import org.apache.hadoop.hdfs.net.DomainPeerServer; //导入依赖的package包/类
static DomainPeerServer getDomainPeerServer(Configuration conf,
    int port) throws IOException {
  String domainSocketPath =
      conf.getTrimmed(DFSConfigKeys.DFS_DOMAIN_SOCKET_PATH_KEY,
          DFSConfigKeys.DFS_DOMAIN_SOCKET_PATH_DEFAULT);
  if (domainSocketPath.isEmpty()) {
    if (conf.getBoolean(DFSConfigKeys.DFS_CLIENT_READ_SHORTCIRCUIT_KEY,
          DFSConfigKeys.DFS_CLIENT_READ_SHORTCIRCUIT_DEFAULT) &&
       (!conf.getBoolean(DFSConfigKeys.DFS_CLIENT_USE_LEGACY_BLOCKREADERLOCAL,
        DFSConfigKeys.DFS_CLIENT_USE_LEGACY_BLOCKREADERLOCAL_DEFAULT))) {
      LOG.warn("Although short-circuit local reads are configured, " +
          "they are disabled because you didn't configure " +
          DFSConfigKeys.DFS_DOMAIN_SOCKET_PATH_KEY);
    }
    return null;
  }
  if (DomainSocket.getLoadingFailureReason() != null) {
    throw new RuntimeException("Although a UNIX domain socket " +
        "path is configured as " + domainSocketPath + ", we cannot " +
        "start a localDataXceiverServer because " +
        DomainSocket.getLoadingFailureReason());
  }
  DomainPeerServer domainPeerServer =
    new DomainPeerServer(domainSocketPath, port);
  domainPeerServer.setReceiveBufferSize(
      HdfsConstants.DEFAULT_DATA_SOCKET_SIZE);
  return domainPeerServer;
}
 

import org.apache.hadoop.hdfs.net.DomainPeerServer; //导入依赖的package包/类
private static DomainPeerServer getDomainPeerServer(Configuration conf,
    int port) throws IOException {
  String domainSocketPath =
      conf.getTrimmed(DFSConfigKeys.DFS_DOMAIN_SOCKET_PATH_KEY,
          DFSConfigKeys.DFS_DOMAIN_SOCKET_PATH_DEFAULT);
  if (domainSocketPath.isEmpty()) {
    if (conf.getBoolean(HdfsClientConfigKeys.Read.ShortCircuit.KEY,
          HdfsClientConfigKeys.Read.ShortCircuit.DEFAULT) &&
       (!conf.getBoolean(HdfsClientConfigKeys.DFS_CLIENT_USE_LEGACY_BLOCKREADERLOCAL,
        HdfsClientConfigKeys.DFS_CLIENT_USE_LEGACY_BLOCKREADERLOCAL_DEFAULT))) {
      LOG.warn("Although short-circuit local reads are configured, " +
          "they are disabled because you didn't configure " +
          DFSConfigKeys.DFS_DOMAIN_SOCKET_PATH_KEY);
    }
    return null;
  }
  if (DomainSocket.getLoadingFailureReason() != null) {
    throw new RuntimeException("Although a UNIX domain socket " +
        "path is configured as " + domainSocketPath + ", we cannot " +
        "start a localDataXceiverServer because " +
        DomainSocket.getLoadingFailureReason());
  }
  DomainPeerServer domainPeerServer =
    new DomainPeerServer(domainSocketPath, port);
  int recvBufferSize = conf.getInt(
      DFSConfigKeys.DFS_DATANODE_TRANSFER_SOCKET_RECV_BUFFER_SIZE_KEY,
      DFSConfigKeys.DFS_DATANODE_TRANSFER_SOCKET_RECV_BUFFER_SIZE_DEFAULT);
  if (recvBufferSize > 0) {
    domainPeerServer.setReceiveBufferSize(recvBufferSize);
  }
  return domainPeerServer;
}