這是我第一次使用Hadoop進行編程,我在hadoop教程網站上根據WordCount v1.0進行了我的任務。hadoop key返回多個值
作業:你有兩個文件。 File0包含字典中的每個單詞。 File1包含一個隨機單詞。例如:'美麗'。
當我運行它應該在File0返回的每一個字的程序,其大小爲文件1字相同
*美將在字典
例如返回每9個字母組成的單詞: 美麗 - AARDVARKS AASVOGELS ABAMPERES .... ZYMOGRAMS ZYMURGIES
所以我的問題是我應該怎麼做呢? hadoop wordcount v1.0返回鍵和單個值。 ----例如(beautiful 4)
是否需要將值從int更改爲字符串或者某種數組包含與密鑰大小相同的每個單詞?
*基本上,我需要的格式從
(美4)
改變
(美麗:土豚AASVOGELS ABAMPERES ... ZYMOGENES酶譜ZYMURGIES)
這裏是代碼(來源於他們的網站):
package org.myorg;
import java.io.IOException;
import java.util.*;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.conf.*;
import org.apache.hadoop.io.*;
import org.apache.hadoop.mapred.*;
import org.apache.hadoop.util.*;
public class WordCount {
public static class Map extends MapReduceBase implements Mapper<LongWritable, Text, Text, IntWritable> {
private final static IntWritable one = new IntWritable(1);
private Text word = new Text();
public void map(LongWritable key, Text value, OutputCollector<Text, IntWritable> output, Reporter reporter) throws IOException {
String line = value.toString();
StringTokenizer tokenizer = new StringTokenizer(line);
while (tokenizer.hasMoreTokens()) {
word.set(tokenizer.nextToken());
output.collect(word, one);
}
}
}
public static class Reduce extends MapReduceBase implements Reducer<Text, IntWritable, Text, IntWritable> {
public void reduce(Text key, Iterator<IntWritable> values, OutputCollector<Text, IntWritable> output, Reporter reporter) throws IOException {
int sum = 0;
while (values.hasNext()) {
sum += values.next().get();
}
output.collect(key, new IntWritable(sum));
}
}
public static void main(String[] args) throws Exception {
JobConf conf = new JobConf(WordCount.class);
conf.setJobName("wordcount");
conf.setOutputKeyClass(Text.class);
conf.setOutputValueClass(IntWritable.class);
conf.setMapperClass(Map.class);
conf.setCombinerClass(Reduce.class);
conf.setReducerClass(Reduce.class);
conf.setInputFormat(TextInputFormat.class);
conf.setOutputFormat(TextOutputFormat.class);
FileInputFormat.setInputPaths(conf, new Path(args[0]));
FileOutputFormat.setOutputPath(conf, new Path(args[1]));
JobClient.runJob(conf);
}
}
我需要改變地圖,減少還是兩者?如何??
有人可以請幫忙!非常感謝