public static Path getMobTableDir(Configuration conf, TableName tableName) {
    return getMobTableDir(new Path(conf.get(HConstants.HBASE_DIR)), tableName);
  }
Gets the table dir of the mob files under the qualified HBase root dir. It's
{rootDir}/mobdir/data/${namespace}/${tableName}
@param rootDir   The qualified path of HBase root directory.
@param tableName The name of table.
@return The table dir of the mob file.
hbase-server/src/main/java/org/apache/hadoop/hbase/mob/MobUtils.java