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Storm WordCount
阅读量:706 次
发布时间:2019-03-17

本文共 5531 字,大约阅读时间需要 18 分钟。

本机模式示例

本机模式下,我们可以通过Storm框架实现一个从消息中间件持续读取消息的场景。每条消息作为一句话输入后,按照空格切分成多个单词,并统计每个单词的出现次数,最终打印出每个单词的出现次数。

1. 引入依赖

在项目中引入必要的依赖项,确保 Storm 核心组件和相关工具包能够正常运行。以下是核心依赖的配置:

org.apache.storm
storm-core
2.1.0
com.codahale.metrics
metrics-core
3.0.2

2. WordCountSpout

这是一个生成单词的Spout拓扑,负责持续输出需要统计的句子。以下是该拓扑的实现代码:

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;
public class WordCountSpout extends BaseRichSpout {
private SpoutOutputCollector collector;
private List
sentenceList = Arrays.asList(
"The quick brown fox jumps over the lazy dog",
"Dog does not eat dog",
"The fox may grow grey but never good"
);
@Override
public void open(Map
conf, TopologyContext context, SpoutOutputCollector collector) {
this.collector = collector;
}
@Override
public void nextTuple() {
Random rand = new Random();
String sentence = sentenceList.get(rand.nextInt(sentenceList.size()));
collector.emit(new Values(sentence));
Utils.sleep(1);
}
@Override
public void declareOutputFields(OutputFieldsDeclarer declarer) {
declarer.declare(new Fields("sentence"));
}
}

3. SplitSentenceBolt

这个Bolt拓扑负责将句子拆分成单词,并将每个单词发射到下一个拓扑。以下是其实现代码:

public class SplitSentenceBolt extends BaseRichBolt {
private OutputCollector collector;
@Override
public void prepare(Map
topoConf, TopologyContext context, OutputCollector collector) {
this.collector = collector;
}
@Override
public void execute(Tuple input) {
String sentence = input.getStringByField("sentence");
String[] words = sentence.split(" ');
for (String word : words) {
collector.emit(new Values(word));
}
collector.ack(input);
}
@Override
public void declareOutputFields(OutputFieldsDeclarer declarer) {
declarer.declare(new Fields("word"));
}
}

4. WordCountBolt

这个Bolt拓扑负责统计每个单词的出现次数,并将结果发射到下一个拓扑。以下是其实现代码:

public class WordCountBolt extends BaseRichBolt {
private OutputCollector collector;
private Map
wordCountMap = null;
@Override
public void prepare(Map
topoConf, TopologyContext context, OutputCollector collector) {
this.collector = collector;
this.wordCountMap = new HashMap<>();
}
@Override
public void execute(Tuple input) {
String word = input.getStringByField("word");
Long count = wordCountMap.get(word);
if (count == null) {
count = 0L;
}
count++;
wordCountMap.put(word, count);
collector.emit(new Values(word, count));
collector.ack(input);
}
@Override
public void declareOutputFields(OutputFieldsDeclarer declarer) {
declarer.declare(new Fields("word", "count"));
}
}

5. PrintResultBolt

这个Bolt拓扑负责将统计结果打印出来。以下是其实现代码:

public class PrintResultBolt extends BaseRichBolt {
private Map
wordCountMap = null;
@Override
public void prepare(Map
topoConf, TopologyContext context, OutputCollector collector) {
this.wordCountMap = new HashMap<>();
}
@Override
public void execute(Tuple input) {
String word = input.getStringByField("word");
Long count = input.getLongByField("count");
wordCountMap.put(word, count);
System.out.println("实时结果:" + word + " = " + count);
}
@Override
public void declareOutputFields(OutputFieldsDeclarer declarer) {
// 无需声明任何输出字段
}
@Override
public void cleanup() {
System.out.println("--------------Result------------");
List
wordList = new ArrayList<>(wordCountMap.keySet());
Collections.sort(wordList);
for (String word : wordList) {
System.out.println(word + " = " + wordCountMap.get(word));
}
System.out.println("----------------------------------");
}
}

6. WordCountTopology

这是一个用于管理所有拓扑的主类。以下是其实现代码:

public class WordCountTopology {
public static void main(String[] args) throws Exception {
TopologyBuilder builder = new TopologyBuilder();
builder.setSpout("WordCountSpout", new WordCountSpout(), 1);
builder.setBolt("SplitSentenceBolt", new SplitSentenceBolt(), 1).shuffleGrouping("WordCountSpout");
builder.setBolt("WordCountBolt", new WordCountBolt(), 1).shuffleGrouping("SplitSentenceBolt");
builder.setBolt("PrintResultBolt", new PrintResultBolt(), 1).globalGrouping("WordCountBolt");
StormTopology topology = builder.createTopology();
Config config = new Config();
config.setDebug(true);
// 集群模式下直接提交
StormSubmitter.submitTopology("WordCountTopology", config, topology);
}
}

集群模式

在集群模式下,只需通过Storm Submitter直接提交拓扑即可运行。以下是提交命令示例:

./bin/storm jar  /Users/sunnan/BigData/storm-wordcount/target/storm-wordcount-1.0-SNAPSHOT.jar  org.example.wordcount.topology.WordCountTopology

运行后可以通过Storm UI查看拓扑状态或使用命令storm list查询运行情况。通过Storm UI还可以对拓扑进行管理,如激活、暂停或杀死。

PrintResultBolt的输出结果会记录在worker.log文件中,可以通过查看这些日志来查看实时统计结果。

通过上述配置,可以在本机模式或集群模式下顺利运行词频统计的Storm拓扑。

转载地址:http://tapez.baihongyu.com/

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