java - Hadoop: Using a Custom Object in a Mapper's Output -
i new hadoop , stumped something: what i'm trying take in list of text-entries in files , have initial mapper crunching on them , output customized object aggregated reducer. i put framework using text values ok--but when try change using our own objects, npe (shown below) here driver's run(): jobconf conf = new jobconf( getconf(), vectorconpreprocessor.class ); conf.setjobname( job_name + " - " + job_isodate ); m_log.info("job name: " + conf.getjobname() ); // need change chain-mapper later on . . . . conf.setinputformat( textinputformat.class ); // reading text files conf.setmapperclass( mapmvandsamples.class ); conf.setmapoutputvalueclass( sparsenessfilter.class ); //conf.setcombinerclass( combinesparsenesstrackers.class ); // not using combiner, because nodes must gathered before reduction conf.setreducerclass( reducesparsenesstrackers.class ); // not sure reducing required here . . . . conf...