在Storm中,可以通過定義Bolt來實現消息過濾和路由功能。具體步驟如下:
public class FilterBolt extends BaseRichBolt {
private OutputCollector collector;
@Override
public void prepare(Map<String, Object> topoConf, TopologyContext context, OutputCollector collector) {
this.collector = collector;
}
@Override
public void execute(Tuple input) {
// 進行消息過濾邏輯
if (/* 判斷條件 */) {
// 繼續傳遞消息
collector.emit(input, new Values(/* 消息內容 */));
} else {
// 忽略該消息
collector.ack(input);
}
}
@Override
public void declareOutputFields(OutputFieldsDeclarer declarer) {
declarer.declare(new Fields("filteredMessage"));
}
}
public class RouterBolt extends BaseRichBolt {
private OutputCollector collector;
@Override
public void prepare(Map<String, Object> topoConf, TopologyContext context, OutputCollector collector) {
this.collector = collector;
}
@Override
public void execute(Tuple input) {
// 進行消息路由邏輯
if (/* 判斷條件 */) {
// 路由到目標Bolt中
collector.emit("targetBolt", input, new Values(/* 消息內容 */));
} else {
// 路由到其他Bolt中
collector.emit("otherBolt", input, new Values(/* 消息內容 */));
}
collector.ack(input);
}
@Override
public void declareOutputFields(OutputFieldsDeclarer declarer) {
declarer.declareStream("targetBolt", new Fields("routedMessage"));
declarer.declareStream("otherBolt", new Fields("routedMessage"));
}
}
TopologyBuilder builder = new TopologyBuilder();
builder.setSpout("spout", new MySpout(), 1);
builder.setBolt("filterBolt", new FilterBolt(), 2).shuffleGrouping("spout");
builder.setBolt("routerBolt", new RouterBolt(), 2).shuffleGrouping("filterBolt");
Config conf = new Config();
conf.setDebug(true);
LocalCluster cluster = new LocalCluster();
cluster.submitTopology("myTopology", conf, builder.createTopology());
通過以上步驟,就可以在Storm中實現消息過濾和路由功能。根據具體的需求,可以進一步定制和擴展Bolt來實現更復雜的消息處理邏輯。