配置:
### set log levels ### D只有一个E也只有一个 log4j.rootLogger = debug,stdout,D,E ### 输出到控制台 ### log4j.appender.stdout = org.apache.log4j.ConsoleAppender log4j.appender.stdout.Target = System.out log4j.appender.stdout.layout = org.apache.log4j.PatternLayout log4j.appender.stdout.layout.ConversionPattern = %d{ABSOLUTE} %5p %c{1}:%L - %m%n ### 输出到日志文件 ### log4j.appender.D = org.apache.log4j.DailyRollingFileAppender log4j.appender.D.File = logs/log.log log4j.appender.D.Append = true log4j.appender.D.Threshold = DEBUG log4j.appender.D.layout = org.apache.log4j.PatternLayout log4j.appender.D.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss} [ %t:%r ] - [ %p ] %m%n # #### 保存Debug信息到单独文件 ### ## 只输出ERROR级别以上的日志!!! #log4j.appender.D = org.apache.log4j.DailyRollingFileAppender #log4j.appender.D.File = logs/error.log #log4j.appender.D.Append = true #log4j.appender.D.Threshold = ERROR #log4j.appender.D.layout = org.apache.log4j.PatternLayout #log4j.appender.D.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss} [ %t:%r ] - [ %p ] %m%n # # #### 保存异常信息到单独文件 ### log4j.appender.E = org.apache.log4j.DailyRollingFileAppender log4j.appender.E.File = logs/error.log log4j.appender.E.Append = true log4j.appender.E.Threshold = ERROR log4j.appender.E.layout = org.apache.log4j.PatternLayout log4j.appender.E.layout.ConversionPattern = %d{yyyy-MM-dd HH:mm:ss} [ %t:%r ] - [%p] - %m%n
异常1:log4j:ERROR Category option " 1 " not a decimal integer.
java.lang.NumberFormatException: For input string: " 1 "
解决办法: log4j.properties 的配置文件中：
log4j.appender.stdout.layout.ConversionPattern = %d{ABSOLUTE} %5p %c{ 1 }:%L - %m%n
把{1}中的空格去掉。