以下几种方式灵活组合使用，例：
log4j.rootLogger=info, stdout, file
#输出到控制台
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%n%-d{yyyy-MM-dd HH:mm:ss}%n[%p]-[Thread: %t]-[%C.%M()]: %m%n
#总创建5个日志文件，循环使用。
log4j.appender.file=org.apache.log4j.RollingFileAppender
#日志将保存在tomcat/logs下
log4j.appender.file.File=${catalina.base}/logs/webclient.log
log4j.appender.file.MaxBackupIndex=5
log4j.appender.file.Append=true
log4j.appender.file.MaxFileSize=100MB
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%n%-d{yyyy-MM-dd HH:mm:ss}%n[%p]-[Thread: %t]-[%C.%M()]: %m%n日志级别控制,级别为info,输出目标为stdout和file
log4j.rootLogger=info, stdout, filea.控制台输出
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%n%-d{yyyy-MM-dd HH:mm:ss}%n[%p]-[Thread: %t]-[%C.%M()]: %m%n1.向文件输出
log4j.appender.file=org.apache.log4j.FileAppender
log4j.appender.file.File=./webclient.log
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%n%-d{yyyy-MM-dd HH:mm:ss}%n[%p]-[Thread: %t]-[%C.%M()]: %m%n2.每天生成一个文件
log4j.appender.file=org.apache.log4j.DailyRollingFileAppender
log4j.appender.file.File=./webclient.log
log4j.appender.file.DatePattern='.'yyyy-MM-dd
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%n%-d{yyyy-MM-dd HH:mm:ss}%n[%p]-[Thread: %t]-[%C.%M()]: %m%n3.循环使用日志
log4j.appender.file=org.apache.log4j.RollingFileAppender
# ${catalina.base}/logs -> tomcat/logs
log4j.appender.file.File=E:/a/log/webclient.log
log4j.appender.file.MaxBackupIndex=5
log4j.appender.file.Append=true
log4j.appender.file.MaxFileSize=100MB
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%n%-d{yyyy-MM-dd HH:mm:ss}%n[%p]-[Thread: %t]-[%C.%M()]: %m%n
