Grep.java
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上传日期:2018-01-08
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- /**
- * 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 org.apache.hadoop.examples;
- import java.util.Random;
- import org.apache.hadoop.conf.Configuration;
- import org.apache.hadoop.conf.Configured;
- import org.apache.hadoop.fs.FileSystem;
- import org.apache.hadoop.fs.Path;
- import org.apache.hadoop.io.LongWritable;
- import org.apache.hadoop.io.Text;
- import org.apache.hadoop.mapred.*;
- import org.apache.hadoop.mapred.lib.*;
- import org.apache.hadoop.util.Tool;
- import org.apache.hadoop.util.ToolRunner;
- /* Extracts matching regexs from input files and counts them. */
- public class Grep extends Configured implements Tool {
- private Grep() {} // singleton
- public int run(String[] args) throws Exception {
- if (args.length < 3) {
- System.out.println("Grep <inDir> <outDir> <regex> [<group>]");
- ToolRunner.printGenericCommandUsage(System.out);
- return -1;
- }
- Path tempDir =
- new Path("grep-temp-"+
- Integer.toString(new Random().nextInt(Integer.MAX_VALUE)));
- JobConf grepJob = new JobConf(getConf(), Grep.class);
-
- try {
-
- grepJob.setJobName("grep-search");
- FileInputFormat.setInputPaths(grepJob, args[0]);
- grepJob.setMapperClass(RegexMapper.class);
- grepJob.set("mapred.mapper.regex", args[2]);
- if (args.length == 4)
- grepJob.set("mapred.mapper.regex.group", args[3]);
- grepJob.setCombinerClass(LongSumReducer.class);
- grepJob.setReducerClass(LongSumReducer.class);
- FileOutputFormat.setOutputPath(grepJob, tempDir);
- grepJob.setOutputFormat(SequenceFileOutputFormat.class);
- grepJob.setOutputKeyClass(Text.class);
- grepJob.setOutputValueClass(LongWritable.class);
- JobClient.runJob(grepJob);
- JobConf sortJob = new JobConf(Grep.class);
- sortJob.setJobName("grep-sort");
- FileInputFormat.setInputPaths(sortJob, tempDir);
- sortJob.setInputFormat(SequenceFileInputFormat.class);
- sortJob.setMapperClass(InverseMapper.class);
- sortJob.setNumReduceTasks(1); // write a single file
- FileOutputFormat.setOutputPath(sortJob, new Path(args[1]));
- sortJob.setOutputKeyComparatorClass // sort by decreasing freq
- (LongWritable.DecreasingComparator.class);
- JobClient.runJob(sortJob);
- }
- finally {
- FileSystem.get(grepJob).delete(tempDir, true);
- }
- return 0;
- }
- public static void main(String[] args) throws Exception {
- int res = ToolRunner.run(new Configuration(), new Grep(), args);
- System.exit(res);
- }
- }