本地Windows环境的Eclipse下MapReduce程序遇到的问题总结

log4j WARN No appenders could be found for logger解决方法

在src目录下添加log4j.properties日志文件# Configure logging for testing: optionally with log file

#log4j.rootLogger=debug,appender
log4j.rootLogger=info,appender
#log4j.rootLogger=error,appender

#\u8F93\u51FA\u5230\u63A7\u5236\u53F0
log4j.appender.appender=org.apache.log4j.ConsoleAppender
#\u6837\u5F0F\u4E3ATTCCLayout
log4j.appender.appender.layout=org.apache.log4j.TTCCLayout

Exception in thread "main" java.lang.IllegalArgumentException: Pathname /C:/Users/XXX from C:/Users/XXX is not a valid DFS filename.

主类的main函数中cfg.set("fs.defaultFS", "hdfs://192.168.157.15:9000");注释掉

job.setNumReduceTasks(2);//设置 reduce 的数量，默认为1，此处为2，输出为两个文件