you can write a EvalFuc like this:
/**
* @author haitao
*
*/
public class HEDataConverter extends EvalFunc<Tuple> {
private TupleFactory tupleFactory = TupleFactory.getInstance();
@Override
public Tuple exec(Tuple input) throws IOException {
byte[] mapValue = (byte[]) input.get(0);
List<Object> all = new ArrayList<Object>(1);
all.set(1, HEFunctions.parsePayload(mapValue));
return tupleFactory.newTuple(all);
}
@Override
public Schema outputSchema(Schema inputSchema) {
FieldSchema newFieldSchema = new FieldSchema("payload",
DataType.MAP);
return new Schema(newFieldSchema);
}
}
and you will get your map like this:
grunt> A = load '/tmp/test_file' using PigStorage(',') as (uid:long,
payload:bytearray, ts:long, type:int);
grunt> B = foreach A generate he.HEDataConverter(payload);
grunt> describe B;
B: {payload: map[]}
hope this is helpful.
在 2012-2-9，上午11:11， Russell Jurney 写道：
> Is it possible to generate maps in Pig? Is this type castable in any
> context?
>
> --
> Russell Jurney
> twitter.com/rjurney
> [email protected]
> datasyndrome.com
