Storm入门（四）WordCount示例

Storm API文档网址如下：

http://storm.apache.org/releases/current/javadocs/index.html

一、关联代码

使用maven，代码如下。

pom.xml  和Storm入门（三）HelloWorld示例相同

RandomSentenceSpout.java

/**
 * 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 cn.ljh.storm.wordcount;

import org.apache.storm.spout.SpoutOutputCollector;
import org.apache.storm.task.TopologyContext;
import org.apache.storm.topology.OutputFieldsDeclarer;
import org.apache.storm.topology.base.BaseRichSpout;
import org.apache.storm.tuple.Fields;
import org.apache.storm.tuple.Values;
import org.apache.storm.utils.Utils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Map;
import java.util.Random;

public class RandomSentenceSpout extends BaseRichSpout {
  private static final Logger LOG = LoggerFactory.getLogger(RandomSentenceSpout.class);

  SpoutOutputCollector _collector;
  Random _rand;

  public void open(Map conf, TopologyContext context, SpoutOutputCollector collector) {
    _collector = collector;
    _rand = new Random();
  }

  public void nextTuple() {
    Utils.sleep(100);
    String[] sentences = new String[]{
            sentence("the cow jumped over the moon"),
            sentence("an apple a day keeps the doctor away"),
            sentence("four score and seven years ago"),
            sentence("snow white and the seven dwarfs"),
            sentence("i am at two with nature")};
    final String sentence = sentences[_rand.nextInt(sentences.length)];

    LOG.debug("Emitting tuple: {}", sentence);

    _collector.emit(new Values(sentence));
  }

  protected String sentence(String input) {
    return input;
  }

  @Override
  public void ack(Object id) {
  }

  @Override
  public void fail(Object id) {
  }

  public void declareOutputFields(OutputFieldsDeclarer declarer) {
    declarer.declare(new Fields("word"));
  }

  // Add unique identifier to each tuple, which is helpful for debugging
  public static class TimeStamped extends RandomSentenceSpout {
    private final String prefix;

    public TimeStamped() {
      this("");
    }

    public TimeStamped(String prefix) {
      this.prefix = prefix;
    }

    protected String sentence(String input) {
      return prefix + currentDate() + " " + input;
    }

    private String currentDate() {
      return new SimpleDateFormat("yyyy.MM.dd_HH:mm:ss.SSSSSSSSS").format(new Date());
    }
  }
}

WordCountTopology.java

/**
 * 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 cn.ljh.storm.wordcount;

import org.apache.storm.Config;
import org.apache.storm.LocalCluster;
import org.apache.storm.StormSubmitter;
import org.apache.storm.task.OutputCollector;
import org.apache.storm.task.TopologyContext;
import org.apache.storm.topology.BasicOutputCollector;
import org.apache.storm.topology.IRichBolt;
import org.apache.storm.topology.OutputFieldsDeclarer;
import org.apache.storm.topology.TopologyBuilder;
import org.apache.storm.topology.base.BaseBasicBolt;
import org.apache.storm.tuple.Fields;
import org.apache.storm.tuple.Tuple;
import org.apache.storm.tuple.Values;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class WordCountTopology {
  public static class SplitSentence implements IRichBolt {
    private OutputCollector _collector;
    public void declareOutputFields(OutputFieldsDeclarer declarer) {
      declarer.declare(new Fields("word"));
    }

    public Map<String, Object> getComponentConfiguration() {
      return null;
    }

    public void prepare(Map stormConf, TopologyContext context,
            OutputCollector collector) {
        _collector = collector;
    }

    public void execute(Tuple input) {
        String sentence = input.getStringByField("word");
        String[] words = sentence.split(" ");
        for(String word : words){
            this._collector.emit(new Values(word));
        }
    }

    public void cleanup() {
        // TODO Auto-generated method stub

    }
  }

  public static class WordCount extends BaseBasicBolt {
    Map<String, Integer> counts = new HashMap<String, Integer>();

    public void execute(Tuple tuple, BasicOutputCollector collector) {
      String word = tuple.getString(0);
      Integer count = counts.get(word);
      if (count == null)
        count = 0;
      count++;
      counts.put(word, count);
      collector.emit(new Values(word, count));
    }

    public void declareOutputFields(OutputFieldsDeclarer declarer) {
      declarer.declare(new Fields("word", "count"));
    }
  }

  public static class WordReport extends BaseBasicBolt {
        Map<String, Integer> counts = new HashMap<String, Integer>();

        public void execute(Tuple tuple, BasicOutputCollector collector) {
          String word = tuple.getStringByField("word");
          Integer count = tuple.getIntegerByField("count");
          this.counts.put(word, count);
        }

        public void declareOutputFields(OutputFieldsDeclarer declarer) {

        }

        @Override
        public void cleanup() {
            System.out.println("-----------------FINAL COUNTS  START-----------------------");
            List<String> keys = new ArrayList<String>();
            keys.addAll(this.counts.keySet());
            Collections.sort(keys);

            for(String key : keys){
                System.out.println(key + " : " + this.counts.get(key));
            }

            System.out.println("-----------------FINAL COUNTS  END-----------------------");
        } 

      }

  public static void main(String[] args) throws Exception {

    TopologyBuilder builder = new TopologyBuilder();

    builder.setSpout("spout", new RandomSentenceSpout(), 5);

    //ShuffleGrouping：随机选择一个Task来发送。
    builder.setBolt("split", new SplitSentence(), 8).shuffleGrouping("spout");
    //FiledGrouping：根据Tuple中Fields来做一致性hash，相同hash值的Tuple被发送到相同的Task。
    builder.setBolt("count", new WordCount(), 12).fieldsGrouping("split", new Fields("word"));
    //GlobalGrouping：所有的Tuple会被发送到某个Bolt中的id最小的那个Task。
    builder.setBolt("report", new WordReport(), 6).globalGrouping("count");

    Config conf = new Config();
    conf.setDebug(true);

    if (args != null && args.length > 0) {
      conf.setNumWorkers(3);

      StormSubmitter.submitTopologyWithProgressBar(args[0], conf, builder.createTopology());
    }
    else {
      conf.setMaxTaskParallelism(3);

      LocalCluster cluster = new LocalCluster();
      cluster.submitTopology("word-count", conf, builder.createTopology());

      Thread.sleep(20000);

      cluster.shutdown();
    }
  }
}

二、执行效果