*************************************************************** *GroupingComparator: SecondarySortBasicGroupingComparator *************************************************************** import org.apache.hadoop.io.WritableComparable; import org.apache.hadoop.io.WritableComparator; public class SecondarySortBasicGroupingComparator extends WritableComparator { protected SecondarySortBasicGroupingComparator() { super(CompositeKeyWritable.class, true); } @Override public int compare(WritableComparable w1, WritableComparable w2) { CompositeKeyWritable key1 = (CompositeKeyWritable) w1; CompositeKeyWritable key2 = (CompositeKeyWritable) w2; return key1.getDeptNo().compareTo(key2.getDeptNo()); } }