在我的用例中，我需要一种方法来将键/值对附加到现有的序列文件中。怎么做？任何线索都会大有帮助。我正在使用hadoop 2x。
另外，我还看到了下面的文档。有人能告诉我怎么用这个附加吗？
public static org.apache.hadoop.io.sequencefile.writer createwriter（filecontext fc，configuration，path name，class keyclass，class valclass，org.apache.hadoop.io.sequencefile.compressiontype compressioncodec codec，org.apache.hadoop.io.sequencefile.metadata metadata，enumset createflag，org.apache.hadoop.fs.options.createopts。。。opts）引发ioexception

Construct the preferred type of SequenceFile Writer.

Parameters:
    fc - The context for the specified file.
    conf - The configuration.
    name - The name of the file.
    keyClass - The 'key' type.
    valClass - The 'value' type.
    compressionType - The compression type.
    codec - The compression codec.
    metadata - The metadata of the file.
  **createFlag - gives the semantics of create: overwrite, append etc.**
    opts - file creation options; see Options.CreateOpts. 
Returns:
    Returns the handle to the constructed SequenceFile Writer. 
Throws:
    IOException