This is the default ImportTSVMapper that is in the ImportTsv utility. This project can be used to develop a new mapper and override the default mapper in the ImportTSV. See below the system property to override the mapper.
Usage: importtsv -Dimporttsv.columns=a,b,c -Dimporttsv.mapper.class=my.Mapper - A user-defined Mapper to use instead of org.apache.hadoop.hbase.mapreduce.TsvImporterMapper