本文演示如何在Eclipse中开发一个Map/Reduce项目: 1、环境说明 Hadoop2.2.0 Eclipse?Juno SR2 Hadoop2.x-eclipse-plugin 插件的编译安装配置的过程参考:http://www.micmiu.com/bigdata/hadoop/hadoop2-x-eclipse-plugin-build-install/ 2、新建MR工程 依次
本文演示如何在Eclipse中开发一个Map/Reduce项目: 1、环境说明package com.micmiu.mr; /** * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import java.io.IOException; import java.util.StringTokenizer; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.IntWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.Job; import org.apache.hadoop.mapreduce.Mapper; import org.apache.hadoop.mapreduce.Reducer; import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; import org.apache.hadoop.util.GenericOptionsParser; public class WordCount { public static class TokenizerMapper extends Mapper<object text intwritable>{ private final static IntWritable one = new IntWritable(1); private Text word = new Text(); public void map(Object key, Text value, Context context ) throws IOException, InterruptedException { StringTokenizer itr = new StringTokenizer(value.toString()); while (itr.hasMoreTokens()) { word.set(itr.nextToken()); context.write(word, one); } } } public static class IntSumReducer extends Reducer<text> { private IntWritable result = new IntWritable(); public void reduce(Text key, Iterable<intwritable> values, Context context ) throws IOException, InterruptedException { int sum = 0; for (IntWritable val : values) { sum += val.get(); } result.set(sum); context.write(key, result); } } public static void main(String[] args) throws Exception { Configuration conf = new Configuration(); String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs(); if (otherArgs.length != 2) { System.err.println("Usage: wordcount <in> <out>"); System.exit(2); } //conf.set("fs.defaultFS", "hdfs://192.168.6.77:9000"); Job job = new Job(conf, "word count"); job.setJarByClass(WordCount.class); job.setMapperClass(TokenizerMapper.class); job.setCombinerClass(IntSumReducer.class); job.setReducerClass(IntSumReducer.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(IntWritable.class); FileInputFormat.addInputPath(job, new Path(otherArgs[0])); FileOutputFormat.setOutputPath(job, new Path(otherArgs[1])); System.exit(job.waitForCompletion(true) ? 0 : 1); } }</out></in></intwritable></text></object>
Hi Michael welcome to Hadoop more see micmiu.com
Hi Michael welcome to BigData more see micmiu.com
Hi Michael welcome to Spark more see micmiu.com
micmiu-mbp:Downloads micmiu$ hdfs dfs -copyFromLocal micmiu-*.txt /user/micmiu/test/input micmiu-mbp:Downloads micmiu$ hdfs dfs -ls /user/micmiu/test/input Found 3 items -rw-r--r-- 1 micmiu supergroup 50 2014-04-15 14:53 /user/micmiu/test/input/micmiu-01.txt -rw-r--r-- 1 micmiu supergroup 50 2014-04-15 14:53 /user/micmiu/test/input/micmiu-02.txt -rw-r--r-- 1 micmiu supergroup 49 2014-04-15 14:53 /user/micmiu/test/input/micmiu-03.txt micmiu-mbp:Downloads micmiu$
原文地址:eclipse中开发Hadoop2.x的Map/Reduce项目, 感谢原作者分享。