7.3. Accessing Other HBase Tables in a MapReduce Job

Although the framework currently allows one HBase table as input to a MapReduce job, other HBase tables can be accessed as lookup tables, etc., in a MapReduce job via creating an HTable instance in the setup method of the Mapper.

public class MyMapper extends TableMapper<Text, LongWritable> {
  private HTable myOtherTable;

  public void setup(Context context) {
    myOtherTable = new HTable("myOtherTable");

  public void map(ImmutableBytesWritable row, Result value, Context context) throws IOException, InterruptedException {
	// process Result...
	// use 'myOtherTable' for lookups


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