MapReduce的Map阶段的指定Combiner

String pathInput = "/tq/in"; String pathOutput = "/tq/out"; String jobName = "mrqt"; int intNumReduceTasks = 2; Configuration conf = null; // job conf = new Configuration(true); Job job = Job.getInstance(conf); job.setJarByClass(mrTQ.class); job.setJobName(jobName); // in out Path pathOut = new Path(pathOutput); Path pathIn = new Path(pathInput); if (!pathIn.getFileSystem(conf).exists(new Path(pathInput + "/tq.txt"))) { System.out.println("[ERROR]:there is no tq.txt"); } else { System.out.println("[OK]:there is a tq.txt"); } if (pathOut.getFileSystem(conf).exists(pathOut)) { pathOut.getFileSystem(conf).delete(pathOut, true); } FileInputFormat.addInputPath(job, pathIn); FileOutputFormat.setOutputPath(job, pathOut); // map job.setMapperClass(mrTQ.MyMapper.class); //// job.setCombinerClass(cls);//not used job.setMapOutputKeyClass(TQ.class); job.setMapOutputValueClass(IntWritable.class); job.setPartitionerClass(mrTQ.MyPartitioner.class); job.setSortComparatorClass(mrTQ.MySort.class); // re job.setReducerClass(mrTQ.MyReducer.class); job.setGroupingComparatorClass(mrTQ.MyGroup.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(NullWritable.class); job.setNumReduceTasks(intNumReduceTasks); // submit job.waitForCompletion(true); System.out.println("[LOG:]" + jobName + "success!!!!YYH-@bj"); String pathInput = "/tq/in"; String pathOutput =