承接前文log4j源码解析，前文主要介绍了log4j的文件加载方式以及Logger对象创建。本文将在此基础上具体看下log4j是如何解析文件并输出我们所常见的日志格式
附例文件的加载方式，我们就选举log4j.properties作为分析的文件例子，并附上相应的通用配置
log4j.rootLogger=info,stdout,logfile,errorfile log4j.logger.org.apache=DEBUG log4j.logger.java.sql.Connection=DEBUG log4j.logger.java.sql.Statement=DEBUG log4j.logger.java.sql.PreparedStatement=DEBUG log4j.logger.java.sql.ResultSet=INFO log4j.logger.freemarker.core=error #standout log appender # log4j.appender.stdout=org.apache.log4j.ConsoleAppender log4j.appender.stdout.layout=org.apache.log4j.PatternLayout log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m%n #common log appender # log4j.appender.logfile=org.apache.log4j.DailyRollingFileAppender log4j.appender.logfile.File=../logs/appender-test/info.log log4j.appender.logfile.append=true log4j.appender.logfile.encoding=GB18030 log4j.appender.logfile.layout=org.apache.log4j.PatternLayout log4j.appender.logfile.layout.ConversionPattern=%d %p [%c] - %m%n #error log appender # log4j.appender.errorfile=org.apache.log4j.DailyRollingFileAppender log4j.appender.errorfile.File=../logs/appender-test/error.log log4j.appender.errorfile.Threshold=WARN log4j.appender.errorfile.append=true log4j.appender.errorfile.encoding=GB18030 log4j.appender.errorfile.layout=org.apache.log4j.PatternLayout log4j.appender.errorfile.layout.ConversionPattern=%d %p [%c] - %m%n