how to change the datatype of mapper input key?

[DataFlair Team]

how to change the datatype of mapper input key?

[DataFlair Team]

The mapperclass definition is as follows :
Class Mapper<KEYIN,VALUEIN,KEYOUT,VALUEOUT>

KEYIN = Mapper input key ( input for Mapper )
VALUEIN = Mapper input value ( input for Mapper )
KEYOUT = Mapper output key ( Output of Mapper, input of Reducer)
VALUEOUT = Mapper output value ( Output of Mapper, input to Reducer)

The class definition has both the input and output type. Here we specify the datatypes.
So to change the datatype of mapper input key , you will need to change the definition of your mapper class

e.g : public class UserMapper extends Mapper<LongWritable, Text, Text, IntWritable>
so the input key is LongWritable , here if we wanty we can change mapper input key to any other desired datatype.

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