==========================================

定義從kafka中讀出的資料

import java.io.UnsupportedEncodingException;
import java.util.List;


import backtype.storm.spout.Scheme;
import backtype.storm.tuple.Fields;
import backtype.storm.tuple.Values;


public class MessageScheme implements Scheme {

private static final long serialVersionUID = 8423372426211017613L;


@Override
public List<Object> deserialize(byte[] bytes) {
try {
String msg = new String(bytes, "UTF-8");
return new Values(msg); 
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
return null;
}


@Override
public Fields getOutputFields() {
return new Fields("msg");
}


}

==========================================

//storm的拓撲圖

import storm.kafka.BrokerHosts;

import storm.kafka.KafkaSpout;
import storm.kafka.SpoutConfig;
import storm.kafka.ZkHosts;
import backtype.storm.Config;
import backtype.storm.LocalCluster;
import backtype.storm.StormSubmitter;
import backtype.storm.spout.SchemeAsMultiScheme;
import backtype.storm.topology.TopologyBuilder;
import backtype.storm.tuple.Fields;
import cn.itcast.storm.bolt.WordSpliter;
import cn.itcast.storm.bolt.WriterBolt;
import cn.itcast.storm.spout.MessageScheme;


public class KafkaTopo {


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

String topic = "wordcount";
String zkRoot = "/kafka-storm";
String spoutId = "KafkaSpout";
BrokerHosts brokerHosts = new ZkHosts("weekend01:2181,weekend02:2181,weekend03:2181"); 
SpoutConfig spoutConfig = new SpoutConfig(brokerHosts, "wordcount", zkRoot, spoutId);
spoutConfig.forceFromStart = true;
spoutConfig.scheme = new SchemeAsMultiScheme(new MessageScheme());
TopologyBuilder builder = new TopologyBuilder();
//設定一個spout用來從kaflka訊息佇列中讀取資料併發送給下一級的bolt元件，此處用的spout元件並非自定義的，而是storm中已經開發好的KafkaSpout
builder.setSpout("KafkaSpout", new KafkaSpout(spoutConfig));
builder.setBolt("word-spilter", new WordSpliter()).shuffleGrouping(spoutId);
builder.setBolt("writer", new WriterBolt(), 4).fieldsGrouping("word-spilter", new Fields("word"));
Config conf = new Config();
conf.setNumWorkers(4);
conf.setNumAckers(0);
conf.setDebug(false);

//LocalCluster用來將topology提交到本地模擬器執行，方便開發除錯
LocalCluster cluster = new LocalCluster();
cluster.submitTopology("WordCount", conf, builder.createTopology());

//提交topology到storm叢集中執行
//StormSubmitter.submitTopology("sufei-topo", conf, builder.createTopology());
}

============================================

切分欄位的bolt

import org.apache.commons.lang.StringUtils;


import backtype.storm.topology.BasicOutputCollector;
import backtype.storm.topology.OutputFieldsDeclarer;
import backtype.storm.topology.base.BaseBasicBolt;
import backtype.storm.tuple.Fields;
import backtype.storm.tuple.Tuple;
import backtype.storm.tuple.Values;


public class WordSpliter extends BaseBasicBolt {


private static final long serialVersionUID = -5653803832498574866L;


@Override
public void execute(Tuple input, BasicOutputCollector collector) {
String line = input.getString(0);
String[] words = line.split(" ");
for (String word : words) {
word = word.trim();
if (StringUtils.isNotBlank(word)) {
word = word.toLowerCase();
collector.emit(new Values(word));
}
}
}


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


}


}

=========================================

寫資料到磁碟的bolt

import java.io.FileWriter;
import java.io.IOException;
import java.util.Map;
import java.util.UUID;


import backtype.storm.task.TopologyContext;
import backtype.storm.topology.BasicOutputCollector;
import backtype.storm.topology.OutputFieldsDeclarer;
import backtype.storm.topology.base.BaseBasicBolt;
import backtype.storm.tuple.Tuple;
/**
 * 將資料寫入檔案
 * @author [email protected]
 *
 */
public class WriterBolt extends BaseBasicBolt {


private static final long serialVersionUID = -6586283337287975719L;

private FileWriter writer = null;

@Override
public void prepare(Map stormConf, TopologyContext context) {
try {
writer = new FileWriter("c:\\storm-kafka\\" + "wordcount"+UUID.randomUUID().toString());
} catch (IOException e) {
throw new RuntimeException(e);
}
}



@Override
public void declareOutputFields(OutputFieldsDeclarer declarer) {
}


@Override
public void execute(Tuple input, BasicOutputCollector collector) {
String s = input.getString(0);
try {
writer.write(s);
writer.write("\n");
writer.flush();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
}

}