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 io.covert.dns.storage; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.conf.Configured; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.NullWritable; import org.apache.hadoop.mapreduce.Job; import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; import org.apache.hadoop.mapreduce.lib.input.SequenceFileInputFormat; import org.apache.hadoop.mapreduce.lib.output.NullOutputFormat; import org.apache.hadoop.util.Tool; import org.apache.hadoop.util.ToolRunner; public class StorageJob extends Configured implements Tool { public static void main(String[] args) throws Exception { ToolRunner.run(new StorageJob(), args); } @Override public int run(String[] args) throws Exception { String inDir = args[0]; Configuration conf = getConf(); Job job = new Job(conf); job.setJarByClass(getClass()); job.setJobName(StorageJob.class.getSimpleName() + ": inDir=" + inDir); job.setMapperClass(StorageMapper.class); job.setNumReduceTasks(0); job.setInputFormatClass(SequenceFileInputFormat.class); FileInputFormat.setInputPaths(job, new Path(inDir)); // This job doesn't write output via Hadoop, it uses the configured storage modules job.setOutputFormatClass(NullOutputFormat.class); job.setMapOutputKeyClass(NullWritable.class); job.setMapOutputValueClass(NullWritable.class); job.setOutputKeyClass(NullWritable.class); job.setOutputValueClass(NullWritable.class); job.submit(); return job.waitForCompletion(true) ? 0 : 1; } }