storm 随机发送字符串

Storm的程序叫做Topology,类似MapReduce job

一个Topolog应该有Spout，代表数据源，和若干个bolt

首先写一个Spout

public class RandomSpout extends BaseRichSpout {

	private String[] names = new String[]{"zhangsan", "lisi", "wangwu", "zhaoliu"};

	private SpoutOutputCollector collector;
	/**
	 * 初始化方法
	 */
	@Override
	public void open(Map conf, TopologyContext context,
			SpoutOutputCollector collector) {

		this.collector = collector;
	}

	/**
	 * 发射一个Tuple到Topology都是通过这个方法来实现的
	 */
	@Override
	public void nextTuple() {
		this.collector.emit(new Values(names[new Random().nextInt(names.length)]));
	}

	/**
	 * 此方法用于声明当前Spout的Tuple发送流， 声明tuple中的字段的名称
	 */
	@Override
	public void declareOutputFields(OutputFieldsDeclarer declarer) {
		declarer.declare(new Fields("name"));
	}

}

写一个字符串大写的bolt

public class UpperBolt extends BaseBasicBolt{

	/**
	 * bolt的核心方法，主要负责对数据进行处理
	 */
	@Override
	public void execute(Tuple input, BasicOutputCollector collector) {
		collector.emit(new Values(input.getString(0).toUpperCase()));
	}

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

写一个输出到文件的bolt

public class ExtBolt extends BaseBasicBolt{
	FileWriter fileWriter = null;

	@Override
	public void prepare(Map stormConf, TopologyContext context) {
		// /home/hemingliang
		File file = new File("/home/hadoop/stormoutput/"
				+ UUID.randomUUID());
		try {
			fileWriter = new FileWriter(file);
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	@Override
	public void execute(Tuple input, BasicOutputCollector collector) {
		String name = input.getString(0);
		name = name + "_\n";
		try {
			fileWriter.write(name);
			fileWriter.flush();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	@Override
	public void declareOutputFields(OutputFieldsDeclarer declarer) {

	}

	@Override
	public void cleanup() {
		try {
			fileWriter.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

}

　

打成jar包，比如为 storm.jar

stormoutput目录应该存在，不然看不到数据

执行 storm.jar ： ./storm jar ~/storm.jar com.storm.RunTopology

列出所有的Topology ：  ./storm list

接触一个Topology  : ./storm kill topology名称