ReduceTask.java 文件源码

public MapOutputCopier(JobConf job, Reporter reporter, SecretKey jobTokenSecret) {
  setName("MapOutputCopier " + reduceTask.getTaskID() + "." + id);
  LOG.debug(getName() + " created");
  this.reporter = reporter;

  this.jobTokenSecret = jobTokenSecret;

  shuffleConnectionTimeout =
    job.getInt("mapreduce.reduce.shuffle.connect.timeout", STALLED_COPY_TIMEOUT);
  shuffleReadTimeout =
    job.getInt("mapreduce.reduce.shuffle.read.timeout", DEFAULT_READ_TIMEOUT);

  if (job.getCompressMapOutput()) {
    Class<? extends CompressionCodec> codecClass =
      job.getMapOutputCompressorClass(DefaultCodec.class);
    codec = ReflectionUtils.newInstance(codecClass, job);
    decompressor = CodecPool.getDecompressor(codec);
  }
}