在自定义键的情况下，如何为自定义分区程序设置numReduceTask

Question

HashPartitioner<Text,Text> hash=new HashPartitioner<Text,Text>();

@Override
public int getPartition(CompositeKeyClass keyClass, Text valClass, int numOfPartition) {
    // TODO Auto-generated method stub
    try {       
        String[] type=valClass.toString().split(",");

        if(type[0].equals("Mapper1")) {
            return (hash.getPartition(keyClass.getFirst(), valClass, numOfPartition))%numOfPartition;
        } else {
            return (hash.getPartition(keyClass.getFirst(), valClass, numOfPartition))%numOfPartition;   
        }
    }
}

I am using the above code in the Partitioner class to get the key for my custom class. All works fine but I want that the value that has the text "Mapper1" sent to first reducer and the other one sent to second. How can I achieve that? I have set job.numOfReduceTaks to 2. Please help!

Answer 1

This is a static decision right? Try this:

if (type[0].equals("Mapper1")) {
    return 0;
} else {
    return 1;
}

And yes, in driver you need to set job.numOfReduceTaks to 2. You did it right.