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这篇文章主要讲解了“Storm 怎么写一个爬虫”，文中的讲解内容简单清晰，易于学习与理解，下面请大家跟着丸趣 TV 小编的思路慢慢深入，一起来研究和学习“Storm 怎么写一个爬虫”吧！
package com.digitalpebble.storm.crawler.bolt.indexing;
import java.util.Map;
import org.slf4j.LoggerFactory;
import backtype.storm.task.OutputCollector;
import backtype.storm.task.TopologyContext;
import backtype.storm.topology.OutputFieldsDeclarer;
import backtype.storm.topology.base.BaseRichBolt;
import backtype.storm.tuple.Tuple;
import com.digitalpebble.storm.crawler.StormConfiguration;
import com.digitalpebble.storm.crawler.util.Configuration;
* A generic bolt for indexing documents which determines which endpoint to use
* based on the configuration and delegates the indexing to it.
***/
@SuppressWarnings(serial)
public class IndexerBolt extends BaseRichBolt {
private Configuration config;
private BaseRichBolt endpoint;
private static final org.slf4j.Logger LOG = LoggerFactory
.getLogger(IndexerBolt.class);
public void prepare(Map conf, TopologyContext context,
OutputCollector collector) { config = StormConfiguration.create();
// get the implementation to use
// and instanciate it
String className = config.get( stormcrawler.indexer.class
if (className == null) {
throw new RuntimeException( No configuration found for indexing
}
try { final Class BaseRichBolt implClass = (Class BaseRichBolt) Class
.forName(className);
endpoint = implClass.newInstance();
} catch (final Exception e) { throw new RuntimeException( Couldn t create + className, e);
}
if (endpoint != null)
endpoint.prepare(conf, context, collector);
}
public void execute(Tuple tuple) { if (endpoint != null)
endpoint.execute(tuple);
}
public void declareOutputFields(OutputFieldsDeclarer declarer) { if (endpoint != null)
endpoint.declareOutputFields(declarer);
}
}感谢各位的阅读，以上就是“Storm 怎么写一个爬虫”的内容了，经过本文的学习后，相信大家对 Storm 怎么写一个爬虫这一问题有了更深刻的体会，具体使用情况还需要大家实践验证。这里是丸趣 TV，丸趣 TV 小编将为大家推送更多相关知识点的文章，欢迎关注！
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