Storm常见模式——BasicBolt

public static class WordCount extends BaseBasicBolt {
　　　　　//记录每个单词及单词出现的次数
        Map<String, Integer> counts = new HashMap<String, Integer>();

        @Override
        public void execute(Tuple tuple, BasicOutputCollector collector) {
            String word = tuple.getString(0);
            Integer count = counts.get(word); //提取单词出现次数
            if(count==null)
　　　　　　　　　count = 0;
            count++;
            counts.put(word, count); //更新单词出现次数
            collector.emit(new Values(word, count)); //发射统计结果
        }

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