Storm1.1.0<组件的并行度和组件的实例个数的关系>

软件环境：

Apache-storm-1.1.0

一个组件类的并行度与其实例化的个数有什么关系？来探索一下，
首先我配置控制台的输出，只输出日志的WARN级别以上和标准输出的信息http://blog.csdn.net/gpwner/article/details/74170806

然后利用storm-starter的例子：

import java.util.Map;

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.testing.TestWordSpout;
import org.apache.storm.topology.BasicOutputCollector;
import org.apache.storm.topology.OutputFieldsDeclarer;
import org.apache.storm.topology.TopologyBuilder;
import org.apache.storm.topology.base.BaseBasicBolt;
import org.apache.storm.topology.base.BaseRichBolt;
import org.apache.storm.tuple.Fields;
import org.apache.storm.tuple.Tuple;
import org.apache.storm.tuple.Values;
import org.apache.storm.utils.Utils;

/**
 * This is a basic example of a Storm topology.
 */
public class ExclamationTopology {
    public static class PrinterBolt extends BaseBasicBolt {
        @Override
        public void execute(Tuple tuple, BasicOutputCollector collector) {
            System.out.println(tuple);
        }

        @Override
        public void declareOutputFields(OutputFieldsDeclarer ofd) {
        }
    }

    public static class ExclamationBolt extends BaseRichBolt {
        OutputCollector _collector;

        public ExclamationBolt() {
        }

        @Override
        public void prepare(Map conf, TopologyContext context, OutputCollector collector) {
            _collector = collector;
            System.out.println("OBJECT:" + this + "   hashcode:" + this.hashCode());
        }

        @Override
        public void execute(Tuple tuple) {
            _collector.emit(tuple, new Values(tuple.getString(0) + "!!!"));
            _collector.ack(tuple);
        }

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

    public static void main(String[] args) throws Exception {
        TopologyBuilder builder = new TopologyBuilder();
        builder.setSpout("word", new TestWordSpout(), 1);
        builder.setBolt("exclaim1", new ExclamationBolt(), 10).shuffleGrouping("word");
        builder.setBolt("exclaim2", new PrinterBolt(), 1).shuffleGrouping("exclaim1");
        Config conf = new Config();
        conf.setDebug(true);
        if (args != null && args.length > 0) {
            conf.setNumWorkers(3);
            StormSubmitter.submitTopology(args[0], conf, builder.createTopology());
        } else {
            LocalCluster cluster = new LocalCluster();
            cluster.submitTopology("test", conf, builder.createTopology());
            Utils.sleep(1000000);
            cluster.killTopology("test");
            cluster.shutdown();
        }
    }
}

一个类的实例的哈希码是各不相同的，因此可以通过打印对象的哈希码来看看组件类Bolt的并行度与其实例个数的关系：

控制台信息：

OBJECT:neu.ExclamationTopology$ExclamationBolt@893f20f   hashcode:143913487
OBJECT:neu.ExclamationTopology$ExclamationBolt@174efa3   hashcode:24440739
OBJECT:neu.ExclamationTopology$ExclamationBolt@1acd5eb9   hashcode:449666745
OBJECT:neu.ExclamationTopology$ExclamationBolt@2ba329fb   hashcode:732113403
OBJECT:neu.ExclamationTopology$ExclamationBolt@4cac74ad   hashcode:1286370477
OBJECT:neu.ExclamationTopology$ExclamationBolt@74cf9261   hashcode:1959760481
OBJECT:neu.ExclamationTopology$ExclamationBolt@741325f7   hashcode:1947411959
OBJECT:neu.ExclamationTopology$ExclamationBolt@655f6a1f   hashcode:1700751903
OBJECT:neu.ExclamationTopology$ExclamationBolt@ddafc5a   hashcode:232455258
OBJECT:neu.ExclamationTopology$ExclamationBolt@1b23229e   hashcode:455287454

        TopologyBuilder builder = new TopologyBuilder();
        builder.setSpout("word", new TestWordSpout(), 1);
        builder.setBolt("exclaim1", new ExclamationBolt(), 10).shuffleGrouping("word");
        builder.setBolt("exclaim2", new PrinterBolt(), 1).shuffleGrouping("exclaim1");

我的拓扑设置的Bolt的并行度为10，从结果有可以看出这个Bolt类产生了十个不同的对象