Java tutorial
/* * Copyright 2013 Alec Ten Harmsel * * Licensed 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. */ /* * FileCombine * * Used to combine large files */ package com.alectenharmsel.research; import java.util.ArrayList; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.BufferedOutputStream; import java.io.IOException; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.LongWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; import org.apache.hadoop.mapreduce.*; import org.apache.hadoop.util.Tool; import org.apache.hadoop.util.ToolRunner; import org.apache.hadoop.util.GenericOptionsParser; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.conf.Configured; public class FileCombine extends Configured implements Tool { public FileCombine() { } public int run(String[] args) throws Exception { if (args.length != 2) { System.err.println("Usage: FileCombine <input> <output>"); System.exit(-1); } Job job = new Job(getConf(), "FileCombine"); job.setJarByClass(FileCombine.class); FileInputFormat.addInputPath(job, new Path(args[0])); FileOutputFormat.setOutputPath(job, new Path(args[1])); job.setMapperClass(FileCombineMapper.class); job.setReducerClass(FileCombineReducer.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(LongWritable.class); return job.waitForCompletion(true) ? 0 : 1; } public static void main(String[] args) throws Exception { GenericOptionsParser parse = new GenericOptionsParser(new Configuration(), args); Configuration conf = parse.getConfiguration(); int res = ToolRunner.run(conf, new FileCombine(), parse.getRemainingArgs()); System.exit(res); } }