hadoop的MultipleOutputs多文件输出

public class Demo {
    public static class MultestMapper extends
            Mapper<Object, Text, Text, NullWritable> {
        private Text outkey = new Text("");
        private MultipleOutputs<Text, NullWritable> mos;
        protected void map(Object key, Text value, Context context)
                throws IOException, InterruptedException {
            String line = value.toString();
            if (line.contains("DOWNLOAD:")){
                outkey.set(line.substring(line.indexOf("DOWNLOAD:")+9));
                mos.write("download", outkey, NullWritable.get());
            } else if (line.contains("LOGGING:")){
                outkey.set(line.substring(line.indexOf("LOGGING:")+8));
                mos.write("logging", outkey, NullWritable.get());
            }
            else if (line.contains("MONITOR:")){
                outkey.set(line.substring(line.indexOf("MONITOR:")+8));
                mos.write("monitor", outkey, NullWritable.get());
            }
            else if (line.contains("ACTIVITIES:")){
                outkey.set(line.substring(line.indexOf("ACTIVITIES:")+11));
                mos.write("activities", outkey, NullWritable.get());
            }
        }

        @Override
        protected void setup(Context context) throws IOException,
                InterruptedException {
            mos = new MultipleOutputs<Text, NullWritable>(context);
            super.setup(context);
        }

        @Override
        protected void cleanup(Context context) throws IOException,
                InterruptedException {
            mos.close();
            super.cleanup(context);
        }
    }
    
    public static void main(String[] args) throws Exception {
        Configuration conf = new Configuration();
        String[] otherArgs = new GenericOptionsParser(conf, args)
                .getRemainingArgs();
        if (otherArgs.length != 2) {
            System.err.println("Usage: <in> <out>");
            System.exit(2);
        }
        Job job = new Job(conf, "multest");
        job.setJarByClass(Demo.class);
        job.setMapperClass(MultestMapper.class);
        job.setNumReduceTasks(0);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(NullWritable.class);
        FileInputFormat.addInputPath(job, new Path(otherArgs[0]));
        FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));
        MultipleOutputs.addNamedOutput(job, "download",TextOutputFormat.class, Text.class, NullWritable.class);
        MultipleOutputs.addNamedOutput(job, "logging",TextOutputFormat.class, Text.class, NullWritable.class);
        MultipleOutputs.addNamedOutput(job, "monitor",TextOutputFormat.class, Text.class, NullWritable.class);
        MultipleOutputs.addNamedOutput(job, "activities",TextOutputFormat.class, Text.class, NullWritable.class);
        System.exit(job.waitForCompletion(true) ? 0 : 1);
    }
}