have a table called User with two columns ,one called visitorId and the other
called friend which is a list of strings. I want to check whether the VisitorId
is in the friendlist. Can anyone direct me as to how to access the table
columns
in a map function? I'm not able to picture how data is output from a map
function in hbase. My code is as follows.
ublic class MapReduce {
static class Mapper1 extends TableMapper<ImmutableBytesWritable, Text> {
private int numRecords = 0;
private static final IntWritable one = new IntWritable(1);
private final IntWritable ONE = new IntWritable(1);
private Text text = new Text();
@Override
public void map(ImmutableBytesWritable row, Result values, Context context)
throws IOException {
//What should i do here??how do i access the individual columns and
compare?
ImmutableBytesWritable userKey = new ImmutableBytesWritable(row.get(),
0, Bytes.SIZEOF_INT);
context.write(userkey,One);
}
//context.write(text, ONE);
} catch (InterruptedException e) {
throw new IOException(e);
}
}
}
public static void main(String[] args) throws Exception {
Configuration conf = HBaseConfiguration.create();
Job job = new Job(conf, "CheckVisitor");
job.setJarByClass(MapReduce.class);
Scan scan = new Scan();
Filter f = new RowFilter(CompareOp.EQUAL,new SubstringComparator("mId2"));
scan.setFilter(f);
scan.addFamily(Bytes.toBytes("visitor"));
scan.addFamily(Bytes.toBytes("friend"));
TableMapReduceUtil.initTableMapperJob("User", scan, Mapper1.class,
ImmutableBytesWritable.class,Text.class, job);
}
