Java JobConf.setMapOutputKeyClass方法代碼示例

import org.apache.hadoop.mapred.JobConf; //導入方法依賴的package包/類
/**
 * Sets up the job for reading from one or more multiple table snapshots, with one or more scans
 * per snapshot.
 * It bypasses hbase servers and read directly from snapshot files.
 *
 * @param snapshotScans     map of snapshot name to scans on that snapshot.
 * @param mapper            The mapper class to use.
 * @param outputKeyClass    The class of the output key.
 * @param outputValueClass  The class of the output value.
 * @param job               The current job to adjust.  Make sure the passed job is
 *                          carrying all necessary HBase configuration.
 * @param addDependencyJars upload HBase jars and jars for any of the configured
 *                          job classes via the distributed cache (tmpjars).
 */
public static void initMultiTableSnapshotMapperJob(Map<String, Collection<Scan>> snapshotScans,
    Class<? extends TableMap> mapper, Class<?> outputKeyClass, Class<?> outputValueClass,
    JobConf job, boolean addDependencyJars, Path tmpRestoreDir) throws IOException {
  MultiTableSnapshotInputFormat.setInput(job, snapshotScans, tmpRestoreDir);

  job.setInputFormat(MultiTableSnapshotInputFormat.class);
  if (outputValueClass != null) {
    job.setMapOutputValueClass(outputValueClass);
  }
  if (outputKeyClass != null) {
    job.setMapOutputKeyClass(outputKeyClass);
  }
  job.setMapperClass(mapper);
  if (addDependencyJars) {
    addDependencyJars(job);
  }

  org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil.resetCacheConfig(job);
}
 

import org.apache.hadoop.mapred.JobConf; //導入方法依賴的package包/類
/**
 * Use this before submitting a TableMap job. It will
 * appropriately set up the JobConf.
 *
 * @param table  The table name to read from.
 * @param columns  The columns to scan.
 * @param mapper  The mapper class to use.
 * @param outputKeyClass  The class of the output key.
 * @param outputValueClass  The class of the output value.
 * @param job  The current job configuration to adjust.
 * @param addDependencyJars upload HBase jars and jars for any of the configured
 *           job classes via the distributed cache (tmpjars).
 */
public static void initTableMapJob(String table, String columns,
  Class<? extends TableMap> mapper,
  Class<?> outputKeyClass,
  Class<?> outputValueClass, JobConf job, boolean addDependencyJars,
  Class<? extends InputFormat> inputFormat) {

  job.setInputFormat(inputFormat);
  job.setMapOutputValueClass(outputValueClass);
  job.setMapOutputKeyClass(outputKeyClass);
  job.setMapperClass(mapper);
  job.setStrings("io.serializations", job.get("io.serializations"),
      MutationSerialization.class.getName(), ResultSerialization.class.getName());
  FileInputFormat.addInputPaths(job, table);
  job.set(TableInputFormat.COLUMN_LIST, columns);
  if (addDependencyJars) {
    try {
      addDependencyJars(job);
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
  try {
    initCredentials(job);
  } catch (IOException ioe) {
    // just spit out the stack trace?  really?
    ioe.printStackTrace();
  }
}
 

import org.apache.hadoop.mapred.JobConf; //導入方法依賴的package包/類
public static JobConf createDataJoinJob(String args[]) throws IOException {

    String inputDir = args[0];
    String outputDir = args[1];
    Class inputFormat = SequenceFileInputFormat.class;
    if (args[2].compareToIgnoreCase("text") != 0) {
      System.out.println("Using SequenceFileInputFormat: " + args[2]);
    } else {
      System.out.println("Using TextInputFormat: " + args[2]);
      inputFormat = TextInputFormat.class;
    }
    int numOfReducers = Integer.parseInt(args[3]);
    Class mapper = getClassByName(args[4]);
    Class reducer = getClassByName(args[5]);
    Class mapoutputValueClass = getClassByName(args[6]);
    Class outputFormat = TextOutputFormat.class;
    Class outputValueClass = Text.class;
    if (args[7].compareToIgnoreCase("text") != 0) {
      System.out.println("Using SequenceFileOutputFormat: " + args[7]);
      outputFormat = SequenceFileOutputFormat.class;
      outputValueClass = getClassByName(args[7]);
    } else {
      System.out.println("Using TextOutputFormat: " + args[7]);
    }
    long maxNumOfValuesPerGroup = 100;
    String jobName = "";
    if (args.length > 8) {
      maxNumOfValuesPerGroup = Long.parseLong(args[8]);
    }
    if (args.length > 9) {
      jobName = args[9];
    }
    Configuration defaults = new Configuration();
    JobConf job = new JobConf(defaults, DataJoinJob.class);
    job.setJobName("DataJoinJob: " + jobName);

    FileSystem fs = FileSystem.get(defaults);
    fs.delete(new Path(outputDir), true);
    FileInputFormat.setInputPaths(job, inputDir);

    job.setInputFormat(inputFormat);

    job.setMapperClass(mapper);
    FileOutputFormat.setOutputPath(job, new Path(outputDir));
    job.setOutputFormat(outputFormat);
    SequenceFileOutputFormat.setOutputCompressionType(job,
            SequenceFile.CompressionType.BLOCK);
    job.setMapOutputKeyClass(Text.class);
    job.setMapOutputValueClass(mapoutputValueClass);
    job.setOutputKeyClass(Text.class);
    job.setOutputValueClass(outputValueClass);
    job.setReducerClass(reducer);

    job.setNumMapTasks(1);
    job.setNumReduceTasks(numOfReducers);
    job.setLong("datajoin.maxNumOfValuesPerGroup", maxNumOfValuesPerGroup);
    return job;
  }
 

import org.apache.hadoop.mapred.JobConf; //導入方法依賴的package包/類
/**
 * Adds a Mapper class to the chain job's JobConf.
 * <p>
 * It has to be specified how key and values are passed from one element of
 * the chain to the next, by value or by reference. If a Mapper leverages the
 * assumed semantics that the key and values are not modified by the collector
 * 'by value' must be used. If the Mapper does not expect this semantics, as
 * an optimization to avoid serialization and deserialization 'by reference'
 * can be used.
 * <p>
 * For the added Mapper the configuration given for it,
 * <code>mapperConf</code>, have precedence over the job's JobConf. This
 * precedence is in effect when the task is running.
 * <p>
 * IMPORTANT: There is no need to specify the output key/value classes for the
 * ChainMapper, this is done by the addMapper for the last mapper in the chain
 * <p>
 *
 * @param job              job's JobConf to add the Mapper class.
 * @param klass            the Mapper class to add.
 * @param inputKeyClass    mapper input key class.
 * @param inputValueClass  mapper input value class.
 * @param outputKeyClass   mapper output key class.
 * @param outputValueClass mapper output value class.
 * @param byValue          indicates if key/values should be passed by value
 * to the next Mapper in the chain, if any.
 * @param mapperConf       a JobConf with the configuration for the Mapper
 * class. It is recommended to use a JobConf without default values using the
 * <code>JobConf(boolean loadDefaults)</code> constructor with FALSE.
 */
public static <K1, V1, K2, V2> void addMapper(JobConf job,
                         Class<? extends Mapper<K1, V1, K2, V2>> klass,
                         Class<? extends K1> inputKeyClass,
                         Class<? extends V1> inputValueClass,
                         Class<? extends K2> outputKeyClass,
                         Class<? extends V2> outputValueClass,
                         boolean byValue, JobConf mapperConf) {
  job.setMapperClass(ChainMapper.class);
  job.setMapOutputKeyClass(outputKeyClass);
  job.setMapOutputValueClass(outputValueClass);
  Chain.addMapper(true, job, klass, inputKeyClass, inputValueClass,
                  outputKeyClass, outputValueClass, byValue, mapperConf);
}