOLE debug info warn error fatal
log4j.rootCategory=debug, CONSOLE, LOGFILE
# Set the enterprise logger category to FATAL and its only appender to CONSOLE.
log4j.logger.org.apache.axis.enterprise=FATAL, CONSOLE
# CONSOLE is set to be a ConsoleAppender using a PatternLayout.
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n
# LOGFILE is set to be a File appender using a PatternLayout.
# log4j.appender.LOGFILE=org.apache.log4j.FileAppender
# log4j.appender.LOGFILE.File=d:\axis.log
# log4j.appender.LOGFILE.Append=true
# log4j.appender.LOGFILE.layout=org.apache.log4j.PatternLayout
# log4j.appender.LOGFILE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n
原文：https://www.cnblogs.com/rao11/p/11757341.html