示例#1
0
  private void onOpen(ChannelHandlerContext ctx) throws IOException {
    final String nnId = params.namenodeId();
    final int bufferSize = params.bufferSize();
    final long offset = params.offset();
    final long length = params.length();

    DefaultHttpResponse response = new DefaultHttpResponse(HTTP_1_1, OK);
    HttpHeaders headers = response.headers();
    // Allow the UI to access the file
    headers.set(ACCESS_CONTROL_ALLOW_METHODS, GET);
    headers.set(ACCESS_CONTROL_ALLOW_ORIGIN, "*");
    headers.set(CONTENT_TYPE, APPLICATION_OCTET_STREAM);
    headers.set(CONNECTION, CLOSE);

    final DFSClient dfsclient = newDfsClient(nnId, conf);
    HdfsDataInputStream in =
        dfsclient.createWrappedInputStream(dfsclient.open(path, bufferSize, true));
    in.seek(offset);

    long contentLength = in.getVisibleLength() - offset;
    if (length >= 0) {
      contentLength = Math.min(contentLength, length);
    }
    final InputStream data;
    if (contentLength >= 0) {
      headers.set(CONTENT_LENGTH, contentLength);
      data = new LimitInputStream(in, contentLength);
    } else {
      data = in;
    }

    ctx.write(response);
    ctx.writeAndFlush(
            new ChunkedStream(data) {
              @Override
              public void close() throws Exception {
                super.close();
                dfsclient.close();
              }
            })
        .addListener(ChannelFutureListener.CLOSE);
  }
 public static ExtendedBlock getFirstBlock(FileSystem fs, Path path) throws IOException {
   HdfsDataInputStream in = (HdfsDataInputStream) ((DistributedFileSystem) fs).open(path);
   in.readByte();
   return in.getCurrentBlock();
 }