Suggestions

Specify the global configuration items in mapred-site.xml

The mapred-site.xml file contains the following configuration items:

setMapperClass(Class <extends Mapper> cls) ->"mapreduce.job.map.class"
setReducerClass(Class<extends Reducer> cls) ->"mapreduce.job.reduce.class"
setCombinerClass(Class<extends Reducer> cls) ->"mapreduce.job.combine.class"
setInputFormatClass(Class<extends InputFormat> cls) ->"mapreduce.job.inputformat.class"
setJar(String jar) ->"mapreduce.job.jar"
setOutputFormat(Class< extends OutputFormat> theClass) ->"mapred.output.format.class"
setOutputKeyClass(Class<> theClass) ->"mapreduce.job.output.key.class"
setOutputValueClass(Class<> theClass) ->"mapreduce.job.output.value.class"
setPartitionerClass(Class<extends Partitioner> theClass) ->"mapred.partitioner.class"
setMapOutputCompressorClass(Class<extends CompressionCodec> codecClass)
->"mapreduce.map.output.compress"&"mapreduce.map.output.compress.codec"
setJobPriority(JobPriority prio) ->"mapreduce.job.priority"
setQueueName(String queueName) ->"mapreduce.job.queuename"
setNumMapTasks(int n) ->"mapreduce.job.maps"
setNumReduceTasks(int n) ->"mapreduce.job.reduces"