An Apache Storm bolt receive multiple input tuples from different spout/bolt

问题

Is it possible for a bolt receive multiple input tuples from different spout/bolt? For instance, Bolt C receive input tuples from Spout A and input tuples from Bolt B to be processed. How should I implement it? I mean writing the Java code for Bolt C and also its topology.

回答1:

Tutorial answers your question.

https://storm.apache.org/documentation/Tutorial.html

Here is the code for your goal(C/P from tutorial):

builder.setBolt("exclaim2", new ExclamationBolt(), 5)
            .shuffleGrouping("words")
            .shuffleGrouping("exclaim1");

exclaim2 will accept tuples from both words and exclaim1, both using shuffle grouping.

回答2:

Yes Possible. Only thing to take care is it should follow DAG structure. In your case, below is the flow. 1. Spout reads the data and sends to bolt C 2. Same Spout reads the data and sends to bolt B 3. Bolt B filters some data and forwards to Bolt C

来源：https://stackoverflow.com/questions/30410661/an-apache-storm-bolt-receive-multiple-input-tuples-from-different-spout-bolt