storm

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遇到的问题

maven缺少依赖，下不了jar包
在网上找了篇博客

修改 Maven 的配置文件（安装目录下的 conf/settings.xml 文件），将 <mirrors>..</mirrors> 间的内容改为:

<mirrors>
    <!-- mirror | Specifies a repository mirror site to use instead of a given 
        repository. The repository that | this mirror serves has an ID that matches 
        the mirrorOf element of this mirror. IDs are used | for inheritance and direct 
        lookup purposes, and must be unique across the set of mirrors. | -->
    <mirror>
        <id>nexus-osc</id>
        <mirrorOf>central</mirrorOf>
        <name>Nexus osc</name>
        <url>http://maven.oschina.net/content/groups/public/</url>
    </mirror>
    <mirror>
        <id>nexus-osc-thirdparty</id>
        <mirrorOf>thirdparty</mirrorOf>
        <name>Nexus osc thirdparty</name>
        <url>http://maven.oschina.net/content/repositories/thirdparty/</url>
    </mirror>
</mirrors>

以及将 <profile>...<profile> 之间的内容改为：

<profile>
    <id>jdk-1.4</id>
 
    <activation>
        <jdk>1.4</jdk>
    </activation>
 
    <repositories>
        <repository>
            <id>nexus</id>
            <name>local private nexus</name>
            <url>http://maven.oschina.net/content/groups/public/</url>
            <releases>
                <enabled>true</enabled>
            </releases>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>nexus</id>
            <name>local private nexus</name>
            <url>http://maven.oschina.net/content/groups/public/</url>
            <releases>
                <enabled>true</enabled>
            </releases>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </pluginRepository>
    </pluginRepositories>
</profile>

改好后保存，再次执行 maven ... 应该就可以了。

第一个小程序，数字累加

public class StormDemo {
   /**
   * 创建spout
   * @author Administrator
   *
   */
   public static class MySpout extends BaseRichSpout{
       Map conf;
       TopologyContext context;
       SpoutOutputCollector collector;

       int i;
       //这是一个死循环，会不停的被调用
       public void nextTuple() {
           this.collector.emit(new Values(i++));


       }
       /**
       * 初始化方法，只会被执行一次，在这里面可以执行一些初始化的操作
       * Map conf 配置类，tolplogy的配置信息
       * TopologyContext context tolplogy的上下文
       * SpoutOutputCollector collector 发射器，向外发射数据
       */
       public void open(Map conf, TopologyContext context, SpoutOutputCollector collector) {
           this.conf = conf;
           this.context = context;
           this.collector = collector;

       }
       //声明输出字段，给发送出去的数据相应的起个名字
       public void declareOutputFields(OutputFieldsDeclarer declarer) {
           declarer.declare(new Fields("num"));

       }

   }

   public static class MyBolt extends BaseRichBolt{

       Map stormConf;
       TopologyContext context;
       OutputCollector collector;

       int sum;
       //会被循环调用，只要spout发送一个tuple，这边就会被调用一次
       public void execute(Tuple input) {
           Integer value = input.getIntegerByField("num");
           sum += value;
           System.out.println("sum="+sum);

       }

       public void prepare(Map stormConf, TopologyContext context, OutputCollector collector) {
           this.stormConf = stormConf;
           this.context = context;
           this.collector = collector;

       }
       //只有spout中的nexttuple或者bolt中的execute中执行了emit发射功能，才需要在这里声明输出字段
       public void declareOutputFields(OutputFieldsDeclarer arg0) {


       }

   }

   public static void main(String[] args) {
       TopologyBuilder topologyBuilder = new TopologyBuilder();
       topologyBuilder.setSpout("aa", new MySpout());
       topologyBuilder.setBolt("bb", new MyBolt()).shuffleGrouping("aa");
       //创建一个本地集群来运行topology任务
       LocalCluster localCluster = new LocalCluster();
       localCluster.submitTopology("localTopology", new Config(), topologyBuilder.createTopology());
   }
}

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