本文整理了Java中org.apache.hadoop.mapred.RecordReader.next方法的一些代码示例，展示了RecordReader.next的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。RecordReader.next方法的具体详情如下：
包路径：org.apache.hadoop.mapred.RecordReader
类名称：RecordReader
方法名：next

RecordReader.next介绍

[英]Reads the next key/value pair from the input for processing.
[中]从输入中读取下一个键/值对进行处理。

代码示例

代码示例来源：origin: apache/flink

protected void fetchNext() throws IOException {
  hasNext = this.recordReader.next(key, value);
  fetched = true;
}

代码示例来源：origin: apache/hive

/**
 * If the current batch is empty, get a new one.
 * @return true if we have rows available.
 */
private boolean ensureBatch() throws IOException {
 if (rowInBatch >= batch.size) {
  rowInBatch = 0;
  return vrbReader.next(key, batch) && batch.size > 0;
 }
 return true;
}

代码示例来源：origin: apache/hive

@Override
public boolean next() throws IOException {
 return sourceReader.next(key, value);
}

代码示例来源：origin: apache/drill

/**
 * If the current batch is empty, get a new one.
 * @return true if we have rows available.
 */
private boolean ensureBatch() throws IOException {
 if (rowInBatch >= batch.size) {
  rowInBatch = 0;
  return vrbReader.next(key, batch) && batch.size > 0;
 }
 return true;
}

代码示例来源：origin: apache/hive

/**
 * Skip header lines in the table file when reading the record.
 *
 * @param currRecReader
 *          Record reader.
 *
 * @param headerCount
 *          Header line number of the table files.
 *
 * @param key
 *          Key of current reading record.
 *
 * @param value
 *          Value of current reading record.
 *
 * @return Return true if there are 0 or more records left in the file
 *         after skipping all headers, otherwise return false.
 */
public static boolean skipHeader(RecordReader<WritableComparable, Writable> currRecReader,
  int headerCount, WritableComparable key, Writable value) throws IOException {
 while (headerCount > 0) {
  if (!currRecReader.next(key, value)) {
   return false;
  }
  headerCount--;
 }
 return true;
}

代码示例来源：origin: apache/drill

/**
 * Skip header lines in the table file when reading the record.
 *
 * @param currRecReader
 *          Record reader.
 *
 * @param headerCount
 *          Header line number of the table files.
 *
 * @param key
 *          Key of current reading record.
 *
 * @param value
 *          Value of current reading record.
 *
 * @return Return true if there are 0 or more records left in the file
 *         after skipping all headers, otherwise return false.
 */
public static boolean skipHeader(RecordReader<WritableComparable, Writable> currRecReader,
  int headerCount, WritableComparable key, Writable value) throws IOException {
 while (headerCount > 0) {
  if (!currRecReader.next(key, value))
   return false;
  headerCount--;
 }
 return true;
}

代码示例来源：origin: apache/hive

@Override
public boolean next(ImmutableBytesWritable key, ResultWritable value) throws IOException {
 return rr.next(key, value.getResult());
}

代码示例来源：origin: apache/hive

/**
 * do next and handle exception inside it.
 * @param key
 * @param value
 * @return
 * @throws IOException
 */
private boolean doNextWithExceptionHandler(K key, V value) throws IOException {
 try {
  return curReader.next(key, value);
 } catch (Exception e) {
  return HiveIOExceptionHandlerUtil
    .handleRecordReaderNextException(e, jc);
 }
}

代码示例来源：origin: apache/incubator-gobblin

/**
 * {@inheritDoc}.
 *
 * This method will throw a {@link ClassCastException} if type {@link #<D>} is not compatible
 * with type {@link #<K>} if keys are supposed to be read, or if it is not compatible with type
 * {@link #<V>} if values are supposed to be read.
 */
@Override
@SuppressWarnings("unchecked")
public D readRecord(@Deprecated D reuse) throws DataRecordException, IOException {
 K key = this.recordReader.createKey();
 V value = this.recordReader.createValue();
 if (this.recordReader.next(key, value)) {
  return this.readKeys ? (D) key : (D) value;
 }
 return null;
}

代码示例来源：origin: apache/hive

@Override
public boolean next(NullWritable key, Row value) throws IOException {
 Preconditions.checkArgument(value != null);
 boolean hasNext = reader.next(key, data);
 if (hasNext) {
  // Deserialize data to column values, and populate the row record
  Object rowObj;
  try {
   StructObjectInspector rowOI = (StructObjectInspector) serde.getObjectInspector();
   rowObj = serde.deserialize(data);
   setRowFromStruct(value, rowObj, rowOI);
  } catch (SerDeException err) {
   if (LOG.isDebugEnabled()) {
    LOG.debug("Error deserializing row from data: " + data);
   }
   throw new IOException("Error deserializing row data", err);
  }
 }
 return hasNext;
}

代码示例来源：origin: apache/drill

/**
 * Writes value in the given value holder if next value available.
 * If value is not, checks if there are any other available readers
 * that may hold next value and tried to obtain value from them.
 *
 * @param value value holder
 * @return true if value was written, false otherwise
 */
protected boolean hasNextValue(Object value) {
 while (true) {
  try {
   if (reader.next(key, value)) {
    return true;
   }
   if (initNextReader(job)) {
    continue;
   }
   return false;
  } catch (IOException | ExecutionSetupException e) {
   throw new DrillRuntimeException(e);
  }
 }
}

代码示例来源：origin: prestodb/presto

@Override
public boolean advanceNextPosition()
{
  try {
    if (closed || !recordReader.next(key, value)) {
      close();
      return false;
    }
    // reset loaded flags
    Arrays.fill(loaded, false);
    // decode value
    rowData = deserializer.deserialize(value);
    return true;
  }
  catch (IOException | SerDeException | RuntimeException e) {
    closeWithSuppression(this, e);
    if (e instanceof TextLineLengthLimitExceededException) {
      throw new PrestoException(HIVE_BAD_DATA, "Line too long in text file: " + path, e);
    }
    throw new PrestoException(HIVE_CURSOR_ERROR, e);
  }
}

代码示例来源：origin: apache/hive

/**
 * Enqueue most recent record read, and dequeue earliest result in the queue.
 *
 * @param job
 *          Current job configuration.
 *
 * @param recordreader
 *          Record reader.
 *
 * @param key
 *          Key of current reading record.
 *
 * @param value
 *          Value of current reading record.
 *
 * @return Return false if reaches the end of file, otherwise return true.
 */
public boolean updateBuffer(JobConf job, RecordReader recordreader,
  WritableComparable key, Writable value) throws IOException {
 key = ReflectionUtils.copy(job, (WritableComparable)buffer.get(cur).getFirst(), key);
 value = ReflectionUtils.copy(job, (Writable)buffer.get(cur).getSecond(), value);
 boolean notEOF = recordreader.next(buffer.get(cur).getFirst(), buffer.get(cur).getSecond());
 if (notEOF) {
  cur = (++cur) % buffer.size();
 }
 return notEOF;
}

代码示例来源：origin: apache/drill

/**
 * Enqueue most recent record read, and dequeue earliest result in the queue.
 *
 * @param job
 *          Current job configuration.
 *
 * @param recordreader
 *          Record reader.
 *
 * @param key
 *          Key of current reading record.
 *
 * @param value
 *          Value of current reading record.
 *
 * @return Return false if reaches the end of file, otherwise return true.
 */
public boolean updateBuffer(JobConf job, RecordReader recordreader,
  WritableComparable key, Writable value) throws IOException {
 key = ReflectionUtils.copy(job, (WritableComparable)buffer.get(cur).getFirst(), key);
 value = ReflectionUtils.copy(job, (Writable)buffer.get(cur).getSecond(), value);
 boolean notEOF = recordreader.next(buffer.get(cur).getFirst(), buffer.get(cur).getSecond());
 if (notEOF) {
  cur = (++cur) % buffer.size();
 }
 return notEOF;
}

代码示例来源：origin: apache/hive

boolean notEOF = recordreader.next(key, value);
if (!notEOF) {
 return false;

代码示例来源：origin: apache/hive

while (i < this.currentReadBlock.length && rr.next(key, val)) {
 nextSplit = false;
 this.currentReadBlock[i++] = (ROW) ObjectInspectorUtils.copyToStandardObject(serde

代码示例来源：origin: apache/hive

private void confirmOutput(DataFormat rType) throws IOException, SerDeException, CloneNotSupportedException {
 Path[] paths = findFilesInBasePath();
 TFSOInputFormat input = new TFSOInputFormat(rType);
 FileInputFormat.setInputPaths(jc, paths);
 InputSplit[] splits = input.getSplits(jc, 1);
 RecordReader<NullWritable, Row> reader = input.getRecordReader(splits[0], jc,
   Mockito.mock(Reporter.class));
 NullWritable key = reader.createKey();
 Row value = reader.createValue();
 List<Row> results = new ArrayList<Row>(rows.size());
 List<Row> sortedRows = new ArrayList<Row>(rows.size());
 for (int i = 0; i < rows.size(); i++) {
  Assert.assertTrue(reader.next(key, value));
  results.add(value.clone());
  sortedRows.add(rows.get(i));
 }
 Assert.assertFalse(reader.next(key, value));
 Collections.sort(results);
 Collections.sort(sortedRows);
 for (int i = 0; i < rows.size(); i++) {
  Assert.assertTrue(sortedRows.get(i).equals(results.get(i)));
 }
}

代码示例来源：origin: apache/hive

public static List<ArrayWritable> read(Path parquetFile) throws IOException {
 List<ArrayWritable> records = new ArrayList<ArrayWritable>();
 RecordReader<NullWritable, ArrayWritable> reader = new MapredParquetInputFormat().
   getRecordReader(new FileSplit(
       parquetFile, 0, fileLength(parquetFile), (String[]) null),
     new JobConf(), null);
 NullWritable alwaysNull = reader.createKey();
 ArrayWritable record = reader.createValue();
 while (reader.next(alwaysNull, record)) {
  records.add(record);
  record = reader.createValue(); // a new value so the last isn't clobbered
 }
 return records;
}

代码示例来源：origin: prestodb/presto

while (recordReader.next(key, value)) {
  Object expectedValue = iterator.next();

代码示例来源：origin: apache/hive

/**
 * Scenario: Empty input directory, i.e. no symlink file.
 *
 * Expected: Should return empty result set without any exception.
 */
public void testAccuracy2() throws IOException {
 fileSystem.mkdirs(symlinkDir);
 FileInputFormat.setInputPaths(job, symlinkDir);
 SymlinkTextInputFormat inputFormat = new SymlinkTextInputFormat();
 ContentSummary cs = inputFormat.getContentSummary(symlinkDir, job);
 assertEquals(0, cs.getLength());
 assertEquals(0, cs.getFileCount());
 assertEquals(0, cs.getDirectoryCount());
 InputSplit[] splits = inputFormat.getSplits(job, 2);
 log.info("Number of splits: " + splits.length);
 // Read all values.
 List<String> received = new ArrayList<String>();
 for (InputSplit split : splits) {
  RecordReader<LongWritable, Text> reader =
    inputFormat.getRecordReader(split, job, reporter);
  LongWritable key = reader.createKey();
  Text value = reader.createValue();
  while (reader.next(key, value)) {
   received.add(value.toString());
  }
  reader.close();
 }
 List<String> expected = new ArrayList<String>();
 assertEquals(expected, received);
}