我试图从reducer将（键和值）写入不同的文件，但我只得到一个键和值的输出文件。

public static class Reduce
   extends Reducer<Text,Text,Text,Text> {
  private MultipleOutputs <Text,Text>mos;
@Override
protected void setup(Context context) throws IOException,           InterruptedException {      
    super.setup(context);
}
public void reduce(Text key, Text values, Context context ) throws IOException, InterruptedException {      
     mos.write(key.toString(),values, key); }  

@Override
    protected void cleanup(Context context) throws IOException,
            InterruptedException {
        super.cleanup(context);
    }   
}// end Reducer

//驱动程序：包含多个输出

job.setMapperClass(Map.class);
    job.setReducerClass(Reduce.class);
    job.setCombinerClass(Reduce.class);
    job.setInputFormatClass(TextInputFormat.class);
    job.setOutputFormatClass(TextOutputFormat.class);
    // set output key type   
    job.setOutputKeyClass(Text.class);
    // set output value type
    job.setOutputValueClass(Text.class);
    //set the HDFS path of the input data
    FileInputFormat.addInputPath(job, new Path(otherArgs[0]));
    // set the HDFS path for the output
    FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));
   //multiple output files
    MultipleOutputs.addNamedOutput(job, "express", TextOutputFormat.class, Text.class, Text.class);