Hadoop: No appenders could be found for logger (org.apache.hadoop.metrics2.lib.MutableMetricsFactory).解決辦法

在eclipse中運行Hadoop程序時出現如下問題：

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.
Exception in thread "main" java.io.IOException: Job failed!
    at org.apache.hadoop.mapred.JobClient.runJob(JobClient.java:836)
    at hadoop.in.action.WordCount.run(WordCount.java:89)
    at hadoop.in.action.WordCount.main(WordCount.java:98)

解決辦法：將${HADOOP_HOME}/etc/hadoop/log4j.properties 拷貝到eclipse項目的sec文件夾下。