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= 實作二十一 Lab21 =

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<p style="text-align: center;"><big style="font-weight: bold;"><big> 修改檔案輸入格式<br/> KeyValueTextInputFormat </big></big></p>
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請先連線至 nodeN.3du.me , N 為您的報名編號
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cd ~/hadoop_labs/lab012
ant
mkdir -p kv_input
printf "A\t1\n" >  kv_input/input1
printf "B\t2\n" >> kv_input/input1
printf "C\t3\n" >> kv_input/input1
printf "A\t1\n" >  kv_input/input2
printf "C\t2\n" >> kv_input/input2
printf "B\t1\n" >> kv_input/input2
hadoop fs -put kv_input kv_input
hadoop jar WordCount.jar kv_input kv_output
hadoop fs -ls kv_output
hadoop fs -cat kv_output/part-*

export HADOOP_CONF_DIR=~/hadoop/conf.local/
hadoop jar WordCount.jar kv_input kv_output
ls -al kv_output
cat kv_output/part-*
unset HADOOP_CONF_DIR
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 * Reference:
   * http://hadoop.apache.org/docs/r1.0.4/api/org/apache/hadoop/mapreduce/lib/input/FileInputFormat.html
   * http://hadoop.apache.org/docs/r1.0.4/api/org/apache/hadoop/mapreduce/lib/input/TextInputFormat.html
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public class TextInputFormat
extends FileInputFormat<LongWritable,Text>
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   * http://hadoop.apache.org/docs/r1.0.4/api/org/apache/hadoop/mapreduce/lib/input/KeyValueTextInputFormat.html
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public class KeyValueTextInputFormat
extends FileInputFormat<Text,Text>
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   * http://hadoop.apache.org/docs/r1.0.4/api/org/apache/hadoop/mapreduce/lib/input/NLineInputFormat.html
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public class NLineInputFormat
extends FileInputFormat<LongWritable,Text>

NLineInputFormat which splits N lines of input as one split.
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== 實作習題 ==

 <問題 1>