java.io.IOException: Type mismatch in key from map: expected org.apache.hadoop.

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导读:本篇文章讲解 java.io.IOException: Type mismatch in key from map: expected org.apache.hadoop.,希望对大家有帮助,欢迎收藏,转发!站点地址:www.bmabk.com,来源:原文

查找设置mapper所用类型

job.setMapperClass(RMapper.class);
job.setMapOutputKeyClass(Text.class);
job.setMapOutputKeyClass(IntWritable.class);
job.setMapperClass(RMapper.class);
job.setMapOutputKeyClass(Text.class);
job.setMapOutputValueClass(IntWritable.class);
20/09/14 23:16:45 WARN mapred.LocalJobRunner: job_local1982901045_0001
java.lang.Exception: java.io.IOException: Type mismatch in key from map: expected org.apache.hadoop.io.IntWritable, received org.apache.hadoop.io.Text
	at org.apache.hadoop.mapred.LocalJobRunner$Job.runTasks(LocalJobRunner.java:462)
	at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:522)
Caused by: java.io.IOException: Type mismatch in key from map: expected org.apache.hadoop.io.IntWritable, received org.apache.hadoop.io.Text
	at org.apache.hadoop.mapred.MapTask$MapOutputBuffer.collect(MapTask.java:1069)
	at org.apache.hadoop.mapred.MapTask$NewOutputCollector.write(MapTask.java:712)
	at org.apache.hadoop.mapreduce.task.TaskInputOutputContextImpl.write(TaskInputOutputContextImpl.java:89)
	at org.apache.hadoop.mapreduce.lib.map.WrappedMapper$Context.write(WrappedMapper.java:112)
	at com.hadoop.mr.recommend.RMapper.map(Recommendation.java:53)
	at com.hadoop.mr.recommend.RMapper.map(Recommendation.java:1)
	at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:145)
	at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:784)
	at org.apache.hadoop.mapred.MapTask.run(MapTask.java:341)
	at org.apache.hadoop.mapred.LocalJobRunner$Job$MapTaskRunnable.run(LocalJobRunner.java:243)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:748)

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