Java tutorial
/** * 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. */ package fire.util.fileformats.combineimagefileinputformat; import java.io.IOException; import org.apache.hadoop.conf.Configured; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.BytesWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.Job; import org.apache.hadoop.mapreduce.Mapper; import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; import org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat; import org.apache.hadoop.util.Tool; import org.apache.hadoop.util.ToolRunner; /** * MultiFileWordCount is an example to demonstrate the usage of * MultiFileInputFormat. This examples counts the occurrences of * words in the text files under the given input directory. */ public class MultiImageFilesToSequenceFiles extends Configured implements Tool { public static class MapClass extends Mapper<Text, BytesWritable, Text, BytesWritable> { private Text word = new Text(); public void map(Text key, BytesWritable value, Context context) throws IOException, InterruptedException { context.write(key, value); } } private void printUsage() { System.out.println("Usage : multifilewc <input_dir> <output>"); } public int run(String[] args) throws Exception { if (args.length < 2) { printUsage(); return 2; } Job job = new Job(getConf()); job.setJobName("MultiImageFilesToSequenceFiles"); job.setJarByClass(MultiImageFilesToSequenceFiles.class); //set the InputFormat of the job to our InputFormat job.setInputFormatClass(CombineFileImageInputFormat.class); job.setOutputFormatClass(SequenceFileOutputFormat.class); // the keys are words (strings) job.setOutputKeyClass(Text.class); // the values are images job.setOutputValueClass(BytesWritable.class); //use the defined mapper job.setMapperClass(MapClass.class); FileInputFormat.addInputPaths(job, args[0]); FileOutputFormat.setOutputPath(job, new Path(args[1])); return job.waitForCompletion(true) ? 0 : 1; } public static void main(String[] args) throws Exception { int ret = ToolRunner.run(new MultiImageFilesToSequenceFiles(), args); System.exit(ret); } }