Solve the problem that the MapReduce program console does not have log information warn please initialize the log4j system properly

  function mapreduce When , No log file found , A warning will be given :
 
log4j:WARN No appenders could be found for logger (org.apache.hadoop.metrics2.lib.MutableMetricsFactory).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.

  It is found that the console has not been output again mapreduce Task information of . Later, it was found that the configuration is required log4j.
  stay resource Create one in the directory log4j.properties file

  Add the following information :

log4j.rootLogger=info, stdout  
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  

log4j.appender.File=org.apache.log4j.DailyRollingFileAppender
log4j.appender.File.File=D:/test/logs.txt
log4j.appender.File.DatePattern='_'yyyy-MM-dd'.txt'
log4j.appender.File.layout=org.apache.log4j.PatternLayout
log4j.appender.File.layout.ConversionPattern=%d %t %-5p [%c] %m%n